METHOD FOR SYNTHESIS OF ISOCYANATES Russian patent published in 2011 - IPC C07C263/04 C07C265/14 

FIELD: chemistry.

SUBSTANCE: invention relates to a method for synthesis of isocyanates without using toxic phosgene. The method involves the following steps: reacting an aliphatic ester of carbamino acid of formula where R⁷ is a group selected from a linear alkyl group containing 1-20 carbon atoms, bis(C₅-C₆-cycloalkyl)alkyl group containing 11-20 carbon atoms, C₅-C₆-cyclalkylalkyl group containing 6-20 carbon atoms, where the cycloalkyl ring can be substituted with 1-3 substitutes selected from alkyl containing 1-8 carbon atoms; and an aromatic group containing 6-20 carbon atoms and having 1 or 2 benzene rings; R⁷ has valence n, R⁸ is an alkyl group containing 1-8 carbon atoms, n equals 2, with an aromatic hydroxy compound of formula , which contains substitute R¹ in at least one ortho position of the hydroxyl group, where ring A is a benzene ring which may contain an additional substitute R² in another ortho position relative the hyroxy group; R¹ is a group different from a hydrogen atom, in form of an alkyl group containing 1-20 carbon atoms; a phenyl or phenylalkyl group containing 7-20 carbon atoms, where the additional substitute R² is selected from hydrogen, alkyl group containing 1-20 carbon atoms; a phenyl group or phenylalkyl group containing 7-20 carbon atoms; to obtain the corresponding aryl carbamate which contains a group originating from an aromatic hydroxy compound; and the corresponding aliphatic alcohol; and thermal decomposition of the aryl carbamate to form the corresponding isocynate and aromatic hydroxyl compound.

EFFECT: method enables to increase output of isocyanates and lower the amount of by-products accumulating inside the equipment.

9 cl, 1 tbl, 7 dwg, 23 ex