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Purification refined method for benzpyrole

A refining method and indole technology, applied in the direction of organic chemistry, can solve the problems of high production cost, gap, low indole yield, etc., and achieve the effect of increasing yield and low cost

Inactive Publication Date: 2014-04-09
NANJING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] CN1424311A discloses a method for separating and refining indole from coal tar methylnaphthalene, through industrial methylnaphthalene decompression azeotropic distillation → vacuum distillation → washing crystallization → vacuum distillation four steps, although can get Indole products with a content greater than or equal to 98%, but there is still a gap compared with the market requirements for products with a purity greater than 99%
The method of recrystallizing indole with alkane or cycloalkane solvents requires a large amount of solvent to dissolve indole to improve the purity of indole, and reclaiming the solvent requires a large amount of heat energy, and the yield of indole is low. Production high cost

Method used

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  • Purification refined method for benzpyrole

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Experimental program
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Effect test

Embodiment 1

[0020] Using indole with a purity of 92.0% as the raw material, according to the ratio of indole: hot water = 1:2, first add 50g of 92.0% indole into 100g of hot water at 90°C, stir and dissolve fully, and then the solution is layered. The upper layer solution was taken away and stirred at 15°C for 3 hours to crystallize, then the precipitated crystals were filtered, and the obtained filtrate was used mechanically. Extraction ends after one application. The crystals were dried in vacuum to obtain 43.1 g of white indole product with a purity of 99.92%, and the yield of indole reached 93.7%.

Embodiment 2

[0022] Using indole with a purity of 92.0% as the raw material, according to the ratio of indole: hot water = 1:1, first add 50g of 92.0% indole into 50g of hot water at 95°C, stir and dissolve fully, and then the solution is layered. The upper layer solution was taken away and stirred at 5°C for 2 hours to crystallize, then the precipitated crystals were filtered, and the obtained filtrate was used mechanically. Extraction ends after one application. The crystals were vacuum dried to obtain 43.8 g of white indole product with a purity of 99.92%, and the yield of indole reached 95.2%.

Embodiment 3

[0024] Using indole with a purity of 95.7% as the raw material, according to the ratio of indole: hot water = 1:0.5, first add 50g of 95.7% indole to 25g of hot water at 90°C, stir and dissolve fully, and then the solution is layered. The upper layer solution was taken away and stirred at 5°C for 2 hours to crystallize, then the precipitated crystals were filtered, and the obtained filtrate was used mechanically. Extraction ends after three applications. The crystals were vacuum dried to obtain a purity of 99.94% (such as figure 1 Shown) white indole product 45.9g, the yield of indole reaches 95.9%.

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Abstract

The invention discloses a purification refined method for benzpyrole. Benzpyrole with a content of being less than 99% is employed as a raw material, and dissolved in hot water. Then the supernatant solution is subjected to cooling crystallization. Then suction filtration and vacuum drying are carried out, and a white benzpyrole product with a purity of 99.9% is obtained and the yield is above 90%. The filtrate after benzpyrole can be used again. In the purification refined method, hot water is employed as a solvent, the cost is low, operation is simple and practicable, and no "three wastes (waste gas, waste water and industrial residue)" are generated during the production process. The method accords with green environmental protection concepts, is especially suitable for industrial production, and lowers production cost effectively.

Description

technical field [0001] The invention belongs to the field of petrochemical industry, and in particular relates to a purification method for extracting indole from coal tar and its industrial application. Background technique [0002] Indole is mainly used as a raw material for spices and dyes and as a drug intermediate. The industrial methylnaphthalene recovered from coal tar contains 85-95% methylnaphthalene, 4.2-5.8% indole, and a small amount of naphthalene, isoquinoline, biphenyl, etc. Because isoquinoline and indole in the raw material are difficult to separate, biphenyl and indole have close boiling points, the separation effect of the two is poor, and the boiling point of indole is relatively high, the fluidity of the still residue after ordinary distillation is poor, and it is easy to block the pipeline etc., therefore simple distillation method is difficult to produce the higher indole product of purity. [0003] Among the many existing processes for extracting i...

Claims

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Application Information

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IPC IPC(8): C07D209/08C07D209/06
CPCC07D209/06C07D209/08
Inventor 夏明珠祁道冉钱梦飞陈连锋雷武王风云
Owner NANJING UNIV OF SCI & TECH
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