Application of supported catalyst in cracking of trifluoromethane

Abstract

The invention relates to a catalyst used in cracking of trifluoromethane and preparation thereof. The catalyst is characterized by adopting zirconium oxide, magnesium oxide, activated carbon, acid treated activated carbon, alumina and the like as carriers, auxiliaries contain alkali metals K, Na and Cs, carrying capability of active components is 1-50% (mass percent), and molar content of metal auxiliaries is not higher than 50% of the total molar content of the active components and the metal auxiliaries. The catalyst provided by the invention has the characteristics that trifluoromethane catalytic cracking reaction temperature is low and is lower than 600 DEG C, catalyst dosage is low, conversion rate and yield are high, selectivity is high, high temperature resistance and strong acid resistance are good and high value-added products can be obtained; the catalyst is not only effectively improved in thermal stability resistant to high temperature agglomeration but also effectively improved in corrosion resistance through fluorination treatment, so that use stability of the catalyst is improved; and raw materials are available, technology is simple, and industrialization application can be realized.

Description

technical field [0001] The invention relates to a catalyst for trifluoromethane cracking in the field of fluorine chemical industry and a preparation method thereof, in particular to the application of a supported catalyst in trifluoromethane cracking. Background technique [0002] Trifluoromethane, referred to as fluoroform, is a very strong greenhouse gas (GWP value is about 14800, equivalent to CO 2 14,800 times of that) and has a long lifespan in the atmosphere, and is currently known as the greenhouse gas with the second highest greenhouse effect. Fluoroform has been listed as a restricted emission gas in the Kyoto Protocol. In the production of R22 in fluorine chemical enterprises, the annual production of fluoroform as the main by-product reaches more than 10,000 tons. Judging from the figure of 3 billion tons of China's carbon emissions trading, fluoroform emissions account for about 1% of China's carbon emissions, and it is a serious industrial waste that pollutes...

AI Technical Summary

Problems solved by technology

Thermal cracking was first proposed, that is, direct cracking of empty tubes. However, due to the relatively stable fluoroform, the cracking temperature of empty tubes is high. Generally, a high temperature above 850°C is required to achieve cracking of fluoroform, and the cracking efficiency is low; not only that, thermal cracking High energy consumption, easy to produce strong carcinogens at high temperature, perfluoroisobutylene

In 2001, William R.Dolbier, Jr. [J.Am.Chem.Soc.2001, 123, 6767-6772] of the University of Florida explored empty tube pyrolysis, and the conversion rate was only 10% at 800 °C, and the by-product More, less target product, this method cannot be applied industrially

Catalytic cracking can be expected to reduce reaction temperature, improve conversion rate and productive rate, but can realize the catalyzer of fluoroform catalytic conversion, only in 2010, Australia Eric M.Kennedy reported activated carbon supported potassium catalyst [Journal of FluorineChemistry 131 (2010) 698 –703] Catalytic cracking of fluoroform can be realized, and a conversion rate of about 30% can be realized at 800 °C, but the space velocity used is low, the selectivity is poor, and the target product is few, and it is still difficult to realize industrial application

In view of the lack of effective catalysts for fluoroform cracking, this patent has invented a high-efficiency fluoroform cracking catalyst through catalyst design, preparation, screening and optimization, which can significantly reduce the catalytic cracking temperature to an industrially usable temperature (below 600°C) And the conversion rate is high, the selectivity is high, and the yield of high value-added products tetrafluoroethylene and hexafluoropropylene is high

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