GB824654A - Improvements in or relating to a method of preparing carboxylic acid esters of sucrose or raffinose - Google Patents

Abstract

Detergent compositions contain 10 to 40% by weight of a mono- or di-ester of sucrose or raffinose with a fatty acid containing from 6 to 30 carbon atoms (see Group IV (b)) in admixture with detergent aids such as molecularly dehydrated phosphates, alkali metal phosphates, alkali metal silicates, borates, carbonates, sulphates and chlorides, and sodium carboxymethylcellulose. Germicidal or bacteriostatic agents such as hexachlorophene or quaternary ammonium salt may also be added when formulating detergent cakes for toilet use. In examples, detergent compositions contain one or more of the esters sucrose mono-tallowate, sucrose mono-cocoate and sucrose mono-oleate together with sodium tripolyphosphate, sodium carboxymethylcellulose and, as optional components, tetrasodium pyrophosphate, sodium silicates, sucrose, sodium chloride, sodium sulphate and sodium dodecylbenzene sulphonates. Optical brighteners may also be incorporated.ALSO:A sucrose or raffinose ester of a resin acid or a fatty acid containing from 6 to 30 carbon atoms is prepared by reacting sucrose or raffinose with an ester of a resin acid or a fatty acid containing from 6 to 30 carbon atoms and a non-saccharide alcohol at a temperature of 20 DEG to 180 DEG C., in the presence of an alkaline catalyst and of a solvent. The latter may be an aromatic, aliphatic, alicyclic or heterocyclic amide or a heterocyclic or aliphatic tertiary amine, or a dialkylsulphoxide. Preferably, anhydrous conditions are employed and the reaction time is between 30 minutes and 24 hours. The non-saccharide alcohol esters used may be simple esters of a monohydric alcohol or esters of a polyhydric alcohol such as di- and triglycerides. It is preferred to employ a fatty acid ester of a readily volatile alcohol such as methanol or ethanol, the volatile alcohol being stripped from the reaction mixture as it is liberated by distillation under reduced pressure, or by heating to the boilingpoint of the alcohol and sweeping the system with an inert gas. Products containing a mixture of fatty acids residues as occur in naturally-occurring glyceridic oils and fats are preferably obtained by first converting the glycerides to mixed esters of a volatile alcohol by ester interchange. As alkaline catalysts there may be used alkali metal hydroxides, salts of alkali metals and weak acids, alkali metal alcoholates, organic bases such as quaternary ammonium bases, alkali metal sucrates or raffinates or metals such as tin and zinc which form the oxide or hydroxide under the reaction conditions. Suitable catalysts when added in a 1% w./v. concentration to a 0.5% w./v. phenolphthalein solution in a solvent containing equal parts of boiled N,N-dimethylformamide and carbon dioxide-free water give the characteristic magenta colour. The products are monoesters of sucrose or raffinose if the reaction mixture contains a ratio of three or more mols. of sucrose or raffinose to one mol. of non-saccharide ester, and if one mol. of sucrose is employed with two mols. of a fatty acid ester the product is essentially a di-ester of sucrose. The monoester products may be purified by distilling off the solvent and dissolving the dry residue in water followed by addition of sodium chloride to precipitate the sucrose ester. The residue remaining after distilling off solvent may also be purified by partitioning between aqueous sodium chloride and n-butanol, separating the butanol layer and distilling off the butanol. Monoesters obtained in a process employing amide or amine solvents may also be purified by distilling off 1/4 to 3/4 of the solvent, and cooling the residue to 20 DEG to 30 DEG C. to separate out the unreacted esters of fatty acids, extracting the resulting solution with an aliphatic hydrocarbon solvent, evaporating the raffinate to low volume and diluting with a polar solvent to precipitate sucrose leaving a clear solution of sucrose monoester which may be distilled to leave pure ester as residue. Where a di-ester is produced, the residue remaining after simple distillation of the solvent is sufficiently pure. The products possess detergent, emulsifying, wetting and dispersing properties and may be used in detergent compositions, shampoos, cosmetics and shaving creams, in foods, for emulsifying salad dressings or chocolate, as antispattering agents for frying oils and fats, bread softeners, lubricants and for secondary oil or petroleum recovery from underground rock.