Reaction of cupric alkoxide and carbon monoxide

Abstract

cm-1; nmr spectrum (CC1.) an unsymmetrical doublet of doublets centered at -6.12 (1.1 , HA °r B, Jab -5.7, /ah or bi = 2.2 cps), an unsymmetrical doublet of doublets centered at -5.68 (HBorA, /ab = 5.7, /bi or ah = 3.0 cps) overlapping with a singlet at -5.51 (H°, HD) (2.8 H total), an unsymmetrical doublet of doublets centered at -3.24 (1.0 H, HF, Jm = 7.9, /fi = 4.0 cps), a multiplet at -3.1 to -2.5 with a maximum at -2.91 (3.1 , H°, HH, Hi), a singlet at -2.15 (0.9 H, Hi), and two overlapping unsymmetrical doublets of triplets centered at -1.55

Theoretical Analysis of Oxidative Carbonylation of Methanol: Saegusa’s Scheme of Dimethylcarbonate Synthesis over Binuclear Cationic Oxo-Clusters in CuNaX Zeolite

“…Two principal mechanisms have been proposed for the carbonylation. The first one is via the formation of DMC via Cu + (CH 3 OCO) carbomethoxides and Cu + (OCH 3 ) methoxides 1,3,8−12 + → + + Cu (OCH )Z CO Cu (CH OCO)Z The difference between various mechanisms is also related to monocationic site 4,7,11−16 or binuclear cationic sites 2,3,9,10,13,17 involved in the reaction mechanism. Anderson et al elaborated kinetic multistep schemes including side products (dimethoxymethane or DMM, formaldehyde, and methylformate) for CuX 3,10 and CuZSM-5 4 in agreement with the Eley−Rideal mechanism for CO introduction into methoxide.…”

“…4 Together with two mechanisms for oxidative carbonylation of methanol via methoxy species 7,8,16 and carbomethoxy species, 1,3,9,11,12,17 two other channels were proposed via carbonates 6,19 and >Cu(OCH 3 ) 2 Cu< species (the last is named below as Saegusa's scheme). 2,13 The first three of them were analyzed theoretically including the route through carbonates. 19 The methoxy intermediate route at one Cu + Recently the route via carbomethoxide intermediates 11,12 has been theoretically tested at the PBE/DNP level 20,21 with DMOL 3 using the 30T 11 or 31T, 12 T = Si or Al, clusters cut from CuY.…”

“…24 The parallel presence of Cu 2+ was shown and discussed involving XANES studies by Bell et al, 14 via pyridine adsorption by Engeldinger et al 25 An ignorance of the Cu 1+ / Cu 2+ transformation cannot construct full redox cycle for the oxidative carbonylation reaction in which the participation of copper cations as intermediates can explain nearly zero order of O 2 for all three Cu form zeolites (MOR, FAU, ZSM-5) whose activity was confirmed in the DMC formation reaction. 18 In the case of binuclear mechanism, i.e., via >Cu-(OCH 3 ) 2 Cu< fragments, 13 one can address the formation of the derivatives of the >Cu(OH) 2 Cu< species previously established in the CuMOR 26 and CuZSM-5 27 zeolites. The >Cu(OH) 2 Cu< moieties can be the products of the reactions with a participation of stable CuOCu and CuO 2 Cu clusters.…”

“…The first one is via the formation of DMC via Cu + (CH 3 OCO) carbomethoxides and Cu + (OCH 3 ) methoxides ,,− where Z denotes a zeolite framework. The second route assumes the formation of monomethylcarbonates (MMC) and methoxides: ,,− …”

“…The difference between various mechanisms is also related to monocationic site ,,− or binuclear cationic sites ,,,,, involved in the reaction mechanism. Anderson et al elaborated kinetic multistep schemes including side products (dimethoxymethane or DMM, formaldehyde, and methylformate) for CuX , and CuZSM-5 4 in agreement with the Eley–Rideal mechanism for CO introduction into methoxide.…”