Hydrogenation of benzene to cyclohexene on an unsupported ruthenium catalyst: Effect of poisons

Abstract

The influence of poisoning of ruthenium catalysing the selective hydrogenation of benzene to cyclohexene has been studied. Both the yield of cyclohexene and the rate of hydrogenation are greatly affected by the degree of poisoning (e.g. FeS04, FeCla, Tic13 and oxygen), and may also be optimised. A reproducible catalyst has been prepared by precipitating the catalyst precursor, as the hydroxide, in a glass vessel at 353 K without influence ofcorrosion products from the reactor material. The influence of the hydrogen pressure on activity has also been investigated. An optimum pressure for maximum yield of cyclohexene was obtained and a rate expression was formulated which could account for reaction orders varying with hydrogen pressure.

Partial hydrogenation of benzene to cyclohexene on a Ru–Zn/m-ZrO2 nanocomposite catalyst

“…There are four phases present: one solid phase, two liquid phases, and a gas phase. Moreover, benzene hydrogenation follows the consecutive and/or parallel reaction routes [29]. Therefore, it is more realistic to derive the optimal reaction conditions for cyclohexene production over the new catalyst by way of experimentation.…”

Selective Hydrogenation of Benzene to Cyclohexene over 2Ru/La2O3‐ZnO Catalyst without Additional Modifiers

“…At higher hydrogen pressure, the rate would decrease owing to higher surface coverage of hydrogen compared with benzene, resulting in lower reaction rates . Furthermore, the maximum reaction rate is attributable to the different dependence on the reaction rates of r 1 and r 2 , see Scheme . Thus, the hydrogenation of benzene ( r 1 ) and cyclohexene ( r 2 ) is a function of the surface adsorbates [H 2 , benzene (BEN), and cyclohexene (CHE)] on the catalyst surface [Eq.…”

“…[12] Furthermore, the maximum reactionr ate is attributable to the different dependence on the reactionr ates of r 1 and r 2 ,s ee Scheme 1. [13] Thus, the hydrogenation of benzene (r 1 )a nd cyclohexene (r 2 )i safunction of the surface adsorbates [H 2 ,b enzene (BEN), and cyclohexene (CHE)] on the catalyst surface [Eq. (1)-(2)]: Table 1.…”

Selective hydrogenation of benzene to cyclohexene using a Ru catalyst suspended in an aqueous solution in a mechanically agitated tetraphase reactor: a study of the influence of the catalyst preparation on the hydrogenation kinetics of benzene and of cyclohexene

“…The selective of benzene in a tetraphase reactor in the presence of Ru-black and an aqueous solution was extensively studied by Odembrand et al in early 1980s [9,10]. They investigated the effect of the composition of the water solution on yield and selectivity, which are significantly influenced by the diffusion of the reagents.…”

“…As other authors pointed out, the diffusion of the reagents at the interfaces, strongly affects catalyst selectivity [10][11][12][13]. In order to compare the reactivity of many catalysts, it is necessary to determine for each one, the extent of the physical limitation at the interfaces.…”