Dehydrofluorination catalyst

A dehydrofluorination and catalyst technology, applied in the field of dehydrofluorination catalysts, can solve the problem of low selectivity of active Z-type fluoroolefins, and achieve the effect of high selectivity and good activity

Active Publication Date: 2010-02-03
XIAN MODERN CHEM RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The catalyst has the problems of low activit

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Dissolve chromium nitrate in water, add precipitant ammonia water at 60°C, control the pH of the solution between 7.5-8.5, and make it fully precipitate under stirring conditions, filter the formed slurry, and wash with deionized water to neutral , And then dried at 150℃ for 12 hours to obtain Cr(OH) 3 .

[0025] The obtained Cr(OH) 3 It is mixed with ammonium hexafluorotitanate into 70% and 30% by mass, and then compressed into tablets to obtain a catalyst precursor. The catalyst precursor is roasted in a muffle furnace at 400°C for 10 hours, and then loaded into a tubular reactor , The temperature is raised to 300 DEG C, and hydrogen fluoride gas is introduced to activate it for 2 hours, then the temperature is raised to 350 DEG C at a heating rate of 1 DEG C / min, and the activation is continued for 10 hours to prepare a dehydrofluorination catalyst.

[0026] The specific surface area of ​​the catalyst measured by the BET low-temperature nitrogen adsorption method is 56.1m...

Embodiment 2

[0029] The preparation process of the catalyst is basically the same as that of Example 1, except for Cr(OH) 3 The mass of ammonium hexafluorotitanate is divided into 80% and 20%.

[0030] The specific surface area of ​​the catalyst determined by the BET low-temperature nitrogen adsorption method is 53.5m 2 ·G -1 , The pore volume is 0.18ml·g -1 , And the proportion of pores with a pore diameter of less than 2nm is 33%.

[0031] A nickel tube fixed bed reactor with an inner diameter of 38mm is filled with 30ml of the dehydrofluorination catalyst prepared above, the reaction temperature is 350℃, and the HFC-236ea space velocity is 100h -1 After 100 hours of reaction, the samples were washed with water, alkali washed and dried, and analyzed by GC-MS. The conversion rate of HFC-236ea was 98% and the selectivity of Z-HFO-1225ye was 96%.

Embodiment 3

[0033] The preparation process of the catalyst is basically the same as that of Example 1, except for Cr(OH) 3 The mass percentage of ammonium hexafluorotitanate becomes 60% and 40%.

[0034] The specific surface area of ​​the catalyst measured by the BET low-temperature nitrogen adsorption method is 46.3m 2 ·G -1 , The pore volume is 0.19ml·g -1 , And the proportion of pores with a pore diameter of less than 2nm is 32%.

[0035] A nickel tube fixed bed reactor with an inner diameter of 38mm is filled with 30ml of the dehydrofluorination catalyst prepared above, the reaction temperature is 350℃, and the HFC-245eb space velocity is 50h -1 After 100 hours of reaction, the samples were washed with water, alkali washed and dried, and analyzed by GC-MS. The conversion rate of HFC-245eb was 95% and the selectivity of Z-HFO-1234ze was 90%.

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Abstract

The invention discloses a dehydrofluorination catalyst aiming at solving the problems of low activity of the catalyst and low selectivity to Z-type fluoroolefin. The precursor of the catalyst consistsof 40-80 percent of trivalent chromium compound and 20-60 percent of fluoride of metal ammonium by mass percent, wherein the trivalent chromium compound is chromic oxide or chromium hydroxide, and the fluoride of metal ammonium is hexafluoro ammonium metatitanic, hexafluoro ammonium antimonite or hexafluoro ammonium stannate. The catalyst is prepared by the following method: evenly mixing the trivalent chromium compound and the fluoride of metal ammonium by mass percent, pressing and shaping the mixture, and then baking and activating hydrogen fluoride. The dehydrofluorination catalyst has high activity and selectivity to the Z-type fluoroolefin, and is mainly used for preparing corresponding Z-type fluoroolefin by dehydrofluorination using hydrofluorocarbon as the material under the condition of gaseous phase reaction.

Description

Technical field [0001] The invention relates to a dehydrofluorination catalyst, in particular to a dehydrofluorination catalyst used for the dehydrofluorination of hydrofluorocarbons to prepare Z-type fluoroolefins under gas phase conditions. Background technique [0002] 1,1,1,3-Tetrafluoropropene (HFO-1234ze) and 1,2,3,3,3-pentafluoropropene (HFO-1225ye) have low greenhouse effect potential (GWP) and zero ozone Loss potential (ODP) is considered to be the third-generation ODS substitute with the most potential to replace 1,1,1,2-tetrafluoroethane (HFC-134a). It is widely used as refrigerant, blowing agent, gas Sol propellant, solvent, etc. The above-mentioned fluoroolefins are usually prepared by dehydrofluorination of hydrofluorocarbons. At present, the dehydrofluorination catalyst of hydrofluorocarbon is usually a chromium catalyst. [0003] The world patent WO2008008350A2 reports a CrF 3 The catalyst can catalyze the dehydrofluorination of 1,1,1,2,2,3-hexafluoropropane (HFC...

Claims

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Application Information

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IPC IPC(8): B01J27/24B01J23/26B01J37/04B01J37/08B01J37/18C07C17/25C07C21/18
Inventor 吕剑张呈平张伟何飞郝志军寇联岗王博
Owner XIAN MODERN CHEM RES INST
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