Phosgene synthesis catalysis: An atom economic perspective

Industrial phosgene production, on the scale of 12 Mt per annum, is almost exclusively performed via the combination of carbon monoxide and chlorine over an activated carbon catalyst. The main industrial use of phosgene is in polyurethane and polycarbonate production chains, estimated to use 95% of the global production of phosgene. However, despite the industrial significance of phosgene, relatively few lab-scale studies are reported in the open literature, largely owing to the chemical hazard associated with the reagents and product.
Reaction testing apparatus capable of safely and effectively synthesising phosgene has been commissioned at the University of Glasgow’s Chemical Process Fundamentals Laboratory. This presentation looks to share the operational parameters utilised in examining this reaction system. This includes the determination of reaction profiles accompanied by mass balance plots. Collectively, these measurements enable the atomic economy of the process over a particular catalyst formulation to be assessed. The presentation will investigate experimental conditions that lead to the on-set of by-product formation that compromises product selectivity. Diagnostic tools for evaluating the reaction system will also be shared, including calibration and quantification procedures, parameters relevant to construction of mass balances, and identification of inter- and intra-phase mass transfer limitations. Experimental outcomes will be presented that are of direct relevance to sustained catalytic performance at the industrial complex.