Verfahren zur Reinigung konzentrierter waessriger Zinkchloridloesungen

摘要

Compounds which adversely affect acrylonitrile polymerization and present in an at least 50% wt. ZnCl2 solution are rendered inactive by adding 0.1 to 1.0% wt. of one or more of ZnO, NH4OH, (NH4)2CO3, NaOH, Na3CO3, CaO, Ca(OH)2, MgO, Mg(OH)2 and adding H2O2 and heating to 90 DEG to 100 DEG C., e.g. for at least 20 min. 0.3 to 1.0% wt. of the solution, of H2O2 may be used. Excess H2O2/t may be removed by adding Zn powder, e.g. in the amount, 0.1 to 0.3% wt. of the solution. The solution may be further purified by adding 0.1 to 0.2% wt. of active charcoal. The pH of the solution during inactivation of the compounds may be between 0 and 2.