High-Performance Catalysts Derived from Cupric Subcarbonate for Selective Hydrogenation of Acetylene in an Ethylene Stream

A high-performance base metal catalyst for acetylene selective hydrogenation was prepared from cupric subcarbonate (Cu-2(OH)(2)CO3) by thermal treatment with an acetylene-containing gas followed by hydrogen reduction. The characterization results revealed that the copper catalyst was composed of interstitial copper carbide (CuxC) and metal Cu, which were embedded in porous carbon matrix. The CuxC crystallites, which showed outstanding hydrogenation activity, were derived from the hydrogen reduction of copper (II) acetylide (CuC2) which was generated from the reaction between acetylene and Cu-2(OH)(2)CO3. The Cu particles and porous carbon were generated from the unavoidable thermal decomposition of CuC2. The prepared Cu-derived catalyst completely removed the acetylene impurity in an ethylene stream with a very low over-hydrogenation selectivity at 110 degrees C and atmospheric pressure. No obvious deactivation was observed in a 180-h test run. In the Cu-derived catalyst, CuxC served as the catalytic site for H-2 dissociation, Cu mainly functioned as the site for selective hydrogenation of acetylene, whereas the porous carbon matrix posed a steric hindrance effect on the chain growth of linear hydrocarbons so as to suppress the undesired oligomerization.

Automated summary

The high-performance base metal catalyst prepared from cupric subcarbonate showed excellent acetylene selective hydrogenation activity, with interstitial copper carbide and metal Cu embedded in a porous carbon matrix. The catalytic site for H-2 dissociation was CuxC, while Cu mainly functioned for selective hydrogenation of acetylene, and the porous carbon matrix suppressed undesired oligomerization.