The present work focused on the screening process of different inorganic oxides and different temperatures for the epoxidation reaction of macaw palm vegetable oil without using solvent, a promising Brazilian biomass that can substitute other vegetable oils (e.g., soybean oil) in technological applications. This oil has an iodine value of 108.48 g of I2 per 100 g being categorized as a semi-dry oil. The epoxidized vegetable oil can be applied in manifold areas in polymer science. The epoxidation reaction here presented avoided organic solvents and organic acids and aimed to produce a greener route using metal oxides or niobium phosphate as a peroxide-activating catalyst. The experimental parameters were maintained as 10 mol% of catalyst loading and a time of 24 h; however, the temperature for some catalysts was changed to improve the epoxide conversion. Experiments were measured by proton nuclear magnetic resonance (1H NMR). Experiments using titanium oxide (TiO2) as a catalyst reached a conversion greater than 84.7%, while experiments using aluminium oxide (Al2O3) or lanthanum oxide (La2O3) achieved conversions of 22.6 and 30.1%, respectively. Furthermore, it was observed that both niobium compounds instantly react with hydrogen peroxide to form peroxy derivatives. solvent e.g., eg e (e.g. applications 10848 108 48 108.4 I semidry semi dry science peroxideactivating activating 1 mol 2 h however 1H H NMR. NMR . NMR) TiO2 TiO (TiO2 847 84 7 84.7% Al2O3 AlO Al O (Al2O3 La2O3 LaO La (La2O3 226 22 6 22. 301 30 30.1% respectively Furthermore derivatives e.g. (e.g 1084 4 108. (TiO 8 84.7 Al2O (Al2O La2O (La2O 3 30.1 e.g 84. 30.