Method for preparing tetrahydropyrane by dehydrating and cyclizing 1,5-pentanediol

A technology of dehydration cyclization and tetrahydropyran, applied in the direction of organic chemistry and the like, can solve the problems of few industrialized production methods and less tetrahydropyran, and achieve the effects of simple reaction steps, simple industrial scale-up and small technical investment.

Active Publication Date: 2018-06-12
MAIQI CHEM CO LTD
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  • Abstract
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  • Claims
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Problems solved by technology

[0004] In summary, there are fewer methods for preparing tetrahydropy

Method used

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  • Method for preparing tetrahydropyrane by dehydrating and cyclizing 1,5-pentanediol

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preparation example Construction

[0018] The preparation steps of the supported heteropolyacid salt catalyst are the same as those of the supported heteropolyacid catalyst, and will not be repeated here.

[0019] What the rectification in the tetrahydropyran preparation method of the present invention adopts is batch rectification, and can select continuous rectification in actual industrial production.

[0020] In the present invention, the main reaction formula for preparing tetrahydropyran by dehydration and cyclization of 1,5-pentanediol is as follows:

[0021]

Embodiment 1

[0023] In a flask equipped with a short fractionation column, add 500ml of 1,5-pentanediol and 15g copper phosphotungstopolyacid / activated carbon catalyst, and carry out dehydration and cyclization reaction under normal pressure, wherein the phosphotungstic heteropolyacid copper in the catalyst is The loading is 10 wt%. Control the reaction temperature to 170°C, control the top temperature of the fractionation column to 95°C, collect the distillate, and the reaction ends after 90 minutes. The distillate is purified by intermittent fractional distillation. Under normal pressure, light components such as water and by-products are removed first, and the distillate with a tower top temperature of 88±1°C is collected as tetrahydropyran. Others Heavier components with a higher boiling point than tetrahydropyran remain in the bottom of the column. The purity of tetrahydropyran is 98.3wt%, and the yield of tetrahydropyran is 83.1%.

Embodiment 2

[0025] In a flask equipped with a short fractionation column, add 200ml of 1,5-pentanediol and 6g of copper phosphotungstopolyacid / kaolin catalyst, and carry out dehydration and cyclization reaction under normal pressure, wherein the amount of copper phosphotungstic heteropolyacid in the catalyst is The loading was 25 wt%. Control the reaction temperature to 260°C, control the top temperature of the fractionation column to 90°C, collect the distillate, and the reaction ends in 30 minutes. The distillate is purified by intermittent fractional distillation. Under normal pressure, light components such as water and by-products are removed first, and the distillate with a tower top temperature of 88±1°C is collected as tetrahydropyran. Others Heavier components with a higher boiling point than tetrahydropyran remain in the bottom of the column. The purity of tetrahydropyran is 98.1wt%, and the yield of tetrahydropyran is 87.4%.

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Abstract

The invention belongs to the technical field of preparation of compounds, and discloses a method for preparing tetrahydropyrane by dehydrating and cyclizing 1,5-pentanediol. The method comprises the following steps: placing the 1,5-pentanediol in a reaction kettle filled with a loading-type heteropolyacid catalyst or loading-type heteropolyacid salt catalyst, performing dehydration and cyclizationreaction at normal pressure, collecting distillates with the distillation temperature less than or equal to 95 DEG C from the upper portion of the reaction kettle, and then rectifying the distillates, thus obtaining the product tetrahydropyrane. The preparation method disclosed by the invention adopts the loading-type heteropolyacid or salt thereof as the catalyst for the dehydration and cyclization reaction of the 1,5-pentanediol, and simple reaction procedures and mild reaction conditions are realized, so that the requirements on reaction equipment is reduced, the safety potential hazard ofthe production is reduced, and the industrialized popularization value is high.

Description

technical field [0001] The invention belongs to the technical field of compound preparation, and in particular relates to a method for preparing tetrahydropyran by dehydration and cyclization of 1,5-pentanediol. Background technique [0002] Tetrahydropyran is an epoxy ether with excellent symmetry, and its structural formula is , freezing point -49.2°C, boiling point 88°C, refractive index 1.4195 (18.5°C), flash point -15°C; can be volatilized with steam, easily soluble in many organic solvents such as ethanol and tetrahydropyran; it can be used as a solvent at room temperature Lower partial pressure, less solvent loss rate, especially its complete stratification with water, more suitable for industrial applications. [0003] The traditional tetrahydropyran production process uses dihydropyran hydrogenation, 1,5-dibromopentane and water as raw materials to react under the action of zinc oxide, but dihydropyran has no industrial production and is expensive; 1, 5-Dibromope...

Claims

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Application Information

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IPC IPC(8): C07D309/04
CPCC07D309/04
Inventor 吴彦彬宋国全闫广学吴正岭李凯杨理周淑飞高培玉任先雷
Owner MAIQI CHEM CO LTD
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