The Catalytic Dehydrogenation, Dehydroxylation, and Dehydroxymethylation of Benzyl Alcohol. III. The Effect of Metal Chlorides as Additives

Abstract

Abstract This paper will describe the reaction of benzyl alcohol in the presence of various kinds of modified stabilized nickel catalysts, which had been prepared from the mother catalyst by treating it with solutions of appropriate metal chlorides. The catalytic activities of each modified catalyst for the formation of benzene, toluene, and benzaldehyde were compared in terms of the fH,fCH3, and fCHO values; the selectivities for the formation of benzene and toluene against that of benzaldehyde, SH and SCH3, were also evaluated. In general, the formation of toluene and benzene was greatly affected both by the kind and by the amount of metal chlorides used as additives. The reaction was promoted by the addition of a proper quantity of alkali metal chloride. In the cases of the reactions by lowlymodified catalysts, the decreasing order of the fH and fCH3 values according to the kind of metal ion adsorbed on the catalyst was as follows: Na+≥K+>Co2+>Ca2+>Cd2+>Ba2+>Hg2+>Cu2+. On the other hand, in the higher degrees of modification, the corresponding order of the fH and fCH3 values was altered to be as follows: K+>Na+>Co2+>Cd2+>Ba2+≥Ca2+>Cu2+>Hg2+. With regard to the modified nickel catalysts treated with 0.08 n solutions, it was found that the sequence of the fH and fCH3 values due to the kind of metal ion was roughly correlated with that of the atomic numbers of the corresponding metals. The results are discussed in connection with the general concept of catalytic chemistry.