Method for preparing 4-bromobenzoic acid

A technology of bromobenzoic acid and p-bromotoluene, which is applied in the field of preparation of 4-bromobenzoic acid, can solve the problems of many reaction steps, only yield, and high cost, and achieve the effects of low cost, few steps, and reduced raw material cost

Inactive Publication Date: 2018-09-21
黄石市利福达医药化工有限公司
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  • Abstract
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Problems solved by technology

[0003] The production method of 4-bromobenzoic acid mainly contains two kinds at present, and a kind of is to make p-bromobenzoic acid by potassium permanganate oxidation p-bromotoluene, and cost is too high, and yield only has 80%; Another kind of method is made by Bromobenzene reacts with acetyl chloride to generate 4-bromoacetophenone, and then reacts 4-bromoacetophenone with sodium hypochlorite to generate 4-bromobenzoic acid. This method has many reaction steps and serious pollution

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  • Method for preparing 4-bromobenzoic acid

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Embodiment 1

[0029] A kind of preparation method of 4-bromobenzoic acid of the present embodiment specifically comprises the steps:

[0030] (1) Put 40g p-bromotoluene, 600g glacial acetic acid, 4.8g cobalt acetate, 4.8g manganese acetate, 2.4 g potassium bromide, warming up to 80 ° C, open oxygen 0.6L / min, until reflux, keep the reflux state and react with oxygen for 7 hours, remove the sample and detect that p-bromotoluene is less than 0.5% as the reaction end point, cool and filter to get the crude product and mother liquor, The crude product is to be refined, and the mother liquor is applied mechanically after being adsorbed by activated carbon;

[0031] (2) Add 10 g of activated carbon to the mother liquor in the upper batch, heat up to 80-90° C. for insulation and adsorption for 1 hour, cool to 60° C., filter, weigh and use as the next batch. Add 40g of p-bromotoluene to the 1000mL reaction bottle, measure the water content of the treated mother liquor and replenish acetic anhydride...

Embodiment 2

[0035] A kind of preparation method of 4-bromobenzoic acid of the present embodiment specifically comprises the steps:

[0036] (1) Put 30g of p-bromotoluene, 500g of glacial acetic acid, 3g of cobalt acetate, 3g of manganese acetate, and 1g of bromide into a 1000mL reaction flask equipped with mechanical stirring, oxygen-passing glass tube, constant pressure dropping funnel, thermometer, and reflux condenser. Potassium, heat up to 75°C, turn on oxygen 0.5L / min, until reflux, keep reflux and react with oxygen for 9 hours, remove the sample and detect that p-bromotoluene is less than 0.5% as the reaction end point, cool and filter to obtain the crude product and mother liquor, the crude product is to be refined , the mother liquor is applied mechanically after being adsorbed by activated carbon;

[0037] (2) Add 10 g of activated carbon to the mother liquor in the upper batch, heat up to 80-90° C. for adsorption for 0.5 hours, cool to 50° C. to filter, weigh and use for the nex...

Embodiment 3

[0041] A kind of preparation method of 4-bromobenzoic acid of the present embodiment specifically comprises the steps:

[0042](1) Put 50g of p-bromotoluene, 700g of glacial acetic acid, 7g of cobalt acetate, 7g of manganese acetate, 4g of Sodium, heat up to 80°C, turn on oxygen 0.7L / min, until reflux, maintain the reflux state and react with oxygen for 6.5 hours, remove the sample and detect that p-bromotoluene is less than 0.5% as the reaction end point, cool and filter to obtain the crude product and mother liquor, the crude product is to be refined , the mother liquor is applied mechanically after being adsorbed by activated carbon;

[0043] (2) Add 10 g of activated carbon to the mother liquor of the previous batch, heat up to 80-90° C. for adsorption for 2 hours, cool to 60° C. to filter, weigh and apply mechanically for the next batch. Add 50g of p-bromotoluene to the 1000mL reaction bottle, measure the water content of the treated mother liquor and supplement the acet...

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Abstract

The invention relates to a method for preparing 4-bromobenzoic acid and belongs to the technical field of compound production and preparation. The method comprises the following steps: by taking bromotoluene as an initial raw material, glacial acetic acid as a solvent and oxygen as an oxidant, carrying out catalytic oxidation on parabromotoluene by using a liquid-phase oxidation method under the action of a catalyst, controlling a reaction temperature to 75-85 DEG C, terminating the reaction when the content of the parabromotoluene in the reaction system accounts for 0.5wt% of an initial content, cooling, filtering so as to obtain a crude product and filtrate of 4-bromobenzoic acid, and further purifying the crude product of the 4-bromobenzoic acid at one step, thereby obtaining a finishedproduct. The melting point of the finished product of the 4-bromobenzoic acid is 252-254 DEG C. In addition, the 4-bromobenzoic acid prepared by using the method is high in yield, that is, the yieldis up to 98% or greater, meanwhile, the finished product is high in purity, that is, the purity is up to 99% or greater, the defects that a product prepared by using a conventional preparation methodis low in purity and low in yield can be overcome, and in addition, the method provided by the invention is simple and easy in raw material obtaining, low in cost and wide in application prospect.

Description

technical field [0001] The invention belongs to the production and preparation technical field of compounds, more specifically, the present invention relates to a kind of preparation method of 4-bromobenzoic acid. Background technique [0002] 4-bromobenzoic acid (4-Bromobenzoic acid) is also known as p-bromobenzoic acid, and its molecular formula is C 7 h 5 o 2 Br, with a molecular weight of 201.02, is a white or light pink crystal. 4-Bromobenzoic acid is an important fine chemical, which can be used as a raw material for spices, an intermediate of 4-bromobenzoate, a standard for measuring strontium, and measuring carbon, hydrogen and bromine in organic trace analysis. [0003] The production method of 4-bromobenzoic acid mainly contains two kinds at present, and a kind of is to make p-bromobenzoic acid by potassium permanganate oxidation p-bromotoluene, and cost is too high, and yield only has 80%; Another kind of method is made by Bromobenzene reacts with acetyl chlor...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/265C07C51/42C07C51/47C07C51/487C07C63/70
CPCC07C51/265C07C51/42C07C51/47C07C51/487C07C63/70
Inventor 包泉兴成家钢
Owner 黄石市利福达医药化工有限公司
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