Preparation of 1,1-difluoroethane and fluorating catalyst

A technology based on fluorination catalyst and difluoroethane, applied in 1 field, can solve problems such as difficulty in disposal, affecting product yield and the like

Active Publication Date: 2009-04-22
ZHEJIANG QUHUA FLUOR CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This conventional method is undesirable because it produces a large amount of tar, affects the yield of the product, and is difficult to dispose of.

Method used

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  • Preparation of 1,1-difluoroethane and fluorating catalyst
  • Preparation of 1,1-difluoroethane and fluorating catalyst
  • Preparation of 1,1-difluoroethane and fluorating catalyst

Examples

Experimental program
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Effect test

Embodiment 1

[0037] After vaporizing anhydrous hydrofluoric acid and acetylene, they are mixed into a 180ml carbon steel fixed-bed reactor with receiving conditions, and the fluorination reaction is carried out under the action of a chromium-based catalyst to control the ratio of anhydrous hydrofluoric acid and acetylene materials 8 : 1, the reaction temperature is 230℃, the pressure is 1.0Mpa, (under the standard condition) the space velocity of the reactor is 800h -1 , the outlet material of the reactor was sampled and analyzed, and the conversion rate of acetylene was 78.55%, and the selectivity of HFC-152a was 95.40%.

preparation Embodiment 1

[0051] Put 0.5gIn (NO 3 ) 3 ·9H 2 O, 4g CoCl 2 ·6H 2 O and 50g Cr (NO 3 ) 3 ·9H 2 O was dissolved in 800 g of pure water to obtain an aqueous solution containing indium, cobalt and chromium. In this solution, ammonia water was added for precipitation reaction, so that the pH value of the reaction solution was in the range of 6.5 to 10, filtered, and washed with distilled water. dry for 12 hours. The obtained solid is ground finely, mixed with graphite, pressed into a tablet shape with a tablet machine, loaded into a roasting furnace, and heated in N 2 The catalyst precursor was obtained by calcining at 400°C for 4 hours in a gas stream. The obtained precursor was charged into a reaction tube, using N 2 The catalyst was prepared by activation at 350° C. in a diluted AHF gas stream, and its physical properties are shown in Table 4.

[0052] Table 4 Physical properties of fluorination catalysts

[0053] catalyst 01 02 Bulk density (g / ml) 0.88 0.90 ...

preparation Embodiment 2

[0056] Cr(NO 3 ) 3 ·9H 2 The O solution was mixed with ammonia water under full stirring to obtain a slurry of chromium hydroxide. The slurry was filtered, and the filter cake was thoroughly washed with distilled water, and then dried at 110° C. for 12 hours. The obtained solid was ground, and In(NO) was slowly added dropwise to 50 g of the thus obtained ground. 3 ) 3 ·nH 2 O and CoCl 2 ·6H 2 Aqueous solution of O. This powder was dried at 110°C for a further 12 hours, then mixed with graphite and subsequently granulated with a granulator. Then, molding, calcination and fluorination treatment were carried out in the same manner as in Catalyst Preparation Example 1. The physical properties of the catalyst are shown in Table 5.

[0057] Table 5 Physical properties of fluorination catalysts

[0058] catalyst 03 04 Bulk density (g / ml) 0.91 0.92 Specific surface area (m 2 ·g -1 ) 112.8 115.6 Pore ​​volume (ml g -1 ) 0.35 0.34

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Abstract

The invention discloses a method for preparing 1, 1-difluoroethane and a fluorination catalyst using the method. The method is characterized in that in the presence of a chromium-based fluorination catalyst, ethyne and anhydrous hydrofluoric acid are gasified and mixed to undergo gas-phase fluorination reaction so as to generate 1,1- difluoroethane HFC-152a(C2H4F2); the reaction temperature is between 140 and 380 DEG C; the pressure is between 0.3 and 1.8 MPa; under the standard condition, air speed of a reactor is between 300 and 2,200 h<-1>; the mixture ratio of the reaction materials of the anhydrous hydrofluoric acid to the ethyne is 4 to 1-30 to 1; the transformation rate of the ethyne in an outlet of the reactor reaches over 75 percent; and the selectivity of HFC-152a reaches over 90 percent.

Description

technical field [0001] The present invention relates to a process for the preparation of hydrofluorocarbons (HFCs). Specifically, 1,1-difluoroethane (CH 4 CF 2 ) preparation method. Background technique [0002] HFC-152a, molecular structure is CH 3 —CHF 2 , the chemical name is 1,1-difluoroethane, the English name is: 1,1-bifluoroethane, the molecular weight is 66, the boiling point is -24.7 ° C, the ozone destruction potential value ODP=0; the global warming coefficient value GWP=0.03, is a An excellent alternative to ODS (Ozone Depleting Substances). Since HFC-152a has very similar physicochemical properties and thermodynamic properties to CFC-12, it is the preferred alternative to CFC-12. The mixed refrigerant HFC-152a / HCFC-22 is one of the main substances used to replace CFC-12, which has a damaging effect on the atmospheric ozone layer in recent years. In my country, as an environmental protection and energy saving working fluid, it is widely used in small refrig...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C19/045C07C17/08B01J27/132
Inventor 周黎旸陈科峰张学良严孝忠苏利红柴龙华
Owner ZHEJIANG QUHUA FLUOR CHEM
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