Methyl isocyanate is usually manufactured by the reaction ofmonomethylamineandphosgene. For large scale production, it is advantageous to combine these reactants at higher temperature in the gas phase. A mixture of methyl isocyanate and two moles ofhydrogen chlorideis formed, but N-methylcarbamoyl chloride (MCC) forms as the mixture is condensed, leaving onemoleof hydrogen chloride as a gas.
The methyl isocyanate is obtained by treating the MCC with a tertiary amine, such asN,N-dimethylaniline, or withpyridine[11]or by separating it by using distillation techniques.[12]
Methyl isocyanate is also manufactured from N-methylformamide and air. In the latter process, it is immediately consumed in a closed-loop process to make methomyl.[13]Other manufacturing methods have been reported
Methyl isocyanate reacts readily with many substances that contain N-H or O-H groups. With water, it forms1,3-dimethylureaandcarbon dioxidewith the evolution of heat (325 calories per gram of MIC):
At 25 °C, in excess water, half of the MIC is consumed in 9 min.;[16]if the heat is not efficiently removed from the mixture, the rate of the reaction will increase and rapidly cause the MIC to boil. If MIC is in excess,1,3,5-trimethylbiuretis formed along withcarbon dioxide.[10]Alcoholsandphenols, which contain an O-H group, react slowly with MIC, but the reaction can be catalyzed by trialkylaminesor dialkyltin dicarboxylate.Oximes,hydroxylamines, andenolsalso react with MIC to form methylcarbamates.[10]These reactions produce the products described below (Uses).

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