DBDCB synthesis

Yield:35691-65-7 510 kg

Reaction Conditions:

Stage #1:acrylonitrile with triethylamine;zinc(II) chloride for 1 h;Autoclave;Green chemistry;Large scale;
Stage #2: with bromine in water at 50 - 100; for 2 h;Green chemistry;Large scale;

Steps:

1) Take 120kg triethylamine, the liquid pumped high vacuum metering tank spare. 2) using the same pumping material way acrylonitrile 1350kg pumped into the 2000L reactor, control of the material to a temperature of about 30 °C, from manhole added pulverized zinc chloride 80kg open stirred for 60 minutes, zinc chloride dissolved completely, to obtain a mixed solution. 3) apply a clip reactor cooling water, the temperature inside the autoclave anti controlled at about 45°C , was added dropwise to the kettle starts from a high weighing vessel in step 1) the triethylamine, the reaction solution was mixed with the reaction vessel , reaction temperature ≤45°C , the reaction mass temperature ≤50°C, was added dropwise while observing the color of the contents of the autoclave, the autoclave until the reaction color changed to reddish brown, the end of the dropwise addition, dropwise addition of the total length 45 ~ 55h; wherein , triethylamine dropwise three times, the first half of the dropwise addition, the cooling clamp to be closed cooling water applied after 4 to 6 hours, the reactor temperature at 40 ~ 45°C not rise, and then a second dropwise addition, after closing the cooling water, 4 to 6 hours and then the reaction, the kettle temperature at 40 ~ 45°C the rise in the liquid feed to the reaction kettle as a brown-red color, the completion of the dropwise addition of triethylamine. 4) The reaction mass was transferred 3000L reaction vessel was charged with 100kg of 50% sulfuric acid solution (+ 50kg 50kg of concentrated sulfuric acid were mixed to form water) was pickled to remove the lower layer, the upper layer retained, then washed twice with water (first water wash an amount of 500kg, the second water consumption is 300kg), the material in the upper layer of water in the lower, the material after washing into a plastic bucket. 5) the material is pumped to an intermediate tank, the valve opens evaporator vapor, the vapor pressure of 0.15Mpa, the degree of vacuum of 600 ~ 650 mmHg (box by vacuum pump) of 2 times concentrated, concentrated to about 3 hours. 6) the material after the treatment of the concentrated distillation, and concentrated in vacuo to close the valve system, the valve open Roots vacuum system, steam pressure 0.6 ~ 1.0MPa, a temperature of 170 ~ 190°C , vacuum degree of 730 ~ 750 mmHg, distillation 4 to 5 times, fine distilled material (ie, intermediate) after sedimentation placed in a plastic bucket 7) In the 1000L reactor before adding the water, 200kg, 450kg and then vacuum was applied to the intermediate stage reactor, with stirring first with negative pressure 150kg bromine pumped into the reactor, the vacuum system immediately stop using the autoclave per hour into the tank to 60kg bromine, until the desired amount of bromine after net weight 850kg pumped into the reactor until the temperature not exceeding 50°C . After the addition for 2 hours, 100°C heating insulation, white observation kettle liquid feed for qualified, qualified after the temperature dropped to 20°C , turn 2000L water tank washing again, the first increase in the crystallization kettle 510kg methanol feed sub-freezing crystallization. 10 suction centrifugal discharge into the drying room drying, wet and dry weight control ≤1%, was bromothalonil finished.

References:

JIANGSU TUOQIU AGRICULTURE CHEMICAL CO., LTD.;LIAO, DAZHANG;LIAO, DAQUAN;SUN, BOWEN CN105218400, 2016, A Location in patent:Paragraph 0018; 0019

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