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Process for preparation of saturated cyclic ethers

A manufacturing method and technology of cyclic ethers, applied in the direction of organic chemistry, etc., can solve problems such as flow control, difficulty in contact time control, reduced activity and catalyst life, and increase in by-products, so as to achieve easy control of contact time and the reduction of by-products The effect of suppressing the production and reducing by-products

Inactive Publication Date: 2003-08-13
MITSUBISHI RAYON CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] (1) Decreased activity due to catalyst blockage;
[0008] (2) Because the liquid is adsorbed on the surface of the catalyst, the control of the flow rate and the control of the contact time become difficult;
[0009] (3) Due to uneven mixing, the concentration of esters in local places is too high, resulting in decreased activity and increased by-products;
[0010] (4) Under high temperature conditions, the detached liquid-phase carboxylic acid will dissolve the catalyst components, resulting in a decrease in activity and catalyst life.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] Under the condition of maintaining normal pressure and 240°C, supply 1,4-diacetoxybutane (1,4- DAB), water was supplied at 9.92 mol / hour (water / 1,4-DAB=1.2), and nitrogen was supplied at 1.35 liter / hour. The reactor was filled with 1 ml (0.95 g) of niobic acid (Nb 2 o 5 ·nH 2 O, manufactured by CBMM Company, niobium hydroxide was roasted at 300°C for 2 hours, the heating rate was 2.5°C / min, SA1 21 meters 2 / gram), the top of the catalyzer is filled with SUS particles, and the resulting liquid obtained from the bottom of the reactor is analyzed by GC to obtain the following results (the following analysis all use GC).

[0051] Conversion rate (1,4-diacetoxybutane) 90.8%

[0052] Selectivity (tetrahydrofuran) 99.3%

Embodiment 2

[0054] Except that the supply rate of water is changed into 74.1 mmol / hour, the catalyst niobic acid is changed into 3 milliliters (2.12 grams), the reaction temperature is changed into 200 ℃, all the other are reacted in the same way as in Example 1, and the resulting liquid is analyzed equally, and obtained The following results.

[0055] Conversion rate (1,4-diacetoxybutane) 100.0%

[0056] Selectivity (tetrahydrofuran) 99.9%

Embodiment 3

[0058] Except that the catalyst was changed to 4 milliliters (5.16 grams) of zirconia (manufactured by Norton, SA335, m 2 / gram), temperature of reaction is changed into outside 280 ℃, all the other are reacted in the same way as in Example 1, and the resulting liquid is analyzed equally, obtains the following results.

[0059] Conversion rate (1,4-diacetoxybutane) 99.9%

[0060] Selectivity (tetrahydrofuran) 99.9%

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PUM

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Abstract

A process for preparing saturated cyclic ethers from fatty acid esters of alpha, delta -diols stably in high yield over a long period. Specifically, a process for preparing saturated cyclic ethers by reacting a mono- or di-ester of an alpha, delta-diol with a fatty acid or both in the presence of a solid acid catalyst, characterized in that the reaction is carried out in such a state that at least 50 mole% of the ester(s) fed into the reaction system is vaporized.

Description

technical field [0001] The present invention relates to a method for producing saturated cyclic ethers, in particular, to the production of saturated cyclic ethers such as tetrahydrofuran by reacting mono- and / or di-fatty acid esters of α, δ-diols in the presence of a solid acid catalyst method. technical background [0002] Saturated cyclic ethers such as tetrahydrofuran are very useful compounds as solvents or as raw materials for substances such as polytetramethylene ether glycol. [0003] Known methods for producing tetrahydrofuran include, for example, hydrogenation of butynediol obtained from acetylene and formaldehyde to butanediol followed by dehydration and cyclization, or the reaction of acetate of 1,4-butanediol in an acid catalyst The method of reacting with water in the presence of [0004] Processes using liquid acids or solid acids as acid catalysts are known. As a method of using a liquid acid, there is known a method of performing a reaction in a liquid p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D307/08
CPCC07D307/08
Inventor 清冈和彦横山寿治
Owner MITSUBISHI RAYON CO LTD
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