Patent GB-951261-A (GB)
Title: Synthetic ester oil manufacture
IPC: C07C69/76
Filed: 1960-11-15
Abstract: In the preparation of diesters of an alcohol and a dicarboxylic acid or a glycol and a monocarboxylic acid, the esterification and subsequent purification are carried out in an inert atmosphere and the diester is stored undere an inert atmosphere. The ester may have the formula R COO R 1OOCR or the formula R OOC R 1COOR, where R is an alkyl radical of 6 to 12 carbon atoms and R1 is a saturated aliphatic hydrocarbon group of 4 to 10 carbon atoms.  The purification comprises washing with sodium carbonate solution, washing with water, stripping off volatile material by heating under a vacuum, contacting with active alumina particles, and filtering.  The esterification and purification operations may be carried out in a series of connected vessels or in a single vessel, under an atmosphere of nitrogen.  In an Example adipic acid is reacted with a C10 oxo alcohol to form a half ester, and then with a C8 oxo alcohol to form a C8/C10 oxo adipate ester, using sodium acid sulphate as a catalyst and benzene as a water entraining agent.  Other esters mentioned are dipropylene glycol dipelargonate, di(C8 oxo) adipate, di(C10 oxo) adipate, di(2-ethylhexyl) azelate, di(C8 oxo) azelate and di(C9 oxo) sebacate. Other catalysts mentioned are sodium methylate, metallic sodium, sulphuric acid, toluenesulphonic acid and zinc oxide. Other entraining agents mentioned are toluene and heptane.ALSO:In the preparation of lubricants comprising diesters of formula R COOR1OOC R or R OO CR1COO R, where R is an alkyl radical of 6 to 12 carbon atoms and R1 is saturated aliphatic hydrocarbon group of 4 to 10 carbon atoms, the esterification, subsequent purification of the ester, blending with other esters and additives, and packaging and storing of the lubricant, are all carried out under an inert, oxygen-free atmosphere, e.g. nitrogen.  The diester may be blended with 5 to 25% by weight of other esters, e.g. di-(2-ethylhexyl) sebacate, di-(2-ethylhexyl) adipate or a complex of formula R1OOCR2COO(R3OOCR4COO)xR5 where R1 and R5 are alkyl radicals containing 6 to 12 carbon atoms, R2 and R4 are saturated hydrocarbon or oxyhydrocarbon radicals of 2 to 20 carbon atoms derived from glycols or polyglycols, R3 is a hydrocarbon radical of 4 to 10 carbon atoms derived from an alkanoic acid, and x is 1 to 6. The composition may contain 0.01 to 10% by weight of each of various additive, e.g. tricresyl phosphate, polymeric silicones of 1,000 to 100,000 molecular weight, sebacic acid and di-(C8-oxo) diesters of pyromellitic acid dianhydride, polymethylene silicon anti-foamants, and antioxidants, e.g. phenothiazine and a tetra-butyl bisphenol.  In an example, an ester is formed from adipic acid, a C10 oxo alcohol and a C8 oxo alcohol, and blended with di-(2-ethylhexyl) sebacate, a complex ester (prepared from a polyethylene glycol, C8 oxo alcohol and adipic acid), tricresyl phosphate, phenothiazine, the C8 oxo diester of pyromellitic dianhydride, sebacic acid and a polymethyl phenol silicone, all under nitrogen. Other esters mentioned are dipropylene glycol dipelargonate, di(C8 oxo) adipate, di(C10 oxo) adipate, di(2-ethylhexyl) azelate, di(C8 oxo) azelate and di(C9 oxo) sebacate.