(Thanks, K. :)

Reader K2. writes:

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Re: Reader: 'The formation of COCl2 (Phosgene)....

The formation of COCl2 (Phosgene) from CHCl3 (Chloroform) involves UV light as a catalyst and the reaction is slow. I'd like to know the mechanism the reader proposes at the cellular level within the body.

Go to page 3 for the explanation.

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/338535/Chloroform_Toxicological_Overview.pdf

Chloroform is metabolised in humans and animals by oxidative or reductive cytochrome P450 dependent pathways. It has been suggested that chloroform metabolism mainly occurs via the oxidative pathway [3, 4]. In the presence of oxygen (oxidative pathway) chloroform undergoes oxidative dechlorination to form trichloromethanol, which spontaneously dehydrochlorinates to form phosgene. Subsequent hydrolysis of phosgene forms hydrochloric acid and the main metabolite carbon dioxide [3, 4], Phosgene may also react with cellular macromolecules (such as enzymes, proteins or the polar heads of phospholipids), leading to the formation of covalent adducts. The adducts can interfere with molecular function which may result in loss of cellular function and cell death [3]. In the absence of oxygen (reductive pathway), the main metabolite is dichloromethyl free radical, which is extremely reactive and forms covalent adducts with microsomal enzymes and fatty acid tails of phospholipids. This may result in the loss of microsomal enzyme activity and can also lead to lipid peroxidation [3].

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