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The production method of tetrahydrofuran

A technology of tetrahydrofuran and a manufacturing method, applied in the directions of organic chemistry methods, organic chemistry, etc., can solve problems such as hindering operation and accumulation, and achieve the effects of reducing generation, avoiding the reduction of reaction selectivity, and reducing high-boiling point by-products

Active Publication Date: 2016-08-17
MITSUBISHI RAYON CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] The following problem has been clarified: According to the method described in Patent Document 3, although 1,4BG can be obtained by separating and removing most of γ-butyrolactone, the trace amount of γ-butyrolactone that cannot be sufficiently separated by this method In the state of 1,4-butanediol, when the 1,4BG is used as a raw material to undergo a dehydration cyclization reaction to obtain the product THF, the high-boiling by-product derived from γ-butyrolactone accumulates in the reaction of producing THF inside, impede operation

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0042] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples unless the gist is exceeded.

[0043] In the following examples, water content was analyzed using the Karl Fischer method. Tetrahydrofuran, γ-butyrolactone, dimers of 1,4BG, 1,4-butanediol, and γ-butyrolactone were analyzed by gas chromatography, and calculated from the area percentage.

[0044] In addition, a value obtained by subtracting the water concentration from 100% by weight was calculated, and the ratio (% by weight) of the remaining component was calculated from the value by area percentage of each component in gas chromatography.

[0045]

[0046] 200 g of 1,4-butanediol containing 0.18% by weight of γ-butyrolactone, p-toluenesulfonate, and 0.4 g (0.2% by weight) of the acid was heated to an internal temperature of 145° C. using an oil bath. Nitrogen gas was introduced into the reaction liquid at 300 mL...

Embodiment 2

[0048] In Example 1, everything was performed in the same manner except that the temperature of the inner liquid was 155°C. A condensate containing tetrahydrofuran, which was discharged from the gas phase portion of the flask as a product gas and condensed by a cooler, was obtained at a rate of 67 g / hr. The temperature of the liquid condensation part at this time was 82.0 degreeC, and the reflux ratio was 0.1. 1,4-Butanediol containing 0.18 wt % of γ-butyrolactone and 12 wt ppm of p-toluenesulfonic acid was continuously supplied at 65 g / hr. The average residence time of the raw material 1,4-butanediol with respect to the capacity of the liquid phase part was 3 hr. The heating reaction, the distillation of the product from the gas phase, and the supply of raw materials continued for 3.8 hr. The amount of the obtained condensate was 287 g, and the composition was 76.5% by weight of tetrahydrofuran, 21.1% by weight of water, and 1496 ppm by weight of γ-butyrolactone. The ratio...

Embodiment 3

[0050] All were performed in the same manner as in Example 1 except that the amount of nitrogen gas introduced into the reaction liquid was 200 mL / min. A condensate containing tetrahydrofuran, which was discharged from the gas phase portion of the flask as a product gas and condensed by a cooler, was obtained at a rate of 47 g / hr. At this time, the temperature of the liquid condensation part is 73.0° C., and the reflux ratio is 0.1. 1,4-Butanediol containing 0.18 wt % of γ-butyrolactone and 12 wt ppm of p-toluenesulfonic acid was continuously supplied at 49 g / hr. The average residence time of the raw material 1,4-butanediol with respect to the capacity of the liquid phase part was 4 hr. The heating reaction, the distillation of the product from the gas phase, and the supply of raw materials continued for 5.2 hr. The amount of the obtained condensate was 281 g, and the composition was 78.0% by weight of tetrahydrofuran, 20.8% by weight of water, and 1470 ppm by weight of γ-bu...

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Abstract

The present invention relates to supplying 1,4-butanediol as a raw material containing γ-butyrolactone to a reaction tank, and performing dehydration in the presence of a homogeneous acid catalyst having a pKa of 4 or less which is soluble in 1,4-butanediol A method for producing tetrahydrofuran that generates tetrahydrofuran through a cyclization reaction, characterized in that the gas containing tetrahydrofuran, γ-butyrolactone, and water in the reaction tank is introduced into a heat exchanger and condensed from the outlet of the heat exchanger. In the case of liquid, the ratio of the concentration of γ-butyrolactone in the condensed liquid to the concentration of γ-butyrolactone in the raw material 1,4-butanediol is 20 to 100%.

Description

technical field [0001] The present invention relates to a method for producing tetrahydrofuran, and more specifically, to a method for producing tetrahydrofuran from 1,4-butanediol under heating using an acid catalyst. Background technique [0002] It is known that tetrahydrofuran (hereinafter, sometimes abbreviated as "THF") can be used not only as a solvent for various organic compounds, but also as a raw material monomer for polyether polyols such as polytetramethylene ether glycol, and is a useful compound of. [0003] As the industrial production methods of cyclic ethers such as tetrahydrofuran, various production methods have been known so far, and most of them are dehydration of dihydroxy compounds such as 1,4-butanediol (hereinafter sometimes abbreviated as "1,4BG") cyclization to manufacture. As a catalyst for the dehydration cyclization reaction of the dihydroxy compound, acid catalysts are known to be effective from the viewpoint of high conversion and selectivi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D307/08C07B61/00
CPCC07D307/08C07B61/00
Inventor 井泽雄辅宇都宫贤服部英次
Owner MITSUBISHI RAYON CO LTD