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Dehydrofluorination catalyst

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

Active Publication Date: 2010-02-03
ZHEJIANG FLUORINE CHEM NEW MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the catalyst has low activity and low selectivity to Z-type fluoroolefins

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Dissolve chromium nitrate in water, add precipitant ammonia water at 60°C, control the pH range of the solution to 7.5-8.5, make it fully precipitate under stirring conditions, filter the formed slurry, wash with deionized water until neutral , and then dried at 150°C for 12 hours to obtain Cr(OH) 3 .

[0028] The obtained Cr(OH) 3 Mix with tin tetrachloride and ammonium fluoride uniformly according to the mass percentage of 60%, 20% and 20%, and press into tablets to obtain a catalyst precursor, which is calcined at 400°C in a muffle furnace for 10 hours, and then Put it into a tubular reactor, raise the temperature to 300°C, pass in hydrogen fluoride gas for activation for 2 hours, then raise the temperature to 350°C at a heating rate of 1°C / min, and continue to activate for 10 hours to obtain a dehydrofluorination catalyst.

[0029] The specific surface area of ​​the catalyst was measured by BET low temperature nitrogen adsorption method to be 55.3m 2 g -1 , the ...

Embodiment 2

[0032] The preparation technology of catalyst is substantially the same as embodiment 1, and difference is that Cr(OH) 3 , tin tetrachloride and ammonium fluoride, the mass percentages are 80%, 10% and 10%.

[0033] The specific surface area of ​​the catalyst was determined by BET low temperature nitrogen adsorption method to be 46.9m 2 g -1 , the pore volume is 0.17ml·g -1 , and the proportion of pores with a diameter smaller than 2nm was 32%.

[0034] In a nickel tube fixed-bed reactor with an inner diameter of 38mm, put 30ml of the dehydrofluorination catalyst prepared above, the reaction temperature is 350°C, and the space velocity of HFC-236ea is 100h -1 , After reacting for 100 hours, the samples were washed with water, washed with alkali and dried, analyzed by GC-MS, and the conversion rate of HFC-236ea was 100%, and the selectivity of Z-HFO-1225ye was 97%.

Embodiment 3

[0036] The preparation technology of catalyst is substantially the same as embodiment 1, and difference is that Cr(OH) 3 , tin tetrachloride and ammonium fluoride, the mass percentages are 30%, 35% and 35%.

[0037] The specific surface area of ​​the catalyst was measured by BET low-temperature nitrogen adsorption method to be 47.6m 2 g -1 , the pore volume is 0.18ml·g -1 , and the proportion of pores with a diameter smaller than 2nm was 34%.

[0038]In a nickel tube fixed-bed reactor with an inner diameter of 38mm, put 30ml of the dehydrofluorination catalyst prepared above, the reaction temperature is 350°C, and the space velocity of HFC-245eb is 50h -1 , After reacting for 100 hours, the samples were washed with water, washed with alkali and dried, analyzed by GC-MS, and the conversion rate of HFC-245eb was 96%, and the selectivity of Z-HFO-1234ze was 92%.

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Abstract

The invention discloses a dehydrofluorination catalyst aiming at solving the problems of low activity of the catalsyt and low selectivity to Z-type fluoroolefin. The precursor of the catalyst consistsof 30-80 percent of trivalent chromium compound, 10-35 percent of metal halide and 10-35 percent of fluoride of ammonium by mass percent, wherein the trivalent chromium compound is chromic oxide or chromium hydroxide, the metal halide is stannic chloride, titanium tetrachloride, tantalum chloride, antimony pentachloride, tin tetrafluoride, titanium tetrafluoride, tantalic fluoride or antimony pentafluoride, and the fluoride of ammonium is ammonium fluoride or ammonium bifluoride. The catalyst is prepared by the following method: evenly mixing the trivalent chromium compound, the metal halideand the fluoride of ammonium by mass percent, pressing and shaping the mixture, and then baking and activating by hydrogen fluoride. The dehydrofluorination catalyst has high activity and selectivityto 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 one-step synthesis of Z-type fluoroolefins by dehydrofluorination isomerization of hydrofluorocarbons under gas phase conditions. Background technique [0002] 1,1,1,3-tetrafluoropropene (HFO-1234ze) and 1,2,3,3,3-pentafluoropropene (HFO-1225ye), with low greenhouse effect potential (GWP) and zero ozone Depletion Potential (ODP), considered to be the third generation ODS substitute with the most potential to replace 1,1,1,2-tetrafluoroethane (HFC-134a), is widely used as refrigerant, blowing agent, gas Sol propellants, solvents, etc. The above-mentioned fluoroolefins are generally produced by dehydrofluorination of hydrofluorocarbons. Currently, dehydrofluorination catalysts for HFCs are usually chromium catalysts. [0003] The world patent WO2008008350A2 reports a CrF 3 Catalyst, catalyzing the dehydrofluorination of 1,1,1,2,2,3-hexafl...

Claims

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Application Information

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IPC IPC(8): B01J27/24B01J27/135B01J27/10B01J27/08B01J23/26B01J37/04B01J37/08B01J37/18C07C17/25C07C21/18
Inventor 张呈平吕剑张伟何飞郝志军王博寇联岗庞国川
Owner ZHEJIANG FLUORINE CHEM NEW MATERIAL
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