Ultrasound as a tool for reducing energy consumption in electrocatalytic hydrogenation of aromatic ketones using graphite as catalyst support

Electroreductive upgradation of biomass into high-value chemicals and energy-intensive biofuels

“…[158][159][160] In addition to Pd and Rh, graphite was reported to convert acetophenone to 1-phenylethanol with the assistance of ultrasound and achieved excellent results (FE and yield of 100%). 161 The ultrasound irradiation accelerates the mass transport of acetophenone from bulk electrolyte to graphite surface, enhancing acetophenone's availability to react with the H ads , and resulting in high current efficiency and yield. Unlike benzaldehyde ECH, there is still no effective catalyst for the directional coupling of acetophenone so far.…”

Developing electrochemical hydrogenation towards industrial application

“…Due to their accessibility from biomass and derived compound mixtures as well as the large synthetic value of their downstream products for pharmacological, specialty chemical-, fuel- or polymer-related applications 107 and many more, oxygenated organic compounds are among the most intensely researched and established substrate classes for electrocatalytic hydrogenations. 108–111 As compounds commonly found in pyrolyzed biomass feedstocks, benzaldehyde (BA) 32,33,112–116 and FF 33,109,110,117 are widespread model substrates for diverse EChH-related investigations, that may yield benzyl alcohol (BAL) or furyl alcohol (FA) and 2-methylfuran (MF), respectively. While other aldehydes, 84,118,119 ketones such as acetophenone 81,120,121 or acetone, 122,123 α-ketoesters 124,125 and α-ketoacids 126 are also widely represented as substrates in literature, the EChH of non-activated carboxylic acids remains challenging.…”

“…130 As catalysts for C–O-hydrogenation, palladium is to be considered the benchmark. 81,110,112,117,131–133 While palladium and other noble metals like platinum, 115,122,134–137 ruthenium 117,128,138,139 and rhodium 117,140,141 dominate the field, there is an increasing number of protocols featuring abundant metal catalysts 107,108,113,117,119,126,130,142 with copper as the most prominent example. 109,110,117,143 Most reported protocols operate at relatively low current densities and electrode areas of <30 mA cm −2 and <10 cm 2 , respectively, while allowing faradaic efficiencies of >90% in many cases are achieved depending on the substrate.…”