Diphosgene boiling point

Oligomers of phosgene, such as diphosgene [503-38-8] (COCl2)2, have found use in the laboratory preparation of isocyanates. Carbamoyl chlorides, A[,A/-disubstituted ureas, dimethyl- and diphenylcarbonates, and arylsulfonyl isocyanates have also been used to convert amines into urea intermediates, which are subsequendy pyroly2ed to yield isocyanates. These methods have found appHcations for preparation of low boiling point aUphatic isocyanates (2,9,17). 

On heating near its boiling point at ordinary pressures, it decomposes to form phosgene and diphosgene, which further decomposes into phosgene. The reaction of decomposition is thus ... 

Diphosgene atid phosgene are also two materials w hich are chemicAlly fhisely related. But the difference in persistence betwreen them is an tmtH>rtant factor in their tactical use. This can be compared directly, as a rule, cnily niuler 8 C. (the boiling point of phosgene). Above this... 

K-Stoff was introduced by the Germans in June 1915 as a more lethal replacement for chlorine. A low-boiling liquid (boiling point 1°C), it was loaded into artillery shells, hence was more convenient to use in combat, and could be delivered independent of the prevailing wind direction. It was manufactured as a mixture of chloromethyl chloroformate and dichloromethyl chloroformate, variously reported to be 70/30 and 90/10, respectively. It is about twice as toxic as chlorine. K-Stoff was itself soon replaced by the more lethal phosgene and diphosgene. The latter are of comparable toxicities, about six times more toxic than chlorine, and soon became the most heavily used nonpersistent lethal agents of the war ... 

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