Patent GB-921482-A (GB)
Title: Process of preparing complex esters and products thereof
IPC: C07C69/34
Filed: 1959-03-06
Abstract: A blended synthetic lubricant comprises about 10-40 wt. per cent of a diester of lubricating viscosity and about 60-90 wt. per cent of a complex ester having a kinematic viscosity greater than about 7,5 cs. at 210 DEG F. and less than about 13,000 cs. at -40 DEG F. and prepared by esterifying, in the presence of a glycol titanate in an amount of about 0,05 to 5% by weight of the reactants, a glycol, an aliphatic primary mono-alcohol and a dibasic aliphatic carboxylic acid in the approximate proportions of one mole of glycol to two moles of alcohol to two moles of acid.  Suitable glycols include C3-12 monoglycols and the polyglycols thereof containing up to 10 ether groups; thioether groups may be present; neopentyl glycol is preferred and used in the examples.  Suitable monohydric alcohols include C5-13 alcohols which may contain other groups; C8-10 branched chain alcohols are preferred, 2-ethylhexanol, isooctanol and isodecanol being used in examples.  Suitable dibasic acids contain up to 12 carbon atoms, sebacic and azelaic acids and mixtures thereof being used in examples.  The diester may be derived from aliphatic monohydric alcohols containing up to about 20 carbon atoms and dibasic acids containing 2 to 12 carbon atoms; di-2-ethylhexyl sebacate and di-isooctyl azelate are used in examples.  The blend may also contain oxidation inhibitors such as phenothiazine and foam inhibitors such as a methyl silicone polymer.ALSO:Complex esters are prepared by esterifying, in the presence of a glycol titanate in an amount of about 0,05 to 5% by weight of the reactants, a glycol, an aliphatic primary mono-alcohol and a dibasic aliphatic carboxylic acid in the approximate proportions of one mole of glycol to two moles of alcohol to two moles of acid.  The esters may be made by either a one-stage or a two-stage process.  In the former all reactants and the catalyst are refluxed in the presence of a water-entrainer until the theoretical quantity of water has been collected, and in the latter the acid or acids and the mono-alcohol are refluxed with the catalyst and entrainer until no more water is evolved and the glycol then added and the reaction continued.  The product may be capped with a monohydric alcohol.  The catalyst may be removed by filtration.  The product may be stripped of volatiles, preferably before filtration and at a temperature of about 175 DEG to 250 DEG C. and a pressure of 2 to 25 mm. Hg.  Suitable glycols include C3-12 monoglycols and the polyglycols thereof containing up to 10 ether groups; thioether groups may be present; neopentyl glycol is preferred and used in the examples. Suitable monohydric alcohols include C5-13 alcohols which may contain other groups; C8-10 branched chain alcohols are preferred, 2-ethylhexanol, isooctanol and isodecanol being used in examples.  Suitable dibasic acids contain up to 12 carbon atoms, sebacic and azelaic acids and mixtures thereof being used in examples.  The products may be blended with diesters to give lubricant compositions (see Group III).ALSO:Complex esters are prepared by esterifying, in the presence of a glycol titanate in an amount of about 0.05 to 5% by weight of the reactants, a glycol, an aliphatic primary monoalcohol and a dibasic aliphatic carboxylic acid in the approximate proportions of one mole of glycol to two moles of alcohol to two moles of acid.  The esters may be made by either a one-stage or a two-stage process.  In the former all reactants and the catalyst are refluxed in the presence of a water-entrainer until the theoretical quantity of water has been collected and in the latter the acid or acids and the mono-alcohol are refluxed with the catalyst and entrainer until no more water is evolved and the glycol then added and the reaction continued.  The product may be capped with a monohydric alcohol.  The catalyst may be removed by filtration.  The product may be stripped of volatiles, preferably before filtration and at a temperature of about 175 to 250 DEG C. and a pressure of 2 to 25 mm. Hg. Suitable glycols include C3-12 monoglycols and the polyglycols thereof containing up to 10 ether groups; thioether groups may be present; neopentyl glycol is preferred and used in the examples.  Suitable monohydric alcohols include C5-13 alcohols which may contain ether groups; C8-10 branched chain alcohols are preferred, 2-ethylhexanol, isooctanol and isodecanol being used in examples. Suitable dibasic acids contain up to 12 carbon atoms, sebacic and azelaic acids and mixtures thereof being used in examples.  The products may be blended with diesters to give lubricant compositions (see Group III).