Patent GB-573524-A (GB)
Title: Manufacture of compositions useful for cleansing and emulsifying purposes
IPC: C11D1/00
Filed: 1944-05-11
Abstract: Compositions useful for cleansing and emulsifying purposes are prepared by a process which comprises sulphating ethanolamides of higher fatty acids, having the general formula RCONH(CH2)2OH, where R represents a fatty acid residue having from 10 to 18 carbon atoms, with sulphuric acid in the presence of a substantial quantity of a lower aliphatic alcohol containing not more than 4 carbon atoms, neutralizing the resulting product by means of a base and, if desired, removing some or all of the water present.  In addition to the sulphated ethanolamides of the fatty acids, the reaction products contain sulphated lower aliphatic alcohols and the salt of the base used. The ethanolamides of fatty acids employed as starting materials may be obtained by known general methods conveniently by interacting the higher fatty acids, their glycerides or lower alkyl esters with monoethanolamine for example in the manner described in Specifications 523,466 and 384,665, and U.S.A. Specification 1,990,453.  Ethanolamides formed from undecylic, lauric, myristic, palmitic or stearic acids or the corresponding glycerides or methyl or ethyl esters, are specified starting materials.  Pure acids or mixtures or fractions of acids, glycerides, or esters such as may be obtained from the naturally occurring fatty oils, for example, coconut or arachis oils or from hardened natural oils, for example, hydrogenated castor, cod or linseed oil or mixtures thereof may also be used.  The sulphuric acid is conveniently used in the form of the monohydrate and the amount employed is usually about one and a half times the weight of the amide.  A convenient temperature of sulphation is about 60 DEG  C. Methyl and ethyl alcohols are particularly suitable for lower aliphatic alcohols for use in this process and the amount used is normally 30-40 per cent by weight based on the ethanolamide.  After sulphation, the product may be neutralised with ammonia, an alkali, or organic base such as an amine or hydroxyalkylamine.  The water present may be removed by drying. To remove inorganic sulphates, there are added to the product an organic material which is a solvent for the ethanolamide sulphate and water and common salt; on warming, there results an aqueous layer containing the inorganic sulphate and a purified oily layer which is separated.  Suitable organic materials for this purpose are cyclohexanol and its homologues, low melting fatty acids, for example, oleic or ricinoleic acid, and the alkylolamides of the low melting fatty acids; these solvents are retained in the purified product.  In examples: (1) stearoethanolamide, ethyl alcohol and sulphuric acid monohydrate are reacted at 60-65 DEG  C. and the product neutralized with aqueous caustic soda; the resulting paste has excellent cleansing and emulsifying properties; (2) the recipe of example 1 is repeated, using, however, the ethanolamide of the fatty acids from coconut oil; (3) the paste obtained according to example 1 is freed from sodium sulphate by adding thereto a mixture of methyl cyclohexanols, known commercially as "Lextol" (Registered Trade Mark), and aqueous sodium chloride and separating the aqueous layer containing the sodium sulphate from the purified oily layer; ricinoleoethanolamide may replace the methyl cyclohexanol. Specification 450,672 also is referred to.