Alkyd resin synthesis by enzymatic alcoholysis

The synthesis of an alkyd resin through an enzymatic alcoholysis provided by Novozym 435 was analyzed in this study. The alcoholyses were performed in different enzyme concentrations (2.63, 4.00, 6.00, 8.00, and 9.36%, based on oil’s mass), oil/glycerin ratios (1.68, 2.50, 3.50, 4.50, and 5.18 oil mol/glycerin mol), at temperatures (33.18, 40.00, 50.00, 60.00, and 66.82 °C) to determine the best reaction conditions for obtaining the highest percentage of monoacylglycerides and diacylglycerides [glycerin/vegetal oil ratio of 1:3.5 (mol/mol), at temperature of 56.73 °C, and 9.36% enzyme concentration based on oil’s mass (w/w)]. It was verified that 2 h was the ideal reaction time. Under the best alcoholysis condition, the alkyd resin was produced using phthalic anhydride and the product presented similar characteristics as the current resin produced by a chemical catalyst in the industrial process (final viscosity = Y2, solid content = 44.00%, and IA ≤ 12). 1 H NMR and FTIR analyses confirmed the formation of an alkyd resin as they showed the presence of characteristic signals of the final product. The re-usability of the enzyme was investigated, and significant results were observed in the reaction after five cycles (by activity reduction of 6%) showing the viability of applying enzymatic steps in industrial procedures to produce resins in the future, once the application of enzymes also reduced the level of toxicity in the processes.