Stability of vegetable based oils used in the formulation of ecofriendly lubricants – a review

Abstract Human need for energy is insatiable. ManBackspace use of conventional and unconventional hydrocarbon sources has served human energy requirements but not without associated challenges of renewability, toxicity, depletion, degradability, and environmental hazards. Since a complete substitute for fossilized-energy sources is yet to be realized, one viable options available to man is alternative, renewable, ecofriendly, and biodegradable energy sources – thus, minimizing complete reliance on mineral based energy sources. Lubricants are finding relevance in product processing, transportation, agriculture, and other key sectors of industrial developments as a result of use of machines to aid human operations. While more than 70% of commercially available lubricants are from crude oil/hydrocarbon, commercial formulation of lubricants using vegetable base oils are gaining global interests. Lubricants obtained from bio-based oils are eco-compatible but are widely reported to be thermally and oxidatively unstable, especially when such biolubricants are produced from crude form of vegetable oils. The aim of this review is to reappraise various scholarly works on thermal-oxidative stability of vegetable oils so as to validate their usefulness as potential alternative and renewable sources of energy used in the production of lubricants as against continuous usage of mineral based energy sources which is ecologically non benign.