Method for separating glycerin from reaction mixtures containing glycerin and fatty acid amides, alkoxylated amides obtained therefrom and the use thereof

A process for preparing an alkoxylated amide of the formula (I):

• R.sup.1 --CO--NR.sup.2 --CHR.sup.3 --CHR.sup.4 --O--(CHR.sup.5 --CHR.sup.6 --O).sub.n --H (I)
• wherein
• R.sup.1 is a linear or branched aliphatic C.sub.5-25 radical containing 0-5 double bonds,
• R.sup.2 is hydrogen or a linear or branched C.sub.1-20 alkyl which may be interrupted by from 1 to 5 oxygens,
• R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are hydrogen, or not more than one of R.sup.3 and R.sup.4 and not more than one of R.sup.5 and R.sup.6 are methyl or ethyl, and
• n is 1-100,
• comprising:
• (1) reacting a glyceride of a fatty acid of the formula (II):
• R.sup.1 --COOH (II)
• wherein R.sup.1 is as defined above,
• with an amine of the formula (III):
• HNR.sup.2 R.sup.7 (III)
• wherein R.sup.7 is hydrogen or --CHR.sup.3 --CHR.sup.4 --OH, in which not more than one of R.sup.2 and R.sup.7 is hydrogen,
• to produce an amide of the formula (IV):
• R.sup.1 --CO--NR.sup.2 --R.sup.7 (IV)
• wherein R.sup.1, R.sup.2 and R.sup.7 are as defined above,
• and glycerol,
• (2) adding an aqueous acid solution to the reaction mixture from (1) until the reaction mixture has a pH from 1 to 7, in order to bring about phase separation into a glycerol-containing aqueous phase and an organic phase containing the amide of the formula (IV), followed by separating off the aqueous phase, thereby separating off the glycerol, and then
• (3) reacting the amide of the formula (IV) with ethylene oxide, propylene oxide and/or butylene oxide to produce the alkoxylated amide of the formula (I).