Response surface methodology for optimization of bio-lubricant basestock synthesis from high free fatty acids castor oil

Abstract

In this paper, an eco-friendly single-step process for the synthesis of biolubricant basestock from high free fatty acid (FFA) castor oil (CO) via epoxidation reaction was investigated. Influence of various process parameters on the structural modification of CO and their interaction with the maximum oxirane oxygen content (OOC) was optimized. Central composite design (CCD) as one of the tools in response surface methodology (RSM) was used to evaluate the effects of process variables on maximum OOC. Iodine value (IV) and OOC was used to monitor the progress of epoxidation. From the RSM study, the optimal condition inferred was H2O2, 1.65 mol; catalyst loading, 15.14 wt%; temperature, 52.81°C; and reaction time, 2.81 h. At this optimum condition, OOC was found to be 3.85 mass%. Further, the epoxide product was confirmed by1H, 13C NMR spectral technique and OOC was determined by the standard HBr method. Finally, the significant physico-chemical properties for the prepared epoxide were determined and compared with the castor oil.