Aerobic Oxidation of Diverse Primary Alcohols to Carboxylic Acids with a Heterogeneous Pd–Bi–Te/C (PBT/C) Catalyst

Abstract

Heterogeneous catalytic aerobic oxidation methods represent a near-ideal approach for the conversion of primary alcohols to carboxylic acids. Here, we report that a heterogeneous catalyst composed of Pd, Bi, and Te supported on activated carbon is highly effective for the oxidation of diverse benzylic and aliphatic primary alcohols, including 5-(hydroxymethyl)furfural (HMF) and substrates bearing heterocycles and other important functional groups. In many cases, the desired carboxylic acid product is obtained in >90% yield. Additionally, the catalyst has been demonstrated in a continuous-flow packed-bed reactor for the oxidation of benzyl alcohol, achieving near-quantitative yield while undergoing over 30 000 turnovers.

Palladium supported on a novel ordered mesoporous polypyrrole/carbon nanocomposite as a powerful heterogeneous catalyst for the aerobic oxidation of alcohols to carboxylic acids and ketones on water

“…While, Pd catalysts without the ligands were extensively deactivated as a result of the Pd black formation. 30,31 Moreover, scientists have focused on the development of efficient heterogeneous Pd catalysts for the aerobic oxidation of alcohols, because of disadvantages of homogeneous catalysts, [32][33][34][35][36][37][38][39][40][41][42] including the necessity to high catalyst loadings and excess of ligands or bases as well as difficulties in removing and recycling expensive catalysts or ligands from the reaction mixture. Although, during the recent years a lot of progress has been achieved in the eld of heterogeneous Pd catalysts.…”

“…Although, during the recent years a lot of progress has been achieved in the eld of heterogeneous Pd catalysts. However, the majority of these reports have concentrated on the conversion of alcohols to aldehydes and ketones and only a few heterogeneous Pd catalysts have been presented for the oxidation of alcohols to carboxylic acids, for example, Pd/carbon, 37 Pd-Bi-Te/activated carbon [39][40][41] and Pd/DNA-MMT. 42 Unfortunately, most of these heterogeneous Pd systems suffer from the necessity to promoters, low catalytic activity, limited substrate scope, high reaction temperature and/or wasteful organic solvents.…”

Platinum catalysed aerobic selective oxidation of cinnamaldehyde to cinnamic acid

“…Platinum group metals (PGMs) are effective heterogeneous catalysts for aerobic selox of alcohol, aldehydes and carbohydrates, and the subject of numerous reviews [9,[12][13][14][15]. In this regard, α, β-unsaturated acids are typically prepared by the cascade oxidation of their corresponding alcohols under strongly basic conditions [16][17][18][19]. Platinum nanoparticles dispersed over oxide and carbon supports are widely studied for the aerobic selox of aliphatic [20][21][22], allylic [23][24][25] and benzylic [26,27] primary and secondary alcohols and carbohydrates [28,29], but typically utilise pblock promoters such as Bi, Pd, Sn and Te [19,23] under basic conditions.…”

“…In this regard, α, β-unsaturated acids are typically prepared by the cascade oxidation of their corresponding alcohols under strongly basic conditions [16][17][18][19]. Platinum nanoparticles dispersed over oxide and carbon supports are widely studied for the aerobic selox of aliphatic [20][21][22], allylic [23][24][25] and benzylic [26,27] primary and secondary alcohols and carbohydrates [28,29], but typically utilise pblock promoters such as Bi, Pd, Sn and Te [19,23] under basic conditions. Nevertheless, the nature of the active site and role(s) of promoters and base remain poorly understood, reflecting the complex solid-liquid-gas interface and necessity for (but attendant difficulties in performing and interpreting) in-situ/operando studies on supported metal catalysts for aerobic selox [30,31].…”

Highly Efficient N-Heterocyclic Carbene/Ruthenium Catalytic Systems for the Acceptorless Dehydrogenation of Alcohols to Carboxylic Acids: Effects of Ancillary and Additional Ligands

“…However, this method usually requires toxic or strong oxidants and produces large amounts of by-products [4][5][6]. Even though oxygen is occasionally utilized as an oxidant [7][8][9][10][11][12][13][14][15][16][17], explosive mixtures may be formed and oxygen-sensitive substrates are not compatible. Therefore, green and sustainable alternatives for the production of various carboxylic acids are still in high demand.…”