The influence of multiwalled carbon nanotubes and graphene oxide additives on the catalytic activity of 3d metal catalysts towards 1-phenylethanol oxidation

3d metal (Cu, Fe, Co, V) containing composite catalysts for the solvent-free microwave-assisted transformation of 1-phenylethanol to acetophenone with tert-butyl hydroperoxide (TBHP) as oxidant were prepared by ball milling. The influence of multiwalled carbon nanotubes (CNTs) and graphene oxide (GO) additives on the catalytic activity of the catalysts was studied. CNTs or GO were mixed by ball milling with the metal salts (CoCl2), oxides (CuO, Fe2O3, V2O5) or binary systems (Fe2O3-CoCl2 CoCl2-V2O5, CuO-Fe2O3). For CoCl2-based catalytic systems, addition of small amounts (0.1\u20135%) of CNTs or GO leads to significant improvement in catalytic activity, e.g. 1% of the CNTs additive allows to rise yields from 28 to 77%, under the same catalytic conditions. The CoCl2-5%CNTs composite is the most active among the studied ones with 85% yield and TON of 43 after 1 h

Ball milling as an effective method to prepare magnetically recoverable heterometallic catalysts for alcohol oxidation

Heterometallic double Fe2O3\u2013CoCl2, CoCl2\u2013V2O5, MoO3\u2013V2O5, and triple CuO\u2013Fe2O3\u2013CoCl23d metal dispersed systems were easily prepared by ball milling at room temperature and characterized by scanning electron microscopy (SEM), field emission gun scanning electron microscopy (FEGSEM), energy-dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). They catalyze the microwave-assisted solvent-free heterogeneous oxidation of 1-phenylethanol to acetophenone with tert-butyl hydroperoxide (t-BuOOH) as oxidant, used as a model reaction. In most of the heterometallic systems a significant improvement in the catalytic activity was observed in comparison to homometallic ones. For the tested catalytic systems and experimental conditions, the CuO\u2013Fe2O3\u2013CoCl2and Fe2O3\u2013CoCl2systems exhibit the highest activity with maximum 78% yield and TON 39 after 1 h. The possibility of magnetic recovery of the catalysts was demonstrated for the Fe2O3\u2013CoCl2(3:1) system