GB1431220A - Preparation of thiohydroximate carbamates - Google Patents

Abstract

1431220 Preparation of thiohydroximate carbamates E I DU PONT DE NEMOURS & CO 18 June 1973 [19 June 1972 22 Dec 1972] 28866/73 Heading C2C 5-Alkyl thiohydroximate carbamates of general Formula I: R-C(SR 1 )=N.O.CO.NHCH 3 , wherein R is CH 3 -, C 2 H 5 -, or R 2 R 3 NCO-; R 1 is CH 3 -, C 2 H 5 -, n-C 3 H 7 -, or isopropyl; R 2 is H, CH 3 -, C 2 H 5 -, n-C 3 H 7 - or isopropyl; and R 3 is H- or CH 3 -, provided that when R 2 is other than H- or CH 3 -, R 3 is hydrogen, are obtained by reacting methyl isocyanate with an S-alkyl thiohydroximate of formula (a) at least in part, by adding the methyl isocyanate, in gaseous or liquid form, to an agitated bed of solid particles of the S-alkyl thiohydroximate in the absence of a continuous liquid phase, a catalyst being present when R represents the group R 1 R 3 NCO-, while removing the heat of reaction, the rates of isocyanate addition and heat removal being balanced so as to maintain the temperature of the reaction mass at or above 0‹ C. but below the melting points of the thiohydroximate starting material and the carbamate product and/or (b) by contacting the reactants, in the case where R and R 1 are both CH 3 -, in the absence of a solvent under conditions such that for at least a terminal portion of the reaction, the reaction mass is maintained as a continuous liquid phase. Specified catalysts are tertiary amines and alkali metal hydroxides. The examples prepare compounds of Formula I in which R=R 1 =CH 3 and R=(CH 3 ) 2 NCO- and R 1 =CH 3 . The carbamates of Formula I are pesticides.