Nickel-Mediated Stepwise Transformation of CO to Acetaldehyde and Ethanol

Abstract

The insertion of CO into the Ni−C bond of synthetic Ni(II)−CH 3 cationic complex ([1-CH 3 ] + ) affords a nickel−acetyl complex ([1-COCH 3 ] + ). Reduction of resultant [1-COCH 3 ] + by borohydrides produces CH 3 CHO, CH 3 CH 2 OH, and an Ni(0) compound ([1] 0 ), which can react with CH 3 I to regenerate [1-CH 3 ] + . By conducting deuterium labeling experiments, we have demonstrated that CH 3 CHO is the primary product from CH 3 CH 2 OH in such CO transformation reactions. In the reduction of [1-COCH 3 ] + , the formation of CH 3 CHO competes with the loss of CH 4 , which leads to a Ni(0)−CO compound ([1-CO] 0 ) as a minor product. Our results establish fundamental steps in the exploration of nickel-mediated CO transformation to valuable chemicals.

Single Pd Atom–In2O3 Catalyzes Production of CH3CH2OH from Atom-Economic C–C Coupling of HCHO and CH4

“…The potential energy profile in Figure clearly shows that the formation of ethanol through C–C coupling of CH 4 with HCHO has an overall reaction energy of −0.71 eV and is thermodynamically favorable. We note that there has been a report of ethanol formation from CO insertion into the M-CH 3 * bond in organometallics, followed by hydrogenation, and formation of ethanol from CH 4 and HCHO has 100% atomic efficiency. In fact, HCHO has been believed to be an important intermediate in a heterogenous CO hydrogenation reaction .…”

“…Among the four covalent complexes formed through C−C or C−O coupling, the transition state of CH 3 CH 2 OH + formation has the lowest energy. Zhang et al demonstrate that insertion of CO into the Ni-CH 3 bond followed by reduction produces acetaldehyde, which can be further hydrogenated to ethanol, 30 whereas half of the adsorbed CO species were believed to convert to formaldehyde on Ni (111). 31 These studies indicated the possibility of C−C coupling of formaldehyde with activated CH 4 under the heterogenous conditions.…”