Abstract
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 °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.
•Enzymatic production of neopentyl glycol esters for use as friendly biolubricants.•High conversions (>95%) were obtained for castor and soybean biodiesel.•Enzymes Novozyme 435 and Lipozyme RM IM could be reused for six reactions.•Soybean NPG esters showed good viscosity index (>198).•Castor NPG esters had good pour point (<−20 °C) and oxidative stability (>30 min).