Process intensified lauric acid self-ketonization and its economic and environmental impact on biolubricant base oil production

Abstract

Lubricant base oils, traditionally derived from non-renewable petroleum, contribute significantly to greenhouse gas emissions. In contrast, oils sourced from furfural and long-chain ketones through aldol condensation and hydrodeoxygenation present a renewable, cost-effective, and environmentally friendly alternative, offering superior cold flow properties. However, the production of long-chain ketones, a crucial component, currently relies on solvent dewaxing in refineries, which is costly and non-selective. One promising biobased approach involves self-ketonization of long-chain fatty acids derived from coconut or palm kernel oils. This method typically employs high boiling point solvents like dodecane or is done in a batch configuration, limiting its scale and industrial viability. This study addresses this bottleneck by eliminating solvents, transitioning to a continuous flow reactor, and achieving kilogram-scale production of long-chain ketones with exceptional selectivity (90%). The lab-scale setup can yield up to 25 kg of 12-tricosanone per month, utilizing earth-abundant MgO as a catalyst. The catalyst underwent slight deactivation due to carbonate formation. Catalyst stabilization, using mixed metal oxides, and regeneration via simple calcination in air are also discussed. Techno-economic analysis (TEA) indicates a 29% lower minimum selling price than the commercial synthetic poly alpha olefin (PAO). Life cycle assessment (LCA) evaluates the global warming potential (GWP) under different environmental assumptions. Under the carbon-neutral assumption for lauric acid production, an 8.9% reduction in GWP was achieved compared to petroleum-based lubricants.