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Device for continuous preparation of o-nitrobenzyl bromide and preparation method thereof

A technology of nitrobenzyl bromide and o-nitrotoluene, which is applied in the field of continuous preparation of o-nitrobenzyl bromide, can solve the problems of difficult separation and extraction, long reaction time, low conversion rate, etc. The effect of shortening the time and reducing by-products

Inactive Publication Date: 2019-07-12
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] In summary, the common problems of the above traditional synthesis methods are: long reaction time, low conversion rate, many by-products, difficult separation and extraction, and potential environmental safety hazards

Method used

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  • Device for continuous preparation of o-nitrobenzyl bromide and preparation method thereof
  • Device for continuous preparation of o-nitrobenzyl bromide and preparation method thereof
  • Device for continuous preparation of o-nitrobenzyl bromide and preparation method thereof

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Effect test

Embodiment 1

[0030] The structure of the reaction device is as figure 1 As shown, the tubular reactor 10 used in this embodiment has a length of 10 m and a diameter of 1 mm, and the material of the tubular reactor 10 is polytetrafluoroethylene; the light source 8 is a 250 nm UV lamp.

[0031] First turn on the light source 8, turn on the circulating constant temperature water bath glass jacket 9 to preheat the tubular reactor 10 to 20°C, and dissolve o-nitrotoluene in methylene chloride to obtain a 0.28mol / L o-nitrotoluene solution and liquid bromine Dissolve in dichloromethane to obtain 0.28mol / L liquid bromine solution, then store o-nitrotoluene solution, liquid bromine solution and water in storage tank Ⅰ1, storage tank Ⅱ2 and storage tank Ⅲ3 respectively, and the three materials pass through the metering pump respectively Ⅰ5, metering pump Ⅱ6 and metering pump Ⅲ7 measure, control the molar flow ratio of o-nitrotoluene solution, liquid bromine solution, and water to 1:0.4:3, and transpo...

Embodiment 2

[0033] The structure of the reaction device is as figure 1 , the pipe length is 50m, the diameter is 2mm, the pipe material is polytetrafluoroethylene; the light source is a 250nm UV lamp.

[0034] First turn on the light source, turn on the circulating constant temperature water bath glass jacket preheating pipeline, and the reaction temperature is 20°C. Dissolve o-nitrotoluene in dichloromethane to obtain a 0.43mol / L o-nitrotoluene solution, and dissolve liquid bromine in dichloromethane to obtain a 0.43mol / L liquid bromine solution, then dissolve the o-nitrotoluene solution, liquid bromine solution 1. Water is stored in storage tank Ⅰ, storage tank Ⅱ and storage tank Ⅲ respectively, and the three materials pass through metering pump Ⅰ, metering pump Ⅱ and metering pump Ⅲ respectively, and are sent to the mixer at the same time, and the flow rate is controlled so that the molar flow ratio of the three is 1 : 1:4, the material enters the tubular reactor after being mixed by ...

Embodiment 3

[0036] The structure of the reaction device is as figure 1 , the pipe length is 100m, the diameter is 1.5mm, the pipe material is polytetrafluoroethylene; the light source is a 250nm UV lamp.

[0037] Firstly, turn on the light source, turn on the circulating constant temperature water bath glass jacket preheating pipeline, and the reaction temperature is 30°C. Dissolve o-nitrotoluene in dichloromethane to obtain a 0.55mol / L o-nitrotoluene solution, and dissolve liquid bromine in dichloromethane to obtain a 0.55mol / L liquid bromine solution, then dissolve the o-nitrotoluene solution, liquid bromine solution, water Stored in storage tank Ⅰ, storage tank Ⅱ and storage tank Ⅲ respectively, the three materials pass through metering pump Ⅰ, metering pump Ⅱ and metering pump Ⅲ respectively, and are transported to the mixer at the same time, and the flow rate is controlled so that the molar flow ratio of the three is 1:1 : 7, after the material is mixed by a mixer, it enters a tubul...

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Abstract

The invention relates to a device for continuous preparation of o-nitrobenzyl bromide and a preparation method thereof. The device mainly comprises a tubular reactor, three storage tanks, three corresponding metering pumps, an efficient mixer and a receiving tank. The storage tanks are connected to the efficient mixer through pipelines. The metering pumps are distributed on the connecting pipelines of the corresponding storage tanks and the efficient mixer. The efficient mixer is successively connected to the tubular reactor and the receiving tank. A light source is arranged above the tubularreactor. A temperature measuring instrument is arranged in the tubular reactor. The preparation method comprises the following steps: raw materials including ortho-nitrotoluene, liquid bromine and water enter the mixer respectively through the three metering pumps to be uniformly mixed; the mixture then enters a pre-insulated tubular reactor to react under illumination; the reaction product entersthe receiving tank after the reaction, followed by standing; and an organic layer is taken, and an organic solvent is removed to obtain the product. The preparation method of o-nitrobenzyl bromide isconvenient to operate; the post-treatment is simple; the product has good yield and high purity, and is suitable for industrial production.

Description

technical field [0001] The invention discloses a device for continuously preparing o-nitrobenzyl bromide and a preparation method thereof. Background technique [0002] O-nitrobenzyl bromide is an important precursor for the synthesis of o-nitrobenzaldehyde, which is generally obtained through o-nitrotoluene bromination, hydrolysis, and oxidation. O-Nitrobenzaldehyde is an important pharmaceutical and organic synthesis intermediate, widely used in the preparation of medicines, dyes and pesticides, etc. It is also an important intermediate for the synthesis of expectorant ambroxol hydrochloride parent 3,5-dibromoanthranilic aldehyde. [0003] The reported benzyl bromination of o-nitrotoluene is as follows: [0004] Mishra et al. (Bioorganic & Medicinal Chemistry Letters 17 (2007) 1326–1331) used NBS as the bromine source, benzoyl peroxide as the free radical initiator, and carbon tetrachloride as the solvent. The yield was 69%. The free radical initiator used in this metho...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J19/24C07C201/12C07C205/11
CPCB01J19/2415C07B2200/13C07C201/12C07C205/11
Inventor 李坚军何云飞周嘉第
Owner ZHEJIANG UNIV OF TECH
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