METHOD OF OBTAINING META-TOLUELENE DIISOCYANATE (ITS VERSIONS) Russian patent published in 2014 - IPC C07C263/10 C07C265/14 

FIELD: medicine, pharmaceutics.

SUBSTANCE: invention relates to method of obtaining m-toluylene diisocyanate by reaction of meta-toluylene diamine with phosgene in gas phase. In accordance with claimed method meta-toluylene diamine and phosgene, separately from each other, are supplied to reactor in gaseous form, and gaseous meta-toluylene diamine is formed by evaporation in, at least, one evaporator. Method is characterised by the following: a) liquid meta-toluylene diamine, supplied into evaporator, contains less than 0.5 wt % calculated per weight of meta-toluylene diamine of meta-toluylene diamine sediment and in total less than 0.2 wt % calculated per weight of meta-toluylene diamine of ammonia and cycloaliphatic amines; b) liquid meta-toluylene diamine, supplied into evaporator, contains less than 20 ppm, calculated per weigh of meta-toluylene diamine, of heavy metals; c) ratio between quantity of liquid V [kg], present in evaporator, and gas flow $$\dot{M}$$ [kg/h], discharged from evaporator, takes value less than 2 p; d) meta-toluylene diamine, supplied into evaporator, is partially evaporated, and part of meta-toluylene diamine is, at least, 0.1 wt % calculated per weight of meta-toluylene diamine does not evaporate; e) non-evaporated part of meta-toluylene diamine is not supplied into reactor.

EFFECT: method makes it possible to reduce formation of interfering solid substances and associated with this adhesions and clotting of equipment.

4 cl, 6 ex