GB668663A - Improvements in or relating to synthetic ester lubricants - Google Patents

Abstract

In the production of ester lubricants (see Group III) by esterifying a saturated dicarboxylic acid of formula <FORM:0668663/IV (a)/1> with a hydroxy ester of the formula <FORM:0668663/IV (a)/2> the hydroxy ester is prepared by reaction of an alkylene oxide with an ester of a hydroxy acid and a mono- or di-hydric alcohol. Examples refer to the esterification of oxalic acid with the product obtained by condensing ethylene oxide with the n-butyl ester of 12-hydroxy stearic acid.ALSO:Ester lubricants are made by fully esterifying a saturated dicarboxylic acid of the formula <FORM:0668663/IV (b)/1> where R is either a hydrocarbon radical containing 0 to 26 carbon atoms or a series of aliphatic hydrocarbon radicals linked by at least one oxygen or sulphur atom, the total number of carbon, oxygen, and sulphur atoms being 3 to 80, at least two carbon atoms being between each pair of non-carbon atoms, and not more than two sulphur atoms being present in the radical, with a hydroxy ester of the formula <FORM:0668663/IV (b)/2> where R1 is an organic radical which is either a saturated aliphatic hydrocarbon radical containing 1-22 carbon atoms, or a saturated radical consisting of two aliphatic hydrocarbon groups interlinked by an oxygen or a sulphur atom, the total number of carbon atoms being 2 to 22; where R11 is either a saturated aliphatic hydrocarbon radical of 1-20 carbon atoms or a radical consisting of a series of saturated aliphatic hydrocarbon radicals linked through 1 to 5 oxygen or sulphur atoms, there is a chain of at least two carbon atoms between the ester group and the first oxygen or sulphur atom and between each pair of oxygen and sulphur atoms, the total number of carbon, oxygen, and sulphur atoms in the radical is 4 to 20. and not more than two sulphur atoms are present; R1, R2, R3 and R4 each represent hydrogen or an alkyl group and together contain not more than two carbon atoms; m is an interger of 1 to 20; n is an integer of 1 to 2; the reactants being so chosen that the molecular weight of the product is at least 300 and the viscosity at 210 DEG F. is not greater than 150 seconds (Saybolt), the proportions of the reactants being such that the product contains the residues of one molecule of the dicarboxylic acid and two molecules of the hydroxy ester. The hydroxy-ester is prepared by reaction of an alkylene oxide with an ester of a hydroxyacid and a mono- or dihydric alcohol. Examples refer to the esterification of oxalic acid with the product obtained from ethylene oxide and the n-butyl ester of 12-hydroxystearic acid, and to the esterification of sebacic and adipic acids with the product from n-butyl lactate and varying amounts of ethylene or propylene oxide. Other starting materials are listed.ALSO:A synthetic ester lubricant is prepared by fully esterifying a saturated dicarboxylic acid of the formula <FORM:0668663/III/1> with a saturated hydroxy ester of the formula <FORM:0668663/III/2> the reactants being so chosen that the molecular weight of the product is at least 300, the viscosity of the product at 210 DEG F. is not greater than 150 seconds Saybolt and the product contains the residues of one mole of the dicarboxylic acid and of two moles of the hydroxy ester. In the formula of the dicarboxylic acid, R is either a hydrocarbon radicle containing 0-26 carbon atoms, or an organic radicle consisting of a series of saturated aliphatic hydrocarbon radicles linked by at least one oxygen or sulphur atom, the total number of carbon, oxygen and sulphur atoms being 3-80, at least two carbon atoms being between each pair of non-carbon atoms, and not more than two sulphur atoms being present in the radicle. In the formula of the hydroxy ester, R1 is an organic radicle which is either a saturated aliphatic hydrocarbon radicle containing 1-22 carbon atoms, or a saturated radicle consisting of two aliphatic hydrocarbon groups interlinked by an oxygen or sulphur atom, the total number of carbon atoms in the radicle being 2-22; R11 is either a saturated aliphatic hydrocarbon radicle of 1-20 carbon atoms or a radicle consisting of a series of saturated aliphatic hydrocarbon groups linked through 1-5 oxygen or sulphur atoms, there being a chain of at least two carbon atoms between the COO group of the formula of the hydroxy ester and the first oxygen or sulphur atom in radicle R11 and between each pair of oxygen and sulphur atoms therein, the total number of carbon, oxygen and sulphur atoms in the radicle being 4-20, and not more than two sulphur atoms being present therein; R1, R2, R3 and R4 each represent hydrogen or an alkyl group and together contain not more than two carbon atoms; m is an integer of 1-20; n is 1 or 2. The hydroxy ester is prepared by reaction of an alkylene oxide with an ester of a hydroxy-acid and a mono-or di-hydro alcohol. Examples refer to the esterification of oxalic acid with the product obtained from ethylene oxide and the n-butyl ester of 12-hydroxystearic acid and to the esterification of sebacic and adipic acids with the product from n-butyl lactate and varying amounts of ethylene or propylene oxide. Other starting materials are listed. Various addition agents such as antioxidants, viscosity index improvers, thickeners, pour depressants and dyes, may be incorporated in the synthetic ester lubricant. Mineral lubricating oils may also be blended with the synthetic ester lubricant.