Preparation of α-Terpineol from Biomass Resource Catalysed by Acid Treated Montmorillonite K10

Abstract

A new type of heterogeneous catalyst for hydration of α-pinene was prepared. Montmorillonite K10 was treated by various acids (H2SO4, HCl, HNO3, and ClCH2COOH) and successfully used for the mentioned reaction. The used characterization techniques showed that the acid treatment improved the properties of K10 important for the catalytic activity (SBET and acidity). On the other hand, the morphology and particle size distribution remained the same. Regarding the selectivity (side and consecutive reactions can proceed), the optimal reaction conditions were found (temperature, type of the catalyst, amount of the catalyst, molar ratio α-pinene: water, type of water, solvent). Using the optimal reaction conditions, 60% conversion of α-pinene was achieved with 45% selectivity to α-terpineol (80 °C, 25 wt% of K10/HCl, or K10/H2SO4, nα-pinene:nwater 1:7.5, 1,4-dioxane as a solvent, 24 h). Higher conversions of α-pinene, as well as higher selectivity to α-terpineol, were achieved using all acid treated K10 in comparison to raw K10. Considering the heterogeneous form of prepared catalysts, its availability, low price and easy method of preparation, these catalysts dispose of a large potential for application as catalysts for hydration reactions.