Phosgene substitution

H Eckert, B Forster. Triphosgene, a crystalline phosgene substitute. Angew Chem Int Ed Engl 894, 1987... 

Chloroform (trichloromethane). [CAS 67-66-3], Although chloroform can be prepared by various means it is almost exclusively produced by the chlorination of methane. It can be oxidized to phosgene, substituted with various halogens, nitrated to chloropicnn (CljCNOi). hydrolyzed lo formic O... 

Bigi F, Maggi R, Sartori G (2000) Selected syntheses of ureas through phosgene substitutes. Green Chem 2(4) 140-148... 

Chlorination of methyi chloroformate and dimethyl carbonate affords useful phosgene substitutes chloromethyi chioroformate [I], trichioromethyl chloroformate [II] also called Diphosgene and bis(trichloromethyi) carbonate [III] known as Triphosgene [see scheme 33] ... 

Trichloromethyl CI3C-0-C-CI II 0 503-38-8 125/748 Phosgene substitute (also called diphosgene )... 

Because of its reputation as a noxious material, there is occasionally an advantage to be obtained by using a phosgene substitute or homologue. This Chapter describes some of the alternatives that are available, and considers what possible advantages may be gained by their... 

DMC is classified as a non-toxic and environmentally compatible chemical [69]. In addition, the photochemical ozone creation potential of DMC is the lowest among common VOCs (2.5 ethylene = 100). The areas in which DMC acts, or can act, as a potential phosgene substitute correspond to the main areas of phosgene industrial exploitation, that is, production of aromatic polycarbonates and isocyanates, leading the production of these important chemicals out of the chlorine cycle. 

Phosgene substitution is thus an emblematic case for sustainable industrial chemistry and how this question should be considered in view of a rational risk assessment more than on generic principles. Phosgene is still central to the... 

Reactions that require phosgene are dangerous, and dimethyl carbonate (DMC) 33 is the most promising phosgene substitute. Current industrial processes for DMC synthesis are oxidative carbonylation of methanol and transesterification of ethylene carbonate with methanol. Hence, the direct reaction of CO2 and methanol (Scheme 58) is regarded as an attractive, next-generation process, but the limitation... 

Phosgene (a toxic and corrosive gas) is inconvenient and sometimes hazardous to use as a reagent. Several phosgene substitutes have been developed. 

Carbonyldiimidazole (GDI) is a crystalline phosgene substitute (mp 117-122 °C) and a preferred reagent for carboxyl activation. Salts (triflate or sulfate) of GDI are also used as activating agents in peptide and ester formation with retention of optical activity [104, 105]. 

Many phosgene substitutes 1, such as 1,1-carbonyldiimidazole, thionyl chloride, bis(nitrophenyl) carbonate, di-fert-butyl dicarbonate, etc., react according to the scheme above and the intermediates can be isolated and characterized. 

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