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1 Polish Journal of Chemical Technology

1 2005

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Characterization of zirconia-magnesia-yttria materials used as catalysts for esters and alcohols fractions transformations by ketonization

Klimkiewicz R., Teterycz H., Sikora E., Rakoczy J., Biskupski A., Trawczyński J.

Polish Journal of Chemical Technology

2005

Vol. 7, nr 1

29-32

In former publications the application of the monophase material Zr(0.89)-Mg(0.10)-Y(0.01)-O as a catalyst of the waste alcohol and ester fractions ketonization was described. In the present work various compositions of the Zr-Mg-Y-O type respecting the reaction group: Zr(0.89)-Mg(0.10)-Y(0.01)-O(CL) synthesized from chlorides, Zr-Mg-Y-O(SULPH) from zirconium sulfate, mixed oxide ZrO2+Y2O(3BOG) and its derivative Zr-Mg-Y-O(BOG) are characterized. The catalytic properties of the materials were characterized with the use of n-butanol test, isopropanol test, cyclohexene + H2 test as well as TPD NH3, and FT-IR (pyridine) spectroscopy. Zr-Mg-Y-O(SULPH) catalyst obtained from the sulfate precursor, as compared to Zr(0.89)-Mg(0.10)-Y(0.01)-O(CL), revealed a much lower selectivity of the reaction of the primary and secondary alcohols into ketones. The surfaces of Zr(0.89)-Mg(0.10)-Y(0.01)-O(CL) and ZrO2 + Y2O(3BOG) materials, although they contained comparable numbers of the Lewis acidic centers (164 and 126 žmol Py/g, respectively), differed considerably as for the selectivity in the reaction of n-butyl alcohol condensation: ZrO2,+Y2O(3BOG) was not a selective catalyst of the ketonization. Under the conditions of the cyclohexene + H2 test over ZrO2 + Y2O(3BOG) the reaction proceeded towards isomerization and cracking, while Zr(0.89)-Mg(0.10)-Y(0.01)-O(CL) catalyzed hydrogenation. The application of Zr-Mg-Y-O(BOG) material of the lower Lewis acidity (62 žmol Py/g) did not result in the higher selectivity of the ketonization. However, the result of the cyclohexene + H2 test changed. Thus, a considerable number of the Lewis acidic centers (such as ZrO2+Y2O(3BOG) was not the only necessary condition for the bimolecular condensation of the primary alcohols and/or aldehydes or for esters transformation. The search for materials should be conducted towards the syntheses of the catalysts of the dehydrogenation properties and containing in their structure oxygen vacancies which could form the Lewis acidic centers.