Verfahren zur Herstellung von Thioaethergruppen enthaltenden Isocyanaten

摘要

A two-stage process for the preparation of isocyanates which contain thioether sulphur atoms and which are substituted by bromine or chlorine comprises (i) reacting an isocyanate containing a disulphide bridge with halogen molecules or with a labile-halogen-containing inorganic compound, and (ii) reacting the resulting isocyanate sulphenyl chloride or bromide with a compound which contains an olefinic carbon-carbon double bond or an acetylenic carbon-carbon triple bond and does not contain in the molecule any groups which react in the cold with free or mashed NCO groups. A mashed isocyanate may be used instead of a free isocyanate, in which case the product contains mashed isocyanate groups and is converted to the free isocyanate by heating.