Analysis of fatty acid composition, structure, and proportion in polyol esters applied in aviation turbine engines

Synthetic esters are widely applied in aviation turbine engines due to its excellent lubrication performance. Mixed acids with varying chain lengths and degrees of isomerization are often used in the esterification process to ensure the comprehensive lubricity of synthetic esters. In industrial production, the feeding ratio of mixed acids is usually adjusted by viscosity properties of synthetic esters, so the exact proportion of each acid in the final product is unknown. A method has been developed here to rapidly extract fatty acids used in commercially available synthetic ester lubricants through transesterification reactions, with methanol as the ester exchange reagent. Accurate qualitative and quantitative analysis of it is performed using GC-MS. Compared with the saponification extraction technique, this method is fast, simple, and easy to operate. The formation of this analytical approach can not only simplify the identification of fatty acids in industrial synthetic esters, but also help to determine the accurate ratio of mixed acids in laboratory esterification products, thereby providing technical support for the upgrading and replacement of products.