Title of Invention	"PROCESS FOR THE COPRODUCTION OF NONCYCLIC CARBONATES AND OF FATTY NITRILES AND/OR AMINES"
Abstract	The invention is targeted at a joint process for the production of fatty nitrites and/or amines and of dialkyl carbonates of formula RiO-CO-ORi, in which Ri comprises from 1 to 4 carbon atoms, from an ester of a saturated or unsaturated fatty acid resulting from natural oils, comprising the following zones: I) zone of synthesis of a nitrile/amine comprising the following stages: a) optional conversion first of all by hydrolysis of the ester of the fatty acid resulting from an oil of natural origin to give a fatty acid, with simultaneous production of the alcohol RiOH, which is recovered and sent to the zone III, followed, in b), by an ammoniation with ammonia of the fatty acid resulting from stage la and/or of the ester of the fatty acid to give a nitrite, respectively producing an ammonia/water mixture and/or an alcohol/ammonia/water mixture, which are conveyed to the zone IV, then followed, in c), by a hydrogenation of the nitrite resulting from stage b), optionally in the presence of ammonia, which converts the nitrite to the corresponding amine, II) zone of synthesis of a monoalcohol carbonate by reaction of urea with the alcohol R1OH, the reaction of said alcohol with urea also producing ammonia, III) zone of recovery and purification of the alcohol R1OH, which acts as feed for the zone II, IV) zone of recovery of the ammonia resulting from the zones I and II, to act as feed for the ammoniation of stage b and optionally the hydrogenation of stage c in the zone I.

Title of Invention

"PROCESS FOR THE COPRODUCTION OF NONCYCLIC CARBONATES AND OF FATTY NITRILES AND/OR AMINES"

Abstract

The invention is targeted at a joint process for the production of fatty nitrites and/or amines and of dialkyl carbonates of formula RiO-CO-ORi, in which Ri comprises from 1 to 4 carbon atoms, from an ester of a saturated or unsaturated fatty acid resulting from natural oils, comprising the following zones: I) zone of synthesis of a nitrile/amine comprising the following stages: a) optional conversion first of all by hydrolysis of the ester of the fatty acid resulting from an oil of natural origin to give a fatty acid, with simultaneous production of the alcohol RiOH, which is recovered and sent to the zone III, followed, in b), by an ammoniation with ammonia of the fatty acid resulting from stage la and/or of the ester of the fatty acid to give a nitrite, respectively producing an ammonia/water mixture and/or an alcohol/ammonia/water mixture, which are conveyed to the zone IV, then followed, in c), by a hydrogenation of the nitrite resulting from stage b), optionally in the presence of ammonia, which converts the nitrite to the corresponding amine, II) zone of synthesis of a monoalcohol carbonate by reaction of urea with the alcohol R1OH, the reaction of said alcohol with urea also producing ammonia, III) zone of recovery and purification of the alcohol R1OH, which acts as feed for the zone II, IV) zone of recovery of the ammonia resulting from the zones I and II, to act as feed for the ammoniation of stage b and optionally the hydrogenation of stage c in the zone I.

Full Text	PROCESS FOR THE COPRODUCTION OF NONCYCLIC CARBONATES AND OF FATTY NITRILES AND/OR AMINES The invention is targeted at a joint process for the synthesis, on the one hand, of fatty nitriles and/or amines and, on the other hand, of monoalcohol carbonates starting from fatty esters resulting from natural oils. Current developments as regards the environment have the consequence of favoring, in the fields of energy and chemistry, the exploitation of natural starting materials originating from a renewable source. These environmental constraints also stipulate the avoidance of the transportation and storage of dangerous starting materials. An example of an industrial process using a fatty acid as starting material is that of the manufacture of fatty nitrites and/or amines from fatty acids extracted from vegetable or animal oils. This process is described in the Kirk-Othmer Encyclopedia, Vol 2, 4th Edition, page 411. The fatty amine is obtained in several stages. The first stage consists of a methanolysis or a hydrolysis of a vegetable oil or of an animal fat, respectively producing the methyl ester of a fatty acid or a fatty acid. The methyl ester of the fatty acid can subsequently be hydrolyzed to form the fatty acid. Subsequently, the fatty acid is converted to a nitrite by reaction with ammonia and, finally, to an amine by hydrogenation of the nitrite thus obtained. The preparation of fatty amines from fatty acids via a nitrite dates from the 1940s. The reaction scheme for the synthesis of the nitrites can be summarized in the following way. There exist two types of processes based on this reaction scheme: a liquid-phase batch process, which is carried out by Ceca, and a vapor-phase continuous process. In the batch process, the fatty acid or a mixture of fatty acids is charged with a catalyst which is generally a metal oxide and most frequently zinc oxide. The reaction medium is brought up to approximately 150°C with stirring and then the introduction of gaseous ammonia is begun. In a first step, an ammonium salt or ammonium soap is formed. The temperature of the reaction medium is subsequently brought to approximately 250-300°C, still while introducing ammonia. The ammonium salt is converted to an amide with release of a first water molecule. Then, in a second step and with the help of a catalyst, the amide is converted to a nitrile with formation of a second water molecule. This water formed is continuously removed from the reactor by entraining the unreacted ammonia and a small amount of fatty chains among the lightest. Passing through a dephlegmator returns the fatty compounds to the reaction medium while the aqueous ammoniacal liquors are conveyed to a system for recovery of the ammonia, which can be recycled. The reaction is finished when the acid functional group is no longer present and when the content of amide is in accordance with the specifications. In the continuous process, the reaction takes place in the vapor phase at high temperature levels and generally over a fixed bed of doped or undoped alumina. The advantage of the batch process is that of resulting in purer nitrites as they are generally distilled, whereas this is not the case in the continuous process. On the other hand, the continuous process is more advantageous when nitrites comprising unsaturated or polyunsaturated fatty chains are involved, these compounds being thermally more sensitive than compounds comprising saturated fatty chains. This is because, in this process, the residence time is short and the iodine number, reflecting the number of insaturations, is better retained. The stage of synthesis of the fatty amines consists of a conventional hydrogenation of the fatty nitrites. There are many catalysts but, preferably, Raney nickel or Raney cobalt is used. In order to promote the formation of the primary amine, the operation is carried out with a partial ammonia pressure, whereas, in the case where it would be desired to obtain a secondary amine, a partial ammonia pressure is not applied and, if possible, the ammonia formed during the reaction is removed. Numerous patent applications describe the conditions for carrying out the synthesis of fatty acid nitrites or fatty amines from fatty acids or fatty acid esters. Mention may be made, for example, of the document JP 2000-16977, which describes the synthesis of nitrites from fatty acids by using a catalyst comprising niobium oxide at a temperature of 260°C in the case of stearic acid. The document JP 2000-7637 describes the synthesis of nitrites from methyl esters of saturated or unsaturated and linear or branched fatty acids comprising from 6 to 22 carbon atoms and from ammonia at a temperature ranging from 180 to 350°C in the presence of a catalyst of niobium oxide type. Patent US 6 005 134, describes a process for the synthesis of aliphatic nitrites from C6-C22 carboxylic acids, from alkyl esters of C6-C22 carboxylic acids or from triglycerides, the reaction with ammonia being carried out in the presence of a catalyst comprising at least titanium. However, the results obtained indicate lower yields starting from esters or from triglycerides, in comparison with the acids. In patent JP 10-195035, a catalysis comprising zirconium oxide doped with iron results in excellent nitrite yields but the authors mention the presence of light amines related to the formation of methanol in the case of the methyl esters. The process for the synthesis of fatty nitrites and/or amines, operated industrially for several decades starting from fatty acids, is satisfactory by and large. However, there are a number of disadvantages to it. The main disadvantage is that the implementation thereof is in practice subject to access to a specific starting material, in particular ammonia, which requires expensive storage and operating precautions. When a fatty acid methyl ester is used as fatty acid source for the process for the synthesis of fatty nitrites and/or amines, the process produces byproducts, which have to be recovered separately, in particular methanol during the stage of hydrolysis of the ester. This methanol is generally treated in order to be recycled in order to carry out the stage of methanolysis of a natural oil, resulting in the fatty acid methyl ester. There exist several known routes for the synthesis of the carbonate of monoalcohols, such as dimethyl carbonate of formula CH3O-CO-OCH3 (DMC) or diethyl carbonate (C2H50-CO-OC2H5). The oldest industrial processes use phosgene as starting material, which reacts with the alcohol in a concentrated sodium hydroxide medium, this reaction occurring in two successive stages, with formation first of all of a chlorocarbonate and then of the neutral carbonate. These processes exhibit problems of safety, due to the high toxicity of the phosgene, and of the waste formed during the process. Manufacturers then turned toward oxidative carbonylation processes or processes for the transesterification of ethylene carbonate. Oxidative carbonylation processes with the oxidative pair CO + O2 have been developed, either in the liquid phase or in the gas phase. For the liquid phase, mention may be made of the Enichem process, patents EP 534 545 and US 5 210 269, carried out in two stages in the presence of copper chloride as catalyst. For the gas phase, mention may be made of the Ube process, patent US 5 885 917, which uses NO as active agent with a palladium catalyst, which process comprises two stages with methyl nitrite as intermediate product. Dialkyl carbonates can also be prepared by transesterification of alkylene carbonates with the corresponding alcohol. Many companies have worked on this type of reaction. Mention may be made of patents US 3 642 858 and US 3 803 201 of Dow, which describe a process for the transesterification of alkylene carbonates with non-tertiary hydroxyl compounds in the presence of alkaline catalysts. Bayer has developed a similar process using a thallium catalyst (patent US 4 307 032). Texaco provides, for its part, soluble catalysts based on zirconium, titanium and/or tin salts (patent US 4 661 609) or based on trivalent sulfur or selenium compounds (patent US 4 734 518). Finally, more recently, Nippon Shokubai describes the use of supported catalysts of rare earth metal oxides (US 5 430 170). In application WO 2004/091778, Mitsubishi describes a synthesis of dialkyl carbonates using supercritical C02 and a solid heterogeneous acidic catalyst in order to react the C02 with acetone dimethyl acetal. The methods for the synthesis of dialkyl carbonates include the reactions of urea with monoalcohols. The carbonation reactions using urea have already been described for monoalcohols, for example by Shaikh and Sivaram, Organic Carbonates, Chem Rev., 1996, 96, 951, and Ball et al., Synthesis of carbonates and polycarbonates by reaction with urea with hydroxy compounds, Mol. Chem., 1984, vol.1, pp 95-108. M. Wang et al., in Catalysis Communication, 7 (2006), 6-10, describe the synthesis of dimethyl carbonate from methanol and urea over basic solids. This reaction comprises two stages, with the intermediate formation of methyl carbamate, itself converted to dimethyl carbonate. Unfortunately, while the first stage makes it possible to obtain good results, the second is much more problematic, with side reactions, and, in this case, the selectivities of the overall reaction remain low. 61 In a patent, US 5 902 894, Catalytic Distillation Technologies describes a process for the synthesis of DMC using organic solvents with high boiling points and electron donors; for example, triethylene glycol dimethyl ether, in combination with a tin catalyst, made it possible to obtain good yields of and good selectivities for DMC, extraction by continuous distillation of the DMC formed being carried out. Analogously, Exxon, in patent application WO 95/17369, minimizes the formation of the byproducts by an extractive distillation of the dialkyl carbonate. Finally, more recently, Chinese patent application CN 1431190 (Shanxi Institute) describes a process for the synthesis of DMC from methanol and urea using catalysts based on tin and on a cocatalyst. In the process for the synthesis of fatty nitrites and/or amines, it is necessary to import and store large amounts of ammonia, which represents, in addition to the problem of the transportation, a major risk in the event of escape, not only for the personnel but also for the neighborhood. This storage consequently imposes major constraints on the site on which this type of process is operated. The problem to be solved is that of limiting these environmental risks while maintaining the performance of the process or even better still while improving it. The invention is thus targeted at a joint process for the production of fatty nitriles and/or amines and of monoalcohol carbonates from a saturated or unsaturated fatty acid ester resulting from natural oils, in which the same fatty acid ester acts as starting material for the synthesis of nitriles and/or amines, on the one hand, and of monoalcohol carbonates, on the other hand. The monoalcohol carbonates are synthesized by the action of urea on the monoalcohol, and the ammonia produced by this reaction is used as reactant for the ammoniation stage during the synthesis of the fatty nitriles and/or amines. The invention is targeted at a joint process for the production of fatty nitriles and/or amines and of monoalcohol carbonates of dialkyl carbonate type of formula R1O-CO-OR1, in which R1 comprises from 1 to 4 carbon atoms, from an ester of a saturated or unsaturated fatty acid resulting from natural oils, comprising the following zones: I) zone of synthesis of a nitrile/amine comprising the following stages: a) optional conversion first of all by hydrolysis of the ester of the fatty acid resulting from an oil of natural origin, of formula R-COOR1, in which R is a saturated or unsaturated alkyl radical comprising from 7 to 21 carbon atoms, preferably from 11 to 17 carbon atoms, and R1 is an alkyl radical comprising from 1 to 4 carbon atoms, to give a fatty acid of formula R-COOH, with simultaneous production of the alcohol R1OH, which is recovered and sent to the section III, followed, in b), by an ammoniation with ammonia of the fatty acid resulting from stage a) and/or of the ester of the fatty acid of formula R-COOR1, to give a nitrile, respectively producing an ammonia/water mixture and/or an alcohol/ammonia/water mixture, which are conveyed to the zone IV, then followed, in c), by a hydrogenation of the nitrile resulting from stage b), optionally in the presence of ammonia, which converts the nitrile to the corresponding amine, II) zone of synthesis of a monoalcohol carbonate by reaction of urea with the alcohol RiOH, the reaction of said alcohol with urea also producing ammonia, III) zone of recovery and purification of the alcohol R1OH, which acts as feed for the zone II, IV) zone of recovery of the ammonia resulting from the zone II and that resulting from the zone lb, where the reaction is carried out with an excess of ammonia, and optionally that resulting from the zone Ic, to act as feed for the ammoniation of stage lb and optionally the hydrogenation of stage Ic of the zone I. The process of the invention is described with reference to the simplified appended scheme in figure 1, taking as example the synthesis of DMC from the methyl ester of a fatty acid which can be obtained directly by methanolysis of a vegetable oil. It is obvious that exactly the same process can be employed with fatty acid esters, such as ethyl, propyl, isopropyl or butyl esters, making possible the synthesis, besides the nitrile/amine, of diethyl carbonate, dipropyl carbonate, di(iso)propyl carbonate, di(tert-butyl) carbonate or di(iso)butyl carbonate. In the case where the ester to be treated is not commercially available, it is naturally possible to esterify beforehand the fatty acid resulting from the natural oil. The zone I is fed via the line 1 with a fatty acid ester, the acid originating from a natural oil, of formula R-COOR1, in which R1 is a methyl, ethyl, propyl, butyl or isopropyl radical and R is a saturated or unsaturated alkyl radical comprising from 7 to 21 carbon atoms, preferably from 11 to 17 carbon atoms. In the zone la, the fatty acid ester is converted to a fatty acid R-COOH by hydrolysis with water introduced via the line 2, simultaneously producing the alcohol R1OH, which is recovered and sent to the section III via the line 14. The fatty acid resulting from the zone la and/or the fatty acid ester introduced via the line 1 are introduced into the zone lb, where they are subjected to an ammoniation reaction with excess ammonia introduced via the line 3, respectively producing an ammonia/water mixture and/or an alcohol/ammonia/water mixture, which are conveyed to the zone IV via the line 8 for purification, according to the following reaction processes: The fatty nitrile formed in zone lb is subsequently transferred into zone Ic, where it is subjected to a hydrogenation with hydrogen introduced via the line 4, optionally in the presence of ammonia introduced via the line 9, in order to obtain the primary fatty amine, according to the following reaction process: The ammonia is recycled via the line 12 and conveyed to the section IV for purification and the fatty amine is extracted from the zone I via the line 6. The alcohol RiOH resulting from zone la is sent via the line 14 to the section III and the alcohol resulting from the zone IV of purification is sent via line 5 to the section III. A back-up line 13 can in addition introduce alcohol directly into the section III. This alcohol, after purification, acts as feed via the line 17 of the zone II for the reaction with urea, introduced via the line 7, to form the carbonate of the alcohol RiOH, according to the following reaction process: The carbonate of the alcohol RiOH synthesized is extracted from the zone II via the line 10 and the ammonia formed is sent to the zone IV via the line 11. The zone IV comprises, in addition to the ammonia feed lines 11 and 12 and the feed line for an alcohol/ammonia/water and/or ammonia/water mixture 8, a back-up line 16 which makes it possible in particular to supply the ammonia necessary for the start-up of the unit and for its regulation in the event of variation in the production of ammonia in the zone II. The ammonia resulting from the zone lb is directed to the zone IV via the line 8 and the alcohol possibly present in this stream is separated and conveyed, with the water produced in zone lb, to the section III via the line 5. The process is particularly well suited to the synthesis of fatty amines and dimethyl carbonate from methyl esters produced by methanolysis of the triglyceride. The various reactions will be as follows: The conditions for carrying out the various stages of the zones I and II are known to a person skilled in the art. However, it may be specified that: - the hydrolysis reaction of stage a) of the zone I is carried out, for example, at ambient temperature or at a higher temperature, - the ammoniation of stage b) of the zone I, resulting in the nitrile, is carried out at a temperature of 150 to 400°C and preferably at a temperature in the vicinity of 300°C, - the hydrogenation of stage c) in the zone I, resulting in an amine, is carried out at a temperature ranging from 80 to 170°C, preferably in the presence of ammonia to form the primary amine, - the conversion of the alcohol RiOH to give dialkyl carbonate, carried out in the zone II, is, as was indicated above, a reaction which has been known for several years. The solution selected for carrying out the process is the reaction, generally referred to as transesterification, of the alcohol RiOH with urea. This reaction is carried out in the presence of catalysts known per se, for example those described in patents US 6 495 703, zinc oxide, or EP 0 955 298, metal or organometallic sulfates, and preferably tin-based catalysts, such as those described in patents US 5 902 894, WO application 95/17369 or CN 1431190. The zones III and IV are zones of storage and of purification of the alcohol RiOH, on the one hand, and of the ammonia, on the other hand, which are carried out according to techniques well known to a person skilled in the art. The alcohol is, for example, separated from the water by distillation and by drying over molecular sieves. The ammonia is used in the gaseous form. It may be observed that the process can be regarded as having a virtually autonomous material balance, which is exceptional. This is because stage lb produces an amount of monoalcohol which is transferred, after purification, into the zone II to react with urea in the ratio of 2 moles of alcohol per one mole of urea. This reaction for the synthesis of the dialkyi carbonate itself produces two moles of ammonia, the exact amount necessary for the ammoniation of stage lb of the zone I. In addition to the savings brought about, the limitation of the storage of ammonia on the site is beneficial environmentally. WHAT IS CLAIMED IS: 1) A joint process for the production of fatty nitriles and/or amines and of monoalcohol carbonates of dialkyi carbonate type of formula R1O-CO-OR1, in which R1 comprises from 1 to 4 carbon atoms, from an ester of a saturated or unsaturated fatty acid resulting from natural oils, comprising the following zones: I) zone of synthesis of a nitrile/amine comprising the following stages: a) optional conversion first of all by hydrolysis of the ester of the fatty acid resulting from an oil of natural origin, of formula R-COOR1, in which R is a saturated or unsaturated alkyl radical comprising from 7 to 21 carbon atoms and R1 is an alkyl radical comprising from 1 to 4 carbon atoms, introduced via the line 1, to give a fatty acid of formula R-COOH, the water being introduced via the line 2, with simultaneous production of the alcohol R1OH, which is recovered and sent to the zone III via the line 14, followed, in b), by an ammoniation with ammonia, introduced via the line 3, of the fatty acid resulting from stage a) and/or of the ester of the fatty acid of formula R-COOR1, introduced via the line 1, to give a nitrile, respectively producing an ammonia/water mixture and/or an alcohol/ammonia/water mixture, which are conveyed to the zone IV via the line 8, then followed, in c), by a hydrogenation of the nitrile resulting from stage b) using hydrogen introduced via the line 4, optionally in the presence of ammonia introduced via the line 9, which converts the nitrile to the corresponding amine extracted via the line 6, with optional recycling of the ammonia to the zone IV via the line 12, II) zone of synthesis of a monoalcohol carbonate by reaction of urea, introduced via line 7, with the alcohol R1OH, introduced via the line 17, the reaction of said alcohol with urea also producing ammonia, the monoalcohol carbonate being extracted via the line 10 and the ammonia formed sent to the zone IV via the line 11, III) zone of recovery and purification of the alcohol R1OH resulting from the zone la via the line 14 or resulting from the zone IV via the line 5, which acts as feed for the zone II via the line 17, IV) zone of recovery of the ammonia resulting from the zone II via the line 11 and that, via the line 8, resulting from the zone lb, where the reaction is carried out with an excess of ammonia, and optionally that, via the line 12, resulting from the zone Ic, to act as feed, via the line 3, for the ammoniation of stage lb and optionally, via the line 9, for the hydrogenation of stage Ic of the zone I. 2) The process as claimed in claim 1, characterized in that the ester of the charge corresponds to the formula R-COOCH3, which is subjected, during stage la, to a hydrolysis in order to form, at the outlet of the stages of the zone I, a fatty amine of formula R-CH2-NH2 and, at the outlet of the zone II, dimethyl carbonate.

Full Text

PROCESS FOR THE COPRODUCTION OF NONCYCLIC CARBONATES AND OF FATTY NITRILES AND/OR AMINES
The invention is targeted at a joint process for the synthesis, on the one hand, of fatty nitriles and/or amines and, on the other hand, of monoalcohol carbonates starting from fatty esters resulting from natural oils.
Current developments as regards the environment have the consequence of favoring, in the fields of energy and chemistry, the exploitation of natural starting materials originating from a renewable source. These environmental constraints also stipulate the avoidance of the transportation and storage of dangerous starting materials.
An example of an industrial process using a fatty acid as starting material is that of the manufacture of fatty nitrites and/or amines from fatty acids extracted from vegetable or animal oils. This process is described in the Kirk-Othmer Encyclopedia, Vol 2, 4th Edition, page 411. The fatty amine is obtained in several stages. The first stage consists of a methanolysis or a hydrolysis of a vegetable oil or of an animal fat, respectively producing the methyl ester of a fatty acid or a fatty acid. The methyl ester of the fatty acid can subsequently be hydrolyzed to form the fatty acid. Subsequently, the fatty acid is converted to a nitrite by reaction with ammonia and, finally, to an amine by hydrogenation of the nitrite thus obtained.
The preparation of fatty amines from fatty acids via a nitrite dates from the 1940s. The reaction scheme for the synthesis of the nitrites can be summarized in the following way.
There exist two types of processes based on this reaction scheme: a liquid-phase batch process, which is carried out by Ceca, and a vapor-phase continuous process.
In the batch process, the fatty acid or a mixture of fatty acids is charged with a catalyst which is generally a metal oxide and most frequently zinc oxide. The reaction medium is brought up to approximately 150°C with stirring and then the introduction of gaseous ammonia is begun. In a first step, an ammonium salt or ammonium soap is formed. The temperature of the reaction medium is subsequently brought to approximately 250-300°C, still while introducing ammonia. The ammonium salt is converted to an amide with release of a first water molecule. Then, in a second step and with the help of a catalyst, the amide is converted to a nitrile with formation of a second water molecule. This water formed is continuously removed from the reactor by entraining the unreacted ammonia and a small amount of fatty chains among the lightest. Passing through a dephlegmator returns the fatty compounds to the reaction medium while the aqueous ammoniacal liquors are conveyed to a system for recovery of the ammonia, which can be recycled. The reaction is finished when the acid functional group is no longer present and when the content of amide is in accordance with the specifications.
In the continuous process, the reaction takes place in the vapor phase at high temperature levels and generally over a fixed bed of doped or undoped alumina.
The advantage of the batch process is that of resulting in purer nitrites as they are generally distilled, whereas this is not the case in the continuous process. On the other hand, the continuous process is more advantageous when nitrites comprising unsaturated or polyunsaturated fatty chains are involved, these compounds being thermally more sensitive than compounds comprising saturated fatty chains. This is because, in this process, the residence time is short and the iodine number, reflecting the number of insaturations, is better retained.
The stage of synthesis of the fatty amines consists of a conventional hydrogenation of the fatty nitrites. There are many catalysts but, preferably, Raney nickel or Raney cobalt is used. In order to promote the formation of the primary amine, the operation is carried out with a partial ammonia pressure, whereas, in the case where it would be desired to obtain a secondary amine, a
partial ammonia pressure is not applied and, if possible, the ammonia formed during the reaction is removed.
Numerous patent applications describe the conditions for carrying out the synthesis of fatty acid nitrites or fatty amines from fatty acids or fatty acid esters. Mention may be made, for example, of the document JP 2000-16977, which describes the synthesis of nitrites from fatty acids by using a catalyst comprising niobium oxide at a temperature of 260°C in the case of stearic acid. The document JP 2000-7637 describes the synthesis of nitrites from methyl esters of saturated or unsaturated and linear or branched fatty acids comprising from 6 to 22 carbon atoms and from ammonia at a temperature ranging from 180 to 350°C in the presence of a catalyst of niobium oxide type. Patent US 6 005 134, describes a process for the synthesis of aliphatic nitrites from C6-C22 carboxylic acids, from alkyl esters of C6-C22 carboxylic acids or from triglycerides, the reaction with ammonia being carried out in the presence of a catalyst comprising at least titanium. However, the results obtained indicate lower yields starting from esters or from triglycerides, in comparison with the acids. In patent JP 10-195035, a catalysis comprising zirconium oxide doped with iron results in excellent nitrite yields but the authors mention the presence of light amines related to the formation of methanol in the case of the methyl esters.
The process for the synthesis of fatty nitrites and/or amines, operated industrially for several decades starting from fatty acids, is satisfactory by and large. However, there are a number of disadvantages to it. The main disadvantage is that the implementation thereof is in practice subject to access to a specific starting material, in particular ammonia, which requires expensive storage and operating precautions.
When a fatty acid methyl ester is used as fatty acid source for the process for the synthesis of fatty nitrites and/or amines, the process produces byproducts, which have to be recovered separately, in particular methanol during the stage of hydrolysis of the ester. This methanol is generally treated in order to be recycled in order to carry out the stage of methanolysis of a natural oil, resulting in the fatty acid methyl ester.
There exist several known routes for the synthesis of the carbonate of monoalcohols, such as dimethyl carbonate of formula CH3O-CO-OCH3 (DMC) or diethyl carbonate (C2H50-CO-OC2H5).
The oldest industrial processes use phosgene as starting material, which reacts with the alcohol in a concentrated sodium hydroxide medium, this reaction occurring in two successive stages, with formation first of all of a chlorocarbonate and then of the neutral carbonate. These processes exhibit problems of safety, due to the high toxicity of the phosgene, and of the waste formed during the process.
Manufacturers then turned toward oxidative carbonylation processes or processes for the transesterification of ethylene carbonate.
Oxidative carbonylation processes with the oxidative pair CO + O2 have been developed, either in the liquid phase or in the gas phase. For the liquid phase, mention may be made of the Enichem process, patents EP 534 545 and US 5 210 269, carried out in two stages in the presence of copper chloride as catalyst. For the gas phase, mention may be made of the Ube process, patent US 5 885 917, which uses NO as active agent with a palladium catalyst, which process comprises two stages with methyl nitrite as intermediate product.
Dialkyl carbonates can also be prepared by transesterification of alkylene carbonates with the corresponding alcohol. Many companies have worked on this type of reaction. Mention may be made of patents US 3 642 858 and US 3 803 201 of Dow, which describe a process for the transesterification of alkylene carbonates with non-tertiary hydroxyl compounds in the presence of alkaline catalysts. Bayer has developed a similar process using a thallium catalyst (patent US 4 307 032). Texaco provides, for its part, soluble catalysts based on zirconium, titanium and/or tin salts (patent US 4 661 609) or based on trivalent sulfur or selenium compounds (patent US 4 734 518). Finally, more recently, Nippon Shokubai describes the use of supported catalysts of rare earth metal oxides (US 5 430 170).
In application WO 2004/091778, Mitsubishi describes a synthesis of dialkyl carbonates using supercritical C02 and a solid heterogeneous acidic catalyst in order to react the C02 with acetone dimethyl acetal.

The methods for the synthesis of dialkyl carbonates include the reactions of urea with monoalcohols.
The carbonation reactions using urea have already been described for monoalcohols, for example by Shaikh and Sivaram, Organic Carbonates, Chem Rev., 1996, 96, 951, and Ball et al., Synthesis of carbonates and polycarbonates by reaction with urea with hydroxy compounds, Mol. Chem., 1984, vol.1, pp 95-108.
M. Wang et al., in Catalysis Communication, 7 (2006), 6-10, describe the synthesis of dimethyl carbonate from methanol and urea over basic solids. This reaction comprises two stages, with the intermediate formation of methyl carbamate, itself converted to dimethyl carbonate. Unfortunately, while the first stage makes it possible to obtain good results, the second is much more problematic, with side reactions, and, in this case, the selectivities of the overall reaction remain low.
61
In a patent, US 5 902 894, Catalytic Distillation Technologies describes a process for the synthesis of DMC using organic solvents with high boiling points and electron donors; for example, triethylene glycol dimethyl ether, in combination with a tin catalyst, made it possible to obtain good yields of and good selectivities for DMC, extraction by continuous distillation of the DMC formed being carried out. Analogously, Exxon, in patent application WO 95/17369, minimizes the formation of the byproducts by an extractive distillation of the dialkyl carbonate.
Finally, more recently, Chinese patent application CN 1431190 (Shanxi Institute) describes a process for the synthesis of DMC from methanol and urea using catalysts based on tin and on a cocatalyst.
In the process for the synthesis of fatty nitrites and/or amines, it is necessary to import and store large amounts of ammonia, which represents, in addition to the problem of the transportation, a major risk in the event of escape, not only for the personnel but also for the neighborhood. This storage consequently imposes major constraints on the site on which this type of process is operated.
The problem to be solved is that of limiting these environmental risks while maintaining the performance of the process or even better still while improving it.
The invention is thus targeted at a joint process for the production of fatty nitriles and/or amines and of monoalcohol carbonates from a saturated or unsaturated fatty acid ester resulting from natural oils, in which the same fatty acid ester acts as starting material for the synthesis of nitriles and/or amines, on the one hand, and of monoalcohol carbonates, on the other hand. The monoalcohol carbonates are synthesized by the action of urea on the monoalcohol, and the ammonia produced by this reaction is used as reactant for the ammoniation stage during the synthesis of the fatty nitriles and/or amines.
The invention is targeted at a joint process for the production of fatty nitriles and/or amines and of monoalcohol carbonates of dialkyl carbonate type of formula R1O-CO-OR1, in which R1 comprises from 1 to 4 carbon atoms, from an ester of a saturated or unsaturated fatty acid resulting from natural oils, comprising the following zones:
I) zone of synthesis of a nitrile/amine comprising the following stages: a) optional conversion first of all by hydrolysis of the ester of the fatty acid resulting from an oil of natural origin, of formula R-COOR1, in which R is a saturated or unsaturated alkyl radical comprising from 7 to 21 carbon atoms, preferably from 11 to 17 carbon atoms, and R1 is an alkyl radical comprising from 1 to 4 carbon atoms, to give a fatty acid of formula R-COOH, with simultaneous production of the alcohol R1OH, which is recovered and sent to the section III, followed, in b), by an ammoniation with ammonia of the fatty acid resulting from stage a) and/or of the ester of the fatty acid of formula R-COOR1, to give a nitrile, respectively producing an ammonia/water mixture and/or an alcohol/ammonia/water mixture, which are conveyed to the zone IV, then followed, in c), by a hydrogenation of the nitrile resulting from stage b), optionally in the presence of ammonia, which converts the nitrile to the corresponding amine,
II) zone of synthesis of a monoalcohol carbonate by reaction of urea with the alcohol RiOH, the reaction of said alcohol with urea also producing ammonia,
III) zone of recovery and purification of the alcohol R1OH, which acts as feed for the zone II,
IV) zone of recovery of the ammonia resulting from the zone II and that resulting from the zone lb, where the reaction is carried out with an excess of ammonia, and optionally that resulting from the zone Ic, to act as feed for the ammoniation of stage lb and optionally the hydrogenation of stage Ic of the zone I.
The process of the invention is described with reference to the simplified appended scheme in figure 1, taking as example the synthesis of DMC from the methyl ester of a fatty acid which can be obtained directly by methanolysis of a vegetable oil. It is obvious that exactly the same process can be employed with fatty acid esters, such as ethyl, propyl, isopropyl or butyl esters, making possible the synthesis, besides the nitrile/amine, of diethyl carbonate, dipropyl carbonate, di(iso)propyl carbonate, di(tert-butyl) carbonate or di(iso)butyl carbonate. In the case where the ester to be treated is not commercially available, it is naturally possible to esterify beforehand the fatty acid resulting from the natural oil.
The zone I is fed via the line 1 with a fatty acid ester, the acid originating from a natural oil, of formula R-COOR1, in which R1 is a methyl, ethyl, propyl, butyl or isopropyl radical and R is a saturated or unsaturated alkyl radical comprising from 7 to 21 carbon atoms, preferably from 11 to 17 carbon atoms. In the zone la, the fatty acid ester is converted to a fatty acid R-COOH by hydrolysis with water introduced via the line 2, simultaneously producing the alcohol R1OH, which is recovered and sent to the section III via the line 14. The fatty acid resulting from the zone la and/or the fatty acid ester introduced via the line 1 are introduced into the zone lb, where they are subjected to an ammoniation reaction with excess ammonia introduced via the line 3, respectively producing an ammonia/water mixture and/or an
alcohol/ammonia/water mixture, which are conveyed to the zone IV via the line 8 for purification, according to the following reaction processes:
The fatty nitrile formed in zone lb is subsequently transferred into zone Ic, where it is subjected to a hydrogenation with hydrogen introduced via the line 4, optionally in the presence of ammonia introduced via the line 9, in order to obtain the primary fatty amine, according to the following reaction process:
The ammonia is recycled via the line 12 and conveyed to the section IV for purification and the fatty amine is extracted from the zone I via the line 6. The alcohol RiOH resulting from zone la is sent via the line 14 to the section III and the alcohol resulting from the zone IV of purification is sent via line 5 to the section III. A back-up line 13 can in addition introduce alcohol directly into the section III. This alcohol, after purification, acts as feed via the line 17 of the zone II for the reaction with urea, introduced via the line 7, to form the carbonate of the alcohol RiOH, according to the following reaction process:
The carbonate of the alcohol RiOH synthesized is extracted from the zone II via the line 10 and the ammonia formed is sent to the zone IV via the line 11. The zone IV comprises, in addition to the ammonia feed lines 11 and 12 and the feed line for an alcohol/ammonia/water and/or ammonia/water mixture 8, a back-up line 16 which makes it possible in particular to supply the ammonia necessary for the start-up of the unit and for its regulation in the event of variation in the production of ammonia in the zone II. The ammonia resulting from the zone lb is directed to the zone IV via the line 8 and the alcohol possibly present in this stream is separated and conveyed, with the water produced in zone lb, to the section III via the line 5.
The process is particularly well suited to the synthesis of fatty amines and dimethyl carbonate from methyl esters produced by methanolysis of the triglyceride. The various reactions will be as follows:
The conditions for carrying out the various stages of the zones I and II are known to a person skilled in the art. However, it may be specified that:
- the hydrolysis reaction of stage a) of the zone I is carried out, for example, at ambient temperature or at a higher temperature,
- the ammoniation of stage b) of the zone I, resulting in the nitrile, is carried out at a temperature of 150 to 400°C and preferably at a temperature in the vicinity of 300°C,
- the hydrogenation of stage c) in the zone I, resulting in an amine, is carried
out at a temperature ranging from 80 to 170°C, preferably in the presence of
ammonia to form the primary amine,
- the conversion of the alcohol RiOH to give dialkyl carbonate, carried out in
the zone II, is, as was indicated above, a reaction which has been known for
several years. The solution selected for carrying out the process is the
reaction, generally referred to as transesterification, of the alcohol RiOH
with urea. This reaction is carried out in the presence of catalysts known per
se, for example those described in patents US 6 495 703, zinc oxide, or
EP 0 955 298, metal or organometallic sulfates, and preferably tin-based
catalysts, such as those described in patents US 5 902 894, WO application
95/17369 or CN 1431190.
The zones III and IV are zones of storage and of purification of the alcohol RiOH, on the one hand, and of the ammonia, on the other hand, which are carried out according to techniques well known to a person skilled in the art. The alcohol is, for example, separated from the water by distillation and by drying over molecular sieves. The ammonia is used in the gaseous form.
It may be observed that the process can be regarded as having a virtually autonomous material balance, which is exceptional. This is because stage lb produces an amount of monoalcohol which is transferred, after purification, into the zone II to react with urea in the ratio of 2 moles of alcohol per one mole of urea.
This reaction for the synthesis of the dialkyi carbonate itself produces two moles of ammonia, the exact amount necessary for the ammoniation of stage lb of the zone I. In addition to the savings brought about, the limitation of the storage of ammonia on the site is beneficial environmentally.

WHAT IS CLAIMED IS:
1) A joint process for the production of fatty nitriles and/or amines and of monoalcohol carbonates of dialkyi carbonate type of formula R1O-CO-OR1, in which R1 comprises from 1 to 4 carbon atoms, from an ester of a saturated or unsaturated fatty acid resulting from natural oils, comprising the following zones:
I) zone of synthesis of a nitrile/amine comprising the following stages: a) optional conversion first of all by hydrolysis of the ester of the fatty acid resulting from an oil of natural origin, of formula R-COOR1, in which R is a saturated or unsaturated alkyl radical comprising from 7 to 21 carbon atoms and R1 is an alkyl radical comprising from 1 to 4 carbon atoms, introduced via the line 1, to give a fatty acid of formula R-COOH, the water being introduced via the line 2, with simultaneous production of the alcohol R1OH, which is recovered and sent to the zone III via the line 14, followed, in b), by an ammoniation with ammonia, introduced via the line 3, of the fatty acid resulting from stage a) and/or of the ester of the fatty acid of formula R-COOR1, introduced via the line 1, to give a nitrile, respectively producing an ammonia/water mixture and/or an alcohol/ammonia/water mixture, which are conveyed to the zone IV via the line 8, then followed, in c), by a hydrogenation of the nitrile resulting from stage b) using hydrogen introduced via the line 4, optionally in the presence of ammonia introduced via the line 9, which converts the nitrile to the corresponding amine extracted via the line 6, with optional recycling of the ammonia to the zone IV via the line 12,
II) zone of synthesis of a monoalcohol carbonate by reaction of urea, introduced via line 7, with the alcohol R1OH, introduced via the line 17, the reaction of said alcohol with urea also producing ammonia, the monoalcohol carbonate being extracted via the line 10 and the ammonia formed sent to the zone IV via the line 11,
III) zone of recovery and purification of the alcohol R1OH resulting from the
zone la via the line 14 or resulting from the zone IV via the line 5, which
acts as feed for the zone II via the line 17,
IV) zone of recovery of the ammonia resulting from the zone II via the line
11 and that, via the line 8, resulting from the zone lb, where the reaction is
carried out with an excess of ammonia, and optionally that, via the line 12,
resulting from the zone Ic, to act as feed, via the line 3, for the ammoniation
of stage lb and optionally, via the line 9, for the hydrogenation of stage Ic of
the zone I.
2) The process as claimed in claim 1, characterized in that the ester of the charge corresponds to the formula R-COOCH3, which is subjected, during stage la, to a hydrolysis in order to form, at the outlet of the stages of the zone I, a fatty amine of formula R-CH2-NH2 and, at the outlet of the zone II, dimethyl carbonate.

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Patent Number

268807

Indian Patent Application Number

8297/DELNP/2009

PG Journal Number

38/2015

Publication Date

18-Sep-2015

Grant Date

17-Sep-2015

Date of Filing

18-Dec-2009

Name of Patentee

ARKEMA FRANCE

Applicant Address

420, RUE D'ESTIENNE D'ORVES, F-92700 COLOMBES, FRANCE

Inventors:

#	Inventor's Name	Inventor's Address
1	JEAN-LUC DUBOIS	190 RUE DU COTEAU, F-69390 MILLERY, FRANCE
2	JEAN-PHILIPPE GILLET	39 RUE DU GAREL, F-69530 BRIGNAIS, FRANCE

PCT International Classification Number

C07C 253/22

PCT International Application Number

PCT/FR08/050868

PCT International Filing date

2008-05-20

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	0755185	2007-05-22	France