Fluorating catalyst and preparation method

A fluorination catalyst, catalyst technology, applied in physical/chemical process catalysts, chemical instruments and methods, metal/metal oxide/metal hydroxide catalysts, etc. Reduce the surface area and other problems to achieve the effect of prolonging life and increasing the number of regenerations

Active Publication Date: 2008-07-09
XIAN MODERN CHEM RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Although the above-mentioned patents have produced a fluorination catalyst with a large specific surface area and a high proportion of micropores, the micropores of the catalyst are likely to be formed due to high-temperature sintering during the use of the catalyst, especially during the regeneration process at 300-500°C under an oxidizing atmosphere. Reduced ratio and specific surface area shorten catalyst life

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Dissolve chromium nitrate in water, react with precipitant ammonia water at 60°C, adjust the pH value of the reaction solution in the range of 7.5 to 8.5, make it fully precipitate under stirring conditions, filter the formed slurry, and use deionized Wash with water until neutral, then dry at 200°C for 12 hours to obtain Cr(OH) 3 .

[0032] The obtained Cr(OH) 3 with a specific surface area of ​​300m 2 The pigment / g was uniformly mixed with channel black at a mass ratio of 70:30, and pressed into tablets to obtain a catalyst precursor. In a tubular reactor, roast in a nitrogen atmosphere at 350°C for 6 hours, then feed a mixture of nitrogen and hydrogen fluoride at a ratio of 4:1, fluoride at 200°C for 4 hours, and then raise the temperature to 350°C at a heating rate of 1°C / min. The fluorination was continued for 8 hours to obtain a fluorination catalyst.

[0033] The specific surface area of ​​the catalyst was measured by BET low temperature nitrogen adsorption m...

Embodiment 2

[0038] The preparation technology of catalyst is substantially the same as embodiment 1, and difference is that Cr(OH) 3 The mass ratio of the tank black to the pigment is 50:50.

[0039] The specific surface area of ​​the catalyst was measured by BET low temperature nitrogen adsorption method to be 54.8m 2 g -1 , the pore volume is 0.19ml·g -1 , and the proportion of micropores is 34%.

[0040] In a nickel tube fixed bed tubular reactor with an internal diameter of 38 mm, 30 ml of the above-mentioned prepared fluorination catalyst are loaded into it, and HF and trichloroethylene are introduced to react, and the mol ratio of HF / trichloroethylene is controlled to be 8: 1. The contact time is 3 seconds, the reaction temperature is 250°C, and after 40 hours of reaction, the reaction product is washed with water and alkali to remove HCl and HF, and the conversion rate of trichlorethylene is 100% according to gas chromatography analysis. HCFC-133a and HFC-134a The overall selec...

Embodiment 3

[0043] The preparation technology of catalyst is substantially the same as embodiment 1, and difference is that Cr(OH) 3 The mass ratio of the tank black to the pigment is 90:10.

[0044] The specific surface area of ​​the catalyst was measured by BET low temperature nitrogen adsorption method to be 45.8m 2 g -1 , the pore volume is 0.18ml·g -1 , and the proportion of micropores is 30%.

[0045] The catalyst is subjected to forced coking deactivation and regeneration again. After the first regeneration, the specific surface area of ​​the fluorination catalyst is 45.6m 2 g -1 , the pore volume is 0.19ml·g -1 , and the proportion of micropores is 29%. After the second regeneration, the specific surface area of ​​the fluorination catalyst is 43.0m 2 g -1 , the pore volume is 0.16ml·g -1 , and the proportion of micropores is 26%.

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Abstract

The invention discloses a fluorinated catalyst and a preparation method thereof. The invention is to solve the problems of reduction of minopore proportion and specific surface area and shortening of service life of the catalyst under high temperature sintering in use of the fluorinated catalyst, in particular in regeneration under 300 DEG C to 500 DEG C in the oxidizing atmosphere. The precursor of the fluorinated catalyst of the invention contains trivalent chromium compound and carbon powder, the mass ratio of which is 50 to 90:10 to 50, wherein, the trivalent chromium compound is chromic oxide or chromium hydroxide, and the carbon powder is activated carbon or carbon black. The preparation method of the fluorinated catalyst of the invention includes the following steps: (1) the trivalent chromium compound and the carbon powder are evenly mixed by the mass ratio, pressed and shaped, and the precursor of the catalyst is obtained; (2) the catalyst precursor obtained in step (1) receives calcination under 300 DEG C to 350 DEG C under nitrogen atmosphere, and then receives fluorination by the mixed gas of hydrogen fluoride and inert gas under 200 DEG C to 350 DEG C to obtain the fluoride catalyst. The catalyst is applicable to preparation of hydroflurocarbon and hydrogenous fluorochlorohydrocarbon with gas-phase fluorinated halohydrocarbon.

Description

technical field [0001] The invention relates to a fluorination catalyst and a preparation method, in particular to a fluorination catalyst and a preparation method for preparing hydrofluorocarbons (abbreviated as HFCs) and hydrofluorochlorocarbons (abbreviated as HCFCs) by gas-phase fluorinated halogenated hydrocarbons. Background technique [0002] Generally, large-scale industrial production of HFCs and HCFCs adopts the method of gas-phase fluorinated halogenated hydrocarbons. This method has the advantages of simple equipment, easy continuous large-scale production, safety, and environmental protection. The fluorination catalyst plays a central role in the gas-phase fluorination of halogenated hydrocarbons. It has been proved that the specific surface area of ​​the carrier and catalyst is closely related to the catalytic activity, the larger the specific surface area, the higher the catalytic activity and the better the stability. [0003] Chinese patent 95115476.1 has r...

Claims

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Application Information

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Patent Type & AuthorityApplications(China)
IPC IPC(8): B01J27/12B01J27/132B01J23/26C07C17/20
CPCY02P20/584
Inventor吕剑张伟石磊王博厐国川崔文华
OwnerXIAN MODERN CHEM RES INST