Title of Invention

METHOD OF MAKING N-[2-AMINOETHYL] AMINOALKYLALKOXYSILANES WITH ETHYLENEDIAMINE SALT RECYCLE

Abstract

LA method of preparing; Q3-|>T-(2-aniinoethyl)]axninoalkyl- . ataysilan© of the formula,, R'RZNCH,CH2JN<R3R\ in. which. RJ, Rz and R* iridopoiidently HUB d member, salfioled, from the group ccuwlntkig of A hydrogen atom or an aikoxysilane of the formula, R'Si(&!)^(OR\ , in which. Rs, R', n»d RT arc each independently CM alkyi and a is 1, 2, or 3, and R'1 is a said aikoxysilane, said method comprising; adding ethylenediamine, ethylenediamine hydrochloride salt, and co-chloroalkylaUcoxysilane of the forrhuja, ClR^SiOR^.^OR^, as defined above, to a reactor at a feed ratio of 340 moles total eraylenediamine per mole ofjj co-chloroaliylalkoxysilane under reaction conditions to produce a said o3-j>T-(2-aiaJiioethyl)}amhoalkylalko?^sUane; the proportions of ethylenediamine and ethylenediamine hydrochloride salt being such that a phase containing said salt is present in said reactor separate from a phase. &#9632; &#9632; . &#9632; i , I . • ' • containing said co-[N-(2-arnmoemyl)|arnboall{yl-alkoxysilane» and following said reaction. separating said salt containing phase from said aikoxysilane containing phase, and returning at least a portion of said salt containing phase to said reactor; as a source of a portion of said emylenediarnine and the source of said ethylenediamine hydrochloride salt.

Full Text

FORM 2 THE PATENTS ACT, 1970 (39 of 1970) COMPLETE SPECIFICATION (See Section 10, rule 13) METHOD OF MAKING N-[2-AMINOETHYL] AMINOALKYLALKOXYSILANES WITH ETHYLENEDIAMINE SALT RI DOW CORNING CORPORATION of 22 00 W. SALZBURG ROAD, MIDLAND, MICHIGAN 48686-0994, U.S.A., AMERICAN Company The following specification particularly describes the nature of the invention and the manner in which it is to be performed : - [OOOlj • Tills invention relates to liie preparation of a-j;N-(2'-nnimoBthyl)) amuioalJkylalkoxysilanes'. More specifically, this invention relates to the preparation of such silanes by reaction of co-chlbroalkylaikoxysilane with i excess ethylenediamine utilizing a recycled ethylenediamine hydrochloride ; salt phase stream, . BACKGROUND OF THEirNVENTION [0002] As is weU lenovm, co-[N-(2- aminoethyl)jaminoalkylalkox}'silanes have the general formula, R'R^NCHiCHaNR^4' in which R\ R2; and R3 independently are a member selected from the group consisting of a hydrogen atom or an alkoxysilane of the formula: in which RJ, Rf, and R7 are each independently C,.B alkyl (including straight chain or branched alkyls) and a is 1, 2, or 3. R4 is a said alkoxysilane. The D-[^-(2-airh^oethyl)]arnkoalkylallcoxysilanes are widely used as silane coupling agents and are effective for various polymer property modification purposes, for example, irhproving adhesion at an organic- i inorganic interface. [0003J These compounds are synthesized by fitting tt-ehlopoallcyl alkoxysilao.es with ethylenediamine to form CD-[N-(arm^oethyI)]anunoalkyl-alkoxy silanes. StoichiometricaUy, this method uses one mole of OD-chlotoalkylalkoxysilane and two moles of emylenediarnine for synthesizing one mole of »-I]N-(2~aminoe&yl)]aimaoal]^Ialkoxysflane) with oue mole of j ethylenediamjjie monohydrochloride being formed at the same t&oae, as ; shown by.the following reaction scheme, 1 ClK5Si(Rc)>5(OR7)a + 2NH2CH2CHjNHi. KH2CH2CH2NHRiSi(R6)3.l(OR7)1 + NH2CH2CH2NB3+Cr [0004] In the above equation R5 is any alJcyl group and each of R6 ax»d R7 Is ii.n alkyl radical having 1 to 8 carbon atoms and a Is equal to 1, 2, or 3, [0005] ' In reality, the end product co-[N-(2^ j ' 1 amiaoethyl)]arrjinoalkylalkoxy- silane further reacts with the starting ! reactantso-chloroalkylalkoxysflane and ethylenediamiae to form poly- r . ■ | ■ alkylated! products as shown; below, | .ClR5Si(R*)3.a(OR7)a + m1CB1CH2mRsSi(^)u(OR\ + > NH2CH2CH2NH2-> NH2CH2CH2N[R5Si(R6)j.i(OR7)J2{or (OR7)J(R6)3.a SiR5NHCHzCH2NHR5Si(R6)3.1(OR7)J + NHiCH2CH2NH3+Ci" [0006] This di-alkylated ethylenediarnine continues to react with co- chloroalkylalkoxysilane and ethylenediarnine to form the tri-alkylated product as shown below: NHaCHjCH^CR^iCR^CQR'JJ^or (OR7),^. aSiR5NHCH2CH2NHRJSi(Rfi)3,s(OR7)4} + ClR'SiCRVCOR7), + NH2CH2CH2NHZ -» (OR7X(R5)3.ISiRsNHCH2CH2N[R5Si(Rs)3.4(OR7)J2 + NH2CH2CH2NH/C1- [0007] Theoretically, this process continues until a nexa-alkylated etiaylenediarnine product is formed, but in actuality only the mono-, di-, and tri-alkylated .products axe seen in detectable'levels using gas chromatography analysis. i J [0008] I In. general, a present method for preparing o-[N'-(2- aminoethyi)] sininoalkyl-alkoxysilanes'iu a continuous flow process is as follows. • [0009] An ethylenediamine stream is co-fed to a reactor wiu\an chloroahcylalkoxysUarie stream of the formula: ciRsSi(R^(OR7X ; [0010] as defined above, at a feed ratio of 3-20 moles of ethylenediamine per mole of cD-chloroalkylalkoxysilane. The optimum molar feed ratio of 'J ethylenedi | died. Typically the molax feed jne to alkoxysilane is dependant upon the specific alkoxysilane ratio just inside the single phase region is f optimum, but also depends upon the desired level of polyalkylated ; I' i i e&ylenediamines in the product. \ [0011] The ethylenediamine and co-chlproalkylalkoxysilane react as described above. A single phase effluent stream from, the reactor . i, - | (continuous stirred tank reactor, plug flow?reactor, or combination of the two), which is a mixture of ethylenediamine, alcohol, co-[N- (2-annnoemyl)]arninoalkylalkoxysilane, and ethylenem'amine monohydrochloride, is passed to a stripping and/or distillation column. In the stripping column enough ethylenediamine is removed overhead to induce a phase separation in the material remaining in the column into .two liquid phases. [0012] The alcohol mentioned above is generated in a side reaction between extraneous water impurity that enters with both the emylenediarnine and th^ alkoxysiiane feeds. The side reaction is shown below, where b is equal to or less than a and a h equal to 1, 2, or 3. . :5i(R%a(OR7)a + b*H20 -> -$i [0013] J The two-phase effluent stream from the distnlationcoluron is passed to a phase separator (gravity, mechanical, electrical, etc,) where the denser phase which is a mixture of ethylenediamine and e&yleuediamine || monohydrochloride is removed. [0014] The lighter silane phase effluent stream, from the phase separator which is mainly a mixture of ethylenediamine, alcohol, and 3-[N-(2-aniinoelhyl)]aminoalkylallcoxysiiane, is passed to a second distillation • column where the arnmoemyiaminoalikylalkoxysilane is purified. The emylenediarnine and alcohol are removed from the top of the column and recycled to an ethylenediamine purification column that may also treat ixicoming eraylenedtamine. The aminoethylaminoalkoxysilane stream is sometimesj further purified in a stripping, distillation, or flash system to reduce Had level of poly-aHcylated ethylenemamine, . £00153 The ethylenediamine overhead stream and new ethylenediamine are also directed to the ethylene purification distillation column where (alcohol is jiremoved. J 1 [0016] I While producing a high yield of high quality alkylated ethylenediamines the prior process requires, as described above, that the . contents of the reactor, the reaction mixture, be passed through a distillation column for removal of a substantial amount of ethylenediamine. The distillation operation, was required before the residual reaction mixture could be separated into a product rich phase for product isolation and purification. It would be more efficient and economical to have a process in which the reaction mixture comprises two phases so that the product rich phase could be obtained without a preliminary distillation step and use of distillation equipment for that purpose. It is an object of this invention to provide such a process. SUMMARY OF THE INVENTION [00X7] I The reaction between two moles of emylenediamine and one mole of a suitable ffi-chloroaUcylalkoxysilane produces an Q-[N-(2-arnmoemyl)]aminoallO'lalk'Oxysilane and a mole of ethylenediamine hydrochloride. As stated above a considerable excess of erhylene&araine is used to suppress the formation of polysilaiie, i.e., poly-all^laEST ' " ethylenediarhine, containing products. Therefore, in a continuous process utilizing this practice, the excess ethylenediamiae must be separated from the product stream and recycled to the reactor. In accordance with this . . Invention, the: byproduct emylenediajmine hydrochloride salt is\aiso recycled to the reactor in sufficient quantity to produce two liquid phases in the reactor and in the stream flowing from it. «?T«T*r«»«*3(*«re»>sts: [0018] The two liquid phase effluent from the reactor is a mixture of co-[N stliylenodlmpic hydrochloride, and oxtruueotw alcohol. The fitrcam is first inducted ti a phaso aepuuiLlMi vciflpl raliei' than to u dtollllnflrm' tclum' upon phase separation, th6 top 'bulk phase contains predominantly silane and sthylenediamine. The heavier bulk phasi contains predominantly sthylenediakine hydrochloride and ethyienediamine. The heavier phase is recycled to the reactor in sufficient quantity to maintain the two phase system in the reactor and used to control the degree of polyalkylation. The balance 3f ths heavier phase is removed from the process. ' [0019] _ The lighter phase is transferred to_a purification system consisting )f a distillation and/or a flash system where m-P^~(2-aniinoethyl)]amino-ilkylalkoxysilane(s) is purified by removal of the lower boiling species. rhus, the silane product is recovered in good yield and.quality while the imylenediamine is further purified by a second distillation and returned to he two phase system reactor. $920] j The reaction is preferably conducted at a temperature in the range if about 60° to 200°C. The.rnoiar ratioFof total emylenediamins to the IkoxysUane nftbe reactor, including the ethylenediamme hydrochloride ecycle, is at least 3 to 1 and no greater than 40 to 1. 0021] j The process of this invention is particularly useful in the oaiinfacture of 3-IK-(2-airrmoemyl)]arrhnopropylallc:oxysilanes and 3-[N-(2- aminoetbyl)]aminoisobutylall^lalkoxysilanes. For example, 3-[N:(2* aminoethyl)]aaiinopropyltriiDjethoxysilane (or -triethoxysilahe) or 3-[N-(2-.;amiaoe%l)]aifiinoisobutylmetiiyldiniethoxysilane (or -metiryldiethoxysilaiie) can be made in high yield and quality. Depending upon product requirements these silanes can be made substantially us the mouo-atkylated • ethylenediarniaes or as mixtures' of predominately the mouo-apcylated .product with some amounts of the di-and tri-alkylated products, BRIEF DESCRIPTION OF THE DRAWING •' [0022) iFigure 1 is a flow diagram of, the process of this Invention fui ' producing to- |>I-(2-aminoethyl)3aLrrjj^oallcylalk:oxysilaries. DESCRIPTION OF A PREFERRED EMBODIMENT [0023] (This invention provides a novel and improved method of ! producing co -2-aminoethyl)3amitioalkylalkoxysilanes such that the , I number of required processing steps is reduced, The method is suitable for ' i ' preparing an Q-[N2-ammoethyl)laminoalkylaJl;u_xysiIane of the general : formula; ; ;._ : R'R*NCH2CH2NR3R4 J ; in which R1, R1 and R5 independently are a member selected from. the group consisting of a hydrogen atom or an alkylalkoxysilane of the formula: l P/Si(Rs),iORin which R5, R6, and R7 are each independently CM alkyl and a is 1, 2, or 3, R* is a said alkylaflcoxysilane, [0024] J The process comprises the establishment of a two-phase reaction • i system. Ethylenediamine is fed to a reactor with a chloroalkylalkoxysilane of the formula, ClR5Si(R6)3.a(OR7)a, as defined above. At a suitable I. i temperature of, for example, 60° to 200°C the diamine and chloroallryl- alkoxysilane react to form a desired silane product and ethylenediamine monohydrochloride salt. In accordance with this invention this byproduct salt is recycled to the reaction mixture in sufficient amount to cause the formation of a salt rich phase that is separable from the silane product containing phase. The.ethylenediamine salt recycle allows the control of the formation of poly-alkylated ethylenediamine. In the case of a reaction mixture for producing 3-I^(2-anu^oethyl)]amhiopropyltrimethoxysilaneI for example, about 1 to 15 moles of ethylenediamine salt in the recycled salt phase reactor effluent per mole of silane product is suitable for forming the two phase mixture in the reactor. [0025] By forming the two phase reaction mixture, a product rich phase can be gravity, mechanically, or electrically separated from the ethylenediamine hydrochloride phase without an intervening distillation [operation, j i f i [0026] Referring to Figure 1, ethylenediamine (flow stream 12), ethylenediamine salt phase (flow stream 14), and a 3-cMoroaIkyIaIkoxysilane f . ' I (flaw stream 16) of the formula: f f I [0027] : as defined above, are co-fed to reactor 10 at a feed ratio of 3-40 moles total ethylenediamine per mole of chloroalkylalkoxysilane. Trie proportions of ethylenediamine, stream 121 and ethylenediainrne hydrochloride, stream 14 are such that a distinct phase, rich in the hydrochloride, is present in reactor 10. It is generally preferable that the molar feed ratio of ethylenediamine to Ethylenediamine hydrochloride be in the range of about 1 to 20, the optimum depending on the alkoxysilane used, when the desired product is predominately a monc-aliylated ethylene diamine. ; [0028] ; The two liquid phase effluent (flow stream 18) from the reactor, I which is predominantly a mixture of ethylenediarnme o-[N-(2- ,'j [ ammoethyl)]ammoalkylalkoxysilane, and ethylenediamine mono- • -I hydrochloride, is passed to a phase separator vessel 20 where the bottom phase (stream 22) •id: .split, iuto a relatively oaiall purge ctatarn (stream ?.4) and i a recycle stream 14 that is fed back to the reactor 10. Recycle stream 14' typically contains both ethylenediamine and its hydrochloride salt. The proportions depend upon the combination required for 'separation from the silane product containing phase. The amount of recycle is determined experimentally to produce the two-phase reactor system and-.efflueht and to control the degree of pofyalkylatian. ;, [0029J The top phase effluent (stream 26) from phase separator 20; which is predominantly a mixture of ethylenediamine-and. co-[N-(2- an^oemyl)]aminoalkylalkoxysilans, is passed to a purification system 28 where the ta-P^-(2-ammoemyl)]ammoalkylalkoxyszlane is purified to varying levels. {Predominantly ethylenediamirie (stream 32) is removed from the silane via the top of column 28 and recycled back to a ethylenediamine purifica'tion column 34. The silane product is removed from the bottom of the column, stream 30. f ! i [0030) [ In addition to the recycled ethylenediamine stream (1), a fresh ethylenediamine stream (stream 36) is fed to the system, preferentially through the emylenediamine purification column 34 where low boiling impurities/byproducts (stream 38) are removed as the overhead stream. The purified emylenedjamiae (stream 12) is then fed to the two-phase system reactor' 10. [0031] As stated, a preferred application for the process of this invention is in the production of HjNCHjCHjhrHR^iR^.^OR2), where R1 is a propyl or isobutyl group, R2 and R3 are each independently methyl or ethyl groups, and a is 1, 2, or 3. Sometimes it is desired to produce essentially all mono- alkylated efaylenediamine or mixtures of different degrees of polyalkylation. Example Using the process equipment shown in Figure 1, 3-[N 2- ! ammoemyl)Jaiumopropyltnmethoxy^iIaDe was prepared by reacting [0032; ethylenediamine, 3-chloropropyltrirneti.oxysiiane, and ethylenediamine ' monobydrochloride at a ratio of 12 moles to 1 mole to 1.9 moles , respectively, at 105° C with a 68 minute residence time in the reactor. Titration analysis of the purified silage product stream for free amine showed the reaction to be at 99.1 % conversion, [0033] :. In the operation of the two-phase reactor 10, recycle stream 14 provided the recycled ethylenediamine monohydrochloride at the above stated rate of 1.9 moles per mole of 3-cMoropropyltrimethoxysIJajae fed to the reactor. In this example, recycle stream 14 also contained about sixty i . • percent of, the ethylenediamine supplied to reactor 10. [0034] I The yield of 3-[N-(2-amii oethyl)]aminopropylD:iiuethoxysilane (per mole of 3s±loropropyltrimetiiotysilane charged to the reactor) obtained using the salt recycle'and the separate salt phase in the reactor was the same as obtained from the prior art practice of adding only salt free ethyleriediarnine to the reactor. ' [0035] [ In the application of the invention to the preparation of a specific | if ~ co-[N-(2-aminoethyl)] aminoail reactor proportions of ethylenediaroine (EDA), ethylenediamine monohydrochloride (EDA HCl) and the ©-cbJoroalkylalkoxysuane precursor to achieve both a desired overall EDA molar ratio and sufficient EDA HCl . to obtain the two-phase system. • :, ' [0036] The invention has been described in terms of some examples and preferred embodiments. However, ,one skilled in the art could readily make additions and modifications in view of the teaching of this specification. Accordingly, the scope of the invention is to be considered limited only by the following claims. LA method of preparing; Q3-|>T-(2-aniinoethyl)]axninoalkyl- . ataysilan© of the formula,, R'RZNCH,CH2JN iridopoiidently HUB d member, salfioled, from the group ccuwlntkig of A hydrogen atom or an aikoxysilane of the formula, R'Si(&!)^(OR\ , in which. Rs, R', n»d RT arc each independently CM alkyi and a is 1, 2, or 3, and R'1 is a said aikoxysilane, said method comprising; adding ethylenediamine, ethylenediamine hydrochloride salt, and co-chloroalkylaUcoxysilane of the forrhuja, ClR^SiOR^.^OR^, as defined | i I '*-—— above, to a reactor at a feed ratio of 340 moles total eraylenediamine per . I! . j | mole ofjj co-chloroaliylalkoxysilane under reaction conditions to produce a said o3-j>T-(2-aiaJiioethyl)}amhoalkylalko?^sUane; the proportions of ethylenediamine and ethylenediamine hydrochloride salt being such that a phase containing said salt is present in said reactor separate from a phase. ■ ■ . ■ i , I . • ' • containing said co-[N-(2-arnmoemyl)|arnboall{yl-alkoxysilane» and following said reaction. separating said salt containing phase from said aikoxysilane containing phase, and returning at least a portion of said salt containing phase to said reactor; as a source of a portion of said emylenediarnine and the source of said ethylenediamine hydrochloride salt. 2. A method as ekliytnajin claim 1 in which said to--chloroalkylalkoxysilane is 3-chloropropylaIkoxysilane or 3~ cbloroisobutyialkylaltoxysilane, j , i . ■ ! ! 3. A method asd1^*-^ in claim 1 in which said a>~ chloroaikylalkoxysilane is. 3^hIoropropyltrmiethoxysiiane or 3-chloroisbutylmethyldimethoxysilaiie. . 4. A method asMri any of claims 1-3 wherein the molar ratio of total ethylenediaminb to co-chloroalkylalkoxysilane is in the range of 6 to 1 to 30 to 1. 5, A method of preparing HiNCHsCHzNHR'SiR^.^COR2), where R1 is a propyl or isobutyl group, R* and R5.ore each independently methyl or ethyl groups, said method comprising;; adding ethylenedJamine, ethylenediamine hydrochloride salt, and S'Cl-R'SKOR^j, with R1 and R2 as defined above, to a reactor at a feed ratio of 12-30 moles total ethylenediamins per mole of said S-Cl-R^iR^OR*), under reaction conditions to produce a said HiNCHjCHjhTHR^iR^j^OR2), ; the proportions ofethylenediamine aid emylenediarhine hydrochloride salt being such that a phase containing said salt is present in said reactor separate 1 from a phase containing said H»NCH2CHiNHRlSi R30.»(0Rl)». aQd ' ■ v ■• i f following said reaction i | J separating said salt containing phase from said H^NCHzCEiNHR^iCOR3^ containing phase, and . returning at least a portion of said salt containing phase to said reactor as a source of a portion of said echylenediamine and the source of ■ said ethylenediamiiiehydrochloride salt'; ij 7. A method asfcl^uwitn claims 5 or 6 comprising returning said salt containing phase to said reactor in the amount of about 1 to 15 moles oif said salt per mole of said 3-Cl-R'Si(OR2)3 fed to said reactor. Dated this 28th day of July, 2004.

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411-mumnp-2004-claims(granted)-(28-07-2004).doc

411-mumnp-2004-claims(granted)-(28-07-2004).pdf

411-mumnp-2004-correspondence(05-12-2004).pdf

411-mumnp-2004-correspondence(ipo)-(05-02-2007).pdf

411-mumnp-2004-drawing(28-07-2004).pdf

411-mumnp-2004-form 1(25-11-2004).pdf

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411-mumnp-2004-form 19(28-07-2004).pdf

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