1,232,179. Dichloromethylene carbamate and thiocarbamate esters. FARBENFABRIKEN BAYER A.G. 3 Dec., 1969 [8 Jan., 1969], No. 58937/69. Heading C2C. Compounds of formula R(XCON=CCl 2 ) n , in which R is an n-valent optionally substituted saturated or unsaturated aliphatic, araliphatic or carbocyclic aromatic radical, X is oxygen or sulphur and n is 1 to 6 are prepared by reaction of a compound R(XH) n with the compound ClCON=CCl 2 . The products are novel apart from the compound C 2 H 5 OCON=CCl 2 . The products have herbicidal, fungicidal and acaricidal activity. Isocyanates of formula R-OCO-NCO are prepared from the above carbamate esters by reaction with anhydrous methane sulphonic acid.