Method for recrystallizing and purifying 2,3,6-trichloropyridine
A technology of trichloropyridine and a purification method, which is applied in the field of recrystallization and purification of 2,3,6-trichloropyridine, can solve the problem that the container has high requirements on pressure resistance, high cost of rectification and purification, unfavorable industrial production, etc. problem, to achieve the effect of controlling purification cost, low cost and high feasibility
Active Publication Date: 2017-12-26
LIER CHEM CO LTD
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Problems solved by technology
However, in actual industrial production, this method has the following main problems: the cost of rectification and purification is high, it needs to be decompressed to 0.1MPa, and the product is collected at 118-124°C, the conditions are harsh, the operation is complicated, and a vacuum is required system, which has high requirements on the pressure resistance of containers, which is not conducive to industrial production
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Embodiment 1
[0073] Mix crude 2,3,6-trichloropyridine with a solvent, heat to 70°C, wait until the solid is completely dissolved, stir and cool to 25°C, stir to crystallize, filter, and dry to obtain the finished product of 2,3,6-trichloropyridine; The parameters and results of recrystallization purification are shown in Table 3.
[0074] Table 3 Example 1 Recrystallization Purification Parameters and Results
[0075]
[0076] From the data in Table 3, it can be seen that by screening the recrystallization solvent and its dosage, crystallization temperature and other parameters in the recrystallization process, under optimized conditions, the crude product E and crude product F were recrystallized: the crude product E was recrystallized, 2, The purity of 3,6-trichloropyridine is 97.7%, the purity of 2,3,6-trichloropyridine is increased by more than 3.8%, and the yield of 2,3,6-trichloropyridine is high; the crude product F is recrystallized, 2, The purity of the finished product of 3,6...
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The invention belongs to the field of compound purification, and particularly relates to a method for recrystallizing and purifying 2,3,6-trichloropyridine, aiming at providing a novel method for purifying 2,3,6-trichloropyridine, which is simpler and more effective and has lower cost. The method comprises the following steps: mixing a 2,3,6-trichloropyridine crude product with a solvent in a solid-liquid mass ratio of 1:(1-4); heating until solid is completely solved, and cooling to 10-30 DEG C; and crystallizing, filtering and drying to obtain the 2,3,6-trichloropyridine. According to the preparation method, the purity of 2,3,6-trichloropyridine is increased by 3-15 percent by controlling a recrystallizing solvent and dosage thereof, crystallizing temperature and other parameters in the recrystallizing process, and the recrystallized finished product has high purity and high yield. The method has simple operation, high recrystallization efficiency and low cost, and provides an efficient means for purifying the 2,3,6-trichloropyridine.
Description
technical field [0001] The invention belongs to the field of compound purification and relates to a method for recrystallization and purification of 2,3,6-trichloropyridine. Background technique [0002] 2,3,6-Trichloropyridine is an important chemical intermediate widely used in the fields of medicine and pesticides. At present, 2,6-dichloropyridine is generally used as raw material to prepare 2,3,6-trichloropyridine through chlorine chlorination, but the purity of 2,3,6-trichloropyridine prepared by this method is generally 80- 92%, the impurities are mainly 2,6-dichloropyridine with a content of 2-10% and 2,3,5,6-tetrachloropyridine with a content of 2-10%, and the purity of 2,3,6-trichloropyridine is partial low, which severely limits its application. [0003] At present, there are few reports on the purification of 2,3,6-trichloropyridine. Patent CN102153507A discloses a method of reacting 2,6-dichloropyridine with chlorine gas and then purifying and separating 2,3,6-...
Claims
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Login to View More IPC IPC(8): C07D213/61
CPCC07D213/61
Inventor 李世洪王福雄程柯
Owner LIER CHEM CO LTD