Ru-Cd/Bentonite for the Partial Hydrogenation of Benzene: A Catalyst without Additives

Clays are very promising, environmentally benign catalyst supports. Herein, RuCd/bentonite (BEN) catalysts were prepared and characterized by TEM, SEM, XPS, and XRD. The as-prepared catalysts were used to catalyze the selective hydrogenation of benzene into cyclohexene with different Ru/Cd molar ratios, hydrogen pressures, and reaction temperatures. We found that the catalytic activity decreased with decreasing Ru/Cd molar ratio, whereas the selectivity was enhanced. The most-favorable Ru/Cd molar ratio was 1 and the optimal hydrogen pressure and temperature were 5 MPa and 150?degrees C, respectively. The yield of cyclohexene reached 24.8?% over RuCd/BEN under the optimal reaction conditions without the need for any additives in the reaction system and this catalyst could be reused several times in the reaction without a drop in the yield of cyclohexene. The Cd in the catalyst enhanced the selectivity for cyclohexene. Furthermore, Cd/BEN could be used an as effective supported additive to promote the hydrogenation of benzene into cyclohexene catalyzed by Ru/BEN or Ru/SBA-15.