the present invention relates to a process for the production of esterquats in which fatty acid glycerol esters are subjected to transesterification with hydroxyfunctionalized tertiary amines in the presence of alkali metal and / or alkaline earth metal borohydrides and hypophosphorous acid or alkali metal and / or alkaline earth metal salts thereof and , optionally , free fatty acid and the resulting products are quaternized in known manner . it has surprisingly been found that the use of borohydrides as opposed to other conventional transesterification catalysts leads to a quick and complete reaction which , in addition , gives reaction products that are distinguished by particularly high color quality . in addition , the process according to the invention affords the advantage that fats and oils can be directly used instead of fatty acids which increases the economy of the process . esterquats are generally understood to be quaternized fatty acid triethanolamine ester salts . these are known substances which may be obtained by the relevant methods of preparative organic chemistry , cf . international patent application wo 91 / 01295 ( henkel ). according to this document , triethanolamine is partly esterified with fatty acids in the presence of hypophosphorous acid , air is passed through and the fatty acid triethanolamine esters are subsequently quaternized with dimethyl sulfate or ethylene oxide . u . s . pat . no . 3 , 915 , 867 , u . s . pat . no . 4 , 370 , 272 , ep - a2 0 239 910 , ep - a2 0 293 955 , ep - a2 0 295 739 and ep - a2 0 309 052 are cited at this juncture as representative of the extensive prior art on this subject . the quaternized fatty acid triethanolamine ester salts correspond to formula ( i ): ## str1 ## in which r 1 co is an acyl radical containing 6 to 22 carbon atoms , r 2 and r 3 independently of one another represent hydrogen or have the same meaning as r 1 co , r 4 is an alkyl radical containing 1 to 4 carbon atoms or a ( ch 2 -- ch 2 o ) q h group , m , n and p have a combined value of 0 or 1 to 12 , q is a number of 1 to 12 and x is halide , alkyl sulfate or alkyl phosphate . typical examples of esterquats which may be used in accordance with the invention are products based on caproic acid , caprylic acid , capric acid , lauric acid , myristic acid , palmitic acid , isostearic acid , stearic acid , oleic acid , elaidic acid , arachic acid , behenic acid and erucic acid and the technical mixtures thereof obtained , for example , in the pressure hydrolysis of natural fats and oils . technical c 12 / 18 cocofatty acids and , in particular , partially hydrogenated c 16 / 18 tallow or palm oil fatty acid and also c 16 / 18 fatty acid cuts rich in elaidic acid are preferably used . quaternized fatty acid triethanolamine ester salts corresponding to formula ( i ), in which r 1 co is an acyl radical containing 16 to 18 carbon atoms , r 2 has the same meaning as r 1 co , r 3 is hydrogen , r 4 is a methyl group , m , n and p have a combined value of 0 and x stands for methyl sulfate , have proved to be particularly advantageous from the performance point of view . besides the quaternized fatty acid triethanolamine ester salts , other suitable esterquats are quaternized ester salts of fatty acids with diethanol alkylamines corresponding to formula ( ii ): ## str2 ## in which r 1 co is an acyl radical containing 6 to 22 carbon atoms , r 2 is hydrogen or has the same meaning as r 1 co , r 4 and r 5 independently of one another represent alkyl radicals containing 1 to 4 carbon atoms , m and n have a combined value of 0 or 1 to 12 and x stands for halide , alkyl sulfate or alkyl phosphate . finally , another group of suitable esterquats are the quaternized ester salts of fatty acids with 1 , 2 - dihydroxypropyl dialkylamines corresponding to formula ( iii ): ## str3 ## in which r 1 co is an acyl radical containing 6 to 22 carbon atoms , r 2 is hydrogen or has the same meaning as r 1 co , r 4 , re and r 7 independently of one another represent alkyl radicals containing 1 to 4 carbon atoms , m and n have a combined value of 0 or 1 to 12 and x stands for halide , alkyl sulfate or alkyl phosphate . so far as the choice of preferred fatty acids is concerned , the examples mentioned for ( i ) also apply to the esterquats of formulae ( ii ) and ( iii ). fatty acid glycerol esters in the context of the invention are synthetic or preferably natural triglycerides , diglycerides , monoglycerides or technical mixtures thereof . the glycerol esters generally contain fatty acids with 6 to 22 and preferably 12 to 18 carbon atoms . they may be saturated or may contain up to 3 double bonds . in addition , the glycerol esters may contain one type of fatty acid or up to three different fatty acids . typical examples of triglycerides which may be used in the process according to the invention are palm oil , palm kernel oil , coconut oil , olive oil , rapeseed oil from old and new plants , sunflower oil from old and new plants , cottonseed oil , linseed oil , peanut oil , beef tallow and lard . from the performance point of view , it is preferred to use completely or partly hydrogenated beef tallow or palm oil with iodine values in the range from 0 to about 50 . in the transesterification reaction , at least one fatty acid of the glyceride reacts with one oh group of a hydroxyfunctionalized tertiary amine . typical examples of suitable amines are diethanol alkylamines such as , for example , diethanol methylamine and 1 , 2 - dihydroxypropyl dialkylamines such as , for example , 1 , 2 - dihydroxypropyl dimethylamine and , in particular , triethanolamine . the fatty acid glycerol esters -- expressed on the basis of the fatty acids present in them -- and the amines may be used in a molar ratio of around 1 . 2 : 1 to 2 . 2 : 1 and preferably 1 . 4 : 1 to 1 . 9 : 1 . alkali metal and / or alkaline earth metal borohydrides may be used as the transesterification catalysts . typical examples are potassium or magnesium borohydride and preferably sodium borohydride . the catalysts are normally used in quantities of 50 to 1000 ppm and preferably in quantities of 100 to 500 ppm , based on the glycerol ester . suitable co - catalysts are hypophosphorous acid and alkali metal and / or alkaline earth metal salts thereof , preferably sodium hypophosphite , used in quantities of 0 . 01 to 0 . 1 % by weight and preferably in quantities of 0 . 05 to 0 . 07 % by weight , based on the glycerol ester . in one preferred embodiment of the process according to the invention , the transesterification reaction takes place in the presence of free fatty acids containing 6 to 22 and preferably 12 to 18 carbon atoms which may be used in quantities of 1 to 5 % by weight and , more particularly , 2 to 3 % by weight , based on the glycerol ester . typical examples of suitable fatty acids are caproic acid , caprylic acid , 2 - ethylhexanoic acid , capric acid , lauric acid , isotridecanoic acid , myristic acid , palmitic acid , palmitoleic acid , stearic acid , isostearic acid , oleic acid , elaidic acid , petroselic acid , linoleic acid , linolenic acid , elaeostearic acid , arachic acid , gadoleic acid , behenic acid and erucic acid and the technical mixtures thereof obtained , for example , in the pressure hydrolysis of natural fats and oils or in the reduction of aldehydes from roelen &# 39 ; s oxosynthesis . technical fatty acids containing 12 to 18 carbon atoms , for example coconut oil , palm oil , palm kernel oil or tallow fatty acid , which correspond to the fatty acid of the triglyceride used are preferred . the transesterification is normally carried out over a period of 1 to 12 hours and preferably 3 to 6 hours at temperatures in the range from 160 ° to 240 ° c . and preferably at temperatures in the range from 180 ° to 220 ° c . the fatty acid hydroxyalkylamine esters and the quaternizing agents may be used in a molar ratio of 1 : 0 . 95 to 1 : 1 . 2 and preferably in a molar ratio of 1 : 1 to 1 : 1 . 1 in the quaternization reaction . suitable alkylating agents are alkyl halides , for example methyl chloride , dialkyl sulfates , for example dimethyl sulfate , dialkyl phosphates and dialkyl carbonates , for example dimethyl carbonate or diethyl carbonate . the reaction usually takes place in a solvent , for example a lower alcohol ( isopropyl alcohol ), a fatty alcohol ( ceteareth alcohol ), a nonionic surfactant ( alkyl oligoglucoside , adducts of ethylene oxide with fatty alcohols or partial glycerides ) or a hydroxycarboxylic acid ( glycolic acid ). the quaternization is preferably carried out at temperatures of 70 ° to 100 ° c . and , more particularly , at temperatures of 80 ° to 90 ° c . the reaction time may be between 1 and 24 h and is preferably between 2 and 8 h . after the quaternization , it is advisable to destroy unreacted alkylating agent by addition of ammonia , glycine or monoethanolamine . the esterquats obtainable by the process according to the invention are distinguished by excellent fabric - softening and antistatic properties . accordingly , the present invention also relates to their use for the production of fabric softeners and hair - care formulations , such as softeners for textiles , yarns and fibers , household fabric softeners , hair shampoos , hair conditioners , hair rinses and the like , in which they may be present in quantities of 1 to 30 % by weight and preferably in quantities of 5 to 15 % by weight , based on the particular formulation . the following examples are intended to illustrate the invention without limiting it in any way . a ) esterification . 0 . 4 to 0 . 63 mole of triglyceride ( corresponding to 1 . 2 to 1 . 9 mole , based on fatty acid ), 149 g ( 1 mole ) of triethanolamine , 0 . 05 % by weight of sodium hypophosphite , 100 to 500 ppm of catalyst and , optionally , 2 . 7 % by weight of tallow fatty acid ( all percentages by weight based on the triglyceride ) were introduced into a 1 liter three - necked flask equipped with a stirrer , internal thermometer and distillation head . the reaction mixture was heated for 5 h to a temperature of 220 ° c . the crude tallow fatty acid triethanolamine ester was then cooled , the reactor was vented and 1 liter of air was passed through over a period of 15 minutes with continuous stirring . the results of the esterification tests are set out in table 1 . b ) quatemization . in a 1 . 5 liter glass autoclave equipped with a stirrer and internal thermometer , 63 g ( 0 . 5 mole ) of dimethyl sulfate were added to 0 . 5 mole of the ester according to a ) in 150 ml of isopropyl alcohol . the reaction mixture was stirred for 2 h at 90 ° c . and , after cooling , the reactor was vented . to destroy traces of unreacted alkylating agent , 2 g of glycine were then added to the reaction mixture , followed by stirring for 1 h at 60 ° c . table 1______________________________________transesterification of triglycerides c ( cat ) c ( fa ) t colorex . e r cat ppm % by weight h gardner______________________________________1 a 1 . 2 : 1 nabh . sub . 4 100 2 . 7 4 1 . 02 a 1 . 6 : 1 nabh . sub . 4 100 2 . 7 4 1 . 23 a 1 . 9 : 1 nabh . sub . 4 100 2 . 7 4 1 . 54 a 1 . 9 : 1 nabh . sub . 4 500 2 . 7 4 1 . 05 a 1 . 9 : 1 nabh . sub . 4 100 -- 4 1 . 56 b 1 . 9 : 1 nabh . sub . 4 100 2 . 7 4 1 . 57 c 1 . 9 : 1 nabh . sub . 4 100 2 . 7 4 1 . 5c1 a 1 . 9 : 1 koh 100 2 . 7 6 3 . 5c2 a 1 . 9 : 1 naome 100 2 . 7 7 3 . 5______________________________________ legend : e = educt a = hydrogenated beef tallow b = partly hydrogenated beef tallow c = palm oil r = ratio of fatty acid ( in the triglyceride ) to triethanolamine cat = catalyst fa = fatty acid ( corresponding to the triglyceride ) c = concentration t = time required to establish an acid value & lt ; 5
esterquats based on natural fats and oils can be directly produced by subjecting fatty acid glyerine ester to ester interchange , in the presence of alkaline and / or alkaline earth boron hydrides and hypophosphoric acid or their alkaline and / or alkaline earth salts and possibly free fatty acid , with hydroxy - functionalised tertiary amines and quaternising the resultant products in the manner known per se .