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 Mg 2 Si 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 (SP NCHC ) and CHC (SP CHC ) were characterized with a Fourier transform infrared spectrometer and gas chromatograph/mass spectrometer (GC/MS). As a result, the yield of SP CHC is significantly higher than that of SP NCHC and most of the GC/MS-detectable compounds in SP CHC are guaiacols , while SP NCHC is rich in guaiacols and esters, indicating that MSSB effectively catalyzed the cleavage of C O bridged bonds in sawdust. The mechanism for catalytically hydrocracking C O 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 C O bridged bonds in sawdust.