Isomerization of alpha-pinene oxide over solid acid catalysts

Abstract

A number of solid acid catalysts were prepared. MSU-S aluminosilicates were synthesized using HY and zeolite Beta seeds. These samples had both micropores and mesopores. The surface area of these micro/mesoporous materials was high, in the order of 800-1000 m2/g and about 10 % of the surface area was due to micropores. From pyridine adsorption studies, only Lewis acid sites were present. In B2O3/SiO2 sampples, B2O3 loadings below 15% resulted in only Lewis acidity while at higher loading, Br??nsted acidity was detected. An increse in boron oxide loading decreased the surface area and pore volume. XRD data showed that boria was present in the hydrated form, H3BO3. Both BO4 and BO3 units were detected by 11B-NMR studies. InCl3/Zr(OH)4 was X-ray amorphous and had both Lewis and Br??nsted acidity. MSU-SHY was a good solid acid catalyst for I?-pinene oxide isomerization. HCl-treated MSU-SHY(70) showed 100% selectivity to campholenic aldehyde. B2O3/SiO2 were also promising catalysts for the isomerization. However, the selectivity was lower than the MSU-compounds.