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Hydrogenation of 2-ethylanthraquinone (EAQ) and 2-ethyltetrahydroanthraquinone (THEAQ) was carried out in a slurry reactor In a 1:1 xylene-2-octanol solvent and in the presence of a commercial size dispersed Raney nickel catalyst. The hydrogenation was found to be first order with respect to hydrogen and zero order with respect to anthraquinone. Accounting for mass transport resistances, the activation energies were found to be 34.4 ± 1.7 kJ/mol and 41.3 ± 10.7 kj/mol for EAQ and THEAQ, respectively. In hydrogenation of mixtures of EAQ and THEAQ, THEAQ reacts selectively in preference to EAQ and with a reaction rate dependent on the EAQ concentration. Mass transport resistances, especially in the pores of the catalyst, were found to play a significant role in hydrogenations with the commercial catalyst.

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Liquid-phase hydrogenation of p-xylene, m-xylene, and 1,4-di-fert-butylbenzene in cyclohexane was performed in a cross-flow catalyst reactor and in a slurry reactor with deposited rhodium as the active metal. The quite different distributions of products obtained in hydrogenation of 1,4-di-fert-butylbenzene in the two reactors were explained on the basis of a reaction mechanism including different modes of adsorption of the reactants. The different competition behavior of chemisorption, together with the particular concentration profiles in the porous plates of the cross-flow catalyst, strongly supported the formation of the cis isomer of 1,4-di-fert-butylcyclohexane compared to this formation in the slurry reactor.