Patent GB-588555-A (GB)
Title: Manufacture of diacylated aliphatic dihydroxy-sulphonic acids
Filed: 1944-04-04
Abstract: Di-acylated aliphatic dihydroxy sulphonic acids and salts thereof having pronounced wetting and foaming properties are prepared by treating an aliphatic dihydroxy sulphonic acid or a salt thereof with at least 2 mols. of an aliphatic carboxylic acid containing 4-10 carbon atoms or a functional derivative thereof. Alternatively, an aliphatic monohalogen-monohydroxy-sulphonic acid or a salt thereof is heated with at least one mol. of a salt of an aliphatic carboxylic acid containing 4-10 carbon atoms and the mono-acyl-dihydroxy-sulphonic acid or salt thereof thus obtained is treated with at least one mol. of an aliphatic carboxylic acid containing 4-10 carbon atoms or a functional derivative thereof.  In another method, an aliphatic dihydroxy-sulphonic acid or a salt thereof is treated with one mol. of an aliphatic carboxylic acid containing 4-10 carbon atoms or a functional derivative thereof, the mono-acylated dihydroxy-sulphonic acid or salt thereof so produced being then treated with at least one mol. of a different aliphatic carboxylic acid of 4-10 carbon atoms or a functional derivative thereof.  In each case the term "functional derivative" excludes salts.  The first method is conducted, for example at a raised temperature and under reduced pressure when acids are used, or in the presence of acid binding agents, such as tertiary amines when acid halides are used.  The acid anhydrides or esters with alcohols of low molecular weight may also be employed.  In examples: (1) and (2) caproic acid chloride and caprylic acid chloride respectively are heated with the sodium salt of 1 : 2-dihydroxy propane sulphonic acid -3- in the presence of pyridine, the reactants being present in the molar proportions indicated in the first-described method. The mixture is then neutralized and evaporated to dryness; (3) and (4) caprylic acid chloride is heated with the same sodium salt in the presence of pyridine and after cooling capric acid chloride and caproic acid chloride respectively are added and evaporated to dryness, the molar proportions employed are those indicated in the third method described above; (5) wool yarn is wetted with an aqueous solution of the product of example (2) and sodium sulphate.  Other dihydroxy-sulphonic acids which may be used are, for example, 1 : 3-dihydroxypropane sulphonic acid-2; 2 : 3-dihydroxy-2-methylpropane sulphonic acid-1 or a dihydroxy butane sulphonic acid.  The acyl residues introduced may be from normal or branched chain fatty acids such as butyric acid and may be from a mixture of fatty acids, e.g. that obtainable by the oxidation of paraffin hydrocarbons. Specifications 372,005 and 516,735 are referred to.  The Specification as open to inspection under Sect. 91 states that another method is to heat diacylated dihydroxyalkyl halides such as diacylated a - or b -glycerine monochlorhydrin with sulphites and states also that in addition to an acyl residue of 4-10 carbon atoms a residue having a larger number of carbon atoms, e.g. a lauryl residue, may be introduced.  The functional derivatives of the acids are also not stated to exclude salts. This subject-matter does not appear in the Specification as accepted.ALSO:An aqueous solution of the diacylated product obtained by treating caproic acid chloride with the sodium salt of 1 : 2 dihydroxy propane sulphonic acid -(3) (see Group IV) constitutes a strongly foaming solution for cleaning living hair.