Background of the invention EP-A-0,111,976 and EP-A-0,112,592 relate to zwitterionic poly- amines which are for example obtained by alkoxylation of polyal- kyleneamines such as triethyleneamine or tetraethylenepentamine, quaternization of the alkoxylated polyalkyleneamines and subse- quent sulfation with chlorosulfonic acid in an inert solvent. The inert solvent and hydrogen chloride formed during the reaction must be removed from the reaction product.

Sulfation of alkoxylated amines and alkoxylated polyamines which are not quaternized with sulfating agents such as chlorosulfonic acid or sulfur trioxide is disclosed in DE-A-2,557,563.

According to the method described in U. S. Patent 4,138,371 zwit- terionic monoamines are prepared by reacting 1 mole of the reaction product of an amine having the formula RNH2 with 5 to 50 moles of ethylene oxide, subsequently with 0.5 to 1.0 mole of a quaternizing agent such as dimethyl sulfate or alkyl halides and then reacting the resulting quaternized polyethoxylated monoamine with 0.1 to 2.0 mole of a sulfating agent selected from the group consisting of chlorosulfonic acid, sulfur trioxide, sulfamic acid and sulfuric acid oleum.

During sulfation of ethoxylated compounds 1,4-dioxane is formed as a by-product. For toxicological reasons dioxane should be re- moved from sulfated polyethylene glycols. U. S. Patent 4,285,881 relates to a method for the removal of dioxane from ether sulfa- tes by treating dioxane containing mixtures with water vapor at temperatures of 25-150°C in a falling film stripper. According to other methods dioxane is removed from polyethylene glycolether sulfates under reduced pressure, azeotropically or with zeoli- thes, cf. DE-A-3,126,175, DE-A-3,044,488 and DE-A-3, 740,695. An- other disadvantage of prior art sulfation methods consists in the fact that the reaction products are more or less colored.

It is therefore an object of the invention to provide a process for sulfation of alkoxylated and quaternized polyamines which gi- ves reaction products having a lower content of dioxane and a lo- wer color number than products obtained by prior art processes.

Summary of the invention The above abject is achieved with a process for the production of zwitterionic polyamines by sulfation of alkoxylated and quaterni- zed amines and subsequent neutralization when continuously sul- fating an alkoxylated and quaternized polyamine having at least two tertiary or quaternary amine nitrogen atoms in the molecule and containing at least one quaternized nitrogen atom, in the form of a film having a thickness of from 100 pm to 4 mm in the absence of a solvent with a sulfur trioxide-containing inert gas at a temperature of up to 90°C. The process is preferably carried out in a falling film reactor with a sulfur trioxide/air or nitro mixture. The alkoxylated and quaternized polyamine contains 2 to 10 nitrogen atoms and at least 20 alkylene oxide unts per nitro- gen atom and has a degree of quaternization of at least 80%.

Detailed description of the invention According to the invention alkoxylated and quaternized polyamines having at least two tertiary or quaternary amine nitrogen atoms in the molecule and containing at least one quaternized nitrogen atom are sulfated. The products which are sulfated are, for example, obtained from polyamines having 2 to 10 nitrogen atoms by alkoxylation and quaternization.

Polyamines of particular interest are hexamethylenediamine, bis (hexamethylenediamine and polyetherpolyamines.

The polyetherpolyamines can be linear or branched and contain 2 to 10, preferably 2 to 6 and most preferably 2 to 4 nitrogen atoms and have a molecular weight of from 100 to 800, preferably 120 to 500. The polyetherpolyamines can be described by the fol- lowing formula: H2N- (B-O) m- (D-O) o- (B-O) p-B-NH2 (I) wherein B is a linear or branched C2-to C4-alkylene D is a linear, branched or cyclic C5-to C16-alkylene, C4-to C16-oxaalkylene or C5-to C16-azaalkylen, m is 0-7,

o is 0 or 1, p is 0-6, with the proviso that m+o+p > 1 up to 9.

Examples of compounds of the above formula I are hydrogenated cy- anomethylated C3-to C12-diols. These compounds are obtained by reacting first a diol with formaldehyde and hydrogencyanide and subsequently hydrogenating the addition product in the presence of ammonia. This method of producing amines is hereinafter re- ferred to as aminoethylation. Compounds so produced are espe- cially 1, 9-diamino-3,7-dioxa-nonane, 1, 10-diamino-3,8-dioxade- cane, 1, 12-diamino-3,10-dodecane and 1, 14-diamino-3,12-tetrade- cane.

Other compounds of formula I are a,-diamino polyalkyleneglycols which are obtained by hydrogenation of cyanomethylated poly- alkylene glycols (aminoethylation). Suitable polyalkylene glycols contain preferably 2 to 10 repeating units and are derived from polyethylene glycol, polypropylene glycol, polybutylene glycol and polytetrahydrofurane. The polyalkylene glycols may contain the repeating units in statistical distribution or as blocks. Ex- amples of such compounds are 1,5-diamino-3-oxapentane, 1,8-diamino-3,6-dioxa-octane, 1,11-diamino-3,6,9-trioxa-undecane, 1,5-diamino-1,4-dimethyl-3-oxa-heptane, 1,8-diamino-1,4,7-tri- methyl-3,6-dioxadecane, 1, 9-diamino-5-oxa-nonane and 1,14-diamino-5,10-dioxa-tridecane.

Further compounds of formula I are hydrogenated cyanoethylated C2- to C12-diols which are obtained by reacting a diol with acrylo- nitrile in a molar ratio of about 1 to 2 in a Michael type addition reaction and hydrogenating the Michael addition product thus obtained in the presence of ammonia. This method of produc- ing amines is hereinafter referred to as aminopropylation. Exam- ples of such compounds are 1, 10-diamino-4,7-dioxa-decane, 1, 10-diamino-5-methyl-4,7-dioxa-undecane, 1, 11-diamino-6,6-dimethyl-4,8-dioxa-tridecane, 1, 12-diamino-4,9-dioxa-dodecane and 1, 14-diamino-4,11-dioxa-te- tradecane.

Another group of compounds of formula I are hydrogenated cyanoe- thylated polyalkylene glycols having 2 to 10 repeating units.

These compounds are obtained by reacting a polyalkylene glycol with acrylonitrile according to a Michael addition to acrylo- nitrile in a molar ratio of 1 to 2 and hydrogenating the addition products (aminopropylation). Suitable polyalkylene glycols are specified above. Examples of compounds of this group are 1, 13-diamino-4,7,10-trioxa-tridecane,

1,13-diamino-5,8-dimethyl-4,7,10-trioxa-undecane, 1,16-diamino-4,7,10,13-tetraoxa-hexadecane, 1, 16-diamino-5,8,11-trimethyl-4,7,10,13-tetraoxa-hexadecane and 1, 17-diamino-4,9,14-trioxa-heptadecane.

Other suitable amines of this type are obtained by amination of polyethylene glycol, polypropylene glycol or polytetrahydrofurane containing blockcopolymers containing 7 to 10 ethylene oxide units and 2 to 5 propylene oxide units, i. e. reaction of ammonia with said blockcopolymers under exchange of the OH end groups of the blockcopolymers by NH2 groups.

Aminoethylated, aminopropylated or aminated polyalkylene glycols derived from polyethylene glycol and polyethylene glycol reacted at the endgroups with 1-2 moles propylene oxide or butylene oxide or poly-tetrahydrofuran are preferred. The preferred total number of alkylene oxide units within these polyalkylene glycols is of from 3 to 9 most preferred from 3 to 6.

The polyetherpolyamines can have the formula H2N- (B-O) m-E-(0-B) m-NH2 (II) wherein B is a linear or branched C2-to C4-alkylene, R2 is-H, C1-to C6-alkyl,

and i is 1-4, m is 0-7.

The polyetherpolyamine of formula II is derived from branched structures which can be obtained from polyols having 3 to 6 hydroxy groups such as glycerol, trimethylolmethane, trimethylo- lethane, trimethylolpropane, pentaerythritol, sorbit and mannit, by alkoxylation with 1 to 4 molecules of ethylene oxide, propylene oxide, butylene oxide or their mixtures per OH group in the polyol and subsequent reaction with ammonia in order to con- vert the OH groups into NH groups. Other methods of producing amines having a spacer of formula IV consist either in aminome- thylation or aminopropylation of the above polyols with 3 to 6 hydroxy groups.

Examples of such compounds are the aminated reaction products of 1 mole of glycerol with 3 to 7 moles of ethylene oxide, aminated block copolymers obtained by reacting 1 mole of glycerol with 3 moles of propylene oxide and subsequently with 7 moles of ethylene oxide, aminated reaction products of 1 mole of tri- methylolpropane with 3 to 7 moles of ethylene oxide, aminated reaction products of block copolymers obtained by reacting 1 mole of trimethylolpropane with 3 moles of propylene oxide and further with 7 moles of ethylene oxide, aminated reaction products of an ethoxylated pentaerythrit containing 4 to 8 ethylene oxide units and aminated reaction products of an alkoxylated pentaerythrit containing blocks of 4 propylene oxide units and 8 ethylene oxide units. Of specific interest is an aminated propoxylated trimethylolpropane containing 9 propylene oxide units.

Preferred polyetherpolyamines of formula II are those obtained from glycerol, trimethylolpropane and pentaerythrit. Especially preferred are those obtained by aminopropylation.

The polyetherpolyamines may also be characterized by the formula H2N- (CH2) q-0-E-0- (CH2) q-NH2 (III) wherein

R1 is H, CH3, C2H5 and q is 2 or 3.

Preferred amines of formula V are the reaction products obtained by aminoethylation of glycerol, trimethylolpropane or penta- erythrit or the aminopropylated reaction products of the said al- cohols with the proviso that all OH groups of the polyols are aminoethylated or aminopropylated respectively.

Suitable polyetherpolyamines may for instance have the following formulae

Another description for polyetherpolyamines may be given by the formula H2N- (CH2) q-0-D-0- (CH2) q-NH2 (IV) wherein D is-CH2-CH2-CH2-CH2-,-CH2-CH2-O-CH2-CH2-, -CH2-CH2-CH2-CH2-CH2-CH2-, wherein in formula V, VI and VII q is 2 or 3.

Preferred polyamines of formula IV are bis (aminoethylated) or bis (aminopropylated) alcohols selected from the group consisting of ethylene glycol, propylene glycol, butanediol-1,4, hexane- diol-1,6 and diethylene glycol.

The polyamines can also be derived from linear or branched hydro- phobic polyamines which may be described by the following formu- lae

B is C2-Cl6-alkylene, C5-Cl5-cycloalkylene D is C4-Cl6-alkylene, Cs-Cls-cycloalkylene o is 1 or 2 and p is 3 to 8 wherein in formula VIII R = C1-to C22-alkyl or C7-C22-aralkyl and n = 2 to 6, and a, w-diamines having a spacer selected from the group consisting of C8-to C16-alkylene and C5-to C15-cycloalkylene between the ni- trogen atoms.

Of particular interest are polyamines selected from the group consisting of bis (hexamethylene) triamine, N, N'-bis (3-aminopro- pyl) piperazine, N, N'-bis (2-aminoethyl) piperazine and N, N'- bis (3-aminopropyl) hexamethylenediamine.

Polyamines contain which a C8-to C, 6-alkylene group as spacer are for example 1, 8-diaminooctane, 1,10-diaminodecane and 1,12-diami- nododecane. Examples of suitable polyamines containing the above spacers of formula V-VIII are dipropylenetriamine, tripropyle- netetramine, bis (hexamethylene) triamine, bis (octamethylene) tria- mine, aminoethylpropylenediamine, aminoethylbutylenediamine, ami- noethylhexamethylenediamine, N, N'-bis (aminoethyl) propylenedia- mine, N, N'-bis (aminoethyl) butylenediamine, N, N'-bis (aminoe- thyl) hexamethylenediamine, N, N'-bis (aminopropyl) ethylendiamine, N, N'-bis (aminopropyl) butylenediamine, N, N'-bis (aminopropyl) buty- lendiamine, N, N'-bis (aminopropyl) hexamethylenediamine, N, N'- bis (aminopropyl) ethylenediamine, N, N-bis (3-aminopropyl)-N-methy- lamine, N- (dimethylaminopropyl) propylenediamine, N, N'-dime- thyl-1, 3-diaminopropane, N, N-bis (3-aminopropyl)-N-octylamine and N, N-bis (3-aminopropyl)-N-ethylamine.

Polyamines with spacers consisting of a cyclic C5-to C15-alky- lene group are for example 1,3-cyclohexylenediamine, 4-methyl-1,3-cyclohexylenediamine, 2-methyl-1,3-cyclohexylene- diamine, isophoronediamine and 4,4'-diamino (biscyclohexy- lene) methane.

Polyamines which contain other cyclic spacers are, for example, o-, m-, and p-di (aminomethylen) benzene, N, N'-bis (aminoethyl) pip- erazine, N, N'-bis (aminopropylpiperazine and N-aminopropylpipera- zine.

Preferred polyamines contain 2 to 6 nitrogen atoms in the mole- cule. Examples of such compounds are ethylenediamine, propylene- diamine-1,3, butylenediamine-1,4, neopentyldiamine, hexa- methylenediamine-1,6, diethylenetriamine, tetraethylenepentamine, 2- (ethylamino) ethylamine, 3- (methylamino) propylamine, 3- (cyclo- hexylamino) propylamine, 3- (2-aminoethyl) aminopropylamine, 2-diethylamino) ethylamine, 3- (dimethylamino) propylamine, dime- thyldipropylentriamine, 4-aminoethyloctane-1, 8-diamine, 3- (diethylamino) propylamine, N; N-diethyl-1, 4-pentanediamine, ami- noethylpiperazine, aminopropylpiperazine, N, N-bis (aminopropyl) he- xylamine, N, N,-dimethyldipropylentriamine, N, N-bis (3-dimethyl- aminopropyl) amine, N, N'-1, 2-ethanediylbis- (1, 3-propanediamine), N- (aminoethyl) piperazine, N- (2-imidazole) piperazine, N-ethylpipe- razine, N- (hydroxyethyl) piperazine, N- (aminopropyl) piperazine, N- (aminoethyl) morpholine, N- (aminopropyl) morpholine, N- (amino- ethyl) imidazole, N- (aminopropyl) imidazole, N- (aminoethyl) hexa- methylenediamine, N- (aminopropyl) hexamethylenediamine, N- (amino- ethyl) ethylenediamine, N- (aminopropyl) ethylenediamine, N- (amino- ethyl) butylenediamine, bis (aminoethyl) hexamethylenediamine and bis (aminoethyl) ethylenediamine.

Suitable polyamines as starting materials for the production of- zwitterionic polyamines are in addition to the above polyamines condensation products which are obtainable by reacting (i) an aliphatic or araliphatic monoamine or a polyamine contai- ning 2 to 5 primary, secondary or tertiary nitrogen groups with (ii) a crosslinker selected from the group consisting of epihalo- hydrins, polyglycidyl ethers with 2 to 4 glycidyl groups, po- lyhalohydrins with 2 to 4 halohydrine groups, dicarboxylic acids, their esters chlorides, amides or anhydrides, diiso- cyanates, urea and melamine,

in a ratio (i) : (ii) of from 20 : 1 to 1 : 1 with reference to molar amounts of amino groups in the amines of (i) and molar amounts of reactive groups in the crosslinker of (ii), resulting in the formation of a crosslinked polyamine having a molecular weight of from 150 to 1,500.

Suitable amines (i) for the preparation of the condensation products are for example primary C1-to C22-alkylamines, C7-to C22-aralkylamines, C6-to C22-cycloalkylamines, monohydroxy-C2- to C4-alkylamines, dihydroxy-C2-to C4-alkylamines trihydroxy-C2- to C4-alkylamines, linear or branched C2-to C12-alkylenedia- mines, C8-to C22-aralkylendiamines, C7-to C22-cycloalkylenedia- mines, a,-polyetherdiamines containing 1 to 10 alkoxy units be- tween the nitrogen atoms and linear or branched polyalkylenepoly- amines having 2 to 4 C2-to C12-alkyleneamine units.

Examples for the above groups of amines are methylamine, ethyl- amine, propylamine, butylamine, octylamine, 2-ethylhexylamine, benzylamine, ethanolamine, 2-hydroxypropylamine, 2-hydroxybutylamine, dietha- nolamine, bis (2-hydroxypropyl) amine, bis (2-hydroxybutyl) amine, triethanolamine, tris (2-hydroxypropylamine), tris (2-hydroxybuty- lamine), ethylenediamine. 1,3-diaminopropane, 1,4-diaminobutane, 1,6-di- aminohexane, 1, 3-diamino-3,3-dimethylpropane, piperazine, 4,9-dioxadodecanediamine-1,12,4,7,10-trioxatridecanedia- mine-1,13,4,11-dioxatetradecanediamine-1,14, a,-diaminopoly- ethyleneglycole with 2-10 ethyleneglycole-units, a,-diaminopoly- propyleneglycole with 2-10 propyleneglycole-units, a,-diamino- polytetrhaydrofurane with 2-10 oxabutylene-units, Isophoronedi- mine, bis (4-aminocyclohexyl) methane, 1,3-diaminhyclohexane, 1,3-diamino-2-methylcyclohexane, 1,3-diamino-4-methylhyclohexane, o-di (aminomethylene) benzene, p-di (aminomethylene) benzene, m-di (aminomethylene) benzene diethylenetriamine, dipropylenetriamine, N- (aminoethyl) propylen- diamine, N, N-bis (aminopropyl) methylamine, N (aminoethyl) butylene- diamine, N, N-bis (aminopropyl) butylamine, N, N-bis (aminopropyl) oc- tylamine, N (aminoethyl) hexamethylendiamine, N- (aminopropyl) hexa- methylendiamine, bishexamethylenetriamine, N-dimethylaminopropy- lethylendiamin, N- (2-aminoethyl) piperazin, N- (3-aminopropyl) pip- erazin

bis (aminoethyl) piperazine, bis (aminopropyl) piperazine, triethy- lentetramine, tetraethylenepentamine, N, N'-bis (aminopropyl) ethy- lendiamine), tripropylentetramine, N, N'-bis (aminopropyl) butylene- diamine-1,4, N, N'-bis (aminoethyl) hexamethylendiamine, N, N'- bis (aminopropyl) hexamethylendiamine Especially preferred amines for the preparation of the condensa- tion products are diethanolamine, bis- (2-hydroxypropyl) amine, 1,3-diaminopropane, 1,4-diaminobutane, 1,6-diaminohexane, 4,9-dioxadodecanediamine-1,12,4,7,10-trioxatridecanedi- amine-1,13, diethylenetriamine, dipropylenetriamine, bishexame- thylenetriamine and bis (aminopropyl) piperazine.

Suitable crosslinkers (ii), which contain at least two functional groups, are for example a-, o- or vicinal dichloroalkanes having at least 4 carbon atoms such as 1,4-dichlorobutane and 1,6-di- chlorohexane. Further suitable crosslinkers are glycidyl halides such as epichlorohydrin, bischlorohydrin ethers of polyols, polychlorohydrin ethers of polyols, bischlorohydrin ethers of polyalkylene glycols, chloroformic acid esters, chlorides of di- basic saturated dicarboxylic acids, phosgene and, in particular, halogen-free crosslinkers.

Preferably used crosslinkers are epichlorohydrin and bischlorohy- drin ethers of ethylene glycol, polyethylene glycol having 2 to 20 especially 2 to 14 ethylene glycol units, propylene glycols, polypropylene glycols, copolymers of ethylene oxide and propylene oxide, butanediol-1,4, neopentyl glycol, hexanediol-1,6, resorci- nol, glycerol, diglycerol and pentaerythritol. Other preferred crosslinkers are trischlorohydrinethers of trimethylolpropane, glycerol and pentaerythrithol and the reaction product 1 mole of pentaerythritol with 4 moles of epichlorohydrin. Halogen-free crosslinkers which are at least bifunctional are preferably se- lected from the group consisting of: (1) melamine and/or urea, (2) dibasic saturated carboxylic acids and also the esters, amides and anhydrides which are in each case derived there- from, (3) diepoxides, polyepoxides, a,-diisocyanates such as hexa- methylene diisocyanate and also mixtures of the said crosslinkers. Diepoxides and poly- epoxide may be obtained from bischlorohydrinethers of alkylene glycols and polyethylene glycols or from tris and tetrachlorohy-

drinethers of polyols such as trimethylolpropane and pentaery- thritol.

Examples of suitable halogen-free group (2) crosslinkers are di- basic saturated carboxylic acids, such as C4-C12-dicarboxylic acids, and also the salts, diesters and diamides which are derived therefrom. Examples of such acids are succinic acid, adipic acid, terephthalic acid, phthalic acid and (x, co-dodecanoic acid.

The esters of the dicarboxylic acids which come into consider- ation are preferably derived from alcohols having from 1 to 4 carbon atoms. Examples of suitable dicarboxylic acid esters are dimethyl succinate, diethyl succinate, diisopropyl succinate, di- n-propyl succinate, diisobutyl succinate, dimethyl adipate, diethyl adipate and diisopropyl adipate.

Examples of suitable dicarboxylic acid anhydrides are phthalic anhydride and succinic anhydride.

Preferred compounds of group (3) are bisglycidyl ethers of ethylene glycol, polyethylene glycol having 2 to 20 ethylene glycol units, propylene glycol, polypropylene glycol ethers, copolymers of ethylene oxide and propylene oxide, butanediol-1,4, neopentyl glycol, hexanediol-1,6 and resorcinol and diisocyanates such as hexamethylene diisocyanate.

It is also preferred to use mixtures of crosslinkers, for example, -mixtures of diglycidyl ether of ethylene glycol with bischlo- rohydrin ether of ethylene glycol, -mixtures of diglycidyl ether of polyethylene glycols having 2 to 20 ethylene glycol units with bischlorohydrin ethers of polyethylene glycols having 2 to 20 ethylene glycol units Crosslinked polyamines are obtainable by reacting at least one compound of group (i) with at least one compound of group (ii).

The reaction may be carried out in substance, in solution in an inert solvent or in dispersion in an aqueous medium or in an in- ert solvent.

Preferred polyamines of this group are those wherein the cross- linked polyamine backbone is obtained by reacting

(i) an amine selected from the group consisting of diethanola- mine, bis (2-hydroxypropyl) amine, 1,3-diaminopropane, 1,4-dia- minobutane, 1, 6-diaminohexane, 4,9-dioxadodecanediamine-1,12, 4,7,10-trioxatridecanediamine-1,13, diethylenetriamine dipro- pylenetriamine, bis (hexamethylene) triamine and bis (aminopro- pyl) piperazine with (ii) a crosslinker selected from the group consisting of epichlo- rohydrin, bischlorohydrinethers of C2-to C6-alkylene gly- cols, bischlorohydrinethers of polyethylene glycols having 2 to 14 ethylene glycol units, trischlorohydrinether of trime- thylolpropane, trischlorohydrinether of glycerol, tetrachlo- rohydrinether of pentaerythritol, bisglycidylether of ethyl- ene glycol, bisglycidylether of polyethylene glycols having 2 to 14 ethylene glycol units, trisglycidylether of trimethy- lolpropane, tetraglycidylether of pentaerythritol, urea, me- lamine, adipic acid, terephthalic acid, phthalic acid, a,-dodecanoic acid and hexamethylene diisocyanate.

In order to prepare the starting materials for sulfation with sulfur trioxide the above described polyamines are alkoxylated and then quaternized. The polyalkoxylated products have groups of formula wherein A means an ethylene oxide unit, a propylene oxide unit, a unit of butylene oxides and a tetrahydrofuran unit, and n is a number of from 1 to 50.

They are produced by reacting one of the above polyamines or a mixture thereof with a least one C2-to C4-alkylene oxide or tetrahydrofurane at such a ratio that each molecule of the poly- amines contains at least 20, preferably 50 to 200 alkylene oxide units. Ethylene oxide and propylene oxide are the preferred al- koxylating agents. If a mixture of alkylene oxides is added to the amino nitrogen then the polymerized alkylene oxides may be present in statistical distribution or as blocks. For example one can add first 10 to 20 of ethylene oxide units per NH group in the polyamines and then add 5 to 10 propylene oxide units or vice versa.

Most preferred ethylene oxide alone or a combination of 1-15% propylene oxide or 1-10% butylene oxide with 85-99,90-99% ethylene oxide respectively are used. If a combination of ethylene oxide and propylene oxide or butylene oxide is used pre- ferably the propylene oxide or butylene oxide is reacted first with the NH and OH-groups of the polyamines and the ethylene ox- ide is added after that. The polyamines are preferably ethoxy- lated.

In order to produce polyamines having end groups of formula X up to 1 glycidol unit is added per NH group of said polyamines to such an extent that at least 50 to 100% of the NH groups of the polyamines are substituted by one glycidol unit. This reaction product is then alkoxylated as described above.

The alkoxylated polyamines are quaternized by reacting them with a quaternizing agent. Suitable quaternizing agents are for example C1-to C22-alkylhalides, C7-to C22-aralkyl halides Cl-C2-dialkylsulfates or alkylene oxides. Examples of quaternizing agents are dimethyl sulfate, diethyl sulfate, methylchloride, ethyl chloride, methyl bromide, ethyl bromide, butyl bromide, hexyl chloride, benzyl chloride, benzyl bromide, ethylene oxide or propylene oxide. Dialkylsulfates especially dimethyl sulfate and diethyl sulfate are the most preferred quaternizing agent. Up to 100% of the tertiary nitrogen atoms of the polyetherpolyamines may be quaternized. The degree of quaternization is, for example, 10 to 100%, preferably at least 80 % and more preferably more than 90 to 100%. In most cases the alkoxylated polyamines are fully quaternized.

The starting materials for the sulfation step are alkoxylated and quaternized polyamines containing 2 to 10 nitrogen atoms and at least 20 alkylene oxide units per molecule with a degree of qua- ternization of at least 80%. More preferably the alkoxylated and quaternized polyamines contain 2 to 6 nitrogen atoms and 50 to 200 alkylene oxide units per molecule and have a degree of qua- ternisation of more than 90%. Most preferred are fully quaterni- zed alkoxylated poyamines as starting materials for the sulfa- tion.

The above starting materials are sulfated in the absence of a solvent. It is however possible to dilute the alkoxylated and quaternized polyamines with compounds which reduce the viscosity of the said polyamines and which react with sulfur trioxide to products used in detergents for textiles or in cleaning composi- tions. Such compounds are for example xylene, cumene, alkoxylated alkohols, monoamines or amides. The viscosity of alkoxylated,

quaternized polyamines is within the range of 20 to 1,500 mPas, most preferably from 40 to 800 mPas (measured in a Brookfield vi- scosimeter at a temperature of 60°C).

The alkoxylated, quaternized polyamines are continuously sulfated in the form of a film having a thickness of from 100 pm to 4 mm, preferably of from 200 Hm to 2 mm with a sulfur trioxide contai- ning inert gas at a temperature of up to 90°C. Air and nitrogen are the most preferred inert gases for the sulfation step. The sulfating may be carried out with a sulfur trioxide/air mixture which contains 1 to 10% by weight of sulfur trioxide or with a sulfur trioxide/nitrogen mixture containing 1 to 10% by weight of sulfur trioxide. The inert gas is preferbably heated to the temperature at which the sulfation is carried out and is then mixed with gaseous sulfur trioxide. The mixture of air or nitro- gen with sulfur trioxide preferably contains 1.2 to 4% by weight of sulfur trioxide. The reaction is usually carried aut in a re- actor operating according to the falling film principle. The sul- tation can be carried out in various types of falling film reac- tors. The alkoxylated, quaternized polyamines are for instance introduced at the top of a perpendicular standing reactor and the sulfur trioxide-containing inert gas is introduced at the bottom of the reactor. This means that the sulfation is preferably car- ried out countercurrently. Reaktor of this type are disclosed in Anionic Surfactants, Surfactant Science Series, Vol. 56, pa- ges 647-697 (1996) (incorporated by reference).

In another preferred method the alkoxylated quaternary polyamine is introduced at the top of a multitube perpendicular standing reactor and the sulfortrioxide containing inert gas is introduced also from the top. This means, that the sulfation can also be carried out concurrently in a tubular reactor.

The reaction temperature is usually in the range of from 20 to 80°C, preferably 50 to 70°C. The mixture of sulfur trioxide with the inert gas contains, as a rule, per kilogramm of sulfur trio- xide 20 to 60 m3, preferably 35 to 45 m3 of the inert gas. The mo- lar ratio of hydroxyl end groups of the alkoxylated, quaternized polyamines to sulfur trioxide is for example 1.0 : 0.2 to 1.0 : 1.2.

The amount of sulfur trioxide necessary for sulfation can be controlled by measuring the acid number of the reaction product.

If the sulfation of the alkoxylated, quaternized polyamines is not complete in the first pass the reaction product can then be transferred to an other reactor in which an afterreaction is car- ried out at a temperature within the range given above. The

afterreaction can be carried out at a temperature which is higher or lower than the reaction temperature. It is preferred to intro- duce the sulfation product obtained in the first pass into at least one other falling film reactor for afterreaction. The af- terreaction can be continuously carried out in a reactor opera- ting according to the falling film principle or discontinuously in a stirred vessel.

The weight average molecular weight Mw of the zwitterionic poly- amines is up to 9,000, preferably from 1,500 to 7,500 and more preferably from 2,000 to 7,000. The zwitterionic polyetherpolya- mines are soluble or at least easily dispersible in water. They are net anionic, i. e. the average number of anionic charges (S03H groups) exceeds the average number of cationic charges resulting from quaternized amine groups by a factor of, for example, more than 1.2, more preferably of more than 1.5 and most preferably of more than 1.8.

The zwitterionic products obtained according to the process of the invention contain less dioxane-1,4 and have additionally a better color number than those zwitterionic products which are produced by prior art methods.

The sulfated alkoxylated, quaternized polyamines are neutralized with bases such as alkali metal hydroxides, alkaline earth metal hydroxides, ammonia and amines. The bases are preferably used in aqueous solution. Suitable bases are for example sodium hydro- xide, potassium hydroxide, sodium carbonate, sodium bicarbonate, calcium hydroxide, magnesium hydroxide, morpholine, ethanolamine, diethanolamine, triethanolamine, cyclohexylamine and dicyclohexy- lamine.

The zwitterionic polyamines are used as additives in laundry de- tergent compositions which provide enhanced hydrophilic soil, in- ter alia, clay, removal benefits. They can also be used in clea- ning agents, cosmetic and pharmaceutical preparations and in the photo industry.

The degree of quaternization and of sulfation was determined by 1H-NMR. The amine number was determined by amine titration accor- ding to DIN 16 945. The color number was measured according to DIN 4630.

Example 1 The reaction product of 1 mole of hexamethylenediamine with 96 moles of ethylene oxide which was fully quaternized with dimethyl sulfate was continuously sulfated with a sulfur trioxide/air mix- ture containing 7.0 % by volume of sulfur trioxide in a one tube perpendicular standing falling film reactor having a length of 95 cm and an internal diameter of 5 cm at a temperature of 55°C. 700 g/h of the alkoxylated, quaternized hexamethylenediamine were in- troduced into the top of the reactor and moved in the form of a film having an average thickness of 1.2 mm downwards and were contacted concurrently with the sulfur trioxide/air mixture ha- ving a temperature of 55°C (52 g/h sulfur trioxide and 190 1/h of air). The sulfation ratio of the OH groups in the alkoxylated, quaternized hexamethylenediamine to sulfur trioxide was 1 : 0.92.

The amount of sulfur trioxide which was fed into the falling film reactor was controlled by the acid number of the sulfated product obtained in the bottom of the reactor. The acid number was 48.

The sulfated alkoxylated, quaternized hexamethylenediamine obtai- ned in the bottom of the reactor was collected and neutralized batchwise by feeding 750 g of the sulfated product into a mixture of 45 ml of a 25% strength by weight aqueous solution of sodium hydroxide and 700 ml of water while keeping the reaction mixture at a temperature of 30°C. The pH of the reaction mixture was then adjusted to 10 by further addition of an aqueous sodium hydroxide solution. The reaction mixture contained 750 ppm of dioxane and had a color number according to Gardner (measured in 50% strength by weight solution) of 1.4. The reaction product contained 1.5% by weight of the starting material which had not been sulfated.

Example 2 The reaction product of 1 mole of 4,7-dioxadodecanediamine with 80 moles of ethylene oxide which was fully quaternized with dimethyl sulfate was continuously sulfated with a sulfur trio- xide/nitrogen mixture containing 6.0 % by volume of sulfur trio- xide in the falling film reactor described in Example 1 at a temperature of 55°C. 700 g/h of the alkoxylated, quaternized diamine were introduced into the top of the reactor and moved in the form of a falling film having an average thickness of 1.3 mm downwards and were continuouly and concurrently contacted with the sulfur trioxide/nitrogen mixture having a temperature of 55°C (43 g/h of sulfur trioxide and 190 1/h of nitrogen). The sulfa- tion ratio of OH groups in the alkoxylated, quaternized diamine to sulfur trioxide was 1 : 0.79. The amount of sulfur trioxide which was fed into the falling film reactor was controlled by the

acid number of the sulfated product obtained in the bottom of the reactor. The acid number was adjusted to 40.

The sulfated alkoxylated, quaternized diamine obtained in the bottom of the reactor was collected and neutralized batchwise by feeding 750 g of the sulfated product into a mixture of 45 ml of a 25% strength by weight aqueous solution of sodium hydroxide and 700 ml of water while keeping the reaction mixture at a temperature of 30°C. The pH of the reaction mixture was then adju- sted to 10 by further addition of an aqueous sodium hydroxide solution. The reaction mixture contained 575 ppm of dioxane and had a color number according to Gardner (measured in 50% strength by weight aqueous solution) of 1.0. The reaction product contai- ned 2.3% by weight of starting material which had not been sulfa- ted.

Example 3 The condensation product which was obtained by condensing 2 moles of 4,7-dioxadodecanediamine and 1 mole of epichlorohydrin was ethoxylated with 120 moles of ethylene oxide. The ethoxylated condensation product was then fully quaternized with dimethyl sulfate. The ethoxylated, quaternized condensation product thus obtained was then continuously sulfated with a sulfur trioxide/ nitrogen mixture containing 6.6 % by volume of sulfur trioxide in the falling film reactor described in Example 1 at a temperature of 60°C. 700 g/h of the alkoxylated, quaternized condensation product were heated to 48°C and introduced into the top of the re- actor and moved in the form of a film having an average thickness of 1.6 mm downwards and were continuously and concurrently con- tacted with the sulfur trioxide/nitrogen mixture having a temperature of 60°C (48 g/h sulfur trioxide and 190 1/h of nitro- gen). The reaction proceeded at a temperature of 60°C. The sulfa- tion ratio of the OH groups of in the alkoxylated, quaternized product to sulfur trioxide was 1 : 0.95. The amount of sulfur trioxide which was fed into the reactor was controlled by the acid number of the sulfated product obtained in the bottom of the reactor. The acid number was 50.

The sulfated alkoxylated, quaternized condensation product obtai- ned in the bottom of the reactor was collected and neutralized batchwise by feeding 750 g of the sulfated product into a mixture of 45 ml of a 25% strength by weight aqueous solution of sodium hydroxide and 700 ml of water while keeping the reaction mixture at a temperature of 30°C. The pH of the reaction mixture was then adjusted to 10 by further addition of an aqueous sodium hydroxide solution. The reaction mixture contained about 600 ppm of dioxane and had a color number according to Gardner (measured in 50% strength by weight aqueous solution) of 1.6. The reaction product contained 2.7% by weight of starting material which had not been sulfated.