METHOD FOR GAS-PHASE PRODUCTION OF ISOCYANATES Russian patent published in 2015 - IPC C07C263/10 C07C265/14 

FIELD: chemistry.

SUBSTANCE: according to the disclosed method at step (i) an amine in a vapour space in the presence of >0.10 to 25 wt % diluent, with respect to the total weight of the diluent and amine, is converted to a gas phase. At step (ii) the gaseous stream obtained at step (i), containing an amine and a diluent, is converted in the reaction space with a gaseous phosgene stream into the corresponding isocyanate. The method is characterised by that the diluent used at step (i) contains 98.09 to 99.9950 wt % substances which are inert in the phosgenation process and 0.0050 to 1.91 wt % oxygen, respectively relative to the weight of the diluent. The molar ratio of the amine to oxygen in the vapour space at step (i) is in the range of 1000:1 to 1000000:1.

EFFECT: method enables to use a substance with low purity as a diluent, which improves cost efficiency of the method.

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