Preparation method of 3,5-dibromopyridine

A technology of dibromopyridine and pyridine, which is applied in the field of synthesis of chemical raw materials, can solve the problems of high requirement of conditions, many pollutions of three wastes, cumbersome steps, etc., and achieve the effect of high reaction yield, good reaction effect and simple reaction steps

Active Publication Date: 2018-09-25
ANHUI XINGYU CHEM
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Problems solved by technology

[0006] Aiming at the problems existing in the existing 3,5-dibromopyridine preparation methods, such as high requirements on conditions, cumbersome steps, many three wastes pollution, and low yield, the present invention provides a preparation method of 3,5-dibromopyridine, which can be produced under high temperature conditions Carrying out the bromination reaction avoids the use of catalyst, so there are few wastes after the reaction, and the method provided by the invention has few reaction steps, high reaction yield, and the purity of the product can be as high as about 99%. increased from 50% to 82%

Method used

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Embodiment 1

[0033] Such as figure 1 Shown, the present invention provides a kind of simple and easy preparation method of 3,5-dibromopyridine, with pyridine as raw material, with concentrated sulfuric acid and thionyl chloride as catalyzer, under high temperature condition (high temperature refers to temperature at 125- 138 ℃) under the dropwise addition of bromine reaction. Concrete reaction steps are:

[0034] (1) 100g pyridine is added in 100g vitriol oil and 300g sulfur oxychloride, heat up and reflux, the massfraction of vitriol oil is 98%;

[0035] (2) Add 550g of bromine dropwise under reflux (completely dropwise within 10 hours), heat up to 130°C for reaction, observe whether there is reddish-brown gas in the reaction test tube to judge whether the reaction is complete;

[0036] (3) The reaction solution is subjected to steam distillation, and the product precipitated in water is crude 3,5-dibromopyridine, which does not need to be dried, and then the crude 3,5-dibromopyridine i...

Embodiment 2

[0049] Such as figure 1 Shown, the present invention provides a kind of simple and easy preparation method of 3,5-dibromopyridine, with pyridine as raw material, with concentrated sulfuric acid and thionyl chloride as catalyzer, under high temperature condition (high temperature refers to temperature at 125- 138 ℃) under the dropwise addition of bromine reaction. Concrete reaction steps are:

[0050] (1) 100g pyridine is joined in 100g vitriol oil and 250g sulfur oxychloride, heats up and refluxes, and the massfraction of vitriol oil is 99%;

[0051](2) Add 500g of bromine dropwise under reflux (completely drop within 12 hours), raise the temperature to about 125°C for reaction, observe whether there is reddish-brown gas in the reaction test tube to judge whether the reaction is complete;

[0052] (3) The reaction solution is subjected to steam distillation, and the product precipitated in water is crude 3,5-dibromopyridine, and then the crude 3,5-dibromopyridine is dissolve...

Embodiment 3

[0062] Such as figure 1 Shown, the present invention provides a kind of simple and easy preparation method of 3,5-dibromopyridine, with pyridine as raw material, with concentrated sulfuric acid and thionyl chloride as catalyzer, under high temperature condition (high temperature refers to temperature at 125- 138 ℃) under the dropwise addition of bromine reaction. Concrete reaction steps are:

[0063] (1) 100g pyridine is added in 100g concentrated sulfuric acid and 300g sulfur oxychloride, heat up and reflux, the massfraction of concentrated sulfuric acid is 99.5%;

[0064] (2) Add 700g of bromine dropwise under reflux (completely add dropwise within 10 hours), heat up to 138°C for reaction, observe whether there is reddish-brown gas in the reaction test tube to judge whether the reaction is complete;

[0065] (3) The reaction solution is subjected to steam distillation, and the product precipitated in water is crude 3,5-dibromopyridine, and then the crude 3,5-dibromopyridin...

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Abstract

The invention discloses a preparation method of 3,5-dibromopyridine, and belongs to the technical field of synthesis of chemical raw materials. The preparation method comprises the following steps: with pyridine as a raw material, and concentrated sulfuric acid and sulfoxide chloride as catalysts, dropwise adding bromine under a high-temperature condition, reacting to obtain 3,5-dibromopyridine, then refining with an alcoholic solution, and performing chromatographic determination on the obtained product, wherein the purity of the obtained product is as high as about 99.8%. The preparation method has the advantages that the reaction catalysts are easy to obtain, the reaction condition is easy to control, the reaction byproducts are less, the use of catalysts, such as nickel powder, copperpowder and aluminium chloride, is avoided, emission of three wastes is reduced, and the problems that in the prior art, pollution is serious, and the yield is low are solved.

Description

technical field [0001] The invention belongs to the technical field of chemical raw material synthesis, and more specifically relates to a preparation method of 3,5-dibromopyridine. Background technique [0002] 3,5-Dibromopyridine is an important pharmaceutical intermediate and an important raw material for the prevention and treatment of central nervous disorders TC-2559. Since the aromatic electrophilic reaction of pyridine is much slower than that of benzene, severe reaction conditions are often required, and usually only the 3-position substitution reaction is generated. Existing literature reports such as Englert et al. synthesized 3 at a high temperature of 230-250 degrees Celsius. , a mixture of 5-dibromopyridine (36%) and 3-bromopyridine (38%), while Mallet et al. synthesized 3,4-dibromopyridine under the action of n-butyllithium at -78 degrees Celsius , 5-dibromopyridine (25%), a mixture of 3-bromopyridine (20%) and 4-bromopyridine (20%), and these synthetic metho...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/61
CPCC07D213/61
Inventor 张升张宽宇金文艺
Owner ANHUI XINGYU CHEM
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