Size-Controlled Pd Nanoparticles in 2-Butyne-1,4-diol Hydrogenation: Support Effect and Kinetics Study

Abstract

Structured catalyst has been developed for C−C triple bond three-phase hydrogenation. The sintered metal fiber (SMF) coated by different oxides served as support for monodispersed Pd nanoparticles (6.4 ± 0.5 nm). The effect of acid−base properties and reducibility of metal oxide coating on catalytic performance in the liquid phase (T = 303− 348 K; P = 1−20 bar) hydrogenation of 2-butyne-1,4-diol to 2-butene-1,4-diol (B2) has been studied. The oxides MgO, ZnO, Ga 2 O 3 , Al 2 O 3 , ZrO 2 , SnO 2 , and SiO 2 and the mixtures of MgO + ZnO + Al 2 O 3 , MgO + Al 2 O 3 , and ZnO + Al 2 O 3 were tested. The catalyst activity was higher up to 10-fold for Pd 0 on acidic supports, like SiO 2 , but demonstrated lower selectivity to B2 as compared to the basic oxides. The highest yield (∼99%) of the target B2 and stability over four consecutive runs were attained over the 0.2% Pd 0 /ZnO/SMF catalyst. The high selectivity to B2 was attributed to the formation of an active phase containing intermetallic PdZn alloy as confirmed by XPS. The reaction kinetics was modeled using a Langmuir−Hinshelwood mechanism and found consistent with the experimental data. The developed structured catalyst is suitable for a design of flow multiphase reactors to perform alkyne semihydrogenations in continuous mode.

Zn-Promoted Selective Gas-Phase Hydrogenation of Tertiary and Secondary C4 Alkynols over Supported Pd

“…Zakarina and co-workers 17 and Bönnemann et al 18 working with several oxide (SiO 2 , Al 2 O 3 , MgO, CaCO 3 , CeO 2 ) supported palladium catalysts, linked their observed increased in activity and alkenol selectivity in the batch liquid-phase hydrogenation of MBY and 3-hexyn-1-ol to an increased basicity of the support that results in the generation of electron-rich Pd nanoparticles. The opposite effect has also been observed, Berguerand and coworkers 19 recorded a drop in activity in the 2-butyne-1,4-diol hydrogenation linked to the presence of Pd δ-nanoparticles using a wide range of supports (MgO, ZnO,…”

Bimetallic Synergy Effects of Phyllosilicate‐Derived NiCu@SiO2 Catalysts for 1,4‐Butynediol Direct Hydrogenation to 1,4‐Butanediol

“…Compared with the traditional catalysts, this core-shell nanomaterial has the advantage of mono-layer dispersity and tunability, which increases the availability of the active sites. [18][19][20] BYD is usually first semi-hydrogenated to form unsaturated BED, which can be then hydrogenated to BDO. [17] Besides, concerning on the structural feature of BYD which has various unsaturated bonds, the hydrogenation of BYD will not only include the C�C and C=C hydrogenation process, but also involved by many side reactions such as isomerization, aldol condensation and C=O hydrogenolysis because of the unsaturated feature of CÀ O bonds (CÀ OH or C=O).…”

“…To be concise, there are a series of reactions during BYD hydrogenation process as shown in Scheme 1. [18][19][20] BYD is usually first semi-hydrogenated to form unsaturated BED, which can be then hydrogenated to BDO. However, the accompanying BED intermediate with allyl alcohol structure is preferably converted to its highly-unstable isomerization product γ-hydroxybutanal (γ-HALD), which results in the formation of aldol condensation byproducts such as 2-hydroxytetrahydrofuran (HTHF) and acetal (HBOTHF); similarly, it can also be excessively hydrogenolysis to form n-butanol (BOL) or crotyl alcohol (CROL).…”

Efficient Pd@MIL-101(Cr) hetero-catalysts for 2-butyne-1,4-diol hydrogenation exhibiting high selectivity

“…1, which leads to an extremely low selectivity. 32 While the use of Pd composites with Zn, Cu, Pb 33 and the introduction of basic reaction modiers such as pyridine, quinoline or isoquinoline 34 has been carried out to improve the selectivity of BED, the conversion efficiency of the hydrogenation of BYD was signicantly decreased.…”