Patent GB-481346-A (GB)
Title: Manufacture of carboxylic acid esters of aromatic sulpho-dicarboxylic acids
IPC: C07C309/52
Filed: 1937-05-24
Abstract: Products stated to have dispersing properties are prepared by treating an aromatic sulpho dicarboxylic acid or an anhydride, halide or ester thereof, with an alcohol containing at least 5 carbon atoms to form the monocarboxylic ester and then treating the latter with an alcohol containing at least 3 fewer carbon atoms than the alcohol used in the first esterification.  The esters produced may be used in association with solvents, soaps, protective colloids or salts.  In examples, 4-sulphophthalicanhydride is esterified first with cetyl alcohol and the second carboxylic group then esterified with amyl or methyl alcohol.  The potassium salt of the sulphophthalicamylcetylester may be used, together with turkey red oil for emulsifying oleic acid to give a lubricant for wool. In a further example, 4-sulphophthalic acid anhydride is esterified first with a mixture of alcohols containing mainly oleic alcohol and then with methylalcohol.  Other specified alcohols which may be used are: octylalcohol, diethyleneglycol and its monoethyl ether, glycerol, wax alcohols, benzyl alcohol, cyclohexanol and methylcyclohexanol. Naphthalic and terephthalic sulpho acids and sulpho-4-chlorphthalic acid are mentioned.  A sample has been furnished under Sect. 2 (5) of a product prepared as follows: the mono sodium salt of 4-sulphophthalic anhydride, obtained by heating the mono-sodium salt of the corresponding acid, is treated first with decahydro-b -naphthol, and the resulting ester heated under reflux in a current of carbon dioxide with hexahydrocresol.  The Specification as open to inspection under Sect. 91 comprises also the use of phenols in the esterification.  This subject-matter does not appear in the Specification as accepted.ALSO:Products stated to have wetting, cleaning, foaming, dispersing, levelling, and softening properties are prepared by treating an aromatic sulpho dicarboxylic acid or an anhydride, halide or ester thereof with an alcohol containing at least 5 carbon atoms to form the mono carboxylic ester and then treating the latter with an alcohol containing at least 3 fewer carbon atoms than the alcohol used in the first esterification.  The sulphonates may be used instead of the free sulphonic acids, and the esterification process may be effected in the presence of solvents such as pyridine, quinoline or dimethylaniline or of esterification catalysts.  Water formed in the reaction may be eliminated together with a substance forming an azeotropic mixture or by using reduced pressure.  The esters may be used in association with solvents, soaps, protective colloids or salts.  In examples, 4-sulphophthalicanhydride is esterified first with cetyl alcohol and the second carboxylic group then esterified with amyl or methyl alcohol, water is removed by using excess methylalcohol. p  The potassium salt of the sulphophthalic amylcetylester may be used, together with turkey red oil for emulsifying oleic acid to give a lubricant for wool.  In a further example, 4-sulphophthalic acid anhydride is esterified first with a mixture of alcohols containing mainly oleic alcohol and then with methylalcohol. Other specified alcohols which may be used are: octyl alcohol, diethyleneglycol and its monoethyl ether, glycerol, wax alcohols, benzyl alcohol, cyclohexanol and methylcyclohexanol.  Naphthalic and terephthalic sulpho acids and sulpho-4-chlorphthalic acid are mentioned.  A sample has been furnished under Sect. 2 (5) of a product prepared as follows: the mono sodium salt of 4-sulphophthalic anhydride, obtained by heating the mono sodium salt of the corresponding acid, is treated first with decahydro b -naphthol, and the resulting ester heated under reflux in a current of carbon dioxide with hexahydrocresol. The Specification as open to inspection under Sect. 91 comprises also the use of phenols in the esterification.  This subject-matter does not appear in the Specification as accepted.