PROCEDE DE PRECIPITATION DE SELS MINERAUX A PARTIR DE MELANGES CONTENANT DES ISOCYANATES

摘要

1319696 Polyisocyanates MARATHON OIL CO 21 July 1971 [24 Sept 1970] 34226/71 Heading C2C In a process for the preparation of a polyisocyanate comprising reacting an organic halide with a metal cyanate in an inert dipolar aprotic solvent having a high dielectric solvent in the presence of a metal bromide or iodide, isocyanurate ring formation is reduced by adding to the reaction medium a selective solvent immiscible with the reaction medium and having a Kauri-Butanol number of from 80 to 160 to precipitate substantially all the inorganic salts from the reaction medium. The selective solvent is preferably xylene, toluene, tetralin and/or benzene.