3,6-BIS(2-CHLOROPHENYL)-1,2-DIHYDRO-1,2,4,5-TETRAZINE

3, 6-bis(2-chlorophenyl)-1, 2-dihydro-1, 2, 4, 5-tetrazine is prepared by the reaction of bis(α, 2-dichlorobenzylidene)hydrazine and hydrazine hydrate Got. Put 260 L of toluene, 85 kg of bis(α, 2-dichlorobenzylidene) hydrazine, 28 kg of sodium carbonate, and 1.5 kg of phase transfer catalyst into a 500 L reactor. Then the temperature is raised to 78°C, and 25.5 kg of hydrazine hydrate is added dropwise. After the addition is completed, keep it warm for 1 hour. After the reaction is completed, the toluene is distilled under reduced pressure, and toluene is recovered for reuse; the residue is washed with water and filtered by a centrifuge. The filter cake is 3, 6-bis(2-chlorophenyl)-1, 2-dihydro-1 , 2, 4, 5-tetrazine. The filtrate is stratified, the water phase is sent to the wastewater treatment section, and the oil phase is incinerated.

3,6-bis(2-chlorophenyl)-1,2-dihydro-1,2,4,5-tetrazine is an intermediate for the preparation of acaricide tetramazine.