Preparation method of 2, 4-dichlorobenzotrifluoride

A technology of dichlorotrifluorotoluene and dichlorotoluene, which is applied in two fields, can solve problems such as high process safety and environmental protection requirements, unsuitability for large-scale production, and difficult control of chlorination depth, so as to improve the effective yield of products and reduce The content of polyalkylation products and the corrosion of the reactor, the effect of avoiding the aggravation of the chlorination depth

Pending Publication Date: 2022-03-01
JIANGSU SANMEI CHEM
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  • Abstract
  • Description
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Problems solved by technology

Australian patent AU2016102216A4 discloses a process for preparing 2,4-dichlorotoluene by reacting 2,4-diaminotoluene as a raw material with a solution of potassium chloride and cobalt chloride, with a yield of 85%. The process starts with The raw materials are expensive, and there are many waste water and waste salts, which are not suitable for large-scale production; Chinese patent CN1080279A discloses a kind of 3-chloro-4-methylaniline as raw material, which is diazotized and Sandmeyer reaction 2,4-dichlorotoluene is prepared with a yield of 88%. The starting materials of this process are also expensive, and the requirements for process safety and environmental protection are relatively high
Therefore, from the point of view of economy, safety and environmental protection, taking p-chlorotoluene as raw material to synthesize 2,4-dichlorobenzotrifluoride is the route most suitable for industrialization at present, but the prior art has low yield, many by-products, chlorine Disadvantages such as difficult depth control

Method used

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  • Preparation method of 2, 4-dichlorobenzotrifluoride

Examples

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preparation example Construction

[0030] 1. Preparation of catalyst

[0031] (1) FeCl 3 Preparation of / C catalyst:

[0032] Into the 2L reaction flask, add 2% Fe(NO 3 ) 3 Solution 1000ml, add 500g activated carbon at the same time, add 30% NaOH solution dropwise under stirring until the pH is about 9-10, filter, put the obtained solid in a muffle furnace, and sinter at 400°C for 2h. Cool down to room temperature, fill it into a tubular reactor, feed hydrogen chloride gas at a space velocity of 60L / h, chlorinate at 200°C for 30h; 2 :N 2 =3: 97 gas, space velocity 60L / h, 300°C treatment for 5h, slowly lowering to room temperature, to get FeCl 3 / C Catalyst. (Other halogenated metal salt catalyst preparation process refers to FeCl 3 / C)

[0033] (2)(C 6 h 4 CH 2 SCH 2 C 10 h 6 )SbCl / CaCl 2 Catalyst preparation:

[0034]Add 80g of 1-bromo-2((2-bromobenzylthio)toluene)naphthalene into a 2L reaction flask, pass nitrogen gas for protection, then add 1000ml of anhydrous diethyl ether, and stir to diss...

Embodiment 1

[0036] (1) Nuclear chlorination

[0037] FeCl 3 The / C catalyst is filled into the Φ200*2000 tubular reactor, after the filling is completed, the end is capped, and the jacket is opened to circulate cooling water. Open the bottom valve of the p-chlorotoluene storage tank, and feed p-chlorotoluene at a rate of 1Kg / h; at the same time, open the valve of the chlorine gas storage tank and the tail gas valve, and first feed Cl at a rate of 0.12Kg / h. 2 . The tail gas enters the tail gas absorption system, the resulting reaction liquid is pumped into the rectification tower, the electric heating is turned on, and rectification is carried out, and the fraction is collected into the receiving buffer tank. Open the bottom valve of the buffer tank, feed p-chlorotoluene at a speed of 0.3Kg / h, and simultaneously adjust the bottom valve of the p-chlorotoluene storage tank to adjust the feed to 0.7Kg / h. Sampling was carried out by GC for detection, and the rate of chlorine gas introductio...

Embodiment 2

[0043] Nuclear chlorination catalyst is FeCl 2 / CaCl 2 , other reaction processes were the same as in Example 1; 287 g of 2,4-dichlorobenzotrifluoride and 94 g of 3,4-dichlorobenzotrifluoride were obtained.

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Abstract

The invention discloses a preparation method of 2, 4-dichlorobenzotrifluoride, which comprises the following steps: (1) nuclear chlorination: taking parachlorotoluene as a raw material, carrying out multiple times of rectification and separation on the raw material nuclear chlorination in a rectification tube type integrated reactor under the action of a Lewis acid catalyst, and carrying out rectification and separation on the product to obtain a mixture of 2, 4-dichlorotoluene and 3, 4-dichlorotoluene; and (2) side chain chlorination: carrying out side chain chlorination on the mixture of the 2, 4-dichlorotoluene and the 3, 4-dichlorotoluene under the action of a photochlorination catalyst and an inhibitor to obtain a mixture of the 2, 4-dichlorotrichlorotoluene and the 3, 4-dichlorotrichlorotoluene. And (3) fluorination: reacting the side chain chlorination product with hydrogen fluoride under the action of a fluorination catalyst, after directional side chain fluorination, removing acid and moisture in the reaction liquid, and rectifying and separating to obtain the product 2, 4-dichlorobenzotrifluoride.

Description

technical field [0001] The invention relates to the field of chemical industry, in particular to a preparation method of 2,4-dichlorobenzotrifluoride. Background technique [0002] 2,4-Dichlorotrifluorotoluene is an intermediate of the herbicide dichloramine, and it can also be used in the fields of medicine, dyes and polymers. It is an important organic intermediate and has a good market application prospect. At present, there are few studies on its synthesis, mainly concentrated in a few domestic companies, and there are no relevant reports on its industrialization. This is mainly due to the fact that in the synthesis process, side reactions easily occur, the products are diversified and have no obvious practical value, and the recovery of catalysts is difficult, etc., which restricts the process of its industrialization. [0003] There are two main preparation techniques for 2,4-dichlorobenzotrifluoride: one is prepared from 2,4-dichlorotoluene through side chain chlorin...

Claims

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Application Information

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IPC IPC(8): C07C17/20C07C25/13C07C17/383
CPCC07C17/20C07C17/14C07C17/12C07C17/383C07C25/13C07C25/02
Inventor 赵恒军潘国东翟志兵徐科张旗
Owner JIANGSU SANMEI CHEM
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