Florination catalyst, its manufacturing method and use

A fluorination catalyst, catalyst technology, applied in physical/chemical process catalysts, chemical instruments and methods, metal/metal oxide/metal hydroxide catalysts, etc. The effect of good selectivity, simple method and high stability

Active Publication Date: 2005-08-10
XIAN MODERN CHEM RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are obvious disadvantages in this type of morphology: (1) the catalyst precursor, after being roasted at a high temperature of 300-450°C, is easy to form high-valent chromium ions, which are easily lost during the fluorination process with hydrogen fluoride, resulting in the loss of the catalyst. The loss of active metals reduces the activity of fluorination catalysts, and high-valent chromium ions are extremely toxic, which not only endangers the environment but also pollutes products; (2) the fluorination of catalyst precursors is a strong exothermic process, and high temperature will cause The chromium oxide of the catalyst changes from an amorphous state to a crystalline state, which will cause the sintering of the catalyst precursor. The proportion of micropores with a diameter of less than 2nm in the catalyst is difficult to exceed 20%, which makes it difficult to improve the activity of the catalyst.

Method used

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  • Florination catalyst, its manufacturing method and use
  • Florination catalyst, its manufacturing method and use
  • Florination catalyst, its manufacturing method and use

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Dissolve trivalent chromium soluble salts (chromium chloride, chromium nitrate, chromium sulfate) in water, react with precipitant ammonia water at 60°C, adjust the pH value of the reaction solution to be in the range of 7.5 to 8.5, and make it under the condition of stirring The resulting slurry was filtered, washed with deionized water until neutral, and then dried at 120°C for 12 hours. Produce Cr(OH) 3 . The obtained Cr(OH) 3 The weight ratio with Mg powder, Zn powder, Ni powder and graphite powder is 55:30:5:5:5, mixed evenly, and pressed into tablets. In the tubular reactor, 100~400℃N 2 Roast in the atmosphere for 6 hours, and then feed a mixture of nitrogen and hydrogen fluoride at a ratio of 4:1, fluoride at 120°C for 4 hours, then increase the temperature to 350°C at a rate of 1°C / min, and continue fluorinating for 8 hours to obtain active Fluorination catalyst.

[0029] The pore distribution of the catalyst was measured by the BET low-temperature nitrogen a...

Embodiment 2

[0063] The catalyst preparation process is substantially the same as in Example 1, except that Cr(OH) 3 The weight ratio of Mg powder, Zn powder, Ni powder and graphite powder is 70:15:5:5:5.

[0064] The pore distribution of the catalyst was measured by the BET low-temperature nitrogen adsorption method, and the micropore ratio of the fluorinated catalyst was measured to be 30%.

[0065] 50ml of the fluorination catalyst prepared above was used in the reaction of the fluorine-chlorine exchange reaction to synthesize a series of HFCs in Example 1. The reaction product was washed with water and alkali, and analyzed by gas chromatography after removing HCl and HF. The results are shown in Table 1.

[0066] Table 2

[0067] Material ratio / molar ratio

[0068] Reaction Temperature / °C Contact Time / s Conversion / % Selectivity / %

[0069] (HF / halogenated hydrocarbon)

[0070] 1 260 8 / 1 3 81 91

[0071] 1 280 8...

Embodiment 3

[0085] The catalyst preparation process is substantially the same as in Example 1, except that Cr(OH) 3 The weight ratio of Mg powder, Zn powder, Ni powder and graphite powder is 80:5:5:5:5.

[0086] The pore distribution of the catalyst was measured by the BET low-temperature nitrogen adsorption method, and the micropore ratio of the catalyst was measured to be 30%.

[0087] 50ml of the fluorination catalyst prepared above was used in the reaction of the series of HFCs synthesized by the fluorine-chlorine exchange reaction in Example 1. The reaction product was washed with water and alkali, and analyzed by gas chromatography after removing HCl and HF. The results are shown in Table 3.

[0088] table 3

[0089] Material ratio / molar ratio

[0090] Reaction Temperature / °C Contact Time / s Conversion / % Selectivity / %

[0091] (HF / organic)

[0092] 1 260 8 / 1 3 77 90

[0093] 1 280 8 / 1 3 85 85

[0094] 2 280 8 / 1 20 5...

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Abstract

A fluorizing catalyst for fluorizing the halohydrocarbon by hydrogen fluoride is prepared from Cr(OH)3 or Cr2O3, Mg or Al powder, Zn powder and Ni powder through proportionally mixing, calcining and fluorizing.

Description

technical field [0001] The invention relates to a fluorination catalyst and its production method and application. In particular, it involves the production of freon substitute hydrofluorocarbons (HFCs for short), such as difluoromethane (HFC-32 for short), 1,1,1,2-tetrafluoroethane (HFC-134a ), pentafluoroethane (referred to as HFC-125) and other fluorination catalysts. Background technique [0002] Generally, the large-scale production of HFCs in industry adopts the gas-phase hydrofluorinated halogenated hydrocarbon method, which has the advantages of simple equipment, easy continuous large-scale production, safety, and environmental protection. The fluorination catalyst plays a key role in the gas phase fluorination of halogenated hydrocarbons. The commonly used fluorination catalysts in industrial production are chromium-containing fluorination catalysts. However, the activity and service life of fluorination catalysts still cannot meet the needs, and fluorination cat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/26B01J23/86C07C17/20C07C17/21
Inventor 吕剑张伟石磊寇联岗王博庞国川何飞
Owner XIAN MODERN CHEM RES INST
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