Synthesis, characterisation and tribological investigation of vegetable oil-based pentaerythryl ester as biodegradable compressor oil

The present investigation is intended to adopt ultrasonication aided transesterification process for the formulation of pentaerythryl ester of rapeseed oil (PE) as biodegradable compressor oil. The formulated pentaerythryl ester was blended with synthetic grade compressor oil (SAE30) in the ratio of 25%, 50%, and 75% by volume. The tribological characterisation of compressor oil was carried out using four ball and high frequency reciprocating tribometer. The tribological investigations showed that pentaerythryl ester of rapeseed oil had better lubricity behaviour as compared to synthetic grade compressor oil. The lowest friction co-efficient, anti-wear behaviour and better thermo-oxidative stability was observed with blended compressor oil sample i.e., 75% by vol. of PE + 25% by vol. of SAE30. The outcome of the tribological investigation is helpful in finding vegetable oil-based compressor oil to replace petroleum-based compressor oil partially for industrial air compressor applications.