Abstract

The effect of the composition of the catalytic system and reaction conditions on the properties of phosphorus-modified palladium catalysts in hydrogenations of alkynols was studied. Modification with phosphorus increased the activity and turnover number of palladium catalysts in the hydrogenation of the model compound 2-methyl-3-butyn-2-ol (MBY) without any reduction in the selectivity to 2-methyl-3-butene-2-ol at 95–98% MBY conversion. The promoting effect of phosphorus on the properties of the palladium catalyst is caused not only by an increase in the particle size, but also, probably, by a change in the energy of interaction of reagents with the active sites. Hypotheses on the nature of the carriers of catalytic activity in Pd–P particles were discriminated using kinetic methods with the differential selectivity of catalytic systems as the main measured parameter under the conditions of competition between two alkynols. The hydrogenation of acetylenic alcohols involves only one of the two potentially active forms in Pd–P nanoparticles—Pd(0) clusters, whereas the hydrogenation of the resulting allyl alcohols involves both Pd(0) clusters and palladium phosphides.

中文翻译：

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钯-磷纳米粒子作为炔醇化学选择性加氢的有效催化剂

摘要

研究了催化体系组成和反应条件对炔烃加氢过程中磷改性钯催化剂性能的影响。用磷进行改性可提高模型化合物2-甲基-3-丁炔-2-醇（MBY）氢化过程中钯催化剂的活性和周转次数，而对2-甲基-3-丁烯-2-的选择性没有任何降低在95％至98％MBY转化率下。磷对钯催化剂性能的促进作用不仅是由于粒径的增加，而且还可能是由于试剂与活性位点相互作用的能量的变化所引起的。使用动力学方法，以两种炔烃之间竞争的条件下，以催化系统的差异选择性为主要测量参数，来区分Pd-P颗粒中催化活性载体性质的假设。炔醇的氢化仅涉及Pd-P纳米颗粒中两种潜在的活性形式之一-Pd（0）簇，而所得的烯丙醇的氢化则涉及Pd（0）簇和磷化钯。