Guanidium thiocyanate prepn from corresp carbonate - with ammonium thiocyanate and alkaline earth (hydr)oxide

摘要

Guanidinium thiocyanate (I) is prepd. by reacting guanidinium carbonate with NH4SCN and alkaline earth oxide or hydroxide, pref. CaO or Ca(OH)2, in equimolar quantities, according to equation (1); (C(NH2)3)2CO3 + 2 NH4SCN + CaO right arrow 2(C(NH2)3)SCN + 2 NH3 + CaCO3 + H2O, in the aq. phase at room temp. to 100 degrees C, with stirring for several hrs. in sort bursts, pref. at 80-40 degrees C for 1-4 hrs. (I) is an organic inter, useful for modifying and flame-proofing cellulose. Aq. solns. of (I) are solvents for acrylonitrile polymers, copolymers and thermoplasts andare useful as adjuvants in acrylic fibre prodn. Sepd., non-recrystallised (I) of 97-100% purity is obtd. in 92-100% yield. Pollution by emission of H2S or through SCN ion-, thiourea-, H2S- or CS2-contg. waste waters is prevented. Process requires no applied press.,and is effected in water in high concns.