GB804197A - Method for preparing fatty acid esters of oligosaccharides - Google Patents

Abstract

Fatty acid esters of non-reducing oligosaccharides (i.e. di-, tri- and tetra-saccharides, containing from 7-16 hydroxyl groups per molecule) are prepared by reacting a non-reducing oligosaccharide with a fatty acid ester of an aliphatic primary monohydric alcohol of from 1-16 carbon atoms or of a polyhydroxy compound (as defined below) in the presence of an interesterification catalyst at 20-150 DEG C., preferably 80-150 DEG C., in the presence of N-formyl-, acetyl- or propionyl-morpholine or piperidine. The term "polyhydroxy compound" includes polyhydric alcohols having from 2-6 hydroxyl groups, glycosides, and oligosaccharides having from 7-16 hydroxyl groups; these may be fully or partially esterified, specific examples being glycol dipalmitate, glycerol mono-, di- and tri-palmitate, mannitol partial palmitates, erythritol tetrapalmitate, pentaerythritol tetrapalmitate and sorbitol hexapalmitate; methyl glucoside tetrapalmitate; and sucrose octapalmitate. Specified starting oligosaccharides are sucrose, trehalose, glucoxylose, raffinose, melezitose, gentianose and stachyose. Suitable fatty acid esters of monohydric alcohols are those of methanol, ethanol, hexanol, decanol, dodecanol and hexanedecanol, such as methyl, dodecyl and hexadecyl palmitates. Esters derived from fatty acids of about 8-22 carbon atoms, such as mixtures of acids obtained from animal, vegetable and marine oils, and fats, are useful. For the preparation of oligosaccharide esters of single fatty acids, fatty acid esters of relatively volatile alcohols, e.g. up to 3 carbon atoms, and of acids having about 12 to about 22 carbon atoms are preferred. Any basic molecular rearrangement or interesterification catalyst may be employed, such as sodium methoxide, anhydrous potassium hydroxide, sodium hydroxide, metallic sodium, sodium/potassium alloy, and quaternary ammonium bases such as trimethyl benzyl ammonium hydroxide. The proportion of catalyst is preferably 0.05-2.0 per cent by weight of fatty acid ester. Depending on the ratio of oligosaccharide to fatty acid ester taken, the oligosaccharide may be partially or completely esterified. The process may be carried out under reduced pressure, so as to remove liberated free alcohol. In examples, sucrose is reacted with a cottonseed oil and soyabean oil mixture, in the presence of formyl, acetyl and propionyl morpholine, and formyl and acetyl piperidine. U.S.A. Specification 2,442,532 is referred to.