Method for synthesizing 2-Bromobenzotrifluoride
A technology of o-bromotrifluorotoluene and o-aminotrifluorotoluene is applied in the synthesis field of o-bromotrifluorotoluene, can solve the problems of many meta- and para-isomers, expensive raw materials, many impurities, etc. And the effect of less para-isomer, low production cost and high product content
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[0024] The invention provides a kind of synthetic method of o-bromobenzotrifluoride, comprising the following steps:
[0025] A) o-aminotrifluorotoluene, hydrobromic acid and sodium nitrite are mixed and reacted to obtain a diazonium salt solution;
[0026] B) Mixing and reacting the above diazonium salt solution with cuprous bromide and hydrobromic acid to obtain o-bromobenzotrifluoride.
[0027] The reaction formula is as follows:
[0028]
[0029] The present invention overcomes the defects of the prior art such as high cost and many impurities in the product, adopts cheap and easy-to-obtain raw materials, has good solvent recovery effect, high yield and high product content, and synthesizes o-bromotrifluorotoluene in one step. Compared with other routes, intermediate There are few position and para isomers, and the production cost is low.
[0030] Specifically, the sodium nitrite solution is added dropwise to the mixed solution of o-aminotrifluorotoluene and hydrobrom...
Embodiment 1
[0046] Add 120g of o-aminobenzotrifluoride and 500ml of 48% hydrobromic acid into a 1000ml four-necked reaction flask, cool down to below -5°C, add dropwise a solution of 54g of sodium nitrite and 100ml of water, the dropping temperature is -5~0°C, Stirring was continued for 15 minutes after dropping. A solution of the diazonium salt was obtained.
[0047] Add 64g of cuprous bromide and 200ml of 48% hydrobromic acid to a 1L four-necked reaction flask equipped with mechanical stirring, a thermometer and a distillation device, heat to reflux, and add the diazonium salt solution prepared above dropwise. While carrying out atmospheric distillation, keep the rate of addition equal to the distillation rate, and collect the evaporated liquid until the evaporated liquid is no longer turbid.
[0048] Add 400ml of dichloromethane to the evaporated liquid for extraction, wash the organic layer with 300ml of water for 3 times, and wash with 300ml of 1mol / L sodium hydroxide solution for 1...
Embodiment 2
[0053] Add 120g of o-aminobenzotrifluoride and 360ml of 48% hydrobromic acid into a 1000ml four-necked reaction flask, cool down to below -5°C, add dropwise a solution of 62g of sodium nitrite and 100ml of water, the dropping temperature is 0-5°C, dropwise Continue stirring for 15 minutes after completion. A solution of the diazonium salt was obtained.
[0054] Add 75g of cuprous bromide and 340ml of 48% hydrobromic acid to a 1L four-necked reaction flask equipped with a mechanical stirrer, a thermometer, and a distillation device, heat to reflux, and add the diazonium salt solution prepared above dropwise. While carrying out atmospheric distillation, keep the rate of addition equal to the distillation rate, and collect the evaporated liquid until the evaporated liquid is no longer turbid.
[0055] Add 400ml of dichloromethane to the evaporated liquid for extraction, wash the organic layer with 300ml of water for 3 times, and wash with 300ml of 1mol / L sodium hydroxide solutio...
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