<scp>Synthesis</scp> of environment‐friendly, sustainable, and nontoxic bio‐lubricants: A critical review of advances and a path forward
Sonam V. Sancheti, Ganapati D. Yadav
Abstract
Abstract Carbon neutral biosources are sought for the protection of the environment and to meet the energy needs of the growing population. For instance, lubricants are required in huge quantities. Synthesis of environment‐friendly, sustainable and non‐toxic bio‐lubricants from renewable and bio‐degradable feedstocks such as vegetable oils and animal fats will be most desirable. The thermal stability and lower volatility of these triglycerides make them suitable as precursors for lubricants. This review briefly covers the chemical modifications required to transform plant‐ and animal‐based triglycerides into efficient bio‐lubricants. Chemical modifications are required to improve one or more physicochemical or tribological properties of bio‐lubricants such as low‐temperature flow properties or the oxidation stability of fatty acids/oils for different applications. The use of heterogeneous catalysts makes the processes clean. The relationship between their molecular structures, physicochemical properties and lubrication performance is reviewed. Additives such as antioxidants, sulfides, phosphates, metal and metal oxide nanoparticles, and ionic liquids are used to enhance the lubricant properties. With proper modifications in a base oil, support and additives, bio‐lubricants can perform similar to or even better than conventional lubricants. A further advantage is that they can be easily adapted using existing infrastructure and lubricant formulations. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.