| 摘要 |
The tendency for the viscosity of a synthetic lubricating oil, consisting of or containing a complex ester (containing 2 or more carboxyl residues), to increase on storage at low temperatures is inhibited by adding a minor proportion of commercial activated charcoal to the oil, heating the mixture to a temperature above 100 DEG C., and filtering the mixture. The complex esters may have the formul R2OOCR1COOR4OOCR3, R2(OOCR1COOR4)n OOCR11COOR12, R3COOR4OOCR13, R3COOR4 (OOCR1COOR14)nOOCR13 or R2OOCR1 COOR12, wherein R1 and R11 are the residues of dicarboxylic acids HOOCR1COOH, R2 and R12 are the residues of monohydric alcohols R2OH, R3 and R13 are the residues of monocarboxylic acids R3COOH, R4 and R14 are the residues of glycols HOR4OH and n is a number, from 1 to 6, which need not be integral. The monohydric alcohols R2OH may be derived from the oxo synthesis and may contain sulphur and oxygen atoms in thioether or ether linkages. The glycols HOR4OH may be alkylene or polyalkylene glycols. A specific complex ester mentioned is one prepared by reacting 1 mol. of tetraethylene glycol with 2 mols. of sebacic acid and esterifying the acid product so formed with 2-ethyl-hexanol. In an example, a blend of this complex ester with dinonyl sebacate is heated with 2 per cent by weight of commercial activated charcoal to 150 DEG C. and then filtered. Specification 666,697 is referred to.ALSO:The tendency for the viscosity of a synthetic lubricating oil, consisting of or containing a complex ester (containing 3 or more carboxyl residues), to increase on storage at low temperatures is inhibited by adding a minor proportion of commercial activated charcoal to the oil, heating the mixture to a temperature above 100 DEG C., and filtering the mixture. A list of suitable types of complex esters is given. The synthetic lubricating oil may also contain diesters, antioxidants, antiwear agents and V.I. improvers. In an example, a blend of dinonyl sebacate and a complex ester (prepared by reacting 1 mol of tetraethylene glycol with 2 mols of sebacic acid and esterifying the acid product so formed with 2-ethyl-hexanol), is heated with 2 per cent by weight of commercial activated charcoal to 150 DEG C., and then filtered. Specification 666,697 is referred to. |
