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Modification of the Acid-base and Catalytic Properties of CuCl2-KCl-LaCl3/-Al2O3 by MgAl2O4 in Ethane Oxychlorination

Liu J., Sui Y., Zhou G., Zhen K., Zhang X., Cheng T.

Polish Journal of Chemistry

2007

Vol. 81, nr 1

95-101

Effect of MgAl2O4 on the structure, acidity as well as catalytic activity of CuCl2-KCl-LaCl3/gamma-Al2O3 catalyst in ethane oxychlorination was studied. Impregnation of gamma-Al2O3 with Mg and Al nitrates formed magnesium aluminate spinel on the support. TPR results showed that Cu species were located on both -Al2O3 and MgA gamma2O4 phases. With modification of -Al2O3 by MgAl2O4, the interaction between Cu species and support weakened and the surface active species CuCl2 increased. Formation of MgA gamma2O4 leads to a decrease of strong acid sites and an increase of weak acid sites. Much larger quantities of coke were deposited on the CuCl2-KCl-LaCl3/gamma-Al2O3 than on the modified catalyst, which was attributed to its more strong acid sites. Based on these factors CuCl2-KCl-LaCl3/MgAl2O4-Al2O3 catalyst exhibits better catalytic activity and stability than gamma-Al2O3 supported catalyst, and the highest vinyl chloride selectivity reached 46.8% and was still 40.6% after 210 h reaction.

GaAs absorber grown at low temperature used in passively Q-switched diode pumped solid state laser

Wang Y., Ma X., Wang C.L., Lin T., Zhen K., Wang J., Zhong L., Jia Y., Wei Z.Y.

Optica Applicata

2006

Vol. 36, nr 1

23-28

We report, for the first time to the best of our knowledge, on a passively Q-switched Nd:YVO4 laser with a GaAs absorber grown at low temperature (LT) by metal organic vapor phase expitaxy. Using the LT GaAs absorber as well as an output coupler, a passively Q-switched laser whose pulse duration is as short as 90 ns was obtained.

Estimation of Consecutive and Parallel Reactions During Dehydrogenation with Carbon Dioxide over Co-MCM-41

Li Y., Guo X., Zhou G., He X., Bi Y., Li W., Cheng T., Wu T., Zhen K.

Polish Journal of Chemistry

2005

Vol. 79 / nr 8

1357-1364

The main reactions between C2H6 and CO2 and their thermodynamics were studied, which indicated that there exist very complicated reactions between them. CO2 can enhance the equilibrium conversion of C2H4 formationvia dehydrogenation of C2H6 and react with the surface deposited carbon, resulting in stabilization of the activity and the prolongation of lifetime of the catalyst. Thus, the exploration of catalyst with desired C2H4 selectivity from oxidative dehydrogenation of ethane (ODE) is most important. In this study, the possible reactions of ODE with CO2 on Co-MCM-41 catalyst are discussed.