Guanidine Hydrochloride CAS 50-01-1

A method for purifying pharmaceutical grade guanidine hydrochloride, which comprises the following steps:

1. Under normal pressure, add 500 g of water into the mixer, then add 1200 g of crude guanidine hydrochloride, stir at 60 ° C for 30 min, stir evenly and then pump into a coarse filter to remove mechanical impurities and incompletely dissolved solid particles to obtain Guanidine hydrochloride crude guanidine aqueous solution;
2. The crude guanidine hydrochloride aqueous solution obtained by removing mechanical impurities and incompletely dissolved solid particle impurities through the coarse filter is pumped into the ultrasonic crystallization system for continuous and cyclic treatment to obtain guanidine hydrochloride clear liquid to induce the precipitation of fine impurities (the ultrasonic crystallization system adopts Continuous treatment type, it has internal circulation system to carry out the circulation treatment of guanidine hydrochloride crude guanidine aqueous solution), obtains guanidine hydrochloride clear liquid;
3. Pump the guanidine hydrochloride clear liquid that has been induced by the ultrasonic crystallization system to remove impurities into the precision filter to remove the fine impurity crystal grains that are not completely removed by the ultrasonic crystallization system; then pump the guanidine hydrochloride solution that has passed through the precision filter into the decolorizer , in order to remove the trace amount of cyanamide impurities dissolved in the solution to obtain a refined guanidine hydrochloride solution, the process conditions of the decolorizer are: temperature 60 ℃, pressure 0.15MPa (G) and hydraulic residence time 30min;
4. Pumping the purified guanidine hydrochloride solution into the finished product crystallizer for crystallization and purification; separating the crystals and drying to obtain pharmaceutical grade guanidine hydrochloride; the yield is 85% (calculated as crude guanidine) and the purity is 99.7%.