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2,6-dimethylpyridine preparation method

A technology of lutidine and dimethyl, applied in 2 fields, can solve the problems of large investment in separation and purification, large influence of catalyst performance and high equipment requirements, and achieves low equipment requirements, low production cost and high safety. Effect

Inactive Publication Date: 2006-02-15
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Method (2) gas-phase cyclization at high temperature requires high equipment requirements, poor safety, low yield and is greatly affected by catalyst performance, more by-products are generated in the reaction, and a large investment is required for separation and purification

Method used

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  • 2,6-dimethylpyridine preparation method

Examples

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Comparison scheme
Effect test

Embodiment 12

[0029] The preparation of embodiment 12,6-dimethyl-4-chloropyridine

[0030] In a 150ml three-necked flask, add 24.6g (0.2mol) of 2,6-dimethyl-4-hydroxypyridine and 4.2g (0.01mol) of phosphorus pentachloride, and add 46.0g of phosphorus oxychloride dropwise within 30 minutes at room temperature (0.3mol), after dropping, the temperature was raised to 110-115°C, and the reaction was continued for 9-11 hours, and finally the reactant turned brown. Phosphorus oxychloride is recovered by distillation. Naturally cooled to room temperature, the reactant was slowly poured into a 300ml ice-water mixture, washed with 20% Na 2 CO 3 Adjust the pH of the solution to 8, extract with 3×100ml chloroform, anhydrous Na 2 SO 4 Dry, distill to recover chloroform, distill the residue under reduced pressure, collect fractions at 92-93°C / 20mmHg, and obtain 26.7 g of light yellow liquid with a yield of 94.3% and a purity of 98.8%.

Embodiment 22

[0031] The preparation of embodiment 22,6-dimethyl-4-chloropyridine

[0032] Except that phosphorus pentachloride was not added, other operating conditions were the same as in Example 1 to obtain 15.4 g of light yellow liquid with a yield of 54.6% and a purity of 98.6%.

Embodiment 32

[0033] The preparation of embodiment 32,6-dimethyl-4-chloropyridine

[0034] Except that the charging amounts of phosphorus oxychloride and phosphorus pentachloride were changed to 30.7g (0.2mol) and 8.4g (0.02mol) respectively, that is, 2,6-dimethyl-4-hydroxypyridine: phosphorus oxychloride: five Except that the molar ratio of phosphorus chloride was 1:1:0.1, other operating conditions were all the same as in Example 1 to obtain 24.1 g of light yellow liquid with a yield of 85.2% and a purity of 98.8%.

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Abstract

The invention discloses a process for preparing 2,6-dimethylpyridine comprising the following steps, using Pd / C as catalyst, C1-C4 alcohols as solvent, subjecting 2,6-dimethyl-4-chloropyridine to hydrogenization dechlorination reaction under the conditions of hydrogen pressure 0.1-0.2MPa, 20-55 deg. C, finally carrying out post-treatment to obtain the 2,6-dimethylpyridine.

Description

(1) Technical field [0001] The invention relates to a preparation method of 2,6-lutidine. (2) Background technology [0002] 2,6-Lutidine is an important intermediate in organic synthesis, widely used in the synthesis of medicines, pesticides, spices, industrial products, etc. 2,6-lutidine was originally extracted from coal tar. In the early 1940s, the world's energy structure changed by "replacing coal with oil", which limited the source of this compound. The development of the compound has greatly increased the demand for this compound, which has prompted the development of the chemical synthesis of 2,6-lutidine. The methods for preparing 2,6-lutidine reported in the literature mainly include the following two methods. (1) Ethyl acetoacetate, formaldehyde and ammonia are under diethylamine as a catalyst to generate 1,4-dihydro-3,5-dicarboethoxy-2,6-lutidine, and the latter uses concentrated Sulfuric acid and concentrated nitric acid are oxidized to obtain 3,5-diethylcar...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/06C07D213/133
Inventor 孙楠胡仙超莫卫民胡宝祥
Owner ZHEJIANG UNIV OF TECH
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