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Synthetic method of 2, 3, 5-trichloropyridine

A triclopyridine and synthetic method technology, applied in the field of chemistry, can solve problems such as complex operation, large investment in reaction equipment, and many by-products

Inactive Publication Date: 2015-04-01
盐城恒盛化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But pyridine chlorination method, see U.S. Patent US4515953, 1985-05-07Marinak Michael J, Simaonso John L.Production of polychlorinated pyridine mixtures by liquid phase chlorination of pyridine or pyridine hydrochloride synthetic 2,3,5-trichloropyridine technology exists relatively Many problems: complex operation, many by-products, difficult separation of products, low yield due to easy coking in the reaction process, large investment in reaction equipment and easy to be corroded, large reaction energy consumption, etc.
These two methods have few reaction steps and ideal yields, but both have the disadvantages of expensive raw materials and difficult availability.

Method used

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  • Synthetic method of 2, 3, 5-trichloropyridine
  • Synthetic method of 2, 3, 5-trichloropyridine
  • Synthetic method of 2, 3, 5-trichloropyridine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Embodiment 1: the hydrolysis reaction of 2-chloropyridine generates 2-alkoxypyridine

[0036] Hydrolysis (alcohol) reaction of 2-chloropyridine: under heating or reflux, raw material (I) reacts with water or alcohols under base catalysis to generate intermediate (III).

[0037]

[0038] Here, the R group can be H or methyl, ethyl, isopropyl, n-butyl, tert-butyl and other straight-chain or branched-chain alkyl groups with 5 to 8 carbons. The reaction temperature ranges from 60°C to the boiling point of various solvents, and generally does not exceed 100°C. Considering the suitable temperature of the alcoholysis reaction and the recovery of chlorinated alkanes produced by the subsequent reaction, the preferred alcohol is n-butanol or isopropanol, and the preferred molar ratio of alcohol to raw material is 3.0-10.0. General alkali metal and alkaline earth metal hydroxides can promote this reaction, the preferred base is NaOH, KOH, Ca(OH) 2Wait. The molar ratio of the...

Embodiment 2

[0039] Example 2: Chlorination of 2-alkoxypyridine to obtain 3,5-dichloro-2-alkoxypyridine

[0040]

[0041] 2-Alkoxypyridine (III) can be reacted with various suitable chlorinating agents such as chlorine gas, alkali metal (such as sodium, potassium, etc.) hypochlorite or a mixture of hydrochloric acid and hydrogen peroxide. The preferred chlorinating agent of the present invention is chlorine gas, and the molar ratio of chlorine gas to substrate (III) is 2.5-4. The catalyst used in the reaction of the present invention is simple substance iodine, and the consumption amount of the catalyst is 0.1 mol% to 2 mol% of the substrate. In the absence of a catalyst, the rate of the chlorination reaction was slightly reduced. The alkali used in the chlorination reaction can be alkali metal, alkaline earth metal oxide, hydroxide, carbonate and organic amine, such as MgO, CaO, NaOH, KOH, Ca(OH) 2 , Na 2 CO 3 , K2CO 3 , CaCO 3 , NaHCO 3 . The preferred base of the present inve...

Embodiment 3

[0043] Example 3: 3,5-Dichloro-2-alkoxypyridine Vielsmeyer-Haack Chlorination

[0044]

[0045] 3,5-Dichloro-2-alkoxypyridines were chlorinated by the well-known Vielsmeyer-Haack. Phosphorus oxychloride, thionyl chloride or oxalyl chloride is used as the chlorine source, and DMF is used as the catalyst. During the implementation of the present invention, it was found that phosphorus oxychloride would cause partial decomposition of the substrate during the reaction. However, using thionyl chloride and oxalyl chloride as the chlorination agent can make the reaction proceed under mild conditions, effectively avoiding the decomposition of the substrate, and significantly improving the yield. Generally, the molar ratio of the chlorinating agent to the substrate is 3-15, preferably 5-10, and the amount of catalyst dimethylformamide is 0.01-0.1 mol%. The reaction is carried out in the temperature range of 50-80°C, and the progress of the reaction is detected by GC. The complete ...

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Abstract

The invention discloses a synthetic method of highly selectively synthesizing 2, 3, 5-trichloropyridine with 2-chloropyridine as a raw material. The synthetic method comprises the following steps: carrying out reaction on the 2-chloropyridine and water or alcohols under base catalysis to produce 2-alkyloxypyridine, carrying out reaction on the 2-alkyloxypyridine and a chlorinating agent under the condition of base to produce 3, 5-dichloro-2-alkyloxypyridine, and finally carrying out chlorination to prepare the 2, 3, 5-trichloropyridine.

Description

technical field [0001] The invention relates to the technical field of chemistry, in particular to a synthesis method of 2,3,5-trichloropyridine. Background technique [0002] 2,3,5-Trichloropyridine is an important fine chemical intermediate, widely used in the fields of medicine and pesticide research. 2,3,5-Trichloropyridine reacts with alkali metal hydroxide to prepare 3,5-dichloro-2-pyridinol, which is an important raw material for synthesizing a series of pesticides such as insecticidal mite and herbicide oxafluben. 2,3,5-trichloropyridine can also be further fluorinated to synthesize 2,3-difluoro-5-chloropyridine, which is the basic raw material for the synthesis of the herbicide clodinafop-propargyl. [0003] At present, the synthetic methods of 2,3,5-trichloropyridine can be divided into two categories according to the difference of starting materials: [0004] 1. Catalytic ring closure method [0005] U.S. Patent US 4245098, Steiner Eginhard, Martin Pierre. Proc...

Claims

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Application Information

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IPC IPC(8): C07D213/61
CPCC07D213/61
Inventor 张小航宋洪亮
Owner 盐城恒盛化工有限公司
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