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Process for preparing high-purity HFC-125

A technology for HFC-125 and HCFC-124, applied in the field of preparing high-purity HFC-125, can solve the problems of safety consumption, high inversion temperature, disadvantage, etc., and achieve the effect of improved method and easy separation

Inactive Publication Date: 2005-12-21
奥西蒙特股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the reaction is difficult and requires very strict reaction conditions, especially high inversion temperature
[0011] The various aftertreatments described in the prior art therefore require special steps and / or devices, which are additionally expensive and in some cases disadvantageous for safety

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] In the above reactor, 3.5 g of the above catalyst was added. Pretreatment with nitrogen, followed by a 1 / 1 ratio nitrogen / HF mixture at 360°C, followed by 5.0cc / min of HCFC-124, 4.0cc / min of HFC-134a at 210°C at atmospheric pressure A mixture with about 10 cc / min of helium was introduced into the reactor. The molar ratio of 134a / 124 is equal to 0.8.

[0042] The contact time refers to the ratio of the volume of the catalytic bed to the volume of the gas fed, which is 5.4 seconds at the reaction temperature and atmospheric pressure.

[0043] Gases from the reactor were analyzed by GLC with a thermal conductivity detector.

[0044] The following analysis results were obtained:

[0045] HFC-125 39.4 (mol%)

[0046] HFC-134a 3.5

[0047] HCFC-124 14.3

[0048] HCFC-133a 41.0

[0049] HCFC-123 1.8

[0050] other negligible

[0051] HCFC-123 and HCFC-124 are mixtures of possible isomers, respectively predominantly symmetrical forms of CF 3 -CHCl 2 and CF 3 -CHClF....

Embodiment 2

[0056] In the same reactor and under the same conditions, the HCFC-124 and 134a flow rates were increased to 8.3 and 8.1 cc / min, respectively, without helium dilution. Therefore, the molar ratio of 134a / 124 is equal to 0.97 and the contact time is 6.2 seconds.

[0057] The following analysis results were obtained:

[0058] HFC-125 28.4 (mol%)

[0059] HFC-134a 19.4

[0060] HCFC-124 21.3

[0061] HCFC-133a 30.2

[0062] HCFC-123 0.8

[0063] other negligible

[0064] The HCFC-124 conversion was equal to 60.5%, and the HFC-125 production rate was about 400 g / Kg catalyst / hour. The CFC-115 analysis yielded 9.2 ppm relative to the HFC-125 produced.

Embodiment 3

[0066] Under the same conditions as in the previous example, a mixture extremely deficient in 134a was fed, with a 134a / 124 molar ratio equal to 0.6, formed from 6.0 cc / min HCFC-124, 3.6 cc / min 134a and 13.2 cc / min helium. The contact time was 4.5 seconds.

[0067] The following analysis results were obtained:

[0068] HFC-125 41.0 (% mole)

[0069] HFC-134a 0.5

[0070] HCFC-124 15.4

[0071] HCFC-133a 35.7

[0072] HCFC-123 7.1

[0073] Other 0.3

[0074] The HCFC-124 conversion was equal to 76.4%, and the HFC-125 production rate was about 330 g / Kg catalyst / hour. The CFC-115 analysis yielded 39 ppm relative to the HFC-125 produced.

[0075] It follows that, by operating in the absence of 134a, the selectivity is reduced, CFC-115 is increased, other by-products occur and large amounts of HCFC-123 are formed.

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PUM

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Abstract

A method for preparing HFC-125 in the gas phase, comprising the steps of: - feeding a mixture of HCFC-124 and HFC-134a on a heterogeneous catalyst; - separating HFC-125 from other reaction products by distillation; wherein more The phase catalyst is selected from fluorination catalysts of halogenated hydrocarbons.

Description

technical field [0001] The invention relates to a method for preparing high-purity HFC-125 (pentafluoroethane C 2 HF 5 )Methods. In particular it relates to the preparation of CFC-115 (chloropentafluoroethane C 2 f 5 Cl) A method with a molar content of less than 100 ppm, preferably less than 50 ppm, of HFC-125. Background technique [0002] The need for available efficient methods for the synthesis of HFC-125, a hydrofluorocarbon that can replace some of the chlorofluorocarbons that are detrimental to stratospheric ozone, is well known in the art. In fact, because there are no chlorine atoms, as required by the Montreal Protocol and subsequent amendments, HFC-125 is not harmful to the atmospheric ozone layer. It is also known that the commercial application of HFC-125 requires the product itself to be of very high purity. [0003] Two industrially feasible methods for the synthesis of HFC-125 are known. The former approach is to fluorinate a suitable precursor with H...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C19/08C07C19/12C07C17/35C07C17/20C07C17/383
CPCC07C17/202C07C17/383C07C19/12C07C19/08
Inventor P·库扎托
Owner 奥西蒙特股份有限公司