Zr(OH)₄‐Catalyzed Semi‐Hydrogenation of Phenylacetylene with Terminal Zr−O−H as Active Site: Inactive for Free Styrene

Abstract

In the field of industrial semi‐hydrogenation of trace alkynes amidst alkene feedstocks, the pivotal challenge lies in circumventing the hydrogenation of alkenes. Herein, we present Zr(OH)4 as an innovative catalyst for the semi‐hydrogenation of phenylacetylene, demonstrating remarkable selectivity towards styrene (>96%), while exhibiting inactivity towards free styrene. Notably, Zr(OH)4 achieves a 95% conversion of quasi‐industry 1 mol% phenylacetylene within styrene, with a mere 0.44% styrene loss. Experimental and theoretical results confirm both terminal Zr‐O‐H and bridge Zr‐O‐H can dissociate H2, while the terminal Zr‐O‐H plays a crucial role on activating phenylacetylene through the sequential hydrogenation process of C6H5C≡CH→C6H5C=CH2→C6H5CH=CH2. The high rate of phenylacetylene removal is attributed to its strong adsorption capacity, while Zr(OH)4 has a significantly weaker adsorption capacity for styrene.