Catalytic synthesis of renewable lubricant base oils with methyl oleate and aromatics†

Abstract

Renewable lubricant base oils derived from biomass can effectively mitigate environmental challenges while exhibiting exceptional properties. Herein, we propose a novel approach for the synthesis of ester-based and alkane-based renewable lubricant base oils, achieving an impressive yield of up to 99%. This strategy involves the utilization of methyl oleate and biomass-derived aromatics through two distinct chemistries: alkylation and alkylation followed by hydrodeoxygenation (HDO). Among the various Lewis acid catalysts screened, AlCl₃ demonstrated superior performance and achieved a remarkable maximum yield of 99% for the alkylation product under the optimized reaction conditions. Subsequent hydrodeoxygenation (HDO) of these alkylation products using the Ir-ReO_x/SiO₂ catalyst resulted in the production of alkane-based lubricant base oils, with an impressive maximum yield of 96.3%. The molecular size and branching of ester-based and alkane-based products can be finely adjusted by employing diverse aromatic compounds during the alkylation process, thereby enabling tuning of their lubricant properties. The as-synthesized base oils exhibit superior properties to petroleum-derived group III base oils and demonstrate comparable performance to synthetic ester and PAO base oils. The presented strategy for synthesizing renewable base oils offers a sustainable alternative to petroleum-derived counterparts, thereby potentially mitigating greenhouse gas emissions.