Selective Synthesis of Perillyl Alcohol from β-Pinene Epoxide over Ti and Mo Supported Catalysts

Abstract

Isomerization of β-pinene epoxide to perillyl alcohol using several materials based on titanium and molybdenum is reported. The metals were incorporated on SBA-15, MCM-41 and SiO2 supports by incipient wetness impregnation and characterized by XRD, atomic absorption, BET, Raman spectroscopy, diffuse reflectance UV–Vis spectroscopy, TPD-NH3 and 29Si NMR. After metal incorporation, crystallinity and surface area of both MCM-41 and SBA-15 decreased. UV–Vis and Raman also revealed the presence of MoO3 species and no presence of TiO2. In addition, Ti materials showed less amount of acid sites than catalysts containing Mo. Synthesis of perillyl alcohol from β-pinene epoxide was affected by the content of acid sites; Mo/SBA-15 catalyst was more active than Mo/MCM-41 and Mo/SiO2 supported materials. Over Mo/SBA-15 a complete β-pinene epoxide conversion and perillyl alcohol selectivity of 63% were obtained at 1 h of reaction, results that are similar to the best activity reported up to now; Mo/SBA-15 can be recycled at least six times without any appreciable loss of conversion nor selectivity. Finally, a reaction pathway is proposed based on experimental information, explaining the exclusive formation of perillyl alcohol from β-pinene epoxide.