A recyclable and highly active magnetic solid superbase for hydrocracking CO bridged bonds in sawdust

A novel and highly active magnetic solid superbase (MSSB) with extraordinary recovery and recycling properties was prepared by impregnating Mg2Si onto mesoporous silica coated magnetite via one-pot preparation and successfully applied in the catalytic hydroconversion (CHC) of sawdust at 220 °C. Detailed molecular compositions of the soluble portions from non-catalytic hydroconversion (SPNCHC) and CHC (SPCHC) were characterized with a Fourier transform infrared spectrometer and gas chromatograph/mass spectrometer (GC/MS). As a result, the yield of SPCHC is significantly higher than that of SPNCHC and most of the GC/MS-detectable compounds in SPCHC are guaiacols, while SPNCHC is rich in guaiacols and esters, indicating that MSSB effectively catalyzed the cleavage of CO bridged bonds in sawdust. The mechanism for catalytically hydrocracking CO bridged bonds over MSSB is proposed using benzyloxybenzene and oxybis(methylene)dibenzene as model compounds. MSSB can be easily separated by using an external magnetic field and the recovered MSSB proved to be still highly active for catalyzing the hydrocracking of CO bridged bonds in sawdust.