Selective Alkyne Semi‐Hydrogenation by PdCu Nanoparticles Immobilized on Stereocomplexed Poly(lactic acid)

Abstract

Polymer-supported PdCu alloy nanoparticles with a palladium to copper atom ratio of 1 have been synthesized upon: (i) Coordination of palladium/copper acetate to 2,2'-bipyridineend functionalized poly(lactic acid) (PLA); (ii) Stereocomplexaation of PLA-based macrocomplexes of opposite stereochemistry, and (iii) metal reduction with hydrogen. The obtained supported PdCu nanoparticles were successfully applied in the semi-hydrogenation of industrially important alkynols, such as 3-hexyn-1-ol and 2-butyne-1,4-diol leading to the correspond-ing cis-alkenol in high selectivity (98 %) under mild reaction conditions (i. e. ethanol, T (25 °C), p(H 2 ) = 3 bar) in the absence of any further additive. From a comparison of the catalytic performance of supported PdCu nanoparticles with those of Pd and Cu, located in the same chemical environment, emerged a clear alloy effect (i. e. high chemoselectivity for the alkene at high alkyne conversion). Recycling experiments conducted with the PdCu-based catalyst proved the stability of the catalyst with time, even by its recovering in air atmosphere.

Copper Application and Copper Nanoparticles in Chemistry

“…It has had an exciting performance in the hydrogenation process. PdCu nanoparticles are synthesized through three steps, including I-synthesis of polylactide as a biodegradable and widely used polymer II-binding of polylactide to metal and formation of metal stereocomplexes based on polylactide III-reduction of metal using hydrogen (Figure 21) [70]. Hydrogenation by Cu nanoparticles catalyst [70].…”

“…Figure 21.Syntheses of the nanoparticles catalysts PdCu, Pd, and Cu[70]. License number: 5680370589458.…”

Application of Metal-Based Catalysts for Semi-Hydrogenation of Alkynol: A Review

“…Recycling tests reaffirmed the catalyst's robustness and stability, even upon exposure to air. This offers a promising and efficient catalytic solution for industrial applications [21].…”

Mesoporous CeO2-supported ultrafine PdCu nanoparticle catalyst for selective hydrogenation of alkynols

“…As a low-cost metal with high electron density, copper (Cu) is often used as a secondary metal dopant to modify the physicochemical properties of the active metals. [19][20][21][22] The study by Jiang et al demonstrated that Cu reduced the d-band center of Pd in the PdCu 2 @MF-X catalyst, thus regulating the adsorption mode of CC and improving the selectivity to alkenes. 23 During the selective hydrogenation of alkynes, the dissociation of H 2 is usually the rate-determining step.…”