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Extraction fractional distillation for separating pyrocatechol in furanol

An extractive distillation method and catechol technology, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of long operation cycle, unstable operation, increase reflux ratio, etc. The effect of shortened time, convenient operation and low cost

Active Publication Date: 2008-12-17
HUNAN CHEM RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the actual operation of the rectification of the furanol production unit, the content of catechol in the collected fractions is always high and concentrated in the late stage of rectification, and it is difficult to improve the product purity by conventional means such as increasing the reflux ratio
Due to the interference of catechol on the rectification process, the purity of the furan phenol product can only reach ≥98%, and the quality requirement of ≥99% cannot be achieved, the operation is unstable, the operation cycle is long, the rectification yield is low, and the residual o-benzene Diphenol is as high as 1% to 2%, which has a great influence on the purity of downstream products

Method used

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  • Extraction fractional distillation for separating pyrocatechol in furanol
  • Extraction fractional distillation for separating pyrocatechol in furanol
  • Extraction fractional distillation for separating pyrocatechol in furanol

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Add ethylene glycol (glycol), diethylene glycol (diglycol), p-tert-butylcatechol (4-TBC) and 3,4′-diglycol at a certain mass ratio of furanol to catechol and separating agent, respectively. Chlorodiphenyl ether (DCDPE) etc. are used as a separating agent, and no separating agent is added to determine the relative volatility of furanol to catechol α 21 The result is as figure 2 :

[0031] figure 2 It shows that in the absence of separation agent, the relative volatility of furanol to catechol α 21 Both are less than 1, and the average is 0.70. This result shows that the boiling point of furanol is higher than that of catechol. If there is no third component, the fraction extracted from the top of the tower should be high-purity phthalate after sufficient separation in the rectifying tower. diphenols. After adding a certain amount of a certain separating agent, α 21 The relative volatility of furanol and p-catechol can be improved by adding diethylene glycol, p-ter...

Embodiment 2-8

[0033] Taking diethylene glycol as the furan phenol extractive distillation experiment of separating agent, the results are listed in Table 1.

[0034] Table 1 diethylene glycol is the extractive distillation test result of separating agent

[0035]

[0036] The results in Table 1 show that the purity of the main fraction furan phenol collected by conventional rectification without adding a separating agent can only reach between 98.0% and 98.5%, and the single-pass yield of rectification is about 67.0%; The purity of the product fraction furan phenol can reach 99.0%-99.5%, and the single-pass yield of rectification is ≥80.0%.

Embodiment 9-14

[0038] The results of the furan phenol extraction and distillation test using p-tert-butylcatechol as a separating agent are shown in Table 2.

[0039] Table 2 p-tert-butylcatechol is the extractive distillation test result of separating agent

[0040]

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Abstract

The invention discloses a method for separating catechol pyrocatechol from furan phenol (2, 3-dihydrogen-2, 2-dimethyl-7-hygroxy benzofuran) by the way of extraction and rectification with high efficiency, low cost and simple and convenient unit operation. Separating agent chosen is a compound with small molecular structure and stereospecific blockade and with boiling point of 240 DEG C to 320 DEG C / 101.33KPa, such as phenol, alcohol, ether, phenolic ether, alcohol ether, etc. with hygroxy or ether bond, specifically as diglycol, para-tert-butylcatechol, 3, 4'-dichlorine diphenyl ether, etc., and the dosage of the separating agent is 0.5 percent to 5.0 percent of the mass of crude products. The method of the invention can increase rectification yield by more than 5.0 percent, shorten rectification time by 25 percent and increase product purity to more than 99.0 percent.

Description

technical field [0001] The invention relates to an extraction and rectification method for separating catechol from furanol (2,3-dihydro-2,2-dimethyl-7-hydroxybenzofuran), a pesticide intermediate. Background technique [0002] Furanol (2,3-dihydro-2,2-dimethyl-7-hydroxybenzofuran), is used in the production of large-tonnage carbamic acid esters such as carbofuran, haoanwei, carbofuran and furancarb As an intermediate of pesticide varieties, companies such as FMC of the United States, Bolliger of Norway and Mitsubishi of Japan realized the industrial production of furanol in the 1980s, and foreign companies have been implementing technical blockades against my country. my country's annual demand is over 5,000 tons, and it is increasing year by year. [0003] Most of the furanol units that have been industrialized at present use catechol as raw material, and its synthetic route is as follows: [0004] [0005] In order to ensure the high selectivity of the etherification ...

Claims

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Application Information

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IPC IPC(8): C07C39/08C07C37/72C07D307/86
Inventor 张建宇王晓光肖旭辉王宇冯建东
Owner HUNAN CHEM RES INST
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