Hydrodeoxygenation of dibenzofuran over mesoporous silica COK-12 supported palladium catalysts

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 sp(3) C-O bond. Finally, a detailed reaction network of HDO of DBF is proposed according to the detected hydrogenated species and cycloketones.