Catalyzer for producing difluoromethane by vapor-phase fluorination and the preparing method

A fluorination catalyst, difluoromethane technology, applied in catalyst activation/preparation, physical/chemical process catalysts, chemical instruments and methods, etc., can solve the problems of small specific surface area, catalyst deactivation, poor activity, etc., and achieve high activity , The operation method is simple, the effect of fast price

Inactive Publication Date: 2007-09-19
ZHEJIANG NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the Cr-based catalysts supported by Al compounds have the following disadvantages in production and use: AlF as a catalyst carrier 3 The specific surface area is too small; at a certain temperature, Al 2 o 3 or AlF 3 It is inevitable that crystal transformation will occur, leading to deactivation of the catalyst and limiting the service life of the catalyst; Al 2 o 3 Convert to AlF 3 When a large amount of water will be produced and the soluble active components of the load will be lost; in addition, the chromium-free catalysts reported in the patent literature are too poor in activity to have practical application value

Method used

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  • Catalyzer for producing difluoromethane by vapor-phase fluorination and the preparing method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] First, weigh CrCl according to the loading of Cr as 10wt%. 3 9H 2 O and Y (NO 3 ) 3 ·6H 2 O, after dissolving with an appropriate amount of water, mix well, add a certain amount (NH 4 ) 2 CO 3 , adjust the pH value of the solution to 8 to make the two precipitate completely, then centrifuge, wash until the filtrate is neutral, and then dry at 120°C for 12 hours; then press into tablets, and then bake at 400°C for 4 hours to obtain Fluorination catalyst precursors. The fluorination catalyst precursor was dried under normal pressure with nitrogen gas at 300°C for 10 hours, and then treated with anhydrous HF at 400°C for 10 hours to obtain a fluorination catalyst. Its reactivity and selectivity are listed in Table 1.

Embodiment 2

[0021] First, weigh Cr(NO 3 ) 3 9H 2 O and Y (NO 3 ) 3 ·6H 2 O, after dissolving with an appropriate amount of water, mix well, add a certain amount (NH 4 ) 2 CO 3 , adjust the pH value of the solution to 8 to make the two precipitate completely, then centrifuge, wash until the filtrate is neutral, and then dry at 120°C for 12 hours; then press into tablets, and then bake at 400°C for 4 hours to obtain Fluorination catalyst precursors. The fluorination catalyst precursor was dried under normal pressure with nitrogen gas at 300°C for 10 hours, and then treated with anhydrous HF at 400°C for 10 hours to obtain a fluorination catalyst. Its reactivity and selectivity are listed in Table 1.

Embodiment 3

[0023] First, weigh Cr(NO 3 ) 3 9H 2 O and YCl 3 ·7H 2 O, after dissolving with an appropriate amount of water, mix well, add a certain amount (NH 4 ) 2 CO 3 , adjust the pH value of the solution to 8 to make the two precipitate completely, then centrifuge, wash until the filtrate is neutral, and then dry at 120°C for 12 hours; then press into tablets, and then bake at 400°C for 4 hours to obtain Fluorination catalyst precursors. The fluorination catalyst precursor was dried under normal pressure with nitrogen gas at 300°C for 10 hours, and then treated with anhydrous HF at 400°C for 10 hours to obtain a fluorination catalyst. Its reactivity and selectivity are listed in Table 1.

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Abstract

The present invention relates to a fluoridation catalyst, in particular to a vapor-phase fluorination catalyst for producing difluoromethane and a preparation method of the same. The present invention is directed to provide a vapor-phase fluorination catalyst with high activity and high stability for producing difluoromethane and a preparation method of the same, so as to overcome the disadvantages of the prior art. The catalyst of the present invention comprises a carrier and an active component, wherein the carrier is a Y compound and the active component is a Cr compound. The preparation method of the catalyst comprises the steps of: weighting proportionally dissoluble Cr salt and Y salt to be dissolved by water and be mixed equably, and adding precipitator to make both of them precipitate, and then executing centrifugal separation, scrubbing until the filtrate is neutrality, and drying; molding the dried precipitate by tabletting mould and calcining to obtain a precursor of the fluoridation catalyst, and then drying by nitrogen gas and processing by anhydrous HF so as to obtain fluoridation catalyst.

Description

technical field [0001] The invention relates to a catalyst for fluorination reaction, in particular to a catalyst for gas-phase fluorination to produce difluoromethane (HFC-32) and a preparation method thereof. Background technique [0002] Difluoromethane (HFC-32) has a low boiling point, a large refrigeration coefficient, almost zero depletion value for the atmospheric ozone layer, and a small greenhouse effect coefficient. It is recognized as an ideal ODS substitute and has been developed and accepted at home and abroad. Applied to various refrigerants. One of the methods for producing HFC-32 is to produce difluorine by gas-phase fluorination of ethylene dichloride (HCFC-30). At present, the commonly used catalyst for this step reaction is a Cr-based catalyst. specifically Al 2 o 3 or AlF 3 or MgF 2 Such as Al sources and Mg sources as carriers, catalysts loaded with active components such as Cr or Cr with additives 2 o 3 catalyst. At present, there are a large nu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/26B01J23/10B01J37/26C07C19/08C07C17/20
Inventor 罗孟飞谢冠群何军谢云龙金凌云
Owner ZHEJIANG NORMAL UNIVERSITY
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