The interaction of CO with a copper(ii) chloride oxy-chlorination catalyst

Abstract

The interaction of CO with an attapulgite-supported, KCl modified CuCl 2 catalyst has previously been examined using a combination of XANES, EXAFS and DFT calculations. Exposing the catalyst to CO at elevated temperatures leads to the formation of CO 2 as the only identifiable product. However, phosgene production can be induced by a catalyst pre-treatment stage, where the supported CuCl 2 sample is exposed to a diluted stream of dichlorine; subsequent CO exposure at  643 K then leads to phosgene production. This communication describes a series of FTIR based, micro-reactor measurements, coupled with characterisation measurements utilising TEM, XRD and XPS to define the nature of the catalyst at different stages of the reaction coordinate. The CuCl 2 catalyst is able to support Deacon activity (2HCl + ½ O 2  Cl 2 + H 2 O), establishing this work with the possibility of utilising the oxy-chlorination of CO to produce phosgene. However, continuous dosing of CO at elevated temperatures over the chlorine pre-dosed CuCl 2 catalyst shows diminishing phosgene production as a function of time-on-stream, indicating surface chlorine supply to be rate-limiting under the reaction conditions studied. A pictorial reaction scheme is proposed to account for the surface chemistry observed.

Operational parameters relevant to the examination of phosgene synthesis catalysis

“…12 The experimental arrangement has also been used to investigate the oxychlorination of CO to synthesise phosgene over a copper( ii )chloride catalyst. 15,16…”

“…12 The experimental arrangement has also been used to investigate the oxychlorination of CO to synthesise phosgene over a copper(II)chloride catalyst. 15,16 A limitation of the fore-mentioned phosgene synthesis laboratory studies on activated carbon is that they are concentrated on a single grade of activated carbon: Donau Supersorbon K40. [11][12][13] This means that the relevance and transferability of the kinetic and mechanistic studies for phosgene synthesis catalysis in general is unknown currently.…”