A new synthesis process of o-nitrobenzyl bromide

A kind of ortho-nitrobenzyl bromide and a new synthesis technology, applied in the field of new synthesis technology of ortho-nitrobenzyl bromide, can solve the problems of unsuitable large-scale industrial synthesis technology and high cost, reduce production technology cost and prevent by-products , Environmental pollution-free effect

Active Publication Date: 2020-04-28
ZHEJIANG ZHONGSHAN CHEM IND GRP
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But at present this kind of test is still in the small test of theoretical attempt, although the effect is good, but because the cost is too high, it is not suitable for large-scale industrial synthesis process (Chemical Industry and Engineering, 2016, 33, 1, 45-50 )
[0004] According to existing literature reports at home and abroad, the current HBr / H 2 o 2 As a brominating agent, azobisisobutyronitrile (AIBN) is used as an initiator (Pesticides, 2013, 52, 6, 408-410; CN103641722) Synthesis process, it is difficult to simultaneously obtain high-yield o-nitro The two conditions of benzyl bromide and no dibromide formation

Method used

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  • A new synthesis process of o-nitrobenzyl bromide

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Comparison scheme
Effect test

Embodiment 1

[0027] In a 5000L bromination kettle, add 300kg of dichloroethane, 226kg of o-nitrotoluene, and 24kg of azobisisobutyronitrile in sequence, and after stirring for 20 minutes, pump the solution into a high-level tank for use; Add 300kg of dichloroethane and 226kg of o-nitrotoluene, stir evenly, add 740.86kg of 40% hydrobromic acid, and heat up and stir to 72-75°C. The mixed solution and 373.55kg of 30% hydrogen peroxide in the overhead tank were slowly added dropwise to the bromination kettle simultaneously at a rate of 1:4. After the dropwise addition, the insulation reaction was continued for 2 hours. After the reaction was completed, the temperature was lowered to room temperature, and the reaction solution was analyzed by HPLC. The conversion rate of raw materials was greater than 98.7%, and no by-products such as dibromo compounds were produced. The molar ratio of raw materials, 40% hydrobromic acid and 30% hydrogen peroxide in the reaction is 1: 1.0: 1.0. The solution w...

Embodiment 2

[0029] In a 5000L bromination kettle, add 300kg of dichloroethane, 226kg of o-nitrotoluene, and 27kg of azobisisobutyronitrile in sequence, and after stirring for 20 minutes, pump the solution into the high-level tank for use; Add 300kg of dichloroethane and 226kg of o-nitrotoluene, stir evenly, add 889.03kg of 40% hydrobromic acid, and heat up and stir to 72-75°C. The mixed solution and 448.26kg of 30% hydrogen peroxide in the head tank were slowly added dropwise to the bromination kettle simultaneously at a rate of 1:4. After the dropwise addition, the insulation reaction was continued for 2 hours. After the reaction was completed, the temperature was lowered to room temperature, and the reaction liquid was analyzed by HPLC. The conversion rate of raw materials was greater than 99.0%, and no by-products such as dibromo compounds were produced. The mol ratio of raw material, 40% hydrobromic acid and 30% hydrogen peroxide in the reaction is 1: 1.2: 1.2. The solution was allo...

Embodiment 3

[0031] In the 5000L bromination kettle, add 260kg of chlorobenzene, 226kg of o-nitrotoluene, and 24kg of azobisisobutyronitrile in sequence, and after stirring for 20 minutes, pump the solution into the high-level tank for use; then put 260kg into the bromination kettle Chlorobenzene and 226kg of o-nitrotoluene were stirred evenly, then 1481.72kg of 40% hydrobromic acid was added, and the temperature was raised and stirred to 72-75°C. The mixed solution and 744.09kg of 30% hydrogen peroxide in the overhead tank were slowly added dropwise to the bromination kettle simultaneously at a rate of 1:4. After the dropwise addition, the insulation reaction was continued for 2 hours. After the reaction was completed, the temperature was lowered to room temperature, and the reaction solution was analyzed by HPLC. The conversion rate of raw materials was greater than 90.4%, and by-products such as dibromo compounds were formed. The molar ratio of raw materials, 40% hydrobromic acid and 3...

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Abstract

The invention relates to a novel nitrobenzyl bromide synthesis process which comprises the following steps: in the presence of 40% hydrobromic acid, 30% hydrogen peroxide and an initiator, namely azodiisobutyronitrile, by taking ortho-nitrotoluene as a raw material, performing a free radical bromination reaction, thereby synthesizing the nitrobenzyl bromide. The 30% hydrogen peroxide is adopted asan oxidant in the process, bromine is provided by oxidizing the hydrobromic acid, the testing conditions are strictly regulated and controlled, then the free radical bromination reaction of the ortho-nitrotoluene has selectivity, the synthesis procedures are controllable, no dibromo-byproduct is generated, meanwhile the yield is far greater than that of the prior art, the production cost is low,the environment is protected, and the process is an ideal method applicable to large-scale industrial production at present.

Description

technical field [0001] The invention belongs to the field of chemical synthesis, relates to the free radical bromination process of o-nitrotoluene, in particular to a new synthesis process of o-nitrobenzyl bromide. Background technique [0002] Pyraclostrobin is a new type of high-efficiency and low-toxicity methoxyacrylate broad-spectrum fungicide containing pyrazole structure developed by BASF in 1993 following Kresstrobin. At present, there are two synthetic routes of pyraclostrobin - first bromination method and post bromination method. Different from the post-bromination method, the first bromination method obtains benzyl bromide by brominating the methyl group in o-nitrotoluene, which is a key step in the synthesis of pyraclostrobin (World Pesticides, 2013, 35, 3, 32 -33). It is widely used in industrial production because of its easy-to-obtain raw materials, simple production process, and easy separation of products. But because the active bromine atom that produce...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C201/12C07C205/11
CPCC07C201/12C07C205/11
Inventor 李劲王涛陈璐余荣华
Owner ZHEJIANG ZHONGSHAN CHEM IND GRP
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