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A method for extracting and crystallizing spice-grade indole

A technology for extracting crystallization and indole, which is applied in the field of extraction and crystallization to prepare spice-grade indole, which can solve the problems of low purity, many impurities, and failure to meet the requirements for the use of spice-grade indole, and achieve improved purity, simple operation, and reduced impurities. The effect of content

Active Publication Date: 2022-02-22
SINOPEC NANJING RES INST OF CHEM IND CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The technical problem to be solved by the present invention is that the indole products in the prior art have low purity and many impurities, which cannot meet the requirements for the use of spice-grade indole, and the product quality needs to be improved. A simple method for preparing spice-grade indole by extraction and crystallization is provided. indole method

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] In a 500mL reaction flask with stirring, add 60g of synthetic indole (purity greater than 98%), 30g of water, 195g of petroleum ether (60-90°C) and 0.06g of hydrochloric acid (30%), stir and reflux for 10min, then 50g Stand still at ℃ for 10 minutes, the oil-water layer is separated, and the water layer is left for use. The oil layer is cooled to 0°C and maintained for 2 hours, and the product is obtained by filtration. It is dried in a low-temperature vacuum at 30°C and 2kPa for 2 hours, and 51g of the product is obtained (recovery rate 85%). Chromatographic analysis, product purity 99.95%, o-toluidine 80ppm.

Embodiment 2

[0028] In a 500mL reaction flask with stirring, add 60g of synthetic indole (purity greater than 98%), 30g of water, 13.5g of ethanol, 195g of petroleum ether (60-90°C) and 0.06g of hydrochloric acid (30%), stir and raise the temperature to reflux 10min, then stand at 50°C for 20min, the oil-water layer is separated, the water layer is left for use, the oil layer is cooled to 0°C and maintained for 2h, the product is obtained by filtration, and the product is obtained by vacuum drying at 30°C and 2kPa for 2h to obtain 49.2g of the product (recovered Rate 82%), chromatographic analysis, product purity 99.99%, o-toluidine 70ppm.

Embodiment 3

[0030] In a 500mL reaction flask with stirring, add 60g of synthetic indole (purity greater than 98%), 31g of the water layer in Example 2, and filter the mother liquor in Example 2, stir and heat up to reflux for 10min, then stand at 50°C for 20min, the oil and water layer, the water layer was left for use, the oil layer was cooled to 0°C and maintained for 2h, the product was obtained by filtration, and dried in a low-temperature vacuum at 30°C and 2kPa for 2h to obtain 59.8g of the product (99.6% recovery rate). Chromatographic analysis showed that the product had a purity of 99.99% %, o-toluidine 80ppm.

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Abstract

The invention relates to a method for preparing spice-grade indole by extraction and crystallization, which mainly solves the problems in the prior art that indole products have low purity and high impurities and cannot meet the requirements of spice-grade indole. The present invention adds a certain amount of crystallization solvent, water and amine-binding solvent to the industrial indole product with a purity ≥ 98%, stirs, heats up and refluxes, stirs and keeps warm for a period of time, then stands for a period of time, separates the water layer and the oil layer, and the oil layer The temperature is lowered to a certain temperature and maintained for a period of time, crystals are precipitated, and the product indole is obtained by filtration and drying. The product purity is ≥99.99%, which meets the requirements of spice grade indole. The method for purifying indole in the invention has the advantages of high indole yield, simple operation, short reaction time, low energy consumption and good product quality.

Description

technical field [0001] The invention relates to a method for preparing spice-grade indole by extraction and crystallization. Specifically, indole with a purity of more than 98% is used as a raw material to obtain spice-grade indole with a purity greater than 99.99% through solvent extraction and crystallization. Background technique [0002] Indole is an important raw material for the preparation of medicines, pesticides, spices, dyes and feed additives, and an important heterocyclic fine chemical intermediate. The current global production capacity is 7000t / a. With the development of its use research, many important high value-added medicines and pesticides have been derived from it, especially the current market demand for indole derivative tryptophan is growing rapidly, and the global long-term demand for this alone is 10,000t / a. Therefore, the market prospect of indole is very broad. Most of the produced indole is used in the synthesis of pesticides, medicines and dy...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D209/08
CPCC07D209/08
Inventor 何志勇黄伟金汉强任磊孔伟伟陶建青杨怀青杨忠林季峰崎
Owner SINOPEC NANJING RES INST OF CHEM IND CO LTD