Hydrodeoxygenation of Dibenzofuran over Mesoporous Silica COK-12 Supported Palladium Catalysts

Abstract

Hydrodeoxygenation (HDO) of dibenzofuran (DBF) with only a hydrogenation (HYD) reaction route was conducted on Pd/COK-12 catalysts with different Pd loadings, which were prepared by metal–organic chemical vapor deposition of [Pd(C3H5)(C5H5)] onto mesoporous silica COK-12. Hydrogenated intermediates with partial or full hydrogenation of the benzene ring were studied in detail. The presence of cycloketones is due to the high selectivity of Pd-based catalysts in the hydrogenation of phenols derived from the C–O bond cleavage of hydrogenated intermediates. The reaction only goes through the HYD reaction route with hardly detected biphenyl, which is further confirmed by HDO of 2-phenylphenol. The increase of Pd loading on the catalysts largely promotes the deoxygenation of saturated oxygen-containing species from hydrogenation of DBF, followed by cleavage of the sp3 C–O bond. Finally, a detailed reaction network of HDO of DBF is proposed according to the detected hydrogenated species and cycloketones.