| 摘要 |
Methyl isocyanate is obtained by reacting an alkali metal cyanate with dimethyl sulphate in the presence of one or more alkaline-earth metal oxides in an inert organic liquid. The alkali metal cyanate may be potassium cyanate or sodium cyanate containing from 25 to 40 mole percent of potassium cyanate. The alkaline-earth metal oxide may be magnesium oxide or calcium oxide. One or more salts of the alkali or alkaline-earth metals, e.g. calcium chloride, may additionally be present during the reaction. The inert organic liquid may be a dichlorobenzene or 1,2,4-trichlorobenzene. Preferably the reaction is carried out at a temperature of 165 to 185 DEG C and the methyl isocyanate formed is immediately removed from the reaction mixture. The process according to the invention allows yields of more than 80% to be obtained in relatively short reaction times. |
