Preparation method of high-purity difluoroethanol

A difluoroethanol and high-purity technology is applied in the field of preparation of high-purity difluoroethanol, which can solve the problems of high pollution, flammability and explosion, hinder the industrialization of difluoroethanol and the like, and achieve the effect of less pollution

Active Publication Date: 2017-06-13
XIAN MODERN CHEM RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But realize in the enforcement process of above-mentioned invention, there are following problems: (1) adding of entrainer makes product contain entrainer, influences the application of difluoroethanol in medicine and cleaning agent; (2) azeotropic rectification difluoroethanol The purity of the ethanol product is only 98.8%, and the purity is relatively low; (3) the entrainer is highly toxic, affects human health, and is flammable and explosive, which pose a threat to the safety and health of operators; (4) the azeotropic distillation process The toluene content in the wastewater produced in the
The existence of the above problems has seriously hindered the industrialization of difluoroethanol

Method used

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  • Preparation method of high-purity difluoroethanol

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Embodiment 1

[0021] The aqueous solution with a mass fraction of difluoroethanol of 80% enters the first packed rectification tower for separation, and the overhead distillate is the azeotrope of difluoroethanol / water with a higher difluoroethanol content, and the difluoroethanol fraction is water, and the first packed rectification The overhead fraction of the distillation tower enters the second packed rectification tower for separation, and the overhead fraction is an azeotrope of difluoroethanol / water with a lower difluoroethanol content, which is circulated to the first packed rectification tower, and the bottom fraction is Difluoroethanol.

[0022] The operating parameters of the first packed rectification tower and the second packed rectification tower in Example 1 are shown in Table 1, and the stream composition is shown in Table 2.

[0023] Operating parameter in the embodiment 1 of table 1

[0024] Distillation column The first packed distillation column The second...

Embodiment 2

[0028] The operation process of Example 2 is shown in Example 1, the operating parameters of the first packed rectification tower and the second packed rectification tower are shown in Table 3, and the stream composition is shown in Table 4.

[0029] Operating parameter in the embodiment 2 of table 3

[0030] Distillation column The first packed distillation column The second packed distillation column Operating pressure / kPa(A) 50 150 Tower top temperature / ℃ 25 103 Tower kettle temperature / ℃ 33 106 Reflux ratio 10 10

[0031] The logistics composition in the embodiment 2 of table 4

[0032] Material / mass fraction 3 5 7 water 5％ 99.88％ 0.01％ Difluoroethanol 95％ 0.12％ 99.99％

Embodiment 3

[0034] The operation process of Example 3 is shown in Example 1, the operating parameters of the first packed rectification tower and the second packed rectification tower are shown in Table 5, and the stream composition is shown in Table 6.

[0035] Operating parameters in table 5 embodiment 3

[0036] Distillation column The first packed distillation column The second packed distillation column Operating pressure / kPa(A) 30 100 Tower top temperature / ℃ 50 92 Tower kettle temperature / ℃ 77 95 Reflux ratio 4.2 5.5

[0037] The logistics composition in the embodiment 3 of table 6

[0038] Material / mass fraction 3 5 7 water 10％ 99.85％ 0.01％ Difluoroethanol 90％ 0.15％ 99.99％

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Abstract

The invention discloses a preparation method of high-purity difluoroethanol, aiming at solving the problems that an azeotrope agent impurity is introduced in a process of preparing the difluoroethanol through an azeotropic distillation method and the purity of a product is low. The preparation method comprises the following steps: (1) conveying a mixture of difluoroethanol and water into a first packed distillation tower and separating, wherein a tower top fraction is a difluoroethanol/water azeotrope with relatively high difluoroethanol content and a tower kettle fraction is water; (2) conveying the tower top fraction of the first packed distillation tower into a second packed distillation tower and separating, wherein a tower top fraction is a difluoroethanol/water azeotrope with relatively low difluoroethanol content; circulating the tower top fraction to the first packed distillation tower, wherein a tower kettle fraction is difluoroethanol. The preparation method of the high-purity difluoroethanol, disclosed by the invention, is applicable to a difluoroethanol crude product which is obtained in a production process of the difluoroethanol through a difluoroethyl acetate and methanol ester separation exchange method or a 1-chloro-2,2-difluoroethane hydrolysis method.

Description

technical field [0001] The invention belongs to the technical field of chemical separation, and in particular relates to a preparation method of high-purity difluoroethanol. Background technique [0002] Difluoroethanol is a basic fluorine-containing organic intermediate with good development prospects and high added value. It is widely used in the fields of agriculture, medicine, medicine, cleaning agents and fluorine-containing polymers. In the production process of difluoroethanol produced by transesterification of difluoroethyl acetate and methanol or hydrolysis of 1-chloro-2,2-difluoroethane, water is formed in the product. Since the boiling points of water (boiling point: 100°C) and difluoroethanol (boiling point: 95°C) are very close, the two form the lowest azeotrope, and it is difficult to separate them by conventional distillation. [0003] In industry, azeotropic distillation is generally used to separate the lowest azeotrope, such as the aqueous solution of p-di...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C29/80C07C31/38
CPCC07C29/80C07C31/38
Inventor 袁俊杨建明吕剑张前李江伟赵锋伟余秦伟梅苏宁王为强李亚妮惠丰
Owner XIAN MODERN CHEM RES INST
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