Preparation of cyanuric and isocyanic acids in a fluidized bed reactor

Abstract

We found out that the reactor suggested for pyrolysis in fluidized bed conditions, with indirect heating of the stock, proved to be convenient for the preparation of cyanuric and isocyanic acids. Under optimal conditions the yield of cyanuric acid from urea was 95% with 96% selectivity, i.e. the content of by-products is considerably lower than in case of processing in the static bed reactor. In the same reactor we prepared isocyanic acid from cyanuric acid in quantitative yield. The amount of gaseous isocyanic acid emitted was up to 50%. The isocyanic acid obtained was utilized in a reaction with aromatic and aliphatic amines to get mono- and disubstituted ureas. In connection with these experiments we studied the kinetics of the degradation of cyanuric acid and trimerization of isocyanic acid to obtain a quantitative description of the process.