Patent GB-664214-A (GB)
Title: Lubricating grease compositions
Filed: 1949-08-12
Abstract: Branched chain aliphatic acids having between 10 and 20 carbon atoms, and of formula R-X-(CH2)n.COOH, where X is oxygen or sulphur, R is a branched chain radical and n is an integer, are prepared (1) by reacting branched chain mercaptans having from 3 to 16 carbon atoms in the molecule with an acidogenic material such as an aliphatic unsaturated nitrile of from 3 to 10 carbon atoms per molecule; (2) by reacting branched chain alcohols or mercaptans, for example C8 or higher Oxo alcohols with lactones, such as b -propiolactone; (3) by reacting salts of mercaptans or alkoxides with halonitriles or haloacids, e.g. chloroacetonitrile or b -chloropropionic acid. Referring to method (1), the mercaptans may be obtained by the reaction with hydrogen sulphide of polyolefins such as diisobutylene, triisobutylene, polypropylene and analogous polymers and copolymers, preferably containing 8-16 carbon atoms.  Alcohols specified are branched-chain oxo-alcohols containing 7 or more carbon atoms. Nitriles referred to are acrylonitrile, methacrylonitrile and ethacrylonitrile.  A catalyst such as sodium methoxide is preferably used in the reaction. which may be carried out below about 45 DEG  C. The product may be hydrolysed to form the acid, for example b -(11,31,51-hexamethyl hexyl thio) propionic acid, and the salts, such as the sodium and lithium salts, of these acids are also mentioned.ALSO:A lubricating grease composition composition comprises a lubricating oil and a thickener comprising a metal soap of one or more fatty acids having between 12 and 24 carbon atoms in the molecule, a metal salt of an organic acid of molecular weight below 160, and a metal soap of a branched chain aliphatic acid having at least one oxygen or sulphur atom in the aliphatic radical of the molecule and having between 10 and 20 carbon atoms. Low molecular organic acids specified are acetic, propionic, acrylic, methacrylic, glycollic or furoic acids.  The branched acid may be of the type R-S-(CH2)n-COOH, where R is a branched chain radical derived from a dimer, trimer or quadrimer of ethylene or propylene and n is an integer; these acids may be derived from mercaptans such as those obtained by the reaction of polyolefines with hydrogen sulphide, or alternatively may be derived from alcohols such as branched-chain oxo-alcohols.  The mercaptans or the branched-chain acids themselves may be sulphurized.  The alkali metal salts, such as those of sodium and lithium, are preferred.  The lubricating oil may be a mineral oil, a synthetic ester or a polyglycol oil.  The grease composition may contain 2-20 per cent of the metal soap, 1-15 per cent of the low molecular weight salt, and 1-10 per cent of the branched chain acid salt.  In an example, a mixture of furfural and caustic soda in mineral lubricating oil was subjected to the Cannizzaro reaction, and hydrogenated fish oil acids, b  (11 31 51 hexamethyl hexyl thio) propionic acid, and additional caustic soda and mineral lubricating oil were then added.  The mixture was heated up to a temperature of 450 DEG F and an p  anti-oxidant (phenyl alpha naphthylamine) was added and the grease allowed to cool, after which the grease was homogenized in a grease kettle.