Carbon-Supported Copper for Gas-Phase Hydrogenation Catalysis

Abstract

as Pb, S, or quinoline (Lindlar catalyst) 161 , has been reported to increase the selectivity, albeit at lower overall activity, by avoiding the presence of extended Pd surfaces. 144 Interestingly, supported Cu catalysts have been reported to be highly selective for the hydrogenation of various alkynes [162][163][164][165][166] and dienes. [75][76][167][168][169][170] Nevertheless, the Cu catalysts in literature consistently showed poor stability, resulting in catalyst deactivation within several hours on stream. In our group, Masoud et al. recently showed that the support can have a major effect on the stability of supported Au catalysts for the hydrogenation of butadiene. 171 Significantly higher stability was observed when using SiO2 compared to TiO2, due to reduced oligomer formation on the support surface. Using carbon or SiO2 as an inert support for monometallic Cu may provide relatively stable catalysts. In Chapter 6, we discuss the catalytic performance of monometallic Cu on carbon for the gas-phase hydrogenation of butadiene at atmospheric pressure, as a model reaction for selective hydrogenation catalysis (Eq. 1.5).

K and Na Promotion Enables High-Pressure Low-Temperature Reverse Water Gas Shift over Copper-Based Catalysts

“…The higher temperature required for CuO reduction on silica has been ascribed to various phenomena: the presence of some macrocrystalline CuO which is more difficult to reduce, the higher hydrophilicity of SiO 2 which induces a stronger retention of in situ generated water and/or a stronger interaction of CuO with the oxidic support than with carbon. 42,52,53 For all of the catalysts, the addition of an alkali promoter significantly lowers the CuO reduction rate, shifting the peak to higher temperatures. Upon the addition of K, the peak temperature shifted to 33 °C for the carbon-supported catalysts and 48 °C for the silica-supported catalysts.…”