Tall Oil Epoxidation in the Presence of Non-Noble Metal Oxide-Modified Heterogeneous Catalysts

Abstract

Catalytic epoxidation of tall oil, a Scandinavian raw material originating from the Kraft pulping process, was studied in this work. Conversely from the industrial process, the reaction was carried out via the hydroperoxide pathway, where the epoxidation of the double bonds takes place by hydrogen peroxide without the need for a reaction carrier. Metal oxide-modified SBA-15 catalysts were screened in the experiments performed in a laboratory-scale reactor where the operating conditions, such as the reaction temperature, the reaction time, and the reactant molar ratio, were kept constant. The main aim was to identify the best catalyst among those synthesized that would give promising results, in terms of activity and selectivity, in the epoxidation reaction. For this purpose, the relationship between the physicochemical properties of the selected catalysts and the obtained performances in the reaction system were studied in depth. Characterization analysis showed that almost all of the catalysts exhibited an organized mesoporous structure typical of SBA-15 without any morphological deformation after the metal introduction, which is present for all of them as oxide. Good activity was shown by most of the catalysts, with almost complete double bond conversion after 24 h reaction. However, selectivity to the target product was not as remarkable as the actvity. Among the tested catalysts, promising results were obtained in the presence of Mn-SBA-15 with a conversion and selectivity of 25 and 23% after 8 h of reaction, respectively.