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Preparation method of high-purity p-nitrochlorobenzene

A technology of p-nitrochlorobenzene and nitrochlorobenzene, which is applied in the field of high-purity p-nitrochlorobenzene preparation, can solve the problems of restricting the quality of aminoanisole products and low purity of p-nitrochlorobenzene, and meet the needs of the market Demand, the effect of increasing economic benefits

Pending Publication Date: 2021-06-25
宁夏华御化工有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In view of this, the present invention provides a kind of high-purity p-nitrochlorobenzene preparation method, to solve the p-nitrochlorobenzene purity that exists in the prior art is relatively low, the technical problem that restricts the product quality of p-aminoanisole

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  • Preparation method of high-purity p-nitrochlorobenzene
  • Preparation method of high-purity p-nitrochlorobenzene

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preparation example Construction

[0037] In a specific embodiment, a method for preparing high-purity p-nitrochlorobenzene comprises the following steps: after nitric acid and sulfuric acid are mixed into a mixed acid, and then carry out nitration reaction with chlorobenzene to generate nitrochlorobenzene; The neutral nitrochlorobenzene is obtained through the steps of oleic acid separation, alkali washing and water washing; after the neutral nitrochlorobenzene is dried, the finished p-nitrochlorobenzene is separated by a crystallization process.

[0038] It is worth noting that the above process belongs to the traditional production process of p-nitrochlorobenzene, and its reaction control conditions, including parameters such as reaction material ratio, reaction temperature, reaction pressure, and space velocity, belong to those skilled in the art. Known or should know technical means, in the present invention, only improve the process of crystallization process separation p-nitrochlorobenzene, do not emphasi...

Embodiment 1

[0066] Using neutral nitrochlorobenzene as raw material, carry out primary crystallization.

[0067] After nitric acid and sulfuric acid are made into mixed acid, they are nitrated with chlorobenzene to generate nitrochlorobenzene; nitrochlorobenzene undergoes oleic acid separation, alkali washing, and water washing steps in sequence to obtain neutral nitrochlorobenzene; neutral nitrochlorobenzene After the chlorobenzene is dried, a crystallization is carried out.

[0068] Please see figure 1 , the initial material temperature of primary crystallization is about 80±1°C, firstly lower the temperature to about 74°C, and start to strictly control the cooling rate, first reduce the temperature to about 73°C at a cooling rate of 1°C / h, and then reduce the temperature to about 1.3°C / h ~1.5°C / h cooling rate, reduce the temperature to about 69°C, and then reduce the temperature to about 65°C at a cooling rate of 2°C / h, so far the crystallization forming period of the first crystalliz...

Embodiment 2

[0074] Using neutral nitrochlorobenzene as a raw material, the primary crystallization process in Example 1 was adjusted.

[0075] The primary crystallization process in Example 1 is adjusted in order to further improve the purity of the primary crystallization p-nitrochlorobenzene. In a preferred implementation process, comprise the following steps:

[0076] Please see Figure 4 , the initial material temperature of primary crystallization is about 80±1°C, firstly cool down to about 76°C, and start to strictly control the cooling rate, firstly lower the temperature to about 74°C at a cooling rate of 1°C / h, and then reduce the temperature to about 74°C at a cooling rate of 1.3°C / h ~1.5°C / h cooling rate, lower the temperature to about 72°C, and then lower the temperature to about 68°C at a cooling rate of 2°C / h, so far the crystallization forming period of the first crystallization is completed. In this stage, the crystal nucleus grows to a certain scale and has a certain str...

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Abstract

The invention provides a preparation method of high-purity p-nitrochlorobenzene, and belongs to the technical field of chemical separation. The method comprises the following steps: preparing nitric acid and sulfuric acid into mixed acid, and carrying out nitration reaction on the mixed acid and chlorobenzene to generate nitrochlorobenzene; making the nitrochlorobenzene sequentially subjected to oleic acid separation, alkali washing and water washing to obtain neutral nitrochlorobenzene; and drying the neutral nitrochlorobenzene, and separating the finished product p-nitrochlorobenzene by adopting a two-time crystallization process. By adopting twice crystallization and adjusting parameters of the crystallization process, the purity of the finished product p-nitrochlorobenzene reaches 99.9% or above on the basis of ensuring the yield of p-nitrochlorobenzene, so that the quality of p-aminoanisole produced by taking p-nitrochlorobenzene as a raw material is improved, the market demand is met, and the economic benefit is increased.

Description

technical field [0001] The invention belongs to the technical field of chemical separation, and in particular relates to a preparation method of high-purity p-nitrochlorobenzene. Background technique [0002] p-Nitrochlorobenzene is one of the important raw materials for producing p-aminoanisole. Its main production process is: after nitric acid and sulfuric acid are mixed into mixed acid, it is nitrated with chlorobenzene to generate nitrochlorobenzene (which contains p- Nitrochlorobenzene about 65%), then separate nitrochlorobenzene and waste acid. After separation, nitrochlorobenzene is washed with water, neutralized to obtain neutral nitrochlorobenzene, and then dried and crystallized to separate the finished p-nitrochlorobenzene. [0003] The purity of p-nitrochlorobenzene seriously restricts the quality and income of p-aminoanisole. However, the crystallization method is used to separate p-nitrochlorobenzene from nitrochlorobenzene, which cannot take into account the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C201/08C07C201/16C07C205/12
CPCC07C201/08C07C201/16C07C205/12
Inventor 顾家立顾行祥徐麟徐小华
Owner 宁夏华御化工有限公司
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