Pairwise hydrogen addition in the selective semihydrogenation of alkynes on silica-supported Cu catalysts.
Pairwise hydrogen addition in the selective semihydrogenation of alkynes on silica-supported Cu catalysts.
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DOI：
10.1039/c6sc05276b
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发表时间：
2017-03-01
期刊：
影响因子：
8.4
通讯作者：
Koptyug IV
中科院分区：
文献类型：
--
作者：
Salnikov OG;Liu HJ;Fedorov A;Burueva DB;Kovtunov KV;Copéret C;Koptyug IV
以部分脱羟基二氧化硅(Cu/SiO_2-700)为载体，以仲氢为催化剂，对1-丁炔和2-丁炔的半加氢反应进行了机理研究。以部分脱羟基二氧化硅(Cu/SiO_2-700)为载体，以仲氢为催化剂，对1-丁炔和2-丁炔的半加氢反应进行了机理研究。在Cu/SiO_2-700催化剂上，1-丁烯加氢生成1-丁烯，≥选择性为97%。用三环己基膦(PCy3)对该催化剂进行表面修饰后，1-丁烯的选择性提高了近100%，但降低了催化活性。在2-丁烯的加氢反应中也观察到了类似的趋势，根据反应条件的不同，铜/SiO_2-700对2-丁烯的选择性在72%-100%之间，而用PCy3改性的催化剂再次表现出近100%的选择性。在铜基催化剂催化的加氢反应中观察到的对氢诱导极化效应证明了在这些催化剂上进行两两加氢的可行性。对未改性的铜/SiO_2-700催化剂来说，成对加氢对1-丁炔的贡献至少为0.2-0.6%，对≥改性的铜/SiO_2-700催化剂的贡献为2.7%，突出了三环己基膦配体的表面修饰效果。
Mechanistic insight into the semihydrogenation of 1-butyne and 2-butyne on Cu nanoparticles supported on partially dehydroxylated silica (Cu/SiO2-700) was obtained using parahydrogen. Mechanistic insight into the semihydrogenation of 1-butyne and 2-butyne on Cu nanoparticles supported on partially dehydroxylated silica (Cu/SiO2-700) was obtained using parahydrogen. Hydrogenation of 1-butyne over Cu/SiO2-700 yielded 1-butene with ≥97% selectivity. The surface modification of this catalyst with tricyclohexylphosphine (PCy3) increased the selectivity to 1-butene up to nearly 100%, although at the expense of reduced catalytic activity. Similar trends were observed in the hydrogenation of 2-butyne, where Cu/SiO2-700 provided a selectivity to 2-butene in the range of 72–100% depending on the reaction conditions, while the catalyst modified with PCy3 again demonstrated nearly 100% selectivity. Parahydrogen-induced polarization effects observed in hydrogenation reactions catalyzed by copper-based catalysts demonstrate the viability of pairwise hydrogen addition over these catalysts. Contribution of pairwise hydrogen addition to 1-butyne was estimated to be at least 0.2–0.6% for unmodified Cu/SiO2-700 and ≥2.7% for Cu/SiO2-700 modified with PCy3, highlighting the effect of surface modification with the tricyclohexylphosphine ligand.