Verfahren zur Herstellung von organischen Isocyanaten

An organic a -isocyanato alkyl, aralkyl, aralkenyl or cyclic aliphatic ether is obtained by reacting an a -halogeno-alkyl (-aralkyl, -aralkenyl or -cyclic aliphatic ether with an alkali metal, ammonium, or alkaline earth metal cyanate at 0 DEG to 200 DEG C. in a solvent mixture composed of 0.01 to 80 volume per cent of a strongly polar solvent as defined below and 99.99 to 20 volume per cent of an aliphatic, cycloaliphatic, araliphatic or aromatic hydrocarbon. The term "strongly polar solvent" refers to a solvent which has a dielectric constant greater than 15 and which does not contain Zerewitinoff-type active hydrogen, e.g. a tertiary amide, carboxylic acid nitrile or a dialkyl dicycloalkyl, aralkyl or diaryl sulphone and several such solvents are specified. Other strongly polar solvents specified are nitroethane, nitropropane, nitrobenzene, nitrotoluene, acetone and acetophenone. The hydrocarbon present in the solvent may be e.g. toluene, benzene, xylene, mesitylene, diethyl benzene, isopropyl benzene, ethyl naphthalene, octane, petroleum ether, gasoline, cyclohexane or methyl cyclohexane. Several examples are given and among the isocyanate products obtainable by the process are those of the general formula R-O-CH(R1)-NCO wherein R is an aralkyl radical, an alkylene radical connected to an O-CH2-NCO group, a Cl-CH2-CH2-radical or CH2=CH-CH2-radical and R1 is a hydrogen atom or an alkyl or aryl radical and the invention includes such products per se as well as the compound C6H5CH.(NCO).O.CH3 formed in one of the examples. Methoxymethyl isocyanate obtainable by the above process can be reacted with O,O-dimethyldithiophosphoryl acetic acid in methylene chloride at 40 DEG C. to form O,O-dimethyl dithiophosphoryl acetic acid N-methoxymethylamide which is effective as an insecticide and acaricide.ALSO:A composition having insecticidal and acaricidal properties is obtained by mixing O,O-dimethyl dithiophosphoryl acetic acid N-methoxymethyl amide with the same amount of dimethyl formamide, adding benzyl hydroxy diphenyl polyglycol ether as emulsifier and then diluting with water.