Selective Hydrogenation of Cinnamaldehyde over Pt and Pd Supported on Multiwalled Carbon Nanotubes in a CO₂-Expanded Alcoholic Medium

Abstract

Pt/MWCNT and Pd/MWCNT nanocatalysts were prepared via a liquid reduction method. The selective hydrogenation of cinnamaldehyde (CAL) was investigated over 5.0 wt.% Pt/MWCNT and 5.0 wt.% Pd/MWCNT catalysts in a CO 2 -expanded alcoholic medium at different reaction conditions. The hydrogenation selectivities over these two catalyst types were shown to be entirely different. It was found that the Pt/MWCNT catalysts are highly selective for CO bonds, giving the unsaturated alcohol a selectivity for cinnamyl alcohol (COL) of 97.3% and a conversion rate for cinnamaldehyde of 99.3%. Conversely, the Pd/MWCNT catalyst is highly selective for CC bonds, producing a saturated aldehyde with a selectivity for hydrocinnamaldehyde (HCAL) of 91.3% and a conversion rate for cinnamaldehyde of 98.6%. The small diameter of the Pt or Pd granules over the multiwalled carbon nanotubes (MWCNTs) leads to a high catalyst activity, and an increase of CO 2 pressure results in a better hydrogenation performance for CO bonds than that for CC bonds.

Platinum nanocrystals supported on CoAl mixed metal oxide nanosheets derived from layered double hydroxides as catalysts for selective hydrogenation of cinnamaldehyde

“…Cinnamaldehyde (CAL) is a particularly important a,bunsaturated aldehyde, since its partial hydrogenation products are important intermediates in the manufacture of chemicals (particularly perfumes, flavors, and pharmaceuticals) [2,3]. Also, it is considered a good model for investigating the catalytic behavior of the microstructures of heterogeneous catalysts.…”

Silicon Carbide Supported Palladium‐Iridium Bimetallic Catalysts for Efficient Selective Hydrogenation of Cinnamaldehyde

“…Pd is well known to be active for C=C hydrogenation but inert for C=O hydrogenation, thus it is usually employed as a main active metal for the hydrogenation of CAL to HALD . To further improve the performance of Pd‐based catalysts, different additives are usually applied.…”

Improvement Effect of Ni to Pd-Ni/SBA-15 Catalyst for Selective Hydrogenation of Cinnamaldehyde to Hydrocinnamaldehyde

“…Table S2 summarizes the selective hydrogenation of CAL over the Pd-based catalysts reported from the literature. The 5.0 wt %Pd/MWCNT catalyst designed by Zhao et al gave 91.3% HALD selectivity at 98.6% CAL conversion under 40 bar H 2 pressure and 148 bar CO 2 pressure [59]. Chen et al reported 80% HALD selectivity with 100% CAL conversion over 3.0 wt % Pd/(SH)MSC catalyst [3].…”