1,5-diphenylaminourea, white crystalline powder. The air is gradually turning red. Slightly soluble in water, soluble in ethanol, acetone and glacial acetic acid, insoluble in ether. It gradually turns red in the air and reacts with Cr2O to show red. It also has color reaction with metal ions such as Ag +, Ni2 +, Pb2 +, Cu2 +, Fe3 +, Hg +, Hg2 +. It belongs to hazardous chemicals.Sensitive to light, sealed and protected from light.
Diphenylcarbazide uses are used as indicators in diphenylcarbazide chromium test. Colorimetric determination of chromium, mercury and lead, detection of cadmium, mercury, magnesium, aldehydes and earth root alkali. Diphenylcarbazide reagent is also a chloride reduction indicator for the determination of dichromate. Adsorption indicators for the determination of chloride and cyanide by mercurimetry. (it is used as a chromogenic agent for spectrophotometric determination of chromium and for verification of Cu2 +, Fe3 +, Hg2 +, etc. it is also used as an indicator for redox, adsorption and coordinated titration.).
Synthesis of 1,5-Diphenylcarbazide：
Preparation of 1,5-Diphenylcarbazide：
1. It is obtained by the reaction of phenylhydrazine with urea. Phenylhydrazine; Urea was added to xylene, refluxed for 32 hours, placed overnight and filtered out the crude product. Then dissolve in the mixed acid solvent of ethanol and a little acetic acid, quickly cool and crystallize, soak and wash again with ethanol after filtration, and filter dry to be the finished product
2. Refluxing phenylhydrazine and slightly excessive urea to 155 ~ 160 ℃ until the reactant completely melts and bubbles disappear:
The reaction ends after holding for 2 ~ 3H. After a little cooling, add 95% ethanol to precipitate some diphenylcarbonyl hydrazide, reheat and reflux until the crystallization is completely dissolved, filter while hot, cool the filtrate with ice salt, and wash it with a small amount of ethanol after suction filtration until it is qualified. Filter dry and dry at 100 ℃ to obtain diphenylcarbonyl dihydrazide.