Sepn. of ammonia from gaseous mixt. with isocyanic acid - by addn. of tert. amine and condensation of adduct of isocyanic acid and amine

摘要

NH3 is sepd from a gaseous mixt of isocyanic acid and NH3 by adding a tert amine at 250-600 deg C, contacting the mixt with an inert diluent, and cooling when the adduct of isocyanic acid and tert amine condenses and the NH3 escapes as gas and is sepd. Addn of the amine is at 320-380 deg C. the amine is a cyclic amine or an amine of formula NR1R2R3, esp a trialkylamine, partic tri(m)ethylamine or triisopentylamine, in molar ratio of isocyanic acid:amine of 1:1-7. The diluent is an opt halogenated aliphatic or aromatic hydrocarbon, an ether, and/or a carboxamide, esp CHC13, toluene or N-methylpyrrolidone. R1, R2, R3 = (un)branched alkyl, aryl, alkaryl or aralkyl. USE/ADVANTAGE - Isocyanic acid is a reactant for synthesis or organic cpds. A soln or suspension of a substd NH4 isocyanate (I) is obtd; (I) is more stable than isocyanic acid.