CA1214778A

CA1214778A - Amphotensides with increased storage stability

Info

Publication number: CA1214778A
Application number: CA000377290A
Authority: CA
Inventors: Uwe Ploog; Gunter Uphues; Manfred Petzold
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 1980-05-13
Filing date: 1981-05-11
Publication date: 1986-12-02
Also published as: MX156685A; BR8102948A; DE3161875D1; EP0040346A1; DE3018201A1; AU541532B2; ES8203830A1; ES502137A0; JPH0249299B2; JPS5716846A; EP0040346B1; ATE5815T1; AU7051181A

Abstract

ABSTRACT OF THE DISCLOSURE

This invention relates to a process for refining the crude condensation product of aminoalkylalkanolamines of the formula H2N-(CH2)m-NH-(CH2)n-OH
wherein m is an integer of from 2 to 6 and n is 2 or 3, and fatty acids having from 6 to 22 carbon atoms, which comprises the step of subjecting the crude condensation product to alkaline hydrolysis.

Description

12~4778 This invention relates to the refining of the crude con-densation products of aminoalkylalkanol amines. More parti-cularly, this invention relates to the refining of such condensation products and the preparation OL ampho~ensides with increased storage stability.

An important process for the preparation of amp~otensid2s starts with condensation products of N~monosubstituted alkyl-enediamines that are alkylated in an additional reaction wi~h alkylating agents, for example, sodium chloroacetateO Also, produc~s based upon N-aminoethylethanolamines and fatty acids are important as tensides that protect the skin.

The preparation of such compounds is kno~Jn principally from U.S. Patents Nos. 2,528,378, 2,528,379, and

2,528,3~0. While it had previouslv ~een assumed that alkylation or quaternization products of imidazoli.ne were formed in this procedure, proof is avail--able nO~.J that the products are mainly alkylation ox quater~
zation products of aminoamides that are form~d by hydrolys.is ~,j~
." --1--~21477~3 of the imidazoline intermediate in the aqueous medium. Re-erence should also be made to, for example, German Published .
Application (DE-AS) No. 1,084,414.

The preparation of such tensides primarily involves the condensation o approximately 1 mol of fatty acid ox fatty acid mi~ture with one mol of an aminoalkylalkanol~mine -- pax-ticularly aminoethylethanolamine -- with a gradual increase in th~ temperature and, finall~, under ~acuum. ~his conden-sation product is then converted into the amphotenside ~Jith variahle amounts of an alkylating agent, for exampler sodiurn _. , , !
chloroacetate, usually in an aqueous al~aline solution.
Details for these steps of the process are ound in the patents men~ioned above as well as in Dr. K Lindner, "Tenside-Tex~ilhilfsmittel-~1asshrohstof~e", Wissenscha~t-liche Verla~s GmbH, Stuttgart, lg64, pages 1041 and 1042, German Published Application (DE-OS) No. 27 52 116, published European Patent Application No. 001,006, and U.S. Paten~s Nos. 2,773,068, and 3,4~,3610 The quality of the amphotensides obtained, an~ particu-larly their storage stability, are dependent upon the purity of the imidazoline derivative obtained in the first conden-sation step. The reaction between fatty acids and amino-~;~1477~3 alkylalkanolamines proceeds toward more than merely theformation of the desired imidazoline derivative, and multiple secondary reactions complicate the reaction process. The significance of this aspect has been emphasized again recently. For example, in E. G. Lomax, "New and Improved Balanced Amphoterics", Manufacturing Chemist and Aerosol News, Vol. 50, No. 8, August 1979, pages 39 and 41, it is disclosed t~at the undesirable secondary reactions in the step of the imidazoline formation can be suppressed withan excess of aminoethylethanolamine but that this excess must be removed by distillation at the end of the reaction. How-ever, aminoethylehtanolamine itself can introduce new dif-ficulties by cyclization to the piperazine.
The purity of the imidazoline obtained in the first reaction step has a decisive influence on the storage stability of the amphotensides obtained by subsequent aklyla-tion of their aqueous solutions. Even minor impurities lead to the separation of a solid phase, in the form of turbidity or sediments, after a shorter or longer storage period. Such products are not suitable for practical application or are at the least of limited value.
It is an object of the invention to provide an improved process for refining the crude condensation products of aminoalkyla}kanolamines.
It is also an object of the invention to provide amphotensides that have increased storage stability.
It is a further objectof the invention to provide a process for the refining of the crude condensation products of aminoalkylalkanolamines of the formula H2N-(CH ) -NH (CH ) OH

- 3 -wherein m is an intege ~ o ~ ~rom 2 to 6 and n is 2 or 3, with fatty acids having from about 6 to 22 carbon atoms, wherein the crude condensation product is subjected to alkaline hydrolysis.
These and other objects of the invention will become more apparent from the description below.
Applicants have surprisingly developed a procedure for obtaining a condensation product that is as pure as possible, that does not employ the circuitous routes now used. According to the invention, it is possible to eliminate interfering by-products in the simplest possible manner by introducing a simple refining step for the primarily obtained condensate.
Applicants have found that the crude condensation product of fatty acids and aminoalkylalkanolamines can be converted into a purified product by a simple alkaline hydrolysis and that this procedure yields improved amphotensides with particularly increased storage stability upon subsequent alkylation and, optionally, quaternization.
Accordingly, the invention relates to a process for the refining of the crude condensation product of aminoalkyl-alkanolamines of the formula H2N-(CH2)m-NH-(CH2)n-OH (I) wherein m is an integer of from 2 to 6, particularly 2, 3, or 6, and n is 2 or 3, particularly 2, with fatty acids having from about 6 to 22 carbon atoms, wherein the crude condensation products of aminoalkylalkanolamines and fatty ~r

- 4 -77~
acids are subjected to alkaline hydrolysis. The invention also relates to the subsequent alkylation and, optionally, quaternization of the refined condensation product into amphotensides with increased storage stability.
In the process according to the invention, the amount of alkali used in the alkallne hydrolysis preferably is adjusted to the amount of diamide of the formula R-co-NH-(cH23m-N-co-R (II) (cH2)n-oH
wherein m and n are as defined above, present in the crude condensate. The amount of alkali in this process step is especially preferably chosen so that it is present in a quantity at least approximately e~uimolor to the diamide in th~ c~u~e condellsation product.

~ n underlyi.n~ basis of ~he invention is th~t the con-tenk of inker~-ering ~y-products in the inished tensi~e,s , .
can be significantly reduced ~7hen the condensation product of fatty acid and amine'is subj~cted to an al~aline pretrea~-ment in ~n aqueous medium prior to a further reac~ion~
~xperiments have particularly demonstrated that the diamide formed duriny the xe~ction is cleaved quarti.ta-tiv~ly ~t thc tertiary amide yxoup ~y aquevus alkali solution to ~o~m the monoamide o~ tl~e primaxy amino group and fatty acid~ The fatty acid ~orn~s soap in the re~ininc~ treatment accordiny to e invention, which soap may remain in the xeaction mix-ture~

... . .
'~ Xt is actually very surprising that the di~ficulties with respeck to the storaye stabi.li,ky o~ the amphotensides ulti.ma~ely obkained, which so ~ar cou~.d be corrected only with relati~ely costl.y refirling steps, are ~limin2tea ~y the intermediary treatrnent accordinc3 to -the inv~ntion. Con-siderin~ the fact. that ~he alkylatiorl and, option~ally, ~uaternization of the reaction product o~tained in the first step are carried out in the aqueous al}~aline medium -- ~or example, ~ h sodium chloroacetate ~- and that t}le tempera-ture and alkalini.ty conditions of the process are chosen SG
~hat they are at least comparablP ~o the cond~tion~ o~ the intermediate step accord~n2g to the invention, this result is the more surprising~ It could not be expected that the separate alkaline hydrolysis according to the invention of the crude condensation product from the first process step could yield bet~er results than a corresponding aqueous-alkaline treatment during the course of the alkyla-tion or quaternization of the condensation product.
However, the alkaline pretreatment according to the invention results in products that remain clear, even after dilution, for more than six months. Costly refining steps such as recovery of the excess amine or distillation of the imidazoline are no longer necessary.
The alkaline hydrolytic treatment according to the invention preferably takes place in the temperature range of from about 70 to 100C, especially in the temperature range of from about 80 to 90C. Particularly suitable as alkalies are alkali metal hydroxides, especially sodium hydroxide. The amount of alkali is preferably in the range of from about l to 3 times the equimolor alkali require-ments, based on the diamide present in the condensation product. Preferably alkali amounts in the range of from about 1 to 2 equivalents, based on the diamide, are used.
The crude condensation product is advantageously suspended in an amount of water corresponding to from about 0.~ to 10 times, especially from about 1 to 5 times, the quantity of ,.

.

crude condensation product for the alkaline hydrolysis according to the in~Jention. The ac~ueous alkaline hydro--lysis is allowed to continue ~ the practically complete removal of the diamide, which is present as by-product.
The diamide content of the crude product and its decrease during the treatment according to the invention can be determined by a kno~n method, for example, by working with ion exchangers.

Th arninoalkylalka-nolamines used according to the in-vention are those of Formula II. The compound aminoethyl-ethanolamine is the starting amine of Formula II that has ~he ~reatest practical significance. l~he fatty acids used for the condensation have frc,m ahout 6 to 22 carbon atoms, prefexably from about 8 to 18 carbon atoms. The f~tty acids may be pxesent-as pure cornponenl:s or a~ mixture3 of fatty acids having diferent chain lengths. They may be natl1ral and/or synthetic in origin.

The conclensation product pret~eated by al3~aline hydro-lysis according to the invention is then converted to the finished amphotenside by a known method. Such methods are described in the references cited above.

~z~,~778 , ` ` - - . `;

The pretreatment accoraing to the invention is valuable no-t only for the preparation of the so-called i3,~ida~01inium tensides but for other tensides as well. Clear products with a long s~orage life are also obtained by the conver-sion of the al~aliwtreated condensation products o amines ith alkylatiny ag~nts o~ such as chlorohydroxypropanesul-fonic acid or propanesulfone, as well as by alkylation with vinyl group--containing compollnds such as acrylic.acid or acry.lic acid es~er, with subs~quen~ saponification and ~-ac.rylamido-2-Tnethylpropanesulfonic acid ox the correspondir,g alkali metal salts.

' The amphotensides may contain alkylaL~ea and optional].y quaternary nitrogen formed in the second reaction step, depending on the structure and the cdegree of c03lversion~
Another embodimcnt of the invention includes the prepa~a-tion of such arnphotensicles with the use of a product that has been treated by t'~le d~scribed alXalin~ h~drolytic pJ:O-cess according to the invention~

The ~ollowiny examples are intended to illustrate the invention and shoula not be construed as ]imiting the inven-tion thexeto. The percentages given in the examples are in percent ~y weight, based on the weigh. o~ the total con~.len-sation procluc~. Th~, clia~rli(lc~ con-tent W,clS dete~!nilled in the followirly manner:

1;~14~8 . ~ . ~ . -~ `1 The condensation produc-t in the fo~rn of an alcoholic so?ution was led over a highly acidic ion exchang~-resin.
The t~luate was evaporated, an~ tht-~ ratio of the residue to. .
the weiyhed-in-amount o~ condensation product introaucecl was determined. The amoun~ of diamide was calcualted ~rom the aeterminakion of the acid numb r and the total nitro~en. -E X ~ M P T, E S

Condensation Products of Fatty Acids with ~minoethylethanol-amine : . ... . .. ..

Example 1 ~ olar ratio of 1:1 ~ n a three-neck flask with agitator, ni.t.rogen inle~
therm~meker~ and distillation attachmerlt, 208 gm (.1 mol) of C8/1~ coconut ~il aci.d ana 10~ ym (.1 mcJl~ of ~minoeth~l-ethanolamine were mi.x~d and slowly heated to 200 C, over a period of appxo~imately SiY. hours. A~t~x a total of 20 gm o~ wa~er containing amine ~Jas distil.led ~f, approximakel~i 290 gm o a slo~Jly conyealiny, y~llo~7 mass ~7ért-~ obkained, ~7hich had the followiny analytical data:
Acid No : .:2.8 NKj : 9.5~

tit~ .7%
Diamid~ cont-.~nt 16~ (= 0.0~ mol/100 gm).
A UV--~pectxoscopy analy.c..is at- 230 mm ind;.ca-tea an im;da~o-line con~ent o 8.0%.

.

Example 2 - Molar ratio 1~

Following the procedure described for Example 1, 208 gm (1 mol) of coconut oil acid were condensed with 114.5 gm (1.1 mol) of aminoethylethanolamine. Approximately 300 gm of a slowly congealing, yellow mass were obtained, which had the following analytical data: !

Acid No. : 2.3 Kj : 10,2%

titr. : 5.6%
Diamide content : 10.7~ (= 0.02 mol/100 gm) Imidazoline content : 3.0%

Example 3 - Molar ratio of 1:1.5 In accordance with the procedure described for Example 1, 208 gm (1 mol) of coconut oil acid were condensed with 156 gm (1.5 mol) of aminoethylethanolamine with slow heating, so that the content of free amine remained as high as possible during the reaction. The reaction tempera-ture at the end was up to 180C, at approximately 14 mbar.
After the excess amine was distilled off, approximately 270 gm of residue were left, which had the following analytical data:

NKi : 10.3%

titr. : 5.2%
Diamide content : 2.7% (= 0.006 mol/100 gm) Imidazoline content : 96%

` ~Z1~77~3 Reactions with~ Sodi.~n Chloroacetate __ Example 4 - Without alkaline pretreatment .

~ dispersion was prepared ~Jith 90 c~m (Ø3 mol, calcula-ted f~om Ntitr ) f product from Example 1 in 148 gm o~
water and reacted ~Jith 203 gm (0.7 mol) o~ freshly prepared 40% solution oE sodium ch],oroacetate, at 60 C. The pH rose to 11.52 upon the addition of 56 gm (0.7 mol) of 50% sodi~
hydroxide solution. The miY~ture was agitatf~d for -t~70 hours at that temperature, which was then increased to 80 C fox one hour. The p~l slowly dropped to about 10. The approxi-mately 40% solids pxoduct bec~an to become ~urbi,d ~fte~ t~70 '-days at roor~ tem~erature, Examr~le 5 - Without alka].inc,~ ~xet.reatrnCIlt A dispersion was prepared with ~0 ~m ~0.3~ mol, calcu-lated f~o~l Ntitr ) of pxoduct from Exam,ole ~. in i3~ gm cJE
water and reacted with ~14 ~m (0~7~ ~.o].) of a :Ere~hly pre-pared 40% sodi.um chloroacet.ate solution, at 60 C. Then, 58.8 gm (0.74 mol) of 50~ sodium hydroxide solution were O O
added at 60 C. The mixture was kept at 60 C for two houl^s, and then the temperature was increased to 80 C~ The p~l rose to 11.5 after the addition of the~ so~ium hydxoxicl~
soluti.on and dropped slow].y to 10.1 ~ ter orle hour of heat-ing at 80 C.

7~, A clear solution with a solids content of approximately 40% was obtained, which solution began to become turbid after only two days at room temperature, however.

Example 6 - Without alkaline pretreatment -A dispersion was prepared with 90 gm (0.3 mol) of imidazoline from Example 3 in 134 gm of water. This was kept at 60C for one hour and then reacted with 203 gm (0.7 mol) of a freshly prepared 40% sodium chloroacetate solution. Next, 56 gm (0.7 mol) o~ 50% sodium hydroxide solution were added, whereupon the pH rose to 11.6. The mixture was agitated at this temperature for two hours and for an additional hour at 80C. After approximately 10 weeks of storage at room temperature, the first signs of turbidity appeared.

Example 7 - With alkaline pretreatment A dispersion was prepared with 90 gm (0.3 mol, calCulated from Ntitr ) f product from Example 1, which contained 0.035 mol of diamide, in 148 gm of water, reacted with 1.2 gm (0.015 mol) of 50% sodium hydroxide solution, and agitated for one hour at 80 to 90C. Then the process was continued as described in Example 4, the product obtained being as clear as that obtained in Example 4. However, the product also became turbid after six days because not all the diamide was saponified.

~ ~Z1477~
I

Exam~le 8 - Wi~h al'~aline pretrea~m~'nt .. _ I

Th~ procedure of Example 7 ~,7as repeated with the exception that ~.8 gm ~,0.06 mol) of 50% sodium hydroxide solution wer~
reacted with the product ~rom Exampie 1. The diamide was quantitatively saponified to the monoacyl product, as was also apparent from the analysis. The product remained clear for more than six months.

F.~amp3,e ~ - With al}~aline pretreatment --A di.spersion was prepared with 80 gm (,0.32 mol) o ~ro-~uct from Exa~nple 2 i.n 60 ~n of ~7ater, reac~ed with 4.8 ~m (0.''06 mol) of 50% sodiurn hydroxide solution, ar~d ayitated O
for one hour at 80 C. After further conversion accoxd.i.nc~
to the procedure describe~ in Exarnple 5, a.tenside -.,as oh-tained that rernained clear for mor~ tslan six m~nchs.

It is apparent from ~xamples 4 to 6 as ~lell as Examples ?
to 9 that even the use of a very pure imidazolin~ in the firs~ step (.see Example 6) does not result in th~ ilnpro~J~-men~ of the quality, such as is obtained ~Jith startin~
materials rich in diami.de (~xamples 1 ana 2), ater al~aline pretreatment. ~dvantageously sodium hydroxide is used in an amollnt that i5 at least equivalent, bllt prefera~ly approximately double, the quantity nece~sary on t~e ~asis of the diami~e conterlt.

12~477~3 Re~ctions with 2-Acrylt~nido~2-methylpropanesulfonic acid (AMPS) Ex~nple 10 - ~Jithout al~a].ine pretreatment A suspension ~s prepared with 75,0 gm (0.3 mol, calcula-ted from Ntitr ) ~f produc~ from Ext~mple 2. in 200 gm of ~laterand reacted with 80 . 6 g (0. 39 mol) AMP5 and then ~ith 31.2 g~n tO.39 mol) or 50% sodium hyd~oxide solution. '~he mixture ~ s agitated for four hours at 80 C. The finish2d product was a clf~ar, thin 1iquid; ho~7ever, precipitatior~ was notlced aftex t'~70 days .

ExaTnpl~ Wi~h alk21ine pretreatment ,~ suspension was prepared wi~h 75. ~ ~m (0 . 3 mol~ o~ pro duc~ f~o.n E~arnp3.~ 2 in 200 grn OL water and agit2tea ~or one .hour ~7ith ~.8 gm (Ø~6 mol~ of 50~-t?; sodium h~dxo~id2 sol~ti.on at 80 to 90 C. Furth~r convcrsion pro_eed~d as in EY~am-ple lO. rrhe product remained completely clear ~ven af~er morc than six months.

eaction~ ~ith Chloroh-ydroxypropanesul~onic acici (Sodiun s~

Example 12 - ~ithout alkaline pretr~atmen~
.

A dispersion prepared from 75 gm (0.3 mol) of product .~rom Exarnple 2 in 200 ml o wa~er ~as reac-~ci ~lith G3.6 cJin (0.3 mol) of chlorohyaro~ypropa3-les~lfollic acid (sodiuTn s~
~ox 30 minutes at 80 C, and with ~.0 cJm (0.3 mol) o-~ SQ'~
~ocdi~lm hydroxidc solution. The mixt~lre ~as then ac~it~:ecl ~or ~our hollrs at 50 C. The end procluct ~as c~ear, but b~-cam~ turbi~ at~r th~:ee da~s.

- ` ~2~77~

- - - . . ~ . , Exa~nple 13 -- ~.ith_alkcllin~ pretreatment The procedllre of Example 10 ~las ~ollowed, eY~cept that O ~ l th~ suspension t7as. agitatea ~or one hour at 80 to 90 C b~-foxe the ctdditi~n o~ chlorohydroxypropanesulfonic acid ~sodium salt), after the addition of 4.g gm ID.06 mol) of 50% sodium hydroY.;de solution. The product remained clear after moxe than 5iX months.

Rea~tions trïtht Acryl.ic Acia Exc~lple 14 - Without alkaline pretreal~ent __ ,__ _ __ __ Seventy-~ive g~ams (0 3 mol) of product from ~xampJ.e 1 and 21.6 ~m (Ø3 Inol~ vf acrylic acid ~7ere mixecl ~na acjita-ted fox one hour at 80 C and then dilu..e~ with 145 g~t of - ~dter. rne product began to b~comQ turDicl af~er t-/c~ week~.

EY.~mple 15 - ~ith al~alin2 pr~treatment .
Seventy-five ~ramx (0.3 mol) OI product from EY.a~.P1C , ~nd 4.8 gm (0.06 mol) of 50~ sodium h~droxide solution ~ere a~itated for one hour at 80 C and the trea~ed furth2r according to the procedure of Example 14. The product remained clear for more than six months.

The preceding specific embodymellts are illust.rative of the practice of the invention~ It is to be understood, however, that other expedients ~nown to those s~illed in the axt or discloscd herein, may be employed without departing from th~ sp:irit of the inventlon or the scope of the appendecl claiMs.

Claims

The embodiments of the invention in which an ex-clusive property or priviledge is claimed are defined as follows:

1. A process for refining the crude condensation product of 1 mol of an aminoalkylalkanolamine of the formula H2N-(CH2)m-NH-(CH2)n-OH
wherein m is an integer of from 2 to 6 and n is 2 or 3, and 1 mol of a fatty acid having from 6 to 22 carbon atoms or a mixture of said fatty acids, which comprises the step of subjecting the crude condensation product to alkaline hydrolysis.

2. The process of Claim 1, wherein m is 2, 3, or 6.

3. The process of Claim 1, wherein n is 2.

4. The process of Claim 1, wherein the amount of alkali used in the alkaline hydrolysis is in proportion to the amount of diamide present in the crude condensation product.

5. The process of Claim 4, wherein the alkali is used in an equimolar amount.

6. The process of Claim 4, wherein the amount of alkali does not exceed 3 times the molar amount of diamide.

7. The process of Claim 1, wherein the alkaline hydro-lysis is carried out at temperatures of from about 70° to 100 °C.

8. The process of Claim 7, wherein the alkaline hydro-lysis is carried out at temperatures of from about 80°C
to 90°C.

9. The process of Claim 1, wherein a fatty acid having from 8 to 18 carbon atoms or a mixture of said fatty acids is used.

10. A process for preparing amphotensides having increased storage stability which comprises the steps of:

(a) condensing 1 mol of an aminoalkylalkanolamine of the formula H2N-(CH2)m-NH-(CH2)n-OH

wherein m is an integer of from 2 to 6 and n is 2 or 3, with 1 mol of a fatty acid having from 6 to 22 carbon atoms or a mixture of said fatty acids;

(b) subjecting the condensation product of step (a) to alkaline hydrolysis; and (c) subjecting the product from step (b) to alkylation and, optionally, quaternization.

11. A process for preparing a condensation product having a low diamide content which comprises subjecting a crude condensation product comprising a mixture of at least one imidazoline of the formula and at least one diamide of the formula wherein m is an integer of from 2 to 6, n is 2 or 3, and R
is an aliphatic radical having from 5 to 21 carbon atoms, to alkaline hydrolysis whereby the alkali used is used in an amount at least equimolar to the molar amount of diamide.

12. The process of Claim 11, wherein m is 2, 3, or 6.

13. The process of Claim 11, wherein n is 2.

14. The process of Claim 11, wherein the molar amount of alkali does not exceed 3 times the molar amount of diamide.

15. The process of Claim 11, wherein the alkaline hydrolysis is carried out at temperatures of from about 70° to 100°C.

16. The process of Claim 15, wherein the alkaline hydrolysis is carried out at temperatures of from about 80° to 90°C.

17. The process of Claim 11, wherein R is an alipha-tic radical having from 7 to 17 carbon atoms.

18. In a process for preparing amphotensides which comprises (a) condensing an aminoalkylalkanolamine of the formula H2N-(CH2)m-NH-(CH2)n-OH

wherein m is an integer of from 2 to 6 and n is 2 or 3, with at least one fatty acid having from 6 to 22 carbon atoms to produce a crude condensation product comprising a mixture of at least one compound of the formula and at least one diamide of the formula wherein m and n are as defined above and R is an aliphatic radical having from about 5 to 21 carbon atoms, and (b) subjecting the crude condensation product from step (a) to alkylation and, optionally, quaternization;
the improvement which comprises subjecting the crude condensation product from step (a) to alkaline hydrolysis whereby the alkali used is used in an amount at least equimolar to the molar amount of diamide, prior to step (b).