The Hydrogenation of 2-butyne-1,4-diol over a Carbon-supported Palladium Catalyst

Abstract

The hydrogenation of 2-butyne-1,4-diol in propan-2-ol over a carbon-supported palladium catalyst has been investigated in a batch reactor. At low conversions complete selectivity to cis-but-2-ene-1,4-diol is observed. However, further hydrogenation leads to a wide variety of products, most notably 2-isopropoxy-tetrahydrofuran and butane, neither of which have previously been associated with this reaction system. The former is thought to occur as a result of a surface-mediated process, involving the insertion of dissociatively adsorbed solvent molecules. Butane formation is attributed to the double condensation and hydrogenation of a chemisorbed cis-but-2-ene-1,4-diol intermediate. The alkane preferentially partitions in the gaseous phase, which results in an marked mass imbalance for the liquid phase. A reaction scheme is presented to rationalise these observations.

Continuous Liquid-Phase Hydrogenation of 1,4-Butynediol to High-Purity 1,4-Butanediol over Particulate Raney Nickel Catalyst in a Fixed Bed Reactor

“…Depending on the catalyst used, the reaction solvent, and the nature of the support material, the ratio between the cis -BED and the γ-HALD may vary over a wide range. It has been shown that, using basic supports or base additives in the liquid phase, the double bond isomerization into γ-HALD route can be completely suppressed resulting in the exclusive formation of cis -BED. ,, In the second Stage B, shown in Scheme , the dominant species on the catalyst surface are the two alkene complexes, 2 and 3 , both generating BAD, trans -BED, and γ-HALD. The observed consumption of cis -BED in this kinetic stage and the accumulation of the trans -BED shows the preferential adsorption of the cis -enol over the trans -form when both compete for the same active sites on the catalyst surface.…”

“…In a subsequent work by Telkar et al on the hydrogenation of BYD over a series of supported palladium catalysts, the formation of n -butanal was attributed to an alternative reaction pathway, described by reactions a–d–h. According to this, the n -butanal is formed through hydrogenolysis of the 4-hydroxybutanal (γ-HALD) which is itself generated from the cis- BED intermediate . The same reaction set was later expanded in the work by Musolino et al reporting on the formation of the cyclic hemiacetal 2-hydroxytetrahydrofuran (HTHF) through reaction sequence a–d–f.…”

Ultra-Small Platinum Nanoparticles with High Catalytic Selectivity Synthesized by an Eco-friendly Method Supported on Natural Hydroxyapatite

“…Samples were analyzed by gas chromatography with a flame ionization detector using a 456 SCION GC (DB-WAX 52 column, length 32 m, inner diameter = 0.3 mm) and helium (30 mL/min) as a carrier gas, according to previously reported analysis methods [30][31][32][33]. Reaction samples were injected into the GC and analyzed under the following conditions: temperature detector was set at 518 K, injector temperature at 513 K, the initial oven temperature was 353 K and this was raised up to 493 K at a rate of 10 K/min.…”

Heteroatom Promoted Ni/Al2O3 Catalysts for Highly Efficient Hydrogenation of 1,4‐Butynediol to 1,4‐Butenediol

“…Nickel‐based catalysts have attracted increased attention due to their relatively low cost and high intrinsic activities . It was already reported that Ni supported catalysts can be used with the desired catalytic properties (e. g. activity, selectivity, and stability) during the hydrogenation process, which is superior in comparison with the Raney nickel catalysts …”

“…Duncanson et al . showed that n‐butanal could be formed through hydrogenolysis of 4‐hydroxybutanal (γ‐HALD) which was generated from cis ‐BED intermediate . Musolino et al .…”