Patent GB-844288-A (GB)
Title: Improvements in dicarboxylic acid esters and in lubricant compositions
Inventor: CRITCHLEY STUART WALTER
IPC: C10M169/00
Filed: 1957-02-08
Abstract: Lubricant compositions comprise a polymerization product of an unsymmetrical ester of a dicarboxylic acid with a saturated monohydric aliphatic alcohol and an unsaturated monohydric aliphatic alcohol, and a diester of a dicarboxylic acid with a saturated monohydric aliphatic alcohol.  They may be obtained by polymerizing, e.g. by heating with a peroxide catalyst, a composition comprising the unpolymerized unsymmetrical ester and the saturated diester. Such compositions may be prepared by blending the components or by esterifying a dicarboxylic acid with more than one but less than two molecular proportions of a saturated monohydric aliphatic alcohol and with less than one molecular proportion of an unsaturated monohydric aliphatic alcohol (see Group IV(b)).  The dicarboxylic acid may be aliphatic, alicyclic or aromatic, specifically adipic, sebacic, azelaic, or phthalic acid; the unsaturated alcohol is preferably allyl alcohol, and the saturated alcohol preferably contains from four to sixteen carbon atoms, specifically 2-ethylhexanol and 3, 5, 5-trimethylhexanol.  Preferably not more than 25% of the total alcohol residues are unsaturated.  For maximum heat stability, polymerization should be carried out substantially to completion or residual unsaturation removed by chemical combination with a reagent which will add on to double bonds, such as sulphur, sulphur monochloride, halogen, phosphorus halides or phosphorus sulphides. The final iodine value is preferably less than 2. Compositions exemplified comprise polymerized allyl 3, 5, 5-trimethylhexyl sebacate and di-3, 5, 5-trimethylhexyl sebacate.ALSO:Unsymmetrical esters are prepared by esterifying a dicarboxylic acid with a saturated monohydric aliphatic alcohol and an unsaturated monohydric aliphatic alcohol.  The invention includes a composition comprising at least one such ester and at least one diester of a dicarboxylic acid with a saturated monohydric aliphatic alcohol.  The composition may be prepared by blending the component esters or, preferably, by esterifying a dicarboxylic acid with more than one but less than two molecular proportions of a saturated monohydric aliphatic alcohol and with less than one molecular proportion of an unsaturated monohydric aliphatic alcohol.  Preferably the molecular proportion of unsaturated alcohol does not exceed 25% of the total alcohol.  The dicarboxylic acid may be aliphatic, cycloaliphatic or aromatic. Specified are adipic, sebacic, azelaic and phthalic acids.  The unsaturated alcohol is preferably alkyl alcohol and the saturated alcohol may have from 4-16 carbon atoms and is preferably branched-chain.  Specified are 2-ethylhexanol and 3,5,5-trimethylhexanol.  Conventional esterification methods are used.ALSO:Lubricant compositions comprise a polymerization product of an unsymmetrical ester of a dicarboxylic acid with a saturated monohydric aliphatic alcohol and an unsaturated monohydric aliphatic alcohol, and a diester of a dicarboxylic acid with a saturated monohydric aliphatic alcohol.  They may be obtained by polymerizing, e.g. by heating with a peroxide catalyst, a composition comprising the unpolymerized unsymmetrical ester and the saturated diester. Such compositions may be prepared by blending the components or by esterifying a dicarboxylic acid with more than one but less than two molecular proportions of a p  saturated monohydric aliphatic alcohol and with less than one molecular proportion of an unsaturated monohydric aliphatic alcohol (see Group IV(b)).  The dicarboxylic acid may be aliphatic, alicyclic or aromatic, specifically adipic, sebacic, azelaic or phthalic acid; the unsaturated alcohol is preferably allyl alcohol, and the saturated alcohol preferably contains from four to sixteen carbon atoms, specifically 2-ethylhexanol and 3,5,5-trimethylhexanol.  Preferably not more than 25% of the total alcohol residues are unsaturated.  For maximum heat stability, polymerization should be carried out substantially to completion or residual unsaturation removed by chemical combination with a reagent which will add on to double bonds, such as sulphur, sulphur monochloride, halogen, phosphorus halides or phosphorus sulphides.  The final iodine value is preferably less than 2. Compositions exemplified comprise polymerized allyl 3,5,5-trimethyl-hexyl sebacate and di-3,5,5-trimethylhexyl sebacate.