Method used for preparing o-nitrobenzyl bromide

A technology of nitrobenzyl bromide and o-nitrotoluene, which is applied in the field of organic synthesis, can solve the problems of poor mixing effect, generation of acidic waste water, and high operational requirements, and achieves large industrial practical value, high utilization rate, and simple post-treatment. Effect

Active Publication Date: 2018-06-26
SHANGDONG HAILIER CHEM
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Patent CN1265639A discloses a preparation method of substituted benzyl bromide, in which it is reported that the combination of hydrobromic acid/hydrogen peroxide, bromine salt/hydrogen peroxide, etc. is used for bromination, but this type of method has high requi...

Method used

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  • Method used for preparing o-nitrobenzyl bromide
  • Method used for preparing o-nitrobenzyl bromide

Examples

Experimental program
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Effect test

Embodiment 1

[0023] Add 127.5 grams of o-nitrotoluene, 325 grams of cyclohexane, 137.2 grams of dibromohydantoin and 6.6 grams of AIBN into a 1L reaction flask equipped with a stirring, thermometer, and condenser tube, and slowly raise the temperature to 80°C, and control the heating rate to prevent Vigorous reflux leads to flushing, reflux for 3-4 hours until the solution is colorless, and the sample is controlled in the center. After passing the test, stop the reaction, cool down to 20 degrees, filter, and the filtrate is precipitated under reduced pressure to 60 degrees to obtain bromide. Normalized to: 90.4% o-nitrobenzyl bromide, 6.5% o-nitrotoluene, 2.2% o-nitrobenzylidene dibromide. The yield of o-nitrobenzyl bromide (in terms of o-nitrotoluene, the same below) reaches 90.1%.

Embodiment 2

[0025] Add 127.5 grams of o-nitrotoluene, 300 grams of 1,2-dichloroethane, 140.2 grams of dibromohydantoin and 6.6 grams of AIBN into a 1L reaction flask equipped with a stirring, thermometer, and condenser, and slowly raise the temperature to 83°C. Control the heating rate to prevent violent reflux from causing flushing, reflux for 3-4 hours until the solution is colorless, take a sample for control, stop the reaction after passing the test, cool down to 20 degrees, filter, and desolvate the filtrate to 60 degrees under reduced pressure to obtain bromide. Normalized to: 91.8% o-nitrobenzyl bromide, 5.3% o-nitrotoluene, 2.1% o-nitrobenzylidene dibromide. The yield of o-nitrobenzyl bromide is 91.1%.

Embodiment 3

[0027] Add 383 grams of o-nitrotoluene, 975 grams of chlorobenzene, 420 grams of dibromohydantoin and 19 grams of AIBN into a 2L reaction flask equipped with a stirring, thermometer, and condenser tube, and slowly raise the temperature to 80°C, and control the heating rate to prevent Punch the material, keep it warm for 4 hours until the red color of bromine fades, take a sample and control it, stop the reaction after passing the test, cool down to 20 degrees, filter, and decompress the filtrate to remove the solvent to obtain the bromide. Normalized to: 89.5% o-nitrobenzyl bromide, 7.3% o-nitrotoluene, 1.9% o-nitrobenzylidene dibromide. The yield of o-nitrobenzyl bromide is 89.7%.

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Abstract

The invention discloses a novel preparation method of o-nitrobenzyl bromide. According to the preparation method, ortho-nitrotoluene is taken as a raw material, azodiisobutyronitrile is taken as a catalyst, at 20 to 100 DEG C, a bromination reagent is adopted for bromination to prepare the target product. Compared with the prior art, the preparation method possesses following advantages: 1, yieldis increased obviously from about 60% to about 90%; 2, the bromination reagent can be recycled, and bromine element utilization rate is relatively high, is 90% or higher; 3, reactants can be subjectedto direct mixing reaction, so that operation complexity is reduced; and 4, reaction conditions are convenient to control, the post-treatment is simple, less three waste is generated, and the industrial using value is relatively high.

Description

[0001] manual technical field [0002] The invention belongs to the field of organic synthesis, and in particular relates to a method for preparing o-nitrobenzyl bromide. Background technique [0003] Pyraclostrobin is a new type of broad-spectrum fungicide developed by BASF in 2002, which can prevent and control plant diseases caused by all types of fungal pathogens. Nitrogen has a more stimulating effect on crop growth. In recent years, the research on N-methoxycarbamic acid derivatives with pyraclostrobin as the parent structure is very active, and o-nitrobenzyl bromide is an important intermediate for the synthesis of pyraclostrobin and such derivatives. Therefore it is particularly important to improve the synthesis technique of o-nitrobenzyl bromide. [0004] Patent CN1265639A discloses a preparation method of substituted benzyl bromide, in which it is reported that bromination is carried out by using a combination of hydrobromic acid / hydrogen peroxide, bromine salt / ...

Claims

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Application Information

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IPC IPC(8): C07C201/12C07C205/11
CPCC07C201/12C07C205/11
Inventor 陈龙龑阎修维荆成材单长岭李建国张志刚王旭韩晴晴葛尧伦
Owner SHANGDONG HAILIER CHEM
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