GB950667A - Process for the preparation of monoglycerides - Google Patents

Abstract

Glycerides having a high monoglyceride content are prepared by a process which comprises the reaction, in a medium which contains at least 50 mols per cent glycerine, 35-10 mol per cent monoglyceride and not more than 15 mol per cent di- and tri-glycerides, at a temperature of at least 260 DEG C., of the components of an agent consisting of compounds from which the monoglyceride may be formed, wherein in said agent at least 2 mol and preferably 3-5 mol glyceride radicals are used per mol of added fatty acid radical, said agent being employed in an amount not more than 0.5 parts by weight and preferably not more than 0.4 parts by weight of the reaction medium, the agent being added during the reaction to maintain said proportion thereof, the expression "components from which the monoglyceride may be formed" being defined as "a mixture of glycerine and fatty acids or their esters with glycerine or other mono- or polyvalent alcohols provided that the other alcohols are more volatile than glycerine". The reaction products comprising glycerine and a glyceride having a high monoglyceride content are preferably separated into two layers by cooling, one layer comprising glycerine which is removed, the remaining glycerine being removed from the other layer by distillation. An extensive purification of the monoglyceride by water-washing is described. The fatty acids are preferably saturated or unsaturated C10-20 fatty acids of natural origin such as occur in the fats of vegetation and of land and aquatic animals, but the hydrogenation products of natural fatty acids and synthetic straight or branched-chain fatty acids may also be used. Suitable esters of these acids include esters with C1-4 alcohols such as methyl and ethyl alcohols and ethylene and propylene glycols. Conventional esterification or re-esterification catalysts such as metal oxides, hydroxides or alcoholates, or free metals, may optionally be added. Examples describe the reaction together in appropriate media of glycerine and (1) hydrogenated tallow fatty acid, (2) a C12-18 fraction of a coconut fatty acid, (3) lauric acid, (4) olive oil, and (5) methyl laurate.ALSO:Glycerides having a high monoglyceride content are prepared by reacting at a temperature of at least 260 DEG C. in a medium which contains at least 50 mols. per cent glycerine, 35-10 mol. per cent mono-glyceride and not more than 15 mol. per cent di- and tri-glycerides, a mixture of glycerine and fatty acids or their esters with glycerine or other mono- or polyvalent alcohols (provided that the other alcohols are more volatile than glycerine), containing at least 2 mol., preferably 3-5 mol., glyceride radicals per mol. of added fatty acid radical, the mixture, which is added during the reaction to maintain said proportions being present in an amount not more than 0.5 parts, preferably not more than 0.4 parts, by weight of the reaction medium. The reaction products comprising glycerine and a glyceride having a high monoglyceride content are preferably separated into two layers by cooling, one layer comprising glycerine which is removed; residual glycerine is removed from the other layer by distillation. An extensive purification of the monoglyceride by water-washing is described. The fatty acids are preferably saturated or unsaturated C10-20 fatty acids derived from vegetable, animal and marine fats, but the hydrogenated natural fatty acids and synthetic straight or branched-chain fatty acids may also be used. Suitable esters of these acids include esters with C1-4 alcohols such as methyl and ethyl alcohols and ethylene and propylene glycols. Conventional esterification or re-esterification catalysts such as metal oxides, hydroxides or alcoholates, or free metals, may optionally be added. Examples describe the reaction together in appropriate media of glycerine and (1) hydrogenated tallow fatty acid, (2) a C12-18 fraction of a coconut fatty acid, (3) lauric acid, (4) olive oil, and (5) methyl laurate.