Enzymatic synthesis of neopentyl glycol-bases biolubricants using biodiesel from soybean and castor bean as raw materials

Synthetic oleochemical esters represents a growing alternative for mineral oil-based lubricants. In this sense, the present study shows the results of enzymatic synthesis of neopentyl glycol-bases biolubricants using biodiesel from soybean and castor bean as raw materials. The potential of two commercial immobilized lipases, lipase B from Candida antarctica (Novozyme 435) and lipase from Rhizomucor miehei (Lipozyme RM IM), to produce NPG esters in a solvent-free medium was evaluated. High conversions (>95%) were obtained for both raw materials, with both enzymes, but in a shorter reaction time for soybean biodiesel (24 h) than castor biodiesel (48 h). Both enzymes could be successfully reused for six reactions, Novozyme 435 maintained >= 70% of the initial conversion using the two raw materials and Lipozyme RM IM maintained >= 90% of the first reaction conversion using castor biodiesel. The soybean NPG esters showed good viscosity index, higher than 198, and the castor NPG esters showed good pour point, lower than -20 degrees C, and good oxidative stability, higher than 30 min. The physico-chemical properties of the biolubricants were dependent on the biodiesel source which directly influence the final application of the products. (C) 2019 Elsevier Ltd. All rights reserved.