Yingwei Li, Dehua He, Zhenxing Cheng
Oct 23, 2001
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Journal
Journal of Molecular Catalysis A-chemical
Abstract
Abstract The promoting effects of various calcium salts on the activity and selectivity of ZrO 2 in isosynthesis were studied in this work. Calcium salts were added into zirconia by mechanical mixing methods. Catalytic tests were performed under relatively mild operation conditions (673 K, 650 h −1 , 5.0 MPa). CaF 2 and CaSO 4 were found to be effective additives, which could remarkably enhance the i- C 4 selectivity in total hydrocarbons while maintaining the activity of pure ZrO 2 when being added into zirconia. However, Ca(NO 3 ) 2 , Ca(BO 2 ) 2 and CaCl 2 wholly changed the distribution of hydrocarbons to favor the methanation. The results of temperature-programmed desorption (TPD) of NH 3 and CO 2 indicated that the performance of the catalysts depended on the acid–base properties of the catalysts. The appropriate amount of acid and base and the ratio of the basic to acidic sites on the catalysts are significant for the synthesis of i- C 4 hydrocarbons from CO hydrogenation.