Study On The Synthesis Technology Of 1-Phenyl-3-Hydroxy-1, 2, 4-Triazolen

Triazophos, an organophosphate insecticide and acaricide, which can combat wireworm, is highly effective, poisonous at intermediate level and of broad spectrum. It is an ideal insecticide instead of highly toxic pesticides. 1- phenyl– 3- hydroxy- 1, 2, 4- triazolen is important intermediate of triazophos, It is useful to enhance the yield of triazophos when we improve reasonably the conditions in the synthesis of 1- phenyl- 3- hydroxy- 1, 2, 4- triazolen.My dissertation comes up with two improved methods for the preparation of 1- phenyl- 3- hydroxy- 1, 2, 4- triazolen. The first method is a process for synthesis of 1- phenyl- 3- hydroxy-1, 2, 4- triazolen in two steps. Effect factors of product quality and yield, such as material ratio, the ratio of primary materials and catalyst, solvent volume, reaction time have been repetitively studied. The optimum conditions have been worked out, the period of condensation reation: n(phenylhydrazine hydrochloride): n(urea): n(concentrated sulfuric acid): n(water)=1(mol): 1.2(mol): 0.2(mol):28(mol), reaction time is 10h, temperature is reflux temperature; the period of cyclization reaction : n(1-phenylSemicarbazide): n(formic acid): n(concentrated sulfuric acid): n(water)=1: 2.5(mol): 0.3(mol):28(mol), reaction time is 4h, temperature is reflux temperature.The second method employs an only one pot for synthesis of 1- phenyl- 3- hydroxy- 1, 2, 4- triazolen. Cited two-step method of synthesis conditions, The optimum conditions of one-pot process have been worked out, the period of condensation reation: n(phenylhydrazine hydrochloride): n(urea): n(concentrated sulfuric acid): n(water)=1(mol): 1.2(mol): 0.2(mol):28(mol); the period of cyclization reaction : n(1-phenylSemicarbazide): n(formic acid): n(concentrated sulfuric acid): n(water)=1(mol): 2.4(mol): 0.2(mol):11(mol), in which the yield is above 90%.