Effects of Snthesis Cnditions on Ctalytic Prformance of Cu-ZnO-MnO_x/Al_2O_3 Ctalyst Dring Hdrogenolysis of α,α-dimethyl-benzyl Acohol

Cu-ZnO-MnOx/Al2O3 catalyst was prepared by a deposition-precipitation method and used in hydrogenolysis of α,α-dimethyl-benzyl alcohol to cumene.Various techniques including: X-ray diffraction,N2 adsorption-desorption,scanning electron microscopy and XRF were employed for characterizing the physico-chemical properties of this kind of catalyst.The effects of synthesis conditions such as pH value,deposition temperature,aging time,and calcinations temperature on catalytic performance were studied in detail.The results indicating that the pH value and aging time mainly affected the the rate of phase changing as well as the rate of substitution between Cu2+ and Zn2 +,the calcination temperature was affected the decomposition of precursor and the size of the catalyst.(Cu0.3Zn0.7)5(CO3)2(OH)6 and(CuZn)2(CO3)(OH)2 in the precursors were the vital phase in correspondence with the high activity of the catalyst.In addition,it seems that the CuO-ZnO solid-solution originating from the decomposition of(Cu0.3Zn0.7)5(CO3)2(OH)6 has higher catalytic activity than it counterpart originating from(CuZn)2CO3(OH)2.