photographic emulsion based on silver halide containing a mercaptide of silver of a compound mercapto groups substituted

摘要

2-Mercaptobenzoselenazole is made by heating o -aminoselenophenol with NaOH and carbon disulphide (Example 1). The zinc salt of o -aminoselenophenol is obtained by reducing 2:21-diaminodiphenyldi-selenide with zinc and HCl (Example 1). 4:5 - Diphenyl - 2 - mercaptoimidazole is made by refluxing benzoin and ammonium thiocyanate (Example 2). 4 - Phenyl- and 4 - (p - nitrophenyl) - 2 - mercaptoimidazoles are made by refluxing potassium thiocyanate with o -amino-acetophenone hydrochloride and o -amino-4-nitroacetophenone hydrochloride respectively (Examples 3 and 4).