Preparation, Characterization, and Catalytical Application of MgCoAl-Hydrotalcite-Like Compounds

MgCoAl-hydrotalcite-like compounds (MgCoAl-HTLcs) were synthesized using the copre- cipitation method of variable pH values. The effect of each factor on the preparation of HTLcs was discussed systematically, which included pH values, mole ratios of Mg2+ to Co2+, the concentrations of the solution, and the temperature and time of the hydrothermal treatment. Besides, the thermal de- composition of MgCoAl-HTLcs was discussed. X-ray diffraction, thermogravimetric analysis, and FT-IR spectroscopy were performed to characterize the MgCoAl-HTLcs samples. The results showed that when the pH = 7.6–8.5 or 5.5–6.2, atomic ratios of (Mg2++Co2+)/Al3+ =2andMg2+/Co2+ ranging from 1.00 to 2.00, temperature and time of hydrothermal treatment being 110 °C and 6 h, unique MgCoAl-HTLcs with high crystallinity could be obtained. When the calcination temperature was up to 250 °C, the MgO phase was detected coexisting with Al2O3 and MgAl2O4 was highly spreaded on the derived mixed oxides. The synthesis reaction of benzoin methyl ether with methanol and benzaldehyde was chosen to study the catalytic activity of MgCoAl-HTLcs. The catalyst showed high activity and high stability in the synthesis of benzoin methyl ether in the feasible condition.