Synthesizing method for 2,3,6-trichlorobenzoic acid and intermediate of 2,3,6-trichlorobenzoic acid

A technology of trichlorotoluene and dichlorotoluene, applied in 2 fields, can solve the problems of complex preparation methods, high production costs, poor reaction selectivity, etc.

Active Publication Date: 2016-01-13
JIANGSU LIANHE CHEM TECH +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by this invention is in order to overcome the high raw material price of the preparation method of 2 in the prior art, 3, 6-trichlorobenzoic acid is not easy to get, the preparation method is complicated, reaction selectivity is poor, the product purity that makes is poor, yield A kind of synthetic method of 2,3,6-trichlorobenzoic acid and its intermediates is provided due to defects such as low, high production cost, and being unsuitable for industrialized production

Method used

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  • Synthesizing method for 2,3,6-trichlorobenzoic acid and intermediate of 2,3,6-trichlorobenzoic acid
  • Synthesizing method for 2,3,6-trichlorobenzoic acid and intermediate of 2,3,6-trichlorobenzoic acid
  • Synthesizing method for 2,3,6-trichlorobenzoic acid and intermediate of 2,3,6-trichlorobenzoic acid

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Experimental program
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Effect test

Embodiment 1

[0064] The preparation method of embodiment 1M-ZSM-12

[0065] The preparation method of M-ZSM-12 is: take a certain amount of ZSM-12 molecular sieve and place it in a round-bottomed flask, add 5 times of mass equivalents of hydrochloric acid with a mass concentration of 5% (the mass concentration refers to the mass of hydrogen chloride) % of the total mass of hydrochloric acid) and one-third of the mass equivalent of metal chloride, reflux and stir at 100°C for 20 hours, wash with water until neutral, then dry at 120°C for 24 hours, and activate at 400°C for 5 hours . When the metal chloride is zinc dichloride, ferric chloride, antimony trichloride or titanium tetrachloride, the obtained composites are respectively recorded as Zn-ZSM-12, Fe-ZSM-12, Sb-ZSM-12, Ti - ZSM-12.

Embodiment 2 2

[0066] The preparation of embodiment 2 dichlorobenzene mixtures

[0067] Add 100g of o-chlorotoluene and 1g of Fe-ZSM-12 into a four-necked round-bottomed flask, stir at 25°C for 30 minutes, and then feed 49.8g of chlorine gas under normal pressure at a rate of 10g / h. After reacting for about 5 hours, the conversion rate is detected by gas phase. 87%, stop logical chlorine. Obtained 124.2 g of reaction liquid, composed of o-chlorotoluene 13%, 2,6-dichlorotoluene 42%, 2,3-dichlorotoluene 27%, 2,5-dichlorotoluene 16%, trichlorotoluene and other impurities 2.0%. Rectification, distilled o-chlorotoluene was recovered and used mechanically, and the dichlorobenzene mixture was 112.3g, with a yield of 88.3% (95.7% after applying mechanically), which could be directly used in the next reaction.

Embodiment 3 2

[0068] The preparation of embodiment 3 dichlorobenzene mixtures

[0069]Add 100g of o-chlorotoluene and 1g of Sb-ZSM-12 into a four-necked round-bottomed flask, stir at 25°C for 30 minutes, and then feed 48.2g of chlorine gas under normal pressure at a rate of 10g / h. After reacting for about 5 hours, the conversion rate is detected by gas phase. 85%, stop passing chlorine. Obtained 123.4 g of reaction solution, composed of 15% o-chlorotoluene, 55% 2,6-dichlorotoluene, 23% 2,3-dichlorotoluene, 6% 2,5-dichlorotoluene, trichlorotoluene and other impurities 1.0%. The ortho-chlorotoluene was distilled by rectification and recovered and used mechanically. The dichlorobenzene mixture distilled was 109.5g, with a yield of 86.1% (96.8% after applying mechanically), which could be directly used in the next reaction.

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Abstract

The invention discloses a synthesizing method for 2,3,6-trichlorobenzoic acid and intermediate of the 2,3,6-trichlorobenzoic acid, and provides a preparation method for 2,3,6-trichlorotoluene. The preparation method for the 2,3,6-trichlorotoluene comprises the following steps that on the condition that a catalyst exists, a chlorination reaction is performed on a mixture of dichlorotoluene and a chlorination agent to obtain the 2,3,6-trichlorotoluene; metal and/or metal halide are/is adopted as the catalyst, and a mixture of 2,6-dichlorotoluene and 2,3-dichlorotoluene or a mixture of 2,6-dichlorotoluene, 2,3-dichlorotoluene and 2,5-dichlorotoluene is adopted as the mixture of the 2,6-dichlorotoluene. The synthesizing method is high in reaction yield, selectivity and purity of the prepared product, low in production cost, easy to operate, mild in reaction condition and suitable for industrialize production.

Description

technical field [0001] The invention relates to a synthesis method of 2,3,6-trichlorobenzoic acid and its intermediate. Background technique [0002] 2,3,6-Trichlorobenzoic acid, trade name Caoyaping, is a benzoic acid herbicide, which can be used to control some annual and perennial deep-rooted broad-leaved weeds and some shrubs. It can be used as an important intermediate in the synthesis of dicamba (US3444192) and dicamba (Dicamba) can be prepared through one-step reaction with sodium methoxide. With the approval of dicamba-resistant genetically modified crops, the market prospect of dicamba is very promising, and accordingly there will be more and more market demand for 2,3,6-trichlorobenzoic acid. [0003] At present, the methods of synthesizing 2,3,6-trichlorobenzoic acid mainly contain the following types: [0004] Patent US3086991A, patent 20030216577A1 and literature (JournaloftheChemicalSociety, 1951,1208-1212) reported that 2,3,6-trichlorotoluene was used as a r...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C17/12C07C25/10C07C51/265C07C51/27C07C51/16C07C63/70
Inventor 樊小彬林行军陈冬辉周述勇陈国彬
Owner JIANGSU LIANHE CHEM TECH
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