A green approach to synthesize polybutene lubricants from mixed C4 monomers using supported dendritic ionic liquids

Lubricants, composed of a base oil and various additives, reduce friction and abrasion between moving surfaces. High-performance lubricants, especially in the automotive and space industries, have driven advancements in synthetic oils like polyalphaolefins (PAOs), known for their high viscosity index and stability. Low molecular weight polyisobutylenes (PIBs) are used in multiple applications, including as viscosity improvers. PIBs are produced via cationic polymerization of isobutylene using Lewis acid initiators and co-initiators, often conducted at low temperatures with harmful substances like BF3. Efforts are being made to develop more eco-friendly processes, such as using AlCl3 and ionic liquids (ILs). In this research, boehmite-supported dendritic ILs (Gen1 and Gen2) were synthesized and tested as co-initiators in Raffinate-1 polymerization. The ILs improved the stability of the catalytic system, allowing for reduced AlCl3 usage, and produced PIBs with desirable molecular weight and viscosity characteristics. Density Functional Theory calculations unveiled the importance of the interaction of AlCl3 with the ionic liquids.