Phosgene substitute dimethyl carbonate

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] ... 

Dimethyl carbonate, (MeO) jCO, is a recognized substitute for phosgene in many carbonylatlon and ring-closing reactions [595]. For example [595] ... 

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... 

If dimethyl carbonate could be substituted for phosgene in such reactions, the by product of the reaction would be methanol, CH30H, rather than HCl. 

Dimethyl carbonate is a recognized substitute for phosgene in many carbonylation... 

Dimethyl carbonate (DMG) is a Uquid equivalent of phosgene (mp 2-4 °G bp 90 °C). Reported toxicity and ecotoxicity data lead to the classification of DMC as both a non-toxic and environmentally benign chemical [116, 117] (see also Chapter 3). The areas in which DMC serves, or can serve, as an actual or potential phosgene substitute correspond to the main areas of phosgene industrial applications, e.g. the production of aromatic polycarbonate and isocyanates, leading the production of these important chemicals out of the chlorine cycle [117]. However, one major aspect has to be considered in this context, i.e. the production of DMC itself, since the traditional process for DMC production has involved phosgene as a raw material [118]. 

In the first group, primary amines are reacted with carbonyl insertion compounds such as phosgene [727, 729], and sometimes phosgene substitutes such as triphosgene [507], various carbonates [503, 730, 731], bis(4-nitrophenyl)carbonate [503], di-ferf-butyl dicarbonate [664], S,S-dimethyl thiocarbonate [577], and N,N -carbonyldiimidazole [732], l,l-carbonylbis(benzotriazole) [728], and trihaloacetyl chlorides. Most of these compounds have been utilized as safer reagents that can be stored and handled without special precautions. 

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