| 摘要 |
<p>Haloformamidinium halides from cyanamide and hydrogen halides. Cpds. X-C(NH2)=NH.HX (where X is Cl, Br or I), useful as etching media, resin curing agents, for example in textile industry, and as herbicide intermediates, are prepared by contacting a conc. aqs. cyanamide solution (A) pref. containing over 40 weight % cyanamide, with a cooled, aqs. conc. hydrogen halide soln. (B) so that temp. during reaction does not exceed 5 degrees C. Pref. (B):(A) mol. ratio >2:1 to 4:1. Pref. hydrogen halide gas, air or inert gas are added to reaction mixture during conversion.</p> |
