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Indole separation and purification

A technology for indole fractions and indole, which is applied in the field of separation and purification of indole, can solve the problems of not being able to meet the requirements of products with a purity greater than 99%, and achieve the effects of high product yield, fewer process steps, and low production cost

Inactive Publication Date: 2006-03-15
BAOWU CHARCOAL MATERIAL TECH CO LTD
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  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

[0002] The existing methods for extracting indole from coal tar wash oil or methylnaphthalene usually have a purity of 95%-99% indole, which cannot meet the requirements for products with a purity greater than 99%.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] The raw material used is mixed methylnaphthalene separated from coal tar, and its indole content is 3.57%. Firstly, rectification enrichment of indole is carried out under the absolute pressure of 20Kpa, the theoretical plate number of the rectification column is 35, and the reflux ratio is 16, to obtain an indole fraction with an indole content of 14.66%. Then press the indole fraction: triethylene glycol: the mass ratio of n-heptane is the ratio of 1: 0.5: 1, after stirring and mixing at room temperature for a certain period of time, pour the mixed solution into a separatory funnel, and let it stand for a certain period of time until the solution is layered. Do liquid metering. The lower layer is an indole extract, the indole content is 16.87%, and the primary indole extraction rate is 90.35%. The upper liquid is the indole extraction raffinate, which is mainly composed of methylnaphthalene and n-heptane. The n-heptane can be recovered and recycled by simple distilla...

Embodiment 2

[0018] The steps of the method adopted in this embodiment are basically the same as those in Embodiment 1. The difference is: the indole content in the raw material mixed methylnaphthalene is 3.12%, and the rectification and enrichment obtains the indole fraction whose indole content is 11.82%. During the extraction and separation, the indole fraction: triethylene glycol: n-heptyl The mass ratio of alkane is 1:0.5:0.5, and the indole content of the primary extract obtained is 13.03%. With primary extract as polar extractant, by indole fraction: primary extract: the mass ratio of n-heptane is 1: 0.5: 0.5, carry out secondary extraction, the indole content that obtains indole secondary extract is 18.50 %; Carry out three extractions, the indole content that obtains indole three extracts is 20.80%. The extract with an indole content of 19.43% is used for rectification and purification to obtain an indole product with a purity greater than 99.0%, the single-pass yield is 55.6%, a...

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Abstract

A separation and purification of indole is carried out by rectifying industrial methylnaphthalene or washing oil dequinazine at 6-30Kpa and 25-45 block column plate, extracting beta-methylnaphthalene, taking residue as indole cuts containing indole 10-20% and methylnaphthalene 70-80%, extracting and separating for indole cuts containing indole 10-20% from extractant, obtaining first indole extract, taking the indole extract as raw material, rectification purifying at 6-30Kpa, 25-45 block column plate and reflux ratio=4-20, and obtaining indole product with purity>99.0%. It costs low and has high recovery rate.

Description

technical field [0001] The invention relates to a method for separating and purifying indole in the field of deep processing of coal tar, in particular to a method for separating and purifying indole from industrial methylnaphthalene of coal tar. Background technique [0002] The existing methods for extracting indole from coal tar wash oil or methylnaphthalene generally yield indole products with a purity between 95% and 99%, which cannot meet the requirements for products with a purity greater than 99%. For example, an indole extraction method disclosed by Sumikin Chemical Company of Japan ("Fuel and Chemical Industry", 2001, Volume 32, Issue 4, Page 224), which uses azeotropic distillation after dealkalizing the washing oil → After the process steps of water washing and crystallization → rectification and purification, the extracted indole has a purity of about 95%; the Chinese invention patent application published on June 18, 2003, CN1424311A, discloses a method for sep...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D209/06
Inventor 王仁远李峻海吕苗王庆梅
Owner BAOWU CHARCOAL MATERIAL TECH CO LTD
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