Guanidinium thiocyanate prepn. - from guanidinium carbonate and ammonium thiocyanate

摘要

Guanidinium thiocyanate (I) is prepd. by heating a stoichiometric mixt. of guanidinium carbonate (II) and ammonium thiocyanate (III) at 80-250 degrees C until gas evolution ceases. (I) is used for modifying and flameproofing cellulose, and aq. solns. of (I) are used as solvents for carylonitrile polymers. The process gives high yields (e.g. 98-100%) of high-purity (I). The gases produced (NH3 and CO2, 2:1) can be used for the prodn. of ammonium (bi)carbonate and urea. The reaction can be effected heating a melt contg. (II) and (III) in a molar ratio of 1:2 to 120-200 degrees C while stirring for 0.25-4 hrs., or by adding a mixt. of (II) and (III) to a melt of (I) of 115-200 degrees C. Alternatively, the reaction can be effected in an aq. or organic diluent at the b.pt. of the mixt. The product gases are pref. continuously removed by passing air or an inert gas over the reaction mixt., or by applying a vacuum.