Patent ID: 8921289

Claim:
A process for improving the oxidation stability of lubricants comprising providing a lubricant comprising one or more esters containing branched alkyl groups which are reaction products of a Guerbet alcohol having 20 carbon atoms with azelaic acid and at least one additional fluid selected from the group consisting of mineral oils, highly refined mineral oils, alkylated mineral oils, poly-α-olefins, polyalkylene glycols, phosphate esters, silicone oils, diesters and esters of polyhydric alcohols, solvent neutral mineral oils, and XHVI, VHVI, Group II and Group III mineral oils, with the proviso that the lubricant has an oxidation stability of 1000 hours or more, as determined by the Turbine Oil Stability Test (TOST test) according to DIN EN ISO 4263-3; wherein the esters containing branched alkyl groups are present in quantities of 95 to 99.5% by weight, based on the total quantity of lubricant.