Method for continuously preparing dinitrochlorobenzene

A technology of dinitrochlorobenzene and mononitrochlorobenzene is applied in the field of preparation of dinitrochlorobenzene, and can solve the problems of unguaranteed safety and product quality, difficulty in large-scale continuous production, and low product purity. , to achieve the effect of expanding production capacity, reducing raw material consumption and reducing labor intensity

Active Publication Date: 2011-05-25
LIANYUNGANG DIPU CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The existing production process of dinitrochlorobenzene in China adopts discontinuous production, which generally has low efficiency, high consumption, safety and product quality cannot be guaranteed
[0009] In response to the above-mentioned defects, scientific and techn...

Method used

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  • Method for continuously preparing dinitrochlorobenzene
  • Method for continuously preparing dinitrochlorobenzene
  • Method for continuously preparing dinitrochlorobenzene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Such as figure 1 As shown, according to the method described in this patent, wherein reactors 1, 2, 3, 4, 5, 6, 7, and 8 all have separation devices. The control conditions of the inorganic phase of each reactor and the average residence time of the organic phase are shown in Table 1 below. The total amount of chlorobenzene, the total amount of nitric acid, and the total amount of sulfuric acid are added in the ratio of chlorobenzene:total amount of nitric acid:total amount of sulfuric acid=1:1.2:1.5.

[0044]

[0045] Table 1

[0046]

[0047] The first step is that chlorobenzene and nitric acid react to generate mononitrochlorobenzene, and mixed acid is formed into 74% sulfuric acid, 4% nitric acid, 18% water in the reaction; The second step is that the mononitrochlorobenzene that reaction generates continues and Nitric acid reacts to generate dinitrochlorobenzene, and the mixed acid standard composition in the reaction is 79% sulfuric acid, 5% nitric acid, and ...

Embodiment 2

[0055] Such as figure 2 As shown, according to the flow process described in this patent, wherein reactors 1, 4, and 5 all have separation devices. The total amount of mononitrochlorobenzene, total amount of nitric acid, and total amount of sulfuric acid are added in the ratio of mononitrochlorobenzene: total amount of nitric acid: total amount of sulfuric acid = 1: (0.4~0.5): (1.0~1.3). The control conditions of the inorganic phase and the average residence time of the organic phase of each reactor are shown in Table 3 below, and the purification conditions of water washing and alkali washing are the same as in Example 1.

[0056]

[0057] table 3

[0058]

[0059] The product quality is as shown in Table 4, and the product yield: 96.5%. :

[0060] Table 4

[0061] components

Embodiment 3

[0063] Such as image 3 As shown in the process flow, p-nitrochlorobenzene is used as raw material to prepare 2,4 dinitrochlorobenzene, and nitrate and nitric acid in the inorganic phase are extracted with chlorobenzene. Chlorobenzene continuously passes through two reactors in series to extract dinitrochlorobenzene in the inorganic phase flowing out of the first dinitrolation reactor, and then p-nitrochlorobenzene passes through two dinitrolation reactors to make dinitrochlorobenzene Nitrochlorobenzene is washed with water, alkali and water to make finished products. Reactors 1, 11, 4, 5, 6, 7, and 8 all have separation devices. Mononitrochlorobenzene: total amount of nitric acid: total amount of sulfuric acid mass ratio=1:0.41~0.45:0.9~1.2. The parameters of the inorganic phase of each reactor and the average residence time of the organic phase are shown in Table 5, and the purification conditions of water washing and alkali washing are the same as in Example 1.

[0064] ...

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Abstract

The invention discloses a method for continuously preparing dinitrochlorobenzene. Multiple dinitration reactors are connected in series for reaction, and mononitrochlorobenzene is continuously added to the first dinitration reactor, and continuously flows through all the dinitration reactors and flows out; a mixed acid nitrating agent is prepared from 75-85% of sulfuric acid, 2-7% of nitric acid and 5-15% of water; the reaction temperature is 40-95 DEG C; and each dinitration reactor is provided with a separation device for separating an organic phase from an inorganic phase, and the inorganic phase is returned into the reactor, thereby keeping the inorganic phase and the organic phase in the required proportion. In the invention, the dinitrochlorobenzene is prepared by continuous reactions, and the reactions are continuously carried out and sequentially completed; chlorobenzene is used for extracting nitrates and nitric acid in an acid phase, thereby lowering the content of the nitric acid in the acid phase and recycling the nitrates in the acid phase; by the invention, the dinitrochlorobenzene can be continuously prepared from two raw materials (chlorobenzene and p-nitrochlorobenzene) by using one set of devices; and the invention has the advantages of low raw material consumption and high production capacity.

Description

[0001] technical field [0002] The invention relates to a method for preparing dinitrochlorobenzene, in particular to a method for continuously preparing dinitrochlorobenzene. Background technique [0003] Dinitrochlorobenzene, referred to as DNCB, is mainly used as an intermediate for the preparation of dyes, pharmaceuticals and pesticides, as a polymerization aid, etc., and its molecular formula is C 6 h 3 Cl (NO 2 ) 2 , it has six isomers in total, and what needs to be produced is dinitrochlorobenzene with a 2,4-DNCB structure. In the products produced with chlorinated benzene as raw materials, 2,4-DNCB generally accounts for about 96%, and 2,6 -DNCB accounts for about 3%, unnitrated mononitrochlorobenzene accounts for 0.2%, and the rest is nitrated by-products. The 2,4-DNCB produced with p-nitrochlorobenzene generally accounts for 99.5%, and the remaining mononitrides and by-products account for 0.5%. [0004] The first stage: nitration of chlorobenzene into mononi...

Claims

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Application Information

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IPC IPC(8): C07C205/12C07C201/08
Inventor 尹世英段孝宁李明
Owner LIANYUNGANG DIPU CHEM
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