Patent GB-1001285-A (GB)
Title: Improvements in or relating to the sulphonation of fatty acids and their esters
IPC: C07C303/44
Filed: 1962-08-02
Abstract: Sulphonation products of saturated fatty acids of 6-28 C atoms per molecule and their esters, obtained by treating the acids or their esters with an excess of sulphur trioxide, in the absence of solvents which form adducts with sulphur trioxide, are worked up by treatment with substances containing a hydrophobic residue and an aliphatic hydroxyl group, the sulphated products of which possess surface active properties.  The hydrophobic residues are hydrocarbon residues of 10 to 28, preferably 12 to 18, C atoms of which, when alkylaromatic or cycloalkylaromatic, at least 8 C atoms are of an aliphatic or cycloaliphatic nature.  The hydroxy compounds are preferably saturated and contain one primary or secondary alcoholic hydroxyl group which is linked directly or via intermediate members with the hydrophobic residue.  These compounds include saturated fatty alcohols or fatty alcohol mixtures of natural or synthetic origin or fatty acid alkylolamides, part ethers of fatty alcohols, alkylphenols, arylphenols, part esters of fatty acids with polyhydric alcohols e.g. ethylene and propylene glycols, glycerol, pentaerythritol and hexite and part ethers and esters of the above substances with e.g. polyethylene glycols and polyglycerols. Preferred hydroxy compounds are fatty alcohols, water insoluble part ethers and part esters of fatty alcohols, alkyl phenols or fatty acids with polyhydric alcohols, the part ethers being the products of addition of ethylene and/or propylene glycol to fatty alcohols, fatty acids, fatty acid amides, alkylphenols or acylphenols or on to part ethers or part esters of fatty alcohols and fatty acids with di-, tri- and poly-hydric alcohols.  The fatty acid and ester starting materials preferably have 8-18 C atoms per molecule and may be derived from plants or animals, e.g. fats of the lauric acid group and hydrogenated tallow, whale and fish oils.  No further sulphatable or sulphonatable groups, other than the a -hydrogen atom, should be present in the acids or their esters and they should have an iodine value of less than 5, preferably below 2. The esters may be derived from mono- or polyhydric alcohols, e.g. hydrogenated oleyl oleate, from sperm oil, or natural or synthetic wax esters.  Preferably the starting materials are purified by distillation before sulphonation is effected.  Inert solvents which do not form adducts with the sulphur trioxide may be present during sulphonation, e.g. perchlorethylene. The sulphonation process of Specifications 999,300, 1,001,284 and 1,001,286 may be used and the products may be bleached, before or after treatment with hydroxy compound, as e.g. in Specification 1,001,283.  The amount of hydroxy compound added to the product should not be substantially less than 1 mol per mol of uncombined sulphur trioxide and sulphonation is preferably effected so that the amount of free sulphonating agent present after esterification is not greater than 3.3, preferably 0.15, mol per mol of hydroxy compound calculated as sulphur trioxide.  Reaction between hydroxy compound and sulphonated product is preferably effected at 20-60 DEG  C. Excess hydroxy compound may be used and if present as water insolubles may serve as foam stabilizers in the detergent product.  The products with any excess hydroxy compound, may be esterified.  A preferred starting material has at least 0.5, preferably more than 0.8, e.g. 1-2.5 mols of sulphur trioxide per mol of sulpho-fatty acid residue.  Examples illustrate the process applied to sulphonation products of such materials as hardened distilled coconut fatty acid ethyl ester, methyl laurate, hydrogenated palm kernel fatty acid ethyl ester, a mixture of hardened coconut oil and hardened palm kernel fatty acid methyl ester, representative of the hydroxy compounds used being a hardened alcohol from tallow fatty acid, lauryl alcohol, an addition product of 2 mols of ethylene oxide to 1 mol of tallow alcohol, reduced fatty acids of coconut oil and oleyl alcohol.