Indian Patents. 252036:"A METHOD FOR THE SYNTHESIS OF SEVERELY STERICALLY HINDERED SECONDARY AMINOETHER ALCOHOLS"

Title of Invention	"A METHOD FOR THE SYNTHESIS OF SEVERELY STERICALLY HINDERED SECONDARY AMINOETHER ALCOHOLS"
Abstract	A method for the synthesis of severely sterically hindered secondary aminoether alcohols of the formula wherein R1, R2 and R3, R4, R5, R6, R7, R8, R9, R10, and R11 are as herein described as in the specification and claims.

Full Text	FIELD OF THE INVENTION [0001] The present invention relates to a method for the preparation of severely sterically hindered secondary aminoether alcohols which are useful in the removal of hydrogen sulfide from gaseous streams containing hydrogen sulfide and which may also contain carbon dioxide. DESCRIPTION OF RELATED ART [0002] It is well-known in the art to treat gases and liquids, such as mixtures containing acidic gases including CO2, H2S, CS2, HCN, COS and oxygen and sulfur derivatives of C1 to C4 hydrocarbons with amine solutions to remove these acidic gases. The amine usually contacts the acidic gases and the liquids as an aqueous solution containing the amine in an absorber tower with the aqueous amine solution contacting the acidic fluid countercurrently. Usually this contacting results in the simultaneous removal of substantial amounts of both the CO2 and H2S. USP 4,112,052, for example, utilizes a sterically hindered amine to obtain nearly complete removal of CO2 and H2S acid gases. This process is particularly suitable for systems in which the partial pressures of the CO2 and related gases are low. For systems where the partial pressure of CO2 is high or where there are many acid gases present, e.g., H2S, COS, CH3SH, CS2, etc., a process utilizing an amine in combination with a physical absorbent, referred to as a "non-aqueous solvent process" is practiced. Such a system is described in USP 4,112,051. [0003] Selective removal of H2S from acid gas systems containing both H2S and CO2, however, is very desirable. Such selective removal results in a relatively high H2S/CO2 ratio in the separated acid gas which facilitates the subsequent conversion of the H2S to elemental sulfur in the Glaus process. [0004] The typical reactions of aqueous secondary and tertiary amines with CO2 and H2S can be represented as follows: where R is the same or different organic radical and may be substituted with a hydroxyl group. Because the reactions are reversible they are sensitive to the CO2 and H2S partial pressures which is determinative of the degree to which the reactions occur. [0005] Selective HS removal is particularly desirable in systems having low H2S/CO2 ratios and relatively low H2S partial pressures as compared to that of the CO2- The ability of amine to selectivity remove H2$ in such systems is very low. [0006] Solutions of primary and secondary amines such as monoethanolamine (MEA), diethanolamine (DEA), diisopropanolamine (DPA), and hydroxyethoxyethylamine (DEA) absorb both H2S and CC2, and thus have proven unsatisfactory for the selective removal of H2S to the exclusion of CO2- The CO2 forms carbamates with such amines relatively easily. [0007] H2S has been selectively removed from gases containing H2S and CO2 by use of diisopropanolamine (DIPA) either alone or mixed with a nonaqueous physical solvent such as sulfolane. Contact times, however, must be kept short to take advantage of the faster reaction of H2S with the amine as compared to the rate of CO2 reaction with the amine. [0008] Frazier and Kohl, Ind. and Eng. Chem., 42,2288 (1950) showed that the tertiary amine methydiethanolamine (MDEA) is more selective toward H2S absorption as compared to C&2- C(2 reacts relatively slowly with tertiary amines as compared to the rapid reaction of the tertiary amine with H2S. However, it has the disadvantage of having a relatively low H2S loading capacity and limited ability to reduce the H2S content to the desired level at low H2S pressures encountered in certain gases. [0009] UK Patent Publication No. 2,017,524A discloses the use of aqueous solutions of dialkylmonoalkanolamines, e.g., diethylmonoethanol amine (DEAE), for the selective removal of H2S, such material having higher selectivity and capacity for H2$ removal at higher loading levels than MDEA. DEAE, however, has the disadvantage of a low boiling point of 161 °C, making it relatively highly volatile resulting in large material loss. [0010] USP 4,471,138 the entire teaching of which is incorporated herein by reference, teaches severely sterically hindered acyclic secondary aminoether alcohols having a high selectivity for H2S compared to CO2- Selectivity is maintained at high H2S and CC2 loadings. [0011] The severely sterically hindered acyclic amine ether alcohols of USP 4,471,138 are represented by the general formula: wherein RI and R2 are each independently selected from the group consisting of alkyl and hydroxyalkyl radicals having 1-4 carbon atoms, R$, R4, RS and Rg are each independently selected from the group consisting of hydrogen, alkyl, and hydroxyalkyl radicals having 1-4 carbon atoms, with the proviso that at least one of R4 or RS bonded to the carbon atom which is directly bonded to the nitrogen atom is an alkyl or hydroxyalkyl radical when R3 is hydrogen, x and y are each positive integers ranging from 2-4, and z is a positive integer ranging from 1-4. These materials are prepared by a high temperature reaction preferably in the presence of a solvent, of a secondary or tertiary alkyl primary amine with an ether alcohol containing a carbonyl functionality in the presence of a source of hydrogen or with a haloalkoxyalkanol. Preferably the composition is of the general formula: wherein: R! = R2 = R3 = CH3CH2-; R4 = RS = Re = H; or R! # R2 # R3 = H, CH3-, CH3CH2-; R4 # R5 # Re = H, CH3-; and where x = 2 or 3. [0012] U.S. Patent 4,487,967 is directed to a process for preparing severely sterically hindered secondary aminoether alcohols by reacting a primary amino compound with a polyalkenyl ether glycol in the presence of a hydrogenation catalyst at elevated temperatures and pressures. The primary amino compounds employed have a general formula: R1 -NH2 where R is selected from the group consisting of secondary or tertiary alkyl radicals having 3 to 8 carbon atoms or cycloalkyl radicals having 3 to 8 carbon atoms. The polyalkenyl ether glycols employed have the general formula: where R2, RS, R4 and RS are each independently selected from the group consisting of hydrogen, Cj-C4 alkyl radicals, and C3-Cg cycloalkyl radicals, with the proviso that if the carbon atom of Rj directly attached to the nitrogen atom is secondary, at least one of R2 and R3 directly bonded to the carbon which is bonded to the hydroxyl group is as alkyl or cycloalkyl radical, x and y are each positive integers independently ranging from 2 to 4 and z is from 1 to 10, preferably 1 to 6, more preferably 1 to 4. The process is carried out in the presence of a catalytically effective amount of a supported Group VDI metal containing hydrogenation catalyst at elevated temperatures and pressure and the mole ratio of amino compound to polyalkenyl ether glycol is less than 2:1 when z is greater than 1. SUMMARY OF THE INVENTION [0013] A new process is disclosed for the production of severely sterically hindered secondary aminoether alcohols of the general formula 1: R2 are each independently selected from the group consisting of alkyl and hydroxyalkyl radicals having 1 to 4 carbon atoms, preferably 1 to 2 carbon atoms, or R and R in combination with the carbon atom to which they are attached form a cycloalkyl group having 3 to 8 carbons; R3 is selected from the group consisting of hydrogen, alkyl or hydroxyalkyl radicals having 1 to 4 carbon atoms, and mixtures thereof, preferably 1 to 2 carbon atoms, preferably alkyl or hydroxyalkyl radicals having 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms; R4, R5, R6, R7, R8, R9, R10, and R11 are the same or different and are selected from hydrogen, alkyl or hydroxyalkyl radicals having 1 to 4 carbon atoms, preferably 1 to 2 carbon atoms, or cycloalkyl radicals having 3 to 8 carbons; R4, R5, R6, R7, R8, R9, R10, and R1 are preferably hydrogen provided that when R is hydrogen at least one of R4 and R bonded to the carbon directly bonded to the nitrogen atom is an alkyl or hydroxyalkyl radical. The process involves reacting an organic carboxylic acid or a salt of a carboxylic acid of the formula: wherein Rl2 is selected from the group consisting of alkyl radicals having 1 to 4 carbon atoms, preferably 1 to 2 carbon atoms, most preferably methyl, radicals, substituted aryl radicals, preferably phenyl substituted with a hydrogen or one or more alkyl radicals having 1-10 carbon atoms, preferably 1-4 carbon atoms, most preferably methyl in the para position, and mixtures thereof, and Y is selected from the group consisting of hydrogen, alkali metal, ammonium, and mixtures thereof, preferably hydrogen or sodium, with a sulfonyl halide, a sulfuryl halide, a mixed sulfuryl ester halide, or a mixed sulfuryl amide halide of the formula: wherein X is selected from the group consisting of F, Cl, Br, I, and mixtures thereof, preferably F, Cl, most preferably Cl, R14 and R14 are the same or different and each is selected from the group consisting of alkyl radicals having 1 to 4 carbon atoms, preferably 1 to 2 carbon atoms, most preferably methyl, haloalkyl radicals of the formula CnH(2n+l)-wZw wherein n is 1 to 4 preferably 1 to 2, and most preferably 1; Z is selected from the group consisting of F, Cl, Br, I, preferably F and Cl, most preferably F; and w ranges from 1 to 5, preferably 1 to 3, most preferably 3, aryl radicals 4 R16 R15 wherein R15, Rl6 Rl7? RlS and Rl9 are me same or different and are selected from hydrogen and alkyl radicals having 1 to 20 carbon atoms, preferably R15, Rl6, Rl8} and Rl9 aj-g hydrogen and R7 js selected from hydrogen and an alkyl radicals having 1-4 carbons, preferably 1 to 2 carbons, more preferably methyl, and mixtures thereof, to yield sulfonic-carboxylic anhydride compounds which is then reacted with a dioxane of the formula 6: SYNTHESIS OF STERICALLY HINDERED SECONDARY AMINOETHER ALCOHOLS FIELD OF THE INVENTION [0001] The present invention relates to a method for the preparation of severely sterically hindered secondary aminoether alcohols which are useful in the removal of hydrogen sulfide from gaseous streams containing hydrogen sulfide and which may also contain carbon dioxide. DESCRIPTION OF RELATED ART [0002] It is well-known in the art to treat gases and liquids, such as mixtures containing acidic gases including CO2, H2S, CS2, HCN, COS and oxygen and sulfur derivatives of Cj to €4 hydrocarbons with amine solutions to remove these acidic gases. The amine usually contacts the acidic gases and the liquids as an aqueous solution containing the amine in an absorber tower with the aqueous amine solution contacting the acidic fluid countercurrently. Usually this contacting results in the simultaneous removal of substantial amounts of both the CO2 and HS. USP 4,112,052, for example, utilizes a sterically hindered amine to obtain nearly complete removal of CO2 and H2S acid gases. This process is particularly suitable for systems in which the partial pressures of the CO2 and related gases are low. For systems where the partial pressure of CO2 is high or where there are many acid gases present, e.g., H2S, COS, CH3SH, CS2, etc., a process utilizing an amine in combination with a physical absorbent, referred to as a "non-aqueous solvent process" is practiced. Such a system is described in USP 4,112,051. [0003] Selective removal of H2S from acid gas systems containing both H2S and CO2, however, is very desirable. Such selective removal results in a relatively high H2S/CO2 ratio in the separated acid gas which facilitates the subsequent conversion of the H2S to elemental sulfur in the Glaus process. [0004] The typical reactions of aqueous secondary and tertiary amines with where R is the same or different organic radical and may be substituted with a hydroxyl group. Because the reactions are reversible they are sensitive to the CO2 and H2S partial pressures which is determinative of the degree to which the reactions occur. [0005] Selective HS removal is particularly desirable in systems having low H2S/CO2 ratios and relatively low H2S partial pressures as compared to that of the CO2- The ability of amine to selectivity remove H2$ in such systems is very low. [0006] Solutions of primary and secondary amines such as monoethanolamine (MEA), diethanolamine (DEA), diisopropanolamine (DPA), and hydroxyethoxyethylamine (DEA) absorb both H2S and CC2, and thus have proven unsatisfactory for the selective removal of H2S to the exclusion of CO2- The CO2 forms carbamates with such amines relatively easily. -3- [0007] H2S has been selectively removed from gases containing H2S and CO2 by use of diisopropanolamine (DIPA) either alone or mixed with a nonaqueous physical solvent such as sulfolane. Contact times, however, must be kept short to take advantage of the faster reaction of H2S with the amine as compared to the rate of CO2 reaction with the amine. [0008] Frazier and Kohl, Ind. and Eng. Chem., 42,2288 (1950) showed that the tertiary amine methydiethanolamine (MDEA) is more selective toward H2S absorption as compared to C&2- C(2 reacts relatively slowly with tertiary amines as compared to the rapid reaction of the tertiary amine with H2S. However, it has the disadvantage of having a relatively low H2S loading capacity and limited ability to reduce the H2S content to the desired level at low H2S pressures encountered in certain gases. [0009] UK Patent Publication No. 2,017,524A discloses the use of aqueous solutions of dialkylmonoalkanolamines, e.g., diethylmonoethanol amine (DEAE), for the selective removal of H2S, such material having higher selectivity and capacity for H2$ removal at higher loading levels than MDEA. DEAE, however, has the disadvantage of a low boiling point of 161 °C, making it relatively highly volatile resulting in large material loss. [0010] USP 4,471,138 the entire teaching of which is incorporated herein by reference, teaches severely sterically hindered acyclic secondary aminoether alcohols having a high selectivity for H2S compared to CO2- Selectivity is maintained at high H2S and CC2 loadings. [0011] The severely sterically hindered acyclic amine ether alcohols of USP 4,471,138 are represented by the general formula: wherein RI and R2 are each independently selected from the group consisting of alkyl and hydroxyalkyl radicals having 1-4 carbon atoms, R$, R4, RS and Rg are each independently selected from the group consisting of hydrogen, alkyl, and hydroxyalkyl radicals having 1-4 carbon atoms, with the proviso that at least one of R4 or RS bonded to the carbon atom which is directly bonded to the nitrogen atom is an alkyl or hydroxyalkyl radical when R3 is hydrogen, x and y are each positive integers ranging from 2-4, and z is a positive integer ranging from 1-4. These materials are prepared by a high temperature reaction preferably in the presence of a solvent, of a secondary or tertiary alkyl primary amine with an ether alcohol containing a carbonyl functionality in the presence of a source of hydrogen or with a haloalkoxyalkanol. Preferably the composition is of the general formula: [0012] U.S. Patent 4,487,967 is directed to a process for preparing severely sterically hindered secondary aminoether alcohols by reacting a primary amino compound with a polyalkenyl ether glycol in the presence of a hydrogenation catalyst at elevated temperatures and pressures. The primary amino compounds employed have a general formula: where R is selected from the group consisting of secondary or tertiary alkyl radicals having 3 to 8 carbon atoms or cycloalkyl radicals having 3 to 8 carbon atoms. The polyalkenyl ether glycols employed have the general formula: where R2, RS, R4 and RS are each independently selected from the group consisting of hydrogen, Cj-C4 alkyl radicals, and C3-Cg cycloalkyl radicals, with the proviso that if the carbon atom of Rj directly attached to the nitrogen atom is secondary, at least one of R2 and R3 directly bonded to the carbon which is bonded to the hydroxyl group is as alkyl or cycloalkyl radical, x and y are each positive integers independently ranging from 2 to 4 and z is from 1 to 10, preferably 1 to 6, more preferably 1 to 4. The process is carried out in the presence of a catalytically effective amount of a supported Group VDI metal containing hydrogenation catalyst at elevated temperatures and pressure and the mole ratio of amino compound to polyalkenyl ether glycol is less than 2:1 when z is greater than 1. -6- SUMMARY OF THE INVENTION [0013] A new process is disclosed for the production of severely sterically hindered secondary aminoether alcohols of the general formula 1: R4 R6 R8 RlO R2 C N C C O C C OH 1 I « I I I I R3 R5 R7 R9 Rll wherein R and R2 are each independently selected from the group consisting of alkyl and hydroxyalkyl radicals having 1 to 4 carbon atoms, preferably 1 to 2 carbon atoms, or R and R in combination with the carbon atom to which they are attached form a cycloalkyl group having 3 to 8 carbons; R3 is selected from the group consisting of hydrogen, alkyl or hydroxyalkyl radicals having 1 to 4 carbon atoms, and mixtures thereof, preferably 1 to 2 carbon atoms, preferably alkyl or hydroxyalkyl radicals having 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms; R4, R5, R6, R7, R8, R9, R10, and R11 are the same or different and are selected from hydrogen, alkyl or hydroxyalkyl radicals having 1 to 4 carbon atoms, preferably 1 to 2 carbon atoms, or cycloalkyl radicals having 3 to 8 carbons; R4, R5, R6, R7, R8, R9, R10, and R1 are preferably hydrogen provided that when R is hydrogen at least one of R4 and R bonded to the carbon directly bonded to the nitrogen atom is an alkyl or hydroxyalkyl radical. The process involves reacting an organic carboxylic acid or a salt of a carboxylic acid of the formula: wherein Rl2 is selected from the group consisting of alkyl radicals having 1 to 4 carbon atoms, preferably 1 to 2 carbon atoms, most preferably methyl, aryl radicals, substituted aryl radicals, preferably phenyl substituted with a hydrogen or one or more alkyl radicals having 1-10 carbon atoms, preferably 1-4 carbon atoms, most preferably methyl in the para position, and mixtures thereof, and Y is selected from the group consisting of hydrogen, alkali metal, ammonium, and mixtures thereof, preferably hydrogen or sodium, with a sulfonyl halide, a sulfuryl halide, a mixed sulfuryl ester halide, or a mixed sulfuryl amide halide wherein X is selected from the group consisting of F, Cl, Br, I, and mixtures thereof, preferably F, Cl, most preferably Cl, R14 and R14 are the same or different and each is selected from the group consisting of alkyl radicals having 1 to 4 carbon atoms, preferably 1 to 2 carbon atoms, most preferably methyl, haloalkyl radicals of the formula CnH(2n+l)-wZw wherein n is 1 to 4 preferably 1 to 2, and most preferably 1; Z is selected from the group consisting of F, Cl, Br, I, preferably F and Cl, most preferably F; and w ranges from 1 to 5, preferably 1 to 3, most preferably 3, aryl radicals 4 R16 R15 wherein R15, Rl6 Rl7? RlS and Rl9 are me same or different and are selected from hydrogen and alkyl radicals having 1 to 20 carbon atoms, preferably R15, Rl6, Rl8} and Rl9 aj-g hydrogen and R7 js selected from hydrogen and an alkyl radicals having 1-4 carbons, preferably 1 to 2 carbons, more preferably methyl, and mixtures thereof, to yield sulfonic-carboxylic anhydride wherein R4, R5, R6, R7t R8, R9, RlO, and R! 1 are the same or different and are selected from hydrogen, alkyl and hydroxyalkyl radicals having 1 to 4 carbons, preferably 1 to 2 carbons or cycloalkyl radicals having 3 to 8 carbons, more preferably R4, R, R6, R?, R8? R9, RlO, and Rl are hydrogen, to yield cleavage product materials of formula 7 or mixtures thereof. It is not necessary that the product from each reaction step be isolated before being reacted with the reactant of a subsequent reaction step up to this point. A cleavage product is still produced The mixing of the organic carboxylic acid or salt thereof with a sulfonyl halide, sulfuryl halide, mixed sulfuryl ester halide or mixed sulfuryl amide halide and the dioxane can be in any order or sequence. Thus, the organic carboxylic acid or salt thereof can be mixed with the sulfonyl halide, etc. and then mixed with the dioxane, or the dioxane can be first mixed with the sulfonyl halide, etc. and then the organic carboxylic acid or salt thereof can be added, or the organic carboxylic acid or salt thereof and the dioxane can be mixed followed by the addition of the sulfonyl halide, etc. Thus, the combination of the organic carboxylic acid or salt thereof with the dioxane and the sulfonyl halide, sulfuryl halide, mixed sulfuryl ester halide or mixed sulfuryl amide halide can be combined into a single reaction mixture and reacted as a single mixture in the one step production of the desired cleavage product. This cleavage product is then reacted with an alkylamine of the formula 8: The preferred compounds defined by the general formula above include: [0015] Other materials of the types described above can be readily envisioned. [0016] This material is then is reacted with second component, typically [0017] Similarly, other materials of the type described above can be readily envisioned. [0018] The reaction of two such components yields acyl sulfonates 5a, 5b, 5c and 5d. The reaction can be conducted at a temperature in the range of between about -20 to 200°C, preferably about -20 to 150°C, more preferably about 0 to 120°C, and a pressure between about 1 bar to 100 bars, preferably about 1 bar to 50 bars, more preferably about 1 bar to 10 bars. [0019] The reaction can be carried out neat, that is, in the absence of any solvent provided one or the other of the reactants in a liquid and capable of dissolving the non-liquid reactant, or both are liquid. Alternatively, an inert added solvent can be used such as sulfolane, hexanes or acetonitrile. Preferably the dioxane for the subsequent cleavage reaction is used as the solvent resulting in all three reactants being present in a unified first step wherein the reaction mixture contains the dioxane, organic carboxylic acid or salt thereof and the sulfonyl halide, sulfuryl halide, mixed sulfuryl ester halide or mixed sulfuryl amide halide. This reaction mixture can then be reacted under the conditions subsequently described for the dioxane cleavage reaction, yielding the cleavage product described by general formula 4. [0020] The sulfonate 5a and/or 5b are reacted with a 1,4-dioxane, which is typically of the formula: Other substituted isomers can be readily envisioned. Preferably, the 1,4-dioxane [0021] Reaction at elevated temperature is for a time sufficient to cleave the dioxane ring and to achieve about 60-90% conversion to cleavage product. The dioxane also serves as the solvent for the reaction. The molar ratio of dioxane to sulfonate can range from about 1:1 to about 10:1, preferably about 1:1 to about 8:1, most preferably about 1:1 to about 5:1. The reaction can be carried out in the absence of any added solvent, e.g., the dioxane serving as the solvent, or an additional solvent such as acetonitrile or toluene can be used, the reaction being conducted at temperatures between about 50°C to about 200°C, preferably about 70°C to about 160°C, more preferably about 80°C to about 140°C. [0022] Preferably, the reaction is carried out in the absence of any added solvent, the dioxane serving as both reactant and solvent, at a temperature in the range of about 50°C to about 160°C, preferably about 70°C to about 160°C, more preferably about 80°C to about 140°C. [0023] The dioxane cleavage step recited above are described in greater detail by Karger and Mazur in "The Cleavage of Ethers by Mixed Sulfonic-Carboxylic Anhydrides", Journal of the American Chemical Society, 1968, 90, 3878-3879. See also, "Mixed sulfonic-carboxylic anhydrides. I. Synthesis and thermal stability. New syntheses of sulfonic anhydrides" Journal of Organic Chemistry, 1971, 36, 528, and "Mixed sulfonic-carboxylic anhydrides. II. Reactions with aliphatic ethers and amines" Journal of Organic Chemistry, 1971, 36, 532. [0024] The cleavage product 7a and/or 7b and/or 7c and/or 7d is then aminated with an amine 8 typically of the formula: CH3 CH3 CH2CH3 CH2CH3 H3C-C-NH2 H3C-C-NH2 H3C-C-NH2 H3C-C-NH2 CH3 H CH3 CH2CH3 i i »for a time sufficient to replace the -O-SO2~R or the sulfonate group in 7a and/or 7b and/or 7c and/or 7d by the amine 8. In the case of the amination of materials 7a, 7c and 7d, the amine to sulfonate group mole ratio is in the range of about 1:1 to about 10:1, preferably about 1:1 to about 8:1, more preferably about 1:1 to 4:1, while in the case of the amination of material 7b the amine to sulfonate group ratio is in the range of about 2:1 to about 10:1, preferably about 2:1 to about 8:1, more preferably about 2:1 to about 4:1. Expressed differently, in general the amine to group being replaced mole ratio can range from about stoichiometric to about 10:1, preferably about stoichiometric to about 8:1, more preferably about stoichiometric to about 4:1. [0025] This amination step can be carried out under any conditions typical in the art. Amination can be conducted at atmospheric or at elevated pressure, elevated pressure being especially suitable when amination is performed using relatively low boiling amines such as f-butyl amine. [0026] The amination can be conducted at pressures of from about atmospheric (1 bar) to about 100 bars, preferably about 1 to about 50 bars, and at temperatures of from about 40°C to about 200°C, preferably about 40°C to about 125°C. The amination can be performed using reflux, but this is not absolutely necessary. An inert solvent can be optionally used, such as benzene, toluene, diethyl ether, hexane, and the like. [0027] Finally, the resultant 9 is hydrolyzed using a base to yield the final desired product 1. Typical bases include an alkali metal hydroxide, an alkali metal carbonate, or an alkali metal alkoxide, such as sodium hydroxide, sodium carbonate, sodium methoxide, sodium tert-butoxide, etc. Reaction is conducted at from about 20°C to about 110°C, preferably about 20°C to about 50°C. Reaction under reflux is effective and a desirable technique. [0028] Use of a solvent is optional for the hydrolysis reaction, one being used if the reactants are not already in the liquid form. Solvents can include water, or alcohol and mixtures thereof. [0029] If alcohols are used, they can be of the same carbon number or are the same alcohols from which the alkoxide bases themselves are derived. Thus, methanol would be a suitable solvent to use where the base is an alkali methoxide. EXAMPLES Cleavage with methvl acetvl sulfate generated in situ using methyl chlorosulfonate and acetic acid in the presence of triethylamine [0030] Methyl chlorosulfonate was prepared according to known procedure [Heller, M. S.; Lorah, D. P.; Cox, C. P., Chem. Eng. Data, 1983,27,134] by the reaction of sulfuryl chloride with methanol as follow: Methanol (15 g, 0.47 mol) was added dropwise to sulfuryl chloride at 0°C (ice-bath cooling) and the reaction mixture was stirred at 0°C for 3 hours. After evolution of hydrogen chloride ceased, the reaction mixture was distilled under reduced pressure to give methyl chlorosulfonate (23.5 g, 38 %, bp 62°C / 52-53 mm Hg; lit.[Heller, M. S.; Lorah, D. P.; Cox, C. P., Chem. Eng. Data, 1983,27,134] 55-56°C / 39 mm Hg). 'H NMR (CDC13) S 4.21 (s, 3H); 13C NMR (CDC13) 8 61.2 [0031] Cleavage of dioxane. A 25 mL one-necked flask was charged with acetic acid (0.97 mL, 1.0 g, 16.7 mmol), dioxane (7 mL, 7.0 g, 80 mmol), methyl chlorosulfonate (2.0 g, 15.3 mmol) and then with triethylamine (2.153 mL, 1.56 g, 15.3 mmol) at room temperature under nitrogen. The reaction mixture was refluxed for 72 h. The reaction progress was monitored by NMR. The reaction mixture was then evaporated under vacuum. Dry toluene (15 mL) and terf-butylamine (8.4 mL, 5.85 g, 80 mmol) were added to the residue and the mixture was gently refluxed for 24 hours. The reaction mixture was then cooled to room temperature and filtered. The solid was washed with toluene. The combined filtrate was evaporated under vacuum. The residue was extracted with toluene; the extract was filtered and evaporated under vacuum to give 0.3 g of brown oil. The NMR test showed the trace presence of desired product (f-BuNHCH2CH2OCH2CH2OAc). The signals in H NMR spectrum suggest the presence of acetates (HOCH2CH2OCH2CH2OAc) and/or (AcOCH2CH2OCH2CH2OAc). wherein R4, R5, R6, R7t R8, R9, RlO, and R! 1 are the same or different and are selected from hydrogen, alkyl and hydroxyalkyl radicals having 1 to 4 carbons, preferably 1 to 2 carbons or cycloalkyl radicals having 3 to 8 carbons, more preferably R4, R, R6, R?, R8? R9, RlO, and Rl are hydrogen, to yield cleavage product materials of formula 7 or mixtures thereof. It is not necessary that the product from each reaction step be isolated before being reacted with the reactant of a subsequent reaction step up to this point. A cleavage product is still produced The mixing of the organic carboxylic acid or salt thereof with a sulfonyl halide, sulfuryl halide, mixed sulfuryl ester halide or mixed sulfuryl amide halide and the dioxane can be in any order or sequence. Thus, the organic carboxylic acid or salt thereof can be mixed with the sulfonyl halide, etc. and then mixed with the dioxane, or the dioxane can be first mixed with the sulfonyl halide, etc. and then the organic carboxylic acid or salt thereof can be added, or the organic carboxylic acid or salt thereof and the dioxane can be mixed followed by the addition of the sulfonyl halide, etc. Thus, the combination of the organic carboxylic acid or salt thereof with the dioxane and the sulfonyl halide, sulfuryl halide, mixed sulfuryl ester halide or mixed sulfuryl amide halide can be combined into a single reaction mixture and reacted as a single mixture in the one step production of the desired cleavage product. This cleavage product is then reacted with an alkylamine of the formula 8: The preferred compounds defined by the general formula above include: 2-[2-( 1 -ethyl-1 -methylpropylamino)ethoxy]ethanol [0014] Typical starting materials to use as the first component are: [0015] Other materials of the types described above can be readily envisioned. [0016] This material is then is reacted with second component, typically ;02C1 H3 02C1 S02C1 CH3CH2 S02C1 H3C-S02C1 H3C-CH2-S02C1, H3C-CH-SO2C1 F3C-SO2 C13C-S02C1 FCH2-CH2S02C1, H3C-CHF-SO2C1 » F2HC-CH2-SO2-Cl F3C-CF2- SO2C1 H3C -CF2 1 -SO2C11 SO2C12, SO2F2SO2I2. 862612 and mixtures thereof. [0017] Similarly, other materials of the type described above can be readily envisioned. [0018] The reaction of two such components yields acyl sulfonates 5a, 5b, 5c and 5d. The reaction can be conducted at a temperature in the range of between about -20 to 200°C, preferably about -20 to 150°C, more preferably about 0 to 120°C, and a pressure between about 1 bar to 100 bars, preferably about 1 bar to 50 bars, more preferably about 1 bar to 10 bars. [0019] The reaction can be carried out neat, that is, in the absence of any solvent provided one or the other of the reactants in a liquid and capable of dissolving the non-liquid reactant, or both are liquid. Alternatively, an inert added solvent can be used such as sulfolane, hexanes or acetonitrile. Preferably the dioxane for the subsequent cleavage reaction is used as the solvent resulting in all three reactants being present in a unified first step wherein the reaction mixture contains the dioxane, organic carboxylic acid or salt thereof and the sulfonyl halide, sulfuryl halide, mixed sulfuryl ester halide or mixed sulfuryl amide halide. This reaction mixture can then be reacted under the conditions subsequently described for the dioxane cleavage reaction, yielding the cleavage product described by general formula 4. [0020] The sulfonate 5a and/or 5b are reacted with a 1,4-dioxane, which is typically of the formula: Other substituted isomers can be readily envisioned. Preferably, the 1,4-dioxane [0021] Reaction at elevated temperature is for a time sufficient to cleave the dioxane ring and to achieve about 60-90% conversion to cleavage product. The dioxane also serves as the solvent for the reaction. The molar ratio of dioxane to sulfonate can range from about 1:1 to about 10:1, preferably about 1:1 to about 8:1, most preferably about 1:1 to about 5:1. The reaction can be carried out in the absence of any added solvent, e.g., the dioxane serving as the solvent, or an additional solvent such as acetonitrile or toluene can be used, the reaction being conducted at temperatures between about 50°C to about 200°C, preferably about 70°C to about 160°C, more preferably about 80°C to about 140°C. [0022] Preferably, the reaction is carried out in the absence of any added solvent, the dioxane serving as both reactant and solvent, at a temperature in the range of about 50°C to about 160°C, preferably about 70°C to about 160°C, more preferably about 80°C to about 140°C. [0023] The dioxane cleavage step recited above are described in greater detail by Karger and Mazur in "The Cleavage of Ethers by Mixed Sulfonic-Carboxylic Anhydrides", Journal of the American Chemical Society, 1968, 90, 3878-3879. See also, "Mixed sulfonic-carboxylic anhydrides. I. Synthesis and thermal stability. New syntheses of sulfonic anhydrides" Journal of Organic Chemistry, 1971, 36, 528, and "Mixed sulfonic-carboxylic anhydrides. II. Reactions with aliphatic ethers and amines" Journal of Organic Chemistry, 1971, 36, 532. [0024] The cleavage product 7a and/or 7b and/or 7c and/or 7d is then aminated with an amine 8 typically of the formula: CH3 CH3 CH2CH3 CH2CH3 H3C-C-NH2 H3C-C-NH2 H3C-C-NH2 H3C-C-NH2 CH3 H CH3 CH2CH3 i i » for a time sufficient to replace the -O-SO2~R or the sulfonate group in 7a and/or 7b and/or 7c and/or 7d by the amine 8. In the case of the amination of materials 7a, 7c and 7d, the amine to sulfonate group mole ratio is in the range of about 1:1 to about 10:1, preferably about 1:1 to about 8:1, more preferably about 1:1 to 4:1, while in the case of the amination of material 7b the amine to sulfonate group ratio is in the range of about 2:1 to about 10:1, preferably about 2:1 to about 8:1, more preferably about 2:1 to about 4:1. Expressed differently, in general the amine to group being replaced mole ratio can range from about stoichiometric to about 10:1, preferably about stoichiometric to about 8:1, more preferably about stoichiometric to about 4:1. [0025] This amination step can be carried out under any conditions typical in the art. Amination can be conducted at atmospheric or at elevated pressure, elevated pressure being especially suitable when amination is performed using relatively low boiling amines such as f-butyl amine. [0026] The amination can be conducted at pressures of from about atmospheric (1 bar) to about 100 bars, preferably about 1 to about 50 bars, and at temperatures of from about 40°C to about 200°C, preferably about 40°C to about 125°C. The amination can be performed using reflux, but this is not absolutely necessary. An inert solvent can be optionally used, such as benzene, toluene, diethyl ether, hexane, and the like. [0027] Finally, the resultant 9 is hydrolyzed using a base to yield the final desired product 1. Typical bases include an alkali metal hydroxide, an alkali metal carbonate, or an alkali metal alkoxide, such as sodium hydroxide, sodium carbonate, sodium methoxide, sodium tert-butoxide, etc. Reaction is conducted at from about 20°C to about 110°C, preferably about 20°C to about 50°C. Reaction under reflux is effective and a desirable technique. [0028] Use of a solvent is optional for the hydrolysis reaction, one being used if the reactants are not already in the liquid form. Solvents can include water, or alcohol and mixtures thereof. [0029] If alcohols are used, they can be of the same carbon number or are the same alcohols from which the alkoxide bases themselves are derived. Thus, methanol would be a suitable solvent to use where the base is an alkali methoxide. EXAMPLES Cleavage with methvl acetvl sulfate generated in situ using methyl chlorosulfonate and acetic acid in the presence of triethylamine [0030] Methyl chlorosulfonate was prepared according to known procedure [Heller, M. S.; Lorah, D. P.; Cox, C. P., Chem. Eng. Data, 1983,27,134] by the reaction of sulfuryl chloride with methanol as follow: Methanol (15 g, 0.47 mol) was added dropwise to sulfuryl chloride at 0°C (ice-bath cooling) and the reaction mixture was stirred at 0°C for 3 hours. After evolution of hydrogen chloride ceased, the reaction mixture was distilled under reduced pressure to give methyl chlorosulfonate (23.5 g, 38 %, bp 62°C / 52-53 mm Hg; lit.[Heller, M. S.; Lorah, D. P.; Cox, C. P., Chem. Eng. Data, 1983,27,134] 55-56°C / 39 mm Hg). 'H NMR (CDC13) S 4.21 (s, 3H); 13C NMR (CDC13) 8 61.2 [0031] Cleavage of dioxane. A 25 mL one-necked flask was charged with acetic acid (0.97 mL, 1.0 g, 16.7 mmol), dioxane (7 mL, 7.0 g, 80 mmol), methyl chlorosulfonate (2.0 g, 15.3 mmol) and then with triethylamine (2.153 mL, 1.56 g, 15.3 mmol) at room temperature under nitrogen. The reaction mixture was refluxed for 72 h. The reaction progress was monitored by NMR. The reaction mixture was then evaporated under vacuum. Dry toluene (15 mL) and terf-butylamine (8.4 mL, 5.85 g, 80 mmol) were added to the residue and the mixture was gently refluxed for 24 hours. The reaction mixture was then cooled to room temperature and filtered. The solid was washed with toluene. The combined filtrate was evaporated under vacuum. The residue was extracted with toluene; the extract was filtered and evaporated under vacuum to give 0.3 g of brown oil. The NMR test showed the trace presence of desired product (f-BuNHCH2CH2OCH2CH2OAc). The signals in H NMR spectrum suggest the We Claim: 1. A method for the synthesis of severely sterically hindered secondary aminoether alcohols of the formula (Formula Removed) wherein R1 and R2 are each selected from the group consisting of alkyl, hydroxylalkyl radicals having 1 to 4 carbon atoms or in combination with the carbon atom to which they are attached they form a cycloalkyl group having 3 to 8 carbon atoms, and R3 is selected from the group consisting of hydrogen, alkyl hydroxyalkyl radicals having 1 to 4 carbon atoms, and mixtures thereof, and R4, R5,R6,R7,R8, R9, R10and R11 are the same or different and are selected from the group consisting of hydrogen, alkyl and hydroxyalkyl radicals having 1 to 4 carbons provided that at least one of R4 or R5 bonded to the carbon atom directly bonded to the nitrogen atom is an alkyl or hydroxyalkyl radical when R3 is hydrogen, the process involving reacting an organic carboxylic acid or salt of a carboxylic acid of the formula (Formula Removed) wherein R12 is selected from the group consisting of alkyl radicals having 1 to 4 carbon atoms, aryl radicals bearing hydrogen or one or more C1-C10 alkyl groups substituted thereon, and mixtures thereof, and Y is selected from the group consisting of hydrogen, alkali metal, ammonium, and mixtures thereof, with a sulfonyl halide, a sulfuryl halide, a mixed sulfuryl ester halide, or a mixed sulfuryl amide halide of the formula (Formula Removed) wherein X is selected from the group consisting of F, Cl, Br, I, and mixtures thereof, and R14 and R14' are the same or different and each is selected from the group consisting of alkyl radicals having 1 to 4 carbon atoms, haloalkyl radicals of the formula CnH(2n+1)-wZw wherein n is 1 to 4, Z is selected from the group consisting of F, Cl, Br, I, and mixtures thereof, and w ranges from 1 to 5, and aryl radicals (Formula Removed) wherein R15, R16, R17, R18, and R19 are the same or different and are selected from hydrogen and alkyl radicals having 1 to 20 carbon atoms, and mixtures thereof, to yield acyl sulfonate material of the general formula (Formula Removed) which is then reacted with a dioxane of the formula (Formula Removed) wherein R4, R5, R6, R7, R8, R9, R10, and R1 1 are the same or different and are selected from hydrogen, alkyl and hydroxyalkyl radicals having 1 to 4 carbons to yield (Formula Removed) which is then aminated with an alkylamine of the formula (Formula Removed) wherein R1, R2, and R3 are as previously defined to yield (Formula Removed) which is then hydrolyzed with base to yield (Formula Removed) 2. The method as claimed in 1 for the synthesis of severely sterically hindered secondary aminoether alcohols using sulfonyl halide of the formula (Formula Removed) 3. The method as claimed in claim 1 for the synthesis of severely sterically hindered secondary aminoether alcohols using sulfuryl halide of the formula SO2X2. 4. The method as claimed in claim 1 for the synthesis of severely sterically hindered secondary aminoether alcohols using the mixed sulfuryl ester halide of the formula (Formula Removed) 5. The method as claimed in claim 1 for the synthesis of severely sterically hindered secondary aminoether alcohols using the mixed sulfuryl amide halide of the formula (Formula Removed) 6. The method as claimed in any one of the preceding claims wherein R1, R2 and R3 are methyl radicals. 7. The method as claimed in any one of the preceding claims wherein R4, R5, R6, R7, R8, R9, R10,and R11 are hydrogen. 8. The method as claimed in any one of the preceding claims wherein R15, R16, R18, and R19 are hydrogen and R17 is hydrogen or methyl. 9. The method as claimed in any one of the preceding claims wherein the base is selected from alkali metal hydroxide, alkali metal alkoxide, or alkali metal carbonate. 10. The method as claimed in any one of the preceding claims wherein Y is hydrogen or sodium. 11. The method as claimed in any one of the preceding claims wherein R1 , R2 and R3 are methyl, R4, R5, R6, R7, R8, R9, R10, and R11 are hydrogen, R15, R16, R18, and R19 are hydrogen, R is hydrogen or methyl, and Y is hydrogen, sodium, or ammonium. 12. The method as claimed in any one of the preceding claims wherein the acyl sulfonate is made by reacting organic carboxylic acid or the salt of a carboxylic acid with the sulfonyl halide, sulfuryl halide, mixed sulfuryl ester halide or mixed sulfuryl amide halide at a temperature in the range of between about -20 to 200°C at a pressure between about 1 bar and 100 bars, the acyl sulfonate is reacted with the dioxane at a molar ratio of dioxane to acyl sulfonate in the range of 1:1 to 10:1 at a temperature of between about 50°C to about 200°C to yield a cleavage product, the cleavage product and the alkyl amine reacted at an amine to sulfonate group ratio ranging from about stoichiometric to about 10:1 at pressure of from about atmospheric (1 bar) to about 100 bars at temperature of from about 40°C to about 200°C, and the resulting aminated product is hydrolyzed with base at a temperature from about 20°C to about 110°C. 13. The method as claimed in any one of the preceding claims wherein the organic carboxylic acid or the salt thereof the sulfonyl halide, sulfuryl halide, mixed sulfuryl ester halide or mixed sulfuryl amide halide and the dioxane care combined in a single step to produce a reaction mixture, reaction mixture being heated at a temperature of between about 50°C to about 200°C to produce the cleavage product, the cleavage product and the alkylamine are reacted at am amine to cleavage product ratio ranging from about stoichiometric to about 10:1 at a pressure from about atmospheric (1 bar) to about 100 bars at a temperature of from about 40°C to about 200°C, the resulting aminated product being reacted with base at a temperature from about 20°C to about 110°C.

Full Text

FIELD OF THE INVENTION
[0001] The present invention relates to a method for the preparation of severely sterically hindered secondary aminoether alcohols which are useful in the removal of hydrogen sulfide from gaseous streams containing hydrogen sulfide and which may also contain carbon dioxide.
DESCRIPTION OF RELATED ART
[0002] It is well-known in the art to treat gases and liquids, such as mixtures containing acidic gases including CO2, H2S, CS2, HCN, COS and oxygen and sulfur derivatives of C1 to C4 hydrocarbons with amine solutions to remove
these acidic gases. The amine usually contacts the acidic gases and the liquids as an aqueous solution containing the amine in an absorber tower with the aqueous amine solution contacting the acidic fluid countercurrently. Usually this contacting results in the simultaneous removal of substantial amounts of both the CO2 and H2S. USP 4,112,052, for example, utilizes a sterically hindered amine to obtain nearly complete removal of CO2 and H2S acid gases. This process is particularly suitable for systems in which the partial pressures of the CO2 and related gases are low. For systems where the partial pressure of
CO2 is high or where there are many acid gases present, e.g., H2S, COS,
CH3SH, CS2, etc., a process utilizing an amine in combination with a physical
absorbent, referred to as a "non-aqueous solvent process" is practiced. Such a system is described in USP 4,112,051.
[0003] Selective removal of H2S from acid gas systems containing both H2S and CO2, however, is very desirable. Such selective removal results in a
relatively high H2S/CO2 ratio in the separated acid gas which facilitates the
subsequent conversion of the H2S to elemental sulfur in the Glaus process.
[0004] The typical reactions of aqueous secondary and tertiary amines with
CO2 and H2S can be represented as follows:
where R is the same or different organic radical and may be substituted with a
hydroxyl group. Because the reactions are reversible they are sensitive to the
CO2 and H2S partial pressures which is determinative of the degree to which the
reactions occur.
[0005] Selective HS removal is particularly desirable in systems having low
H2S/CO2 ratios and relatively low H2S partial pressures as compared to that of
the CO2- The ability of amine to selectivity remove H2$ in such systems is very
low.
[0006] Solutions of primary and secondary amines such as monoethanolamine
(MEA), diethanolamine (DEA), diisopropanolamine (DPA), and
hydroxyethoxyethylamine (DEA) absorb both H2S and CC2, and thus have
proven unsatisfactory for the selective removal of H2S to the exclusion of CO2-
The CO2 forms carbamates with such amines relatively easily.
[0007] H2S has been selectively removed from gases containing H2S and
CO2 by use of diisopropanolamine (DIPA) either alone or mixed with a nonaqueous
physical solvent such as sulfolane. Contact times, however, must be
kept short to take advantage of the faster reaction of H2S with the amine as
compared to the rate of CO2 reaction with the amine.
[0008] Frazier and Kohl, Ind. and Eng. Chem., 42,2288 (1950) showed that
the tertiary amine methydiethanolamine (MDEA) is more selective toward H2S
absorption as compared to C&2- C(2 reacts relatively slowly with tertiary
amines as compared to the rapid reaction of the tertiary amine with H2S.
However, it has the disadvantage of having a relatively low H2S loading
capacity and limited ability to reduce the H2S content to the desired level at low
H2S pressures encountered in certain gases.
[0009] UK Patent Publication No. 2,017,524A discloses the use of aqueous
solutions of dialkylmonoalkanolamines, e.g., diethylmonoethanol amine
(DEAE), for the selective removal of H2S, such material having higher
selectivity and capacity for H2$ removal at higher loading levels than MDEA.
DEAE, however, has the disadvantage of a low boiling point of 161 °C, making it
relatively highly volatile resulting in large material loss.
[0010] USP 4,471,138 the entire teaching of which is incorporated herein by
reference, teaches severely sterically hindered acyclic secondary aminoether
alcohols having a high selectivity for H2S compared to CO2- Selectivity is
maintained at high H2S and CC2 loadings.
[0011] The severely sterically hindered acyclic amine ether alcohols of USP
4,471,138 are represented by the general formula:
wherein RI and R2 are each independently selected from the group consisting of
alkyl and hydroxyalkyl radicals having 1-4 carbon atoms, R$, R4, RS and Rg are
each independently selected from the group consisting of hydrogen, alkyl, and
hydroxyalkyl radicals having 1-4 carbon atoms, with the proviso that at least one
of R4 or RS bonded to the carbon atom which is directly bonded to the nitrogen
atom is an alkyl or hydroxyalkyl radical when R3 is hydrogen, x and y are each
positive integers ranging from 2-4, and z is a positive integer ranging from 1-4.
These materials are prepared by a high temperature reaction preferably in the
presence of a solvent, of a secondary or tertiary alkyl primary amine with an
ether alcohol containing a carbonyl functionality in the presence of a source of
hydrogen or with a haloalkoxyalkanol. Preferably the composition is of the
general formula:
wherein:
R! = R2 = R3 = CH3CH2-; R4 = RS = Re = H; or
R! # R2 # R3 = H, CH3-, CH3CH2-; R4 # R5 # Re = H, CH3-;
and where x = 2 or 3.
[0012] U.S. Patent 4,487,967 is directed to a process for preparing severely
sterically hindered secondary aminoether alcohols by reacting a primary amino
compound with a polyalkenyl ether glycol in the presence of a hydrogenation
catalyst at elevated temperatures and pressures. The primary amino compounds
employed have a general formula:
R1 -NH2
where R is selected from the group consisting of secondary or tertiary alkyl
radicals having 3 to 8 carbon atoms or cycloalkyl radicals having 3 to 8 carbon
atoms. The polyalkenyl ether glycols employed have the general formula:
where R2, RS, R4 and RS are each independently selected from the group
consisting of hydrogen, Cj-C4 alkyl radicals, and C3-Cg cycloalkyl radicals,
with the proviso that if the carbon atom of Rj directly attached to the nitrogen
atom is secondary, at least one of R2 and R3 directly bonded to the carbon which
is bonded to the hydroxyl group is as alkyl or cycloalkyl radical, x and y are
each positive integers independently ranging from 2 to 4 and z is from 1 to 10,
preferably 1 to 6, more preferably 1 to 4. The process is carried out in the
presence of a catalytically effective amount of a supported Group VDI metal
containing hydrogenation catalyst at elevated temperatures and pressure and the
mole ratio of amino compound to polyalkenyl ether glycol is less than 2:1 when
z is greater than 1.
SUMMARY OF THE INVENTION
[0013] A new process is disclosed for the production of severely sterically
hindered secondary aminoether alcohols of the general formula 1:
R2 are each independently selected from the group consisting of
alkyl and hydroxyalkyl radicals having 1 to 4 carbon atoms, preferably 1 to 2
carbon atoms, or R and R in combination with the carbon atom to which they
are attached form a cycloalkyl group having 3 to 8 carbons; R3 is selected from
the group consisting of hydrogen, alkyl or hydroxyalkyl radicals having 1 to 4
carbon atoms, and mixtures thereof, preferably 1 to 2 carbon atoms, preferably
alkyl or hydroxyalkyl radicals having 1 to 4 carbon atoms, more preferably 1 to
2 carbon atoms; R4, R5, R6, R7, R8, R9, R10, and R11 are the same or different
and are selected from hydrogen, alkyl or hydroxyalkyl radicals having 1 to 4
carbon atoms, preferably 1 to 2 carbon atoms, or cycloalkyl radicals having 3 to
8 carbons; R4, R5, R6, R7, R8, R9, R10, and R1 are preferably hydrogen
provided that when R is hydrogen at least one of R4 and R bonded to the
carbon directly bonded to the nitrogen atom is an alkyl or hydroxyalkyl radical.
The process involves reacting an organic carboxylic acid or a salt of a carboxylic
acid of the formula:
wherein Rl2 is selected from the group consisting of alkyl radicals having 1 to 4
carbon atoms, preferably 1 to 2 carbon atoms, most preferably methyl,
radicals, substituted aryl radicals, preferably phenyl substituted with a hydrogen
or one or more alkyl radicals having 1-10 carbon atoms, preferably 1-4 carbon
atoms, most preferably methyl in the para position, and mixtures thereof, and Y
is selected from the group consisting of hydrogen, alkali metal, ammonium, and
mixtures thereof, preferably hydrogen or sodium, with a sulfonyl halide, a
sulfuryl halide, a mixed sulfuryl ester halide, or a mixed sulfuryl amide halide of
the formula:
wherein X is selected from the group consisting of F, Cl, Br, I, and mixtures
thereof, preferably F, Cl, most preferably Cl, R14 and R14 are the same or
different and each is selected from the group consisting of alkyl radicals having
1 to 4 carbon atoms, preferably 1 to 2 carbon atoms, most preferably methyl,
haloalkyl radicals of the formula CnH(2n+l)-wZw wherein n is 1 to 4 preferably
1 to 2, and most preferably 1; Z is selected from the group consisting of F, Cl,
Br, I, preferably F and Cl, most preferably F; and w ranges from 1 to 5,
preferably 1 to 3, most preferably 3, aryl radicals 4
R16 R15
wherein R15, Rl6 Rl7? RlS and Rl9 are me same or different and are selected
from hydrogen and alkyl radicals having 1 to 20 carbon atoms, preferably R15,
Rl6, Rl8} and Rl9 aj-g hydrogen and R7 js selected from hydrogen and an
alkyl radicals having 1-4 carbons, preferably 1 to 2 carbons, more preferably
methyl, and mixtures thereof, to yield sulfonic-carboxylic anhydride compounds
which is then reacted with a dioxane of the formula 6:
SYNTHESIS OF STERICALLY
HINDERED SECONDARY AMINOETHER ALCOHOLS
FIELD OF THE INVENTION
[0001] The present invention relates to a method for the preparation of
severely sterically hindered secondary aminoether alcohols which are useful in
the removal of hydrogen sulfide from gaseous streams containing hydrogen
sulfide and which may also contain carbon dioxide.
DESCRIPTION OF RELATED ART
[0002] It is well-known in the art to treat gases and liquids, such as mixtures
containing acidic gases including CO2, H2S, CS2, HCN, COS and oxygen and
sulfur derivatives of Cj to €4 hydrocarbons with amine solutions to remove
these acidic gases. The amine usually contacts the acidic gases and the liquids
as an aqueous solution containing the amine in an absorber tower with the
aqueous amine solution contacting the acidic fluid countercurrently. Usually
this contacting results in the simultaneous removal of substantial amounts of
both the CO2 and HS. USP 4,112,052, for example, utilizes a sterically
hindered amine to obtain nearly complete removal of CO2 and H2S acid gases.
This process is particularly suitable for systems in which the partial pressures of
the CO2 and related gases are low. For systems where the partial pressure of
CO2 is high or where there are many acid gases present, e.g., H2S, COS,
CH3SH, CS2, etc., a process utilizing an amine in combination with a physical
absorbent, referred to as a "non-aqueous solvent process" is practiced. Such a
system is described in USP 4,112,051.
[0003] Selective removal of H2S from acid gas systems containing both H2S
and CO2, however, is very desirable. Such selective removal results in a
relatively high H2S/CO2 ratio in the separated acid gas which facilitates the
subsequent conversion of the H2S to elemental sulfur in the Glaus process.
[0004] The typical reactions of aqueous secondary and tertiary amines with
where R is the same or different organic radical and may be substituted with a
hydroxyl group. Because the reactions are reversible they are sensitive to the
CO2 and H2S partial pressures which is determinative of the degree to which the
reactions occur.
[0005] Selective HS removal is particularly desirable in systems having low
H2S/CO2 ratios and relatively low H2S partial pressures as compared to that of
the CO2- The ability of amine to selectivity remove H2$ in such systems is very
low.
[0006] Solutions of primary and secondary amines such as monoethanolamine
(MEA), diethanolamine (DEA), diisopropanolamine (DPA), and
hydroxyethoxyethylamine (DEA) absorb both H2S and CC2, and thus have
proven unsatisfactory for the selective removal of H2S to the exclusion of CO2-
The CO2 forms carbamates with such amines relatively easily.
-3-
[0007] H2S has been selectively removed from gases containing H2S and
CO2 by use of diisopropanolamine (DIPA) either alone or mixed with a nonaqueous
physical solvent such as sulfolane. Contact times, however, must be
kept short to take advantage of the faster reaction of H2S with the amine as
compared to the rate of CO2 reaction with the amine.
[0008] Frazier and Kohl, Ind. and Eng. Chem., 42,2288 (1950) showed that
the tertiary amine methydiethanolamine (MDEA) is more selective toward H2S
absorption as compared to C&2- C(2 reacts relatively slowly with tertiary
amines as compared to the rapid reaction of the tertiary amine with H2S.
However, it has the disadvantage of having a relatively low H2S loading
capacity and limited ability to reduce the H2S content to the desired level at low
H2S pressures encountered in certain gases.
[0009] UK Patent Publication No. 2,017,524A discloses the use of aqueous
solutions of dialkylmonoalkanolamines, e.g., diethylmonoethanol amine
(DEAE), for the selective removal of H2S, such material having higher
selectivity and capacity for H2$ removal at higher loading levels than MDEA.
DEAE, however, has the disadvantage of a low boiling point of 161 °C, making it
relatively highly volatile resulting in large material loss.
[0010] USP 4,471,138 the entire teaching of which is incorporated herein by
reference, teaches severely sterically hindered acyclic secondary aminoether
alcohols having a high selectivity for H2S compared to CO2- Selectivity is
maintained at high H2S and CC2 loadings.
[0011] The severely sterically hindered acyclic amine ether alcohols of USP
4,471,138 are represented by the general formula:
wherein RI and R2 are each independently selected from the group consisting of
alkyl and hydroxyalkyl radicals having 1-4 carbon atoms, R$, R4, RS and Rg are
each independently selected from the group consisting of hydrogen, alkyl, and
hydroxyalkyl radicals having 1-4 carbon atoms, with the proviso that at least one
of R4 or RS bonded to the carbon atom which is directly bonded to the nitrogen
atom is an alkyl or hydroxyalkyl radical when R3 is hydrogen, x and y are each
positive integers ranging from 2-4, and z is a positive integer ranging from 1-4.
These materials are prepared by a high temperature reaction preferably in the
presence of a solvent, of a secondary or tertiary alkyl primary amine with an
ether alcohol containing a carbonyl functionality in the presence of a source of
hydrogen or with a haloalkoxyalkanol. Preferably the composition is of the
general formula:
[0012] U.S. Patent 4,487,967 is directed to a process for preparing severely
sterically hindered secondary aminoether alcohols by reacting a primary amino
compound with a polyalkenyl ether glycol in the presence of a hydrogenation
catalyst at elevated temperatures and pressures. The primary amino compounds
employed have a general formula:
where R is selected from the group consisting of secondary or tertiary alkyl
radicals having 3 to 8 carbon atoms or cycloalkyl radicals having 3 to 8 carbon
atoms. The polyalkenyl ether glycols employed have the general formula:
where R2, RS, R4 and RS are each independently selected from the group
consisting of hydrogen, Cj-C4 alkyl radicals, and C3-Cg cycloalkyl radicals,
with the proviso that if the carbon atom of Rj directly attached to the nitrogen
atom is secondary, at least one of R2 and R3 directly bonded to the carbon which
is bonded to the hydroxyl group is as alkyl or cycloalkyl radical, x and y are
each positive integers independently ranging from 2 to 4 and z is from 1 to 10,
preferably 1 to 6, more preferably 1 to 4. The process is carried out in the
presence of a catalytically effective amount of a supported Group VDI metal
containing hydrogenation catalyst at elevated temperatures and pressure and the
mole ratio of amino compound to polyalkenyl ether glycol is less than 2:1 when
z is greater than 1.
-6-
SUMMARY OF THE INVENTION
[0013] A new process is disclosed for the production of severely sterically
hindered secondary aminoether alcohols of the general formula 1:
R4 R6 R8 RlO
R2 C N C C O C C OH 1
I « I I I I
R3 R5 R7 R9 Rll
wherein R and R2 are each independently selected from the group consisting of
alkyl and hydroxyalkyl radicals having 1 to 4 carbon atoms, preferably 1 to 2
carbon atoms, or R and R in combination with the carbon atom to which they
are attached form a cycloalkyl group having 3 to 8 carbons; R3 is selected from
the group consisting of hydrogen, alkyl or hydroxyalkyl radicals having 1 to 4
carbon atoms, and mixtures thereof, preferably 1 to 2 carbon atoms, preferably
alkyl or hydroxyalkyl radicals having 1 to 4 carbon atoms, more preferably 1 to
2 carbon atoms; R4, R5, R6, R7, R8, R9, R10, and R11 are the same or different
and are selected from hydrogen, alkyl or hydroxyalkyl radicals having 1 to 4
carbon atoms, preferably 1 to 2 carbon atoms, or cycloalkyl radicals having 3 to
8 carbons; R4, R5, R6, R7, R8, R9, R10, and R1 are preferably hydrogen
provided that when R is hydrogen at least one of R4 and R bonded to the
carbon directly bonded to the nitrogen atom is an alkyl or hydroxyalkyl radical.
The process involves reacting an organic carboxylic acid or a salt of a carboxylic
acid of the formula:
wherein Rl2 is selected from the group consisting of alkyl radicals having 1 to 4
carbon atoms, preferably 1 to 2 carbon atoms, most preferably methyl, aryl
radicals, substituted aryl radicals, preferably phenyl substituted with a hydrogen
or one or more alkyl radicals having 1-10 carbon atoms, preferably 1-4 carbon
atoms, most preferably methyl in the para position, and mixtures thereof, and Y
is selected from the group consisting of hydrogen, alkali metal, ammonium, and
mixtures thereof, preferably hydrogen or sodium, with a sulfonyl halide, a
sulfuryl halide, a mixed sulfuryl ester halide, or a mixed sulfuryl amide halide
wherein X is selected from the group consisting of F, Cl, Br, I, and mixtures
thereof, preferably F, Cl, most preferably Cl, R14 and R14 are the same or
different and each is selected from the group consisting of alkyl radicals having
1 to 4 carbon atoms, preferably 1 to 2 carbon atoms, most preferably methyl,
haloalkyl radicals of the formula CnH(2n+l)-wZw wherein n is 1 to 4 preferably
1 to 2, and most preferably 1; Z is selected from the group consisting of F, Cl,
Br, I, preferably F and Cl, most preferably F; and w ranges from 1 to 5,
preferably 1 to 3, most preferably 3, aryl radicals 4
R16 R15
wherein R15, Rl6 Rl7? RlS and Rl9 are me same or different and are selected
from hydrogen and alkyl radicals having 1 to 20 carbon atoms, preferably R15,
Rl6, Rl8} and Rl9 aj-g hydrogen and R7 js selected from hydrogen and an
alkyl radicals having 1-4 carbons, preferably 1 to 2 carbons, more preferably
methyl, and mixtures thereof, to yield sulfonic-carboxylic anhydride
wherein R4, R5, R6, R7t R8, R9, RlO, and R! 1 are the same or different and are
selected from hydrogen, alkyl and hydroxyalkyl radicals having 1 to 4 carbons,
preferably 1 to 2 carbons or cycloalkyl radicals having 3 to 8 carbons, more
preferably R4, R, R6, R?, R8? R9, RlO, and Rl are hydrogen, to yield
cleavage product materials of formula 7
or mixtures thereof. It is not necessary that the product from each reaction step
be isolated before being reacted with the reactant of a subsequent reaction step
up to this point. A cleavage product is still produced The mixing of the organic
carboxylic acid or salt thereof with a sulfonyl halide, sulfuryl halide, mixed
sulfuryl ester halide or mixed sulfuryl amide halide and the dioxane can be in
any order or sequence. Thus, the organic carboxylic acid or salt thereof can be
mixed with the sulfonyl halide, etc. and then mixed with the dioxane, or the
dioxane can be first mixed with the sulfonyl halide, etc. and then the organic
carboxylic acid or salt thereof can be added, or the organic carboxylic acid or
salt thereof and the dioxane can be mixed followed by the addition of the
sulfonyl halide, etc. Thus, the combination of the organic carboxylic acid or salt
thereof with the dioxane and the sulfonyl halide, sulfuryl halide, mixed sulfuryl
ester halide or mixed sulfuryl amide halide can be combined into a single
reaction mixture and reacted as a single mixture in the one step production of the
desired cleavage product. This cleavage product is then reacted with an
alkylamine of the formula 8:
The preferred compounds defined by the general formula above include:
[0015] Other materials of the types described above can be readily
envisioned.
[0016] This material is then is reacted with second component, typically
[0017] Similarly, other materials of the type described above can be readily
envisioned.
[0018] The reaction of two such components yields acyl sulfonates 5a, 5b, 5c
and 5d. The reaction can be conducted at a temperature in the range of between
about -20 to 200°C, preferably about -20 to 150°C, more preferably about 0 to
120°C, and a pressure between about 1 bar to 100 bars, preferably about 1 bar to
50 bars, more preferably about 1 bar to 10 bars.
[0019] The reaction can be carried out neat, that is, in the absence of any
solvent provided one or the other of the reactants in a liquid and capable of
dissolving the non-liquid reactant, or both are liquid. Alternatively, an inert
added solvent can be used such as sulfolane, hexanes or acetonitrile. Preferably
the dioxane for the subsequent cleavage reaction is used as the solvent resulting
in all three reactants being present in a unified first step wherein the reaction
mixture contains the dioxane, organic carboxylic acid or salt thereof and the
sulfonyl halide, sulfuryl halide, mixed sulfuryl ester halide or mixed sulfuryl
amide halide. This reaction mixture can then be reacted under the conditions
subsequently described for the dioxane cleavage reaction, yielding the cleavage
product described by general formula 4.
[0020] The sulfonate 5a and/or 5b are reacted with a 1,4-dioxane, which is
typically of the formula:
Other substituted isomers can be readily envisioned. Preferably, the 1,4-dioxane
[0021] Reaction at elevated temperature is for a time sufficient to cleave the
dioxane ring and to achieve about 60-90% conversion to cleavage product. The
dioxane also serves as the solvent for the reaction. The molar ratio of dioxane to
sulfonate can range from about 1:1 to about 10:1, preferably about 1:1 to about
8:1, most preferably about 1:1 to about 5:1. The reaction can be carried out in
the absence of any added solvent, e.g., the dioxane serving as the solvent, or an
additional solvent such as acetonitrile or toluene can be used, the reaction being
conducted at temperatures between about 50°C to about 200°C, preferably about
70°C to about 160°C, more preferably about 80°C to about 140°C.
[0022] Preferably, the reaction is carried out in the absence of any added
solvent, the dioxane serving as both reactant and solvent, at a temperature in the
range of about 50°C to about 160°C, preferably about 70°C to about 160°C,
more preferably about 80°C to about 140°C.
[0023] The dioxane cleavage step recited above are described in greater detail
by Karger and Mazur in "The Cleavage of Ethers by Mixed Sulfonic-Carboxylic
Anhydrides", Journal of the American Chemical Society, 1968, 90, 3878-3879.
See also, "Mixed sulfonic-carboxylic anhydrides. I. Synthesis and thermal
stability. New syntheses of sulfonic anhydrides" Journal of Organic Chemistry,
1971, 36, 528, and "Mixed sulfonic-carboxylic anhydrides. II. Reactions with
aliphatic ethers and amines" Journal of Organic Chemistry, 1971, 36, 532.
[0024] The cleavage product 7a and/or 7b and/or 7c and/or 7d is then
aminated with an amine 8 typically of the formula:
CH3 CH3 CH2CH3 CH2CH3
H3C-C-NH2 H3C-C-NH2 H3C-C-NH2 H3C-C-NH2
CH3 H CH3 CH2CH3
i i »for a time sufficient to replace the -O-SO2~R or the sulfonate group in 7a
and/or 7b and/or 7c and/or 7d by the amine 8. In the case of the amination of
materials 7a, 7c and 7d, the amine to sulfonate group mole ratio is in the range
of about 1:1 to about 10:1, preferably about 1:1 to about 8:1, more preferably
about 1:1 to 4:1, while in the case of the amination of material 7b the amine to
sulfonate group ratio is in the range of about 2:1 to about 10:1, preferably about
2:1 to about 8:1, more preferably about 2:1 to about 4:1. Expressed differently,
in general the amine to group being replaced mole ratio can range from about
stoichiometric to about 10:1, preferably about stoichiometric to about 8:1, more
preferably about stoichiometric to about 4:1.
[0025] This amination step can be carried out under any conditions typical in
the art. Amination can be conducted at atmospheric or at elevated pressure,
elevated pressure being especially suitable when amination is performed using
relatively low boiling amines such as f-butyl amine.
[0026] The amination can be conducted at pressures of from about
atmospheric (1 bar) to about 100 bars, preferably about 1 to about 50 bars, and at
temperatures of from about 40°C to about 200°C, preferably about 40°C to about
125°C. The amination can be performed using reflux, but this is not absolutely
necessary. An inert solvent can be optionally used, such as benzene, toluene,
diethyl ether, hexane, and the like.
[0027] Finally, the resultant 9
is hydrolyzed using a base to yield the final desired product 1. Typical bases
include an alkali metal hydroxide, an alkali metal carbonate, or an alkali metal
alkoxide, such as sodium hydroxide, sodium carbonate, sodium methoxide,
sodium tert-butoxide, etc. Reaction is conducted at from about 20°C to about
110°C, preferably about 20°C to about 50°C. Reaction under reflux is effective
and a desirable technique.
[0028] Use of a solvent is optional for the hydrolysis reaction, one being used
if the reactants are not already in the liquid form. Solvents can include water, or
alcohol and mixtures thereof.
[0029] If alcohols are used, they can be of the same carbon number or are the
same alcohols from which the alkoxide bases themselves are derived. Thus,
methanol would be a suitable solvent to use where the base is an alkali
methoxide.
EXAMPLES
Cleavage with methvl acetvl sulfate generated in situ using methyl
chlorosulfonate and acetic acid in the presence of triethylamine
[0030] Methyl chlorosulfonate was prepared according to known procedure
[Heller, M. S.; Lorah, D. P.; Cox, C. P., Chem. Eng. Data, 1983,27,134] by the
reaction of sulfuryl chloride with methanol as follow: Methanol (15 g, 0.47 mol)
was added dropwise to sulfuryl chloride at 0°C (ice-bath cooling) and the
reaction mixture was stirred at 0°C for 3 hours. After evolution of hydrogen
chloride ceased, the reaction mixture was distilled under reduced pressure to
give methyl chlorosulfonate (23.5 g, 38 %, bp 62°C / 52-53 mm Hg; lit.[Heller,
M. S.; Lorah, D. P.; Cox, C. P., Chem. Eng. Data, 1983,27,134] 55-56°C / 39
mm Hg). 'H NMR (CDC13) S 4.21 (s, 3H); 13C NMR (CDC13) 8 61.2
[0031] Cleavage of dioxane. A 25 mL one-necked flask was charged with
acetic acid (0.97 mL, 1.0 g, 16.7 mmol), dioxane (7 mL, 7.0 g, 80 mmol), methyl
chlorosulfonate (2.0 g, 15.3 mmol) and then with triethylamine (2.153 mL,
1.56 g, 15.3 mmol) at room temperature under nitrogen. The reaction mixture
was refluxed for 72 h. The reaction progress was monitored by NMR. The
reaction mixture was then evaporated under vacuum. Dry toluene (15 mL) and
terf-butylamine (8.4 mL, 5.85 g, 80 mmol) were added to the residue and the
mixture was gently refluxed for 24 hours. The reaction mixture was then cooled
to room temperature and filtered. The solid was washed with toluene. The
combined filtrate was evaporated under vacuum. The residue was extracted with
toluene; the extract was filtered and evaporated under vacuum to give 0.3 g of
brown oil. The NMR test showed the trace presence of desired product
(f-BuNHCH2CH2OCH2CH2OAc). The signals in H NMR spectrum suggest the
presence of acetates (HOCH2CH2OCH2CH2OAc) and/or
(AcOCH2CH2OCH2CH2OAc).
wherein R4, R5, R6, R7t R8, R9, RlO, and R! 1 are the same or different and are
selected from hydrogen, alkyl and hydroxyalkyl radicals having 1 to 4 carbons,
preferably 1 to 2 carbons or cycloalkyl radicals having 3 to 8 carbons, more
preferably R4, R, R6, R?, R8? R9, RlO, and Rl are hydrogen, to yield
cleavage product materials of formula 7
or mixtures thereof. It is not necessary that the product from each reaction step
be isolated before being reacted with the reactant of a subsequent reaction step
up to this point. A cleavage product is still produced The mixing of the organic
carboxylic acid or salt thereof with a sulfonyl halide, sulfuryl halide, mixed
sulfuryl ester halide or mixed sulfuryl amide halide and the dioxane can be in
any order or sequence. Thus, the organic carboxylic acid or salt thereof can be
mixed with the sulfonyl halide, etc. and then mixed with the dioxane, or the
dioxane can be first mixed with the sulfonyl halide, etc. and then the organic
carboxylic acid or salt thereof can be added, or the organic carboxylic acid or
salt thereof and the dioxane can be mixed followed by the addition of the
sulfonyl halide, etc. Thus, the combination of the organic carboxylic acid or salt
thereof with the dioxane and the sulfonyl halide, sulfuryl halide, mixed sulfuryl
ester halide or mixed sulfuryl amide halide can be combined into a single
reaction mixture and reacted as a single mixture in the one step production of the
desired cleavage product. This cleavage product is then reacted with an
alkylamine of the formula 8:
The preferred compounds defined by the general formula above include:
2-[2-( 1 -ethyl-1 -methylpropylamino)ethoxy]ethanol
[0014] Typical starting materials to use as the first component are:
[0015] Other materials of the types described above can be readily
envisioned.
[0016] This material is then is reacted with second component, typically
;02C1 H3
02C1
S02C1 CH3CH2 S02C1
H3C-S02C1 H3C-CH2-S02C1, H3C-CH-SO2C1 F3C-SO2
C13C-S02C1 FCH2-CH2S02C1, H3C-CHF-SO2C1
»
F2HC-CH2-SO2-Cl F3C-CF2- SO2C1 H3C -CF2 1 -SO2C11
SO2C12, SO2F2SO2I2. 862612 and mixtures thereof.
[0017] Similarly, other materials of the type described above can be readily
envisioned.
[0018] The reaction of two such components yields acyl sulfonates 5a, 5b, 5c
and 5d. The reaction can be conducted at a temperature in the range of between
about -20 to 200°C, preferably about -20 to 150°C, more preferably about 0 to
120°C, and a pressure between about 1 bar to 100 bars, preferably about 1 bar to
50 bars, more preferably about 1 bar to 10 bars.
[0019] The reaction can be carried out neat, that is, in the absence of any
solvent provided one or the other of the reactants in a liquid and capable of
dissolving the non-liquid reactant, or both are liquid. Alternatively, an inert
added solvent can be used such as sulfolane, hexanes or acetonitrile. Preferably
the dioxane for the subsequent cleavage reaction is used as the solvent resulting
in all three reactants being present in a unified first step wherein the reaction
mixture contains the dioxane, organic carboxylic acid or salt thereof and the
sulfonyl halide, sulfuryl halide, mixed sulfuryl ester halide or mixed sulfuryl
amide halide. This reaction mixture can then be reacted under the conditions
subsequently described for the dioxane cleavage reaction, yielding the cleavage
product described by general formula 4.
[0020] The sulfonate 5a and/or 5b are reacted with a 1,4-dioxane, which is
typically of the formula:
Other substituted isomers can be readily envisioned. Preferably, the 1,4-dioxane
[0021] Reaction at elevated temperature is for a time sufficient to cleave the
dioxane ring and to achieve about 60-90% conversion to cleavage product. The
dioxane also serves as the solvent for the reaction. The molar ratio of dioxane to
sulfonate can range from about 1:1 to about 10:1, preferably about 1:1 to about
8:1, most preferably about 1:1 to about 5:1. The reaction can be carried out in
the absence of any added solvent, e.g., the dioxane serving as the solvent, or an
additional solvent such as acetonitrile or toluene can be used, the reaction being
conducted at temperatures between about 50°C to about 200°C, preferably about
70°C to about 160°C, more preferably about 80°C to about 140°C.
[0022] Preferably, the reaction is carried out in the absence of any added
solvent, the dioxane serving as both reactant and solvent, at a temperature in the
range of about 50°C to about 160°C, preferably about 70°C to about 160°C,
more preferably about 80°C to about 140°C.
[0023] The dioxane cleavage step recited above are described in greater detail
by Karger and Mazur in "The Cleavage of Ethers by Mixed Sulfonic-Carboxylic
Anhydrides", Journal of the American Chemical Society, 1968, 90, 3878-3879.
See also, "Mixed sulfonic-carboxylic anhydrides. I. Synthesis and thermal
stability. New syntheses of sulfonic anhydrides" Journal of Organic Chemistry,
1971, 36, 528, and "Mixed sulfonic-carboxylic anhydrides. II. Reactions with
aliphatic ethers and amines" Journal of Organic Chemistry, 1971, 36, 532.
[0024] The cleavage product 7a and/or 7b and/or 7c and/or 7d is then
aminated with an amine 8 typically of the formula:
CH3 CH3 CH2CH3 CH2CH3
H3C-C-NH2 H3C-C-NH2 H3C-C-NH2 H3C-C-NH2
CH3 H CH3 CH2CH3
i i »
for a time sufficient to replace the -O-SO2~R or the sulfonate group in 7a
and/or 7b and/or 7c and/or 7d by the amine 8. In the case of the amination of
materials 7a, 7c and 7d, the amine to sulfonate group mole ratio is in the range
of about 1:1 to about 10:1, preferably about 1:1 to about 8:1, more preferably
about 1:1 to 4:1, while in the case of the amination of material 7b the amine to
sulfonate group ratio is in the range of about 2:1 to about 10:1, preferably about
2:1 to about 8:1, more preferably about 2:1 to about 4:1. Expressed differently,
in general the amine to group being replaced mole ratio can range from about
stoichiometric to about 10:1, preferably about stoichiometric to about 8:1, more
preferably about stoichiometric to about 4:1.
[0025] This amination step can be carried out under any conditions typical in
the art. Amination can be conducted at atmospheric or at elevated pressure,
elevated pressure being especially suitable when amination is performed using
relatively low boiling amines such as f-butyl amine.
[0026] The amination can be conducted at pressures of from about
atmospheric (1 bar) to about 100 bars, preferably about 1 to about 50 bars, and at
temperatures of from about 40°C to about 200°C, preferably about 40°C to about
125°C. The amination can be performed using reflux, but this is not absolutely
necessary. An inert solvent can be optionally used, such as benzene, toluene,
diethyl ether, hexane, and the like.
[0027] Finally, the resultant 9
is hydrolyzed using a base to yield the final desired product 1. Typical bases
include an alkali metal hydroxide, an alkali metal carbonate, or an alkali metal
alkoxide, such as sodium hydroxide, sodium carbonate, sodium methoxide,
sodium tert-butoxide, etc. Reaction is conducted at from about 20°C to about
110°C, preferably about 20°C to about 50°C. Reaction under reflux is effective
and a desirable technique.
[0028] Use of a solvent is optional for the hydrolysis reaction, one being used
if the reactants are not already in the liquid form. Solvents can include water, or
alcohol and mixtures thereof.
[0029] If alcohols are used, they can be of the same carbon number or are the
same alcohols from which the alkoxide bases themselves are derived. Thus,
methanol would be a suitable solvent to use where the base is an alkali
methoxide.
EXAMPLES
Cleavage with methvl acetvl sulfate generated in situ using methyl
chlorosulfonate and acetic acid in the presence of triethylamine
[0030] Methyl chlorosulfonate was prepared according to known procedure
[Heller, M. S.; Lorah, D. P.; Cox, C. P., Chem. Eng. Data, 1983,27,134] by the
reaction of sulfuryl chloride with methanol as follow: Methanol (15 g, 0.47 mol)
was added dropwise to sulfuryl chloride at 0°C (ice-bath cooling) and the
reaction mixture was stirred at 0°C for 3 hours. After evolution of hydrogen
chloride ceased, the reaction mixture was distilled under reduced pressure to
give methyl chlorosulfonate (23.5 g, 38 %, bp 62°C / 52-53 mm Hg; lit.[Heller,
M. S.; Lorah, D. P.; Cox, C. P., Chem. Eng. Data, 1983,27,134] 55-56°C / 39
mm Hg). 'H NMR (CDC13) S 4.21 (s, 3H); 13C NMR (CDC13) 8 61.2
[0031] Cleavage of dioxane. A 25 mL one-necked flask was charged with
acetic acid (0.97 mL, 1.0 g, 16.7 mmol), dioxane (7 mL, 7.0 g, 80 mmol), methyl
chlorosulfonate (2.0 g, 15.3 mmol) and then with triethylamine (2.153 mL,
1.56 g, 15.3 mmol) at room temperature under nitrogen. The reaction mixture
was refluxed for 72 h. The reaction progress was monitored by NMR. The
reaction mixture was then evaporated under vacuum. Dry toluene (15 mL) and
terf-butylamine (8.4 mL, 5.85 g, 80 mmol) were added to the residue and the
mixture was gently refluxed for 24 hours. The reaction mixture was then cooled
to room temperature and filtered. The solid was washed with toluene. The
combined filtrate was evaporated under vacuum. The residue was extracted with
toluene; the extract was filtered and evaporated under vacuum to give 0.3 g of
brown oil. The NMR test showed the trace presence of desired product
(f-BuNHCH2CH2OCH2CH2OAc). The signals in H NMR spectrum suggest the

We Claim:
1. A method for the synthesis of severely sterically hindered secondary aminoether alcohols of the formula
(Formula Removed)
wherein R1 and R2 are each selected from the group consisting of alkyl, hydroxylalkyl radicals having 1 to 4 carbon atoms or in combination with the carbon atom to which they are attached they form a cycloalkyl group having 3 to 8 carbon atoms, and R3 is selected from the group consisting of hydrogen, alkyl hydroxyalkyl radicals having 1 to 4 carbon atoms, and mixtures thereof, and R4, R5,R6,R7,R8, R9, R10and R11 are the same or different and are selected from the group consisting of hydrogen, alkyl and hydroxyalkyl radicals having 1 to 4 carbons provided that at least one of R4 or R5 bonded to the carbon atom directly bonded to the nitrogen atom is an alkyl or hydroxyalkyl radical when R3 is hydrogen, the process involving reacting an organic carboxylic acid or salt of a carboxylic acid of the formula
(Formula Removed)
wherein R12 is selected from the group consisting of alkyl radicals having 1 to 4 carbon atoms, aryl radicals bearing hydrogen or one or more C1-C10 alkyl groups substituted thereon, and mixtures thereof, and Y is selected from the group consisting of hydrogen, alkali metal, ammonium, and mixtures thereof, with a sulfonyl halide, a sulfuryl halide, a mixed sulfuryl ester halide, or a mixed sulfuryl amide halide of the formula
(Formula Removed)
wherein X is selected from the group consisting of F, Cl, Br, I, and mixtures thereof, and R14 and R14' are the same or different and each is selected from the

group consisting of alkyl radicals having 1 to 4 carbon atoms, haloalkyl radicals of the formula CnH(2n+1)-wZw wherein n is 1 to 4, Z is selected from the group consisting of F, Cl, Br, I, and mixtures thereof, and w ranges from 1 to 5, and aryl radicals
(Formula Removed)
wherein R15, R16, R17, R18, and R19 are the same or different and are selected from hydrogen and alkyl radicals having 1 to 20 carbon atoms, and mixtures thereof, to yield acyl sulfonate material of the general formula
(Formula Removed)
which is then reacted with a dioxane of the formula
(Formula Removed)
wherein R4, R5, R6, R7, R8, R9, R10, and R1 1 are the same or different and are selected from hydrogen, alkyl and hydroxyalkyl radicals having 1 to 4 carbons to yield
(Formula Removed)
which is then aminated with an alkylamine of the formula
(Formula Removed)
wherein R1, R2, and R3 are as previously defined to yield
(Formula Removed)
which is then hydrolyzed with base to yield
(Formula Removed)
2. The method as claimed in 1 for the synthesis of severely sterically hindered secondary aminoether alcohols using sulfonyl halide of the formula
(Formula Removed)
3. The method as claimed in claim 1 for the synthesis of severely sterically hindered secondary aminoether alcohols using sulfuryl halide of the formula SO2X2.
4. The method as claimed in claim 1 for the synthesis of severely sterically hindered secondary aminoether alcohols using the mixed sulfuryl ester halide of the formula (Formula Removed)

5. The method as claimed in claim 1 for the synthesis of severely sterically hindered secondary aminoether alcohols using the mixed sulfuryl amide halide of the formula
(Formula Removed)
6. The method as claimed in any one of the preceding claims wherein R1, R2 and R3 are methyl radicals.
7. The method as claimed in any one of the preceding claims wherein R4, R5, R6, R7, R8, R9, R10,and R11 are hydrogen.
8. The method as claimed in any one of the preceding claims wherein R15, R16, R18, and R19
are hydrogen and R17 is hydrogen or methyl.
9. The method as claimed in any one of the preceding claims wherein the base is selected from alkali metal hydroxide, alkali metal alkoxide, or alkali metal carbonate.
10. The method as claimed in any one of the preceding claims wherein Y is hydrogen or sodium.
11. The method as claimed in any one of the preceding claims wherein R1 , R2 and R3 are methyl, R4, R5, R6, R7, R8, R9, R10, and R11 are hydrogen, R15, R16, R18, and R19 are hydrogen, R is hydrogen or methyl, and Y is hydrogen, sodium, or ammonium.
12. The method as claimed in any one of the preceding claims wherein the acyl sulfonate is made by reacting organic carboxylic acid or the salt of a carboxylic acid with the sulfonyl halide, sulfuryl halide, mixed sulfuryl ester halide or mixed sulfuryl amide halide at a temperature in the range of between about -20 to 200°C at a pressure between about 1 bar and 100 bars, the acyl sulfonate is reacted with the dioxane at a molar ratio of dioxane to acyl sulfonate in the range of 1:1 to 10:1 at a temperature of between about 50°C to about 200°C to yield a cleavage product, the cleavage product and the alkyl amine reacted at an amine to sulfonate group ratio ranging from about stoichiometric to about 10:1 at pressure of from about atmospheric (1 bar) to about 100 bars at temperature of from about 40°C to about 200°C, and the resulting aminated product is hydrolyzed with base at a temperature from about 20°C to about 110°C.
13. The method as claimed in any one of the preceding claims wherein the organic carboxylic acid or the salt thereof the sulfonyl halide, sulfuryl halide, mixed sulfuryl ester halide or mixed sulfuryl amide halide and the dioxane care combined in a single step to produce a reaction mixture, reaction mixture being heated at a temperature of between about 50°C to about 200°C to produce the cleavage product, the cleavage product and the alkylamine are reacted at am amine to cleavage product ratio ranging from about stoichiometric to about 10:1 at a pressure from about atmospheric (1 bar) to about 100 bars at a temperature of from about 40°C to about 200°C, the resulting aminated product being reacted with base at a temperature from about 20°C to about 110°C.

Documents:

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4238-delnp-2006-abstract.pdf

4238-DELNP-2006-Claims-(30-08-2011).pdf

4238-delnp-2006-claims.pdf

4238-DELNP-2006-Correspondence Others-(22-09-2011).pdf

4238-DELNP-2006-Correspondence Others-(30-08-2011).pdf

4238-delnp-2006-correspondence-others.pdf

4238-DELNP-2006-Description (Complete)-(30-08-2011).pdf

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4238-DELNP-2006-Form-1-(30-08-2011).pdf

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4238-delnp-2006-form-2.pdf

4238-DELNP-2006-Form-3-(22-09-2011).pdf

4238-DELNP-2006-Form-3-(30-08-2011).pdf

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Patent Number

252036

Indian Patent Application Number

4238/DELNP/2006

PG Journal Number

17/2012

Publication Date

27-Apr-2012

Grant Date

23-Apr-2012

Date of Filing

24-Jul-2006

Name of Patentee

EXXONMOBIL RESEARCH AND ENGINEERING COMPANY

Applicant Address

1545 ROUTE 22 EAST, P.O. BOX 900, ANNANDALE, NEW JERSEY 08801-0900, UNITED STATES OF AMERICA.

Inventors:

#	Inventor's Name	Inventor's Address
1	ALAN ROY KATRITZKY	1221 SOUTH WEST 21st STREET, GAINESVILLE, FL 32601, USA.
2	KOSTYANTYN MYKOLAYEVICH KIRICHENKO	999 SOUTHWEST, 16th AVENUE, APT. 28, GAINESVILLE, FL 32601, USA.
3	MICHAEL SISKIN	56 SHONGUM ROAD, RANDOLPH, NJ 07869, USA.

PCT International Classification Number

C07C 213/00

PCT International Application Number

PCT/US2005/003052

PCT International Filing date

2005-02-01

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	60/545,118	2004-02-17	U.S.A.