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A method of selective chlorination

A selective, chlorinated reagent technology, used in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., and can solve problems such as low products

Active Publication Date: 2015-09-16
SHANDONG WEIFANG RAINBOW CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In foreign research, sodium hypochlorite is used instead of chlorine to reduce the danger in the production process and the requirements for equipment, but compared with chlorine chlorination, the product is lower

Method used

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  • A method of selective chlorination
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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Add 32g (98%, 0.193mol) of o-tolyloxyacetic acid, 24.1g (0.193mol) of 32% sodium hydroxide solution and 260g of water into a 1000ml four-necked reaction flask, stir well at room temperature, and then immerse the reaction flask at 25°C In the water bath, add 0.5g acetamide, then add 10% sodium hypochlorite solution dropwise at a uniform speed, and at the same time add an appropriate amount of 30% hydrochloric acid dropwise, control the pH of the reaction system to be 6-9, and wait until the theoretical amount of sodium hypochlorite solution is added dropwise Take samples and use high performance liquid chromatography to detect the reaction results. When the liquid phase of o-tolyloxyacetic acid is normalized to ≤1.0%, stop the dropwise addition, add hydrochloric acid to the reaction solution at 65 ° C to acidify to pH ≤ 1, cool down and suction filter and dried to obtain 38.1 g of 2-methyl-4-chlorine technical substance with a yield of 95.6% and a purity of 98.65%.

[00...

Embodiment 2

[0045] Add 32g (98%, 0.193mol) o-tolyloxyacetic acid, 24.1g (0.193mol) 32% sodium hydroxide solution and 260g water into a 1000ml four-necked reaction flask, stir well at room temperature, and then immerse the reaction flask at 25°C In the water bath, add 1.5g DMF, then add 12% sodium hypochlorite solution dropwise at a constant speed, and add an appropriate amount of 30% hydrochloric acid dropwise at the same time, control the pH of the reaction system to be 5-7, and take a sample after adding the theoretical amount of sodium hypochlorite solution dropwise , using high performance liquid chromatography to detect the reaction results, when the liquid phase normalization of o-tolyloxyacetic acid is ≤1.0%, stop the dropwise addition, add hydrochloric acid to acidify the reaction solution at 65 ° C to pH ≤ 1, cool down and suction filter and After drying, 37.9 g of 2-methyl-4-chlorine technical substance was obtained, with a yield of 95.3% and a purity of 97.4%.

Embodiment 3

[0047] Add 32g (98%, 0.193mol) o-tolyloxyacetic acid, 24.1g (0.193mol) 32% sodium hydroxide solution and 260g water into a 1000ml four-necked reaction flask, stir well at room temperature, and then immerse the reaction flask at 25°C In the water bath, add 1.0g propionamide, then add 12% sodium hypochlorite solution dropwise at a constant speed, and add an appropriate amount of 30% hydrochloric acid dropwise at the same time, control the pH of the reaction system to be 5-7, and wait until the theoretical amount of sodium hypochlorite solution is added dropwise Take samples and use high performance liquid chromatography to detect the reaction results. When the liquid phase of o-tolyloxyacetic acid is normalized to ≤1.0%, stop the dropwise addition, add hydrochloric acid to the reaction solution at 65 ° C to acidify to pH ≤ 1, cool down and suction filter and dried to obtain 38.2 g of 2-methyl-4-chlorine technical substance with a yield of 95.9% and a purity of 97.3%.

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Abstract

The invention provides a selective chlorination method which comprises the following step of: mixing a compound with a structural formula (I), a basic compound, water and a chlorinating regent under the condition of a catalyst for chlorination reaction to obtain a compound with a structural formula (II), wherein the catalyst is an amide compound or a pyridine compound, and the chlorinating regent is an oxydol hydrochloric acid system or sodium hypochlorite. Compared with the prior art, firstly, the selective chlorination method provided by the invention adopts the oxydol hydrochloric acid system or the sodium hypochlorite as the chlorinating regent and carries out chlorination by adopting a water-phase chlorination method, thereby enhancing the selectivity of the chlorination reaction; the selective chlorination method provided by the invention can obtain the qualified product through separation, thereby achieving the safety of a chlorination method and reducing the pollution on the environment and the corrosion on equipment; and secondly, the selective chlorination method provided by the invention increases the yield of the chlorination reaction by adding the added amide compound or pyridine compound as the catalyst.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis, in particular to a selective chlorination method. Background technique [0002] 2-methyl-4-chlorophenoxyacetic acid (abbreviated as 2-methyl-4-chloro) is a hormone-type systemic herbicide, which has strong physiological activity on plants and can promote plant growth at low concentrations, while At high concentrations, it has a growth inhibitory effect on dicotyledonous plants, which can cause deformities and even death of plants. When used as a herbicide, 2-methyl-4-chloro has the excellent characteristics of high efficiency, low toxicity, low residue, and no pollution to the environment, so it belongs to an excellent type of herbicide. [0003] There are generally two production methods for 2-methyl-4-chlorine: the first method is to chlorinate first and then condense, chlorinate o-cresol with chlorine gas and condense with chloroacetic acid under alkaline price adjustment, and prec...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C59/70C07C51/363
Inventor 孙国庆侯永生李宗清李志清陈桂元刘凯
Owner SHANDONG WEIFANG RAINBOW CHEM