This Review chronicles the progress made in the field of small fluorocarbon synthesis since their invention in the early 1930s by Thomas Midgley, Jr., and his coworkers, with special focus on their...

Fluorocarbon Refrigerants and their Syntheses: Past to Present.

Efficient synthesis of dimethyl carbonate via transesterification of ethylene carbonate with methanol over binary zinc-yttrium oxides

The porous alumina catalysts with different acidity were prepared and tested for dehydrofluorination of 1,1,1,2-tetrafluoroethane to synthesize trifluoroethylene. The XRD, BET, SEM, NH3-TPD and py-IR techniques were used to characterize the alumina catalysts with different calcination temperatures. The porous θ-Al2O3 showed the excellent catalytic performance, with 35.1 % conversion and the selectivity to trifluoroethylene of 99.0 %. The active sites of catalysts for formation of trifluoroethylene are appropriate weak Lewis acid sites, and the strong Lewis acid sites may result in its rapid deactivation, due to the coke or polymerization of trifluoroethylene. Dehydrofluorination of 1,1,1,2-tetrafluoroethane (CF3CFH2) is a promising route to synthesize trifluoroethylene over θ-Al2O3, the conversion is 35.1 % and the selectivity to trifluoroethylene is 99 % at 450 °C. It was suggested that appropriate number of weak Lewis acid sites was beneficial to the catalysis for dehydrofluorination of CF3CFH2, the weak Lewis acid sites as the active sites of synthesis of trifluoroethylene. On the other hand, the strong Lewis acid sites easily result in deactivation of catalysts derived from the coke or polymerization of trifluoroethylene.

Influence of Lewis Acidity on Catalytic Activity of the Porous Alumina for Dehydrofluorination of 1,1,1,2-Tetrafluoroethane to Trifluoroethylene

The sources of halogenated compounds in East Asia associated with stratospheric ozone depletion and climate change are relatively poorly understood High-precision in situ measurements of 18 halogenated compounds and carbonyl sulfide (COS) made at Gosan, Jeju Island, Korea, from November 2007 to December 2011 were analyzed by a positive matrix factorization (PMF) Seven major industrial sources were identified from the enhanced concentrations of halogenated compounds observed at Gosan and corresponding concentration-based source contributions were also suggested: primary aluminum production explaining 37% of total concentration enhancements, solvent usage of which source apportionment is 25%, fugitive emissions from HCFC/HFC production with 11%, refrigerant replacements (9%), semiconductor/electronics industry (9%), foam blowing agents (6%), and fumigation (3%) Statistical trajectory analysis was applied to specify the potential emission regions for seven sources using back trajectories Primary aluminum production, solvent usage and fugitive emission sources were mainly contributed by China Semiconductor/electronics sources were dominantly located in Korea Refrigerant replacement, fumigation and foam blowing agent sources were spread throughout East Asian countries The specified potential source regions are consistent with country-based consumptions and emission patterns, verifying the PMF analysis results The industry-based emission sources of halogenated compounds identified in this study help improve our understanding of the East Asian countries' industrial contributions to halogenated compound emissions

Source identification and apportionment of halogenated compounds observed at a remote site in East Asia

Catalytic dehydrofluorination of 1,1,1,3,3-pentafluoropropane to 1,3,3,3-tetrafluoropropene over fluorinated NiO/Cr 2 O 3 catalysts

Effect of calcination temperature on CrOx–Y2O3 catalysts for fluorination of 2-chloro-1,1,1-trifluoroethane to 1,1,1,2-tetrafluoroethane

The invention relates to a catalyst used for making tetrafluoromethane through gas-phase fluorination and a preparation method thereof, and aims at providing a catalyst used for making tetrafluoromethane through gas-phase fluorination characterized by high activity and high stability and a preparation method thereof in consideration of poor activity and low stability existing in the existing gas-phase fluorination catalyst. The preparation method of the catalyst of the invention is as follows: one or more than one compound of Y, compound of Cr, compound of magnesium, aluminum, indium, gallium, zinc, scandium, strontium, iron, cobalt, nickel and cadmium are measured according to a certain proportion; the precipitator adopts one among ammonia, sodium hydroxide, ammonium carbonate, sodium carbonate and potassium hydroxide, and sediments are obtained by a coprecipitation method, and the precursor of the catalyst is obtained by baking and roasting the sediments then the catalyst is obtained after being treated with anhydrous hydrogen fluoride.

Catalyst for producing tetrafluoromethane with gas-phase fluoridation and production method

Vapor phase hydrofluorination of acetylene to vinyl fluoride over La2O3-Al2O3 catalysts

The invention relates to a catalyst for producing fluorothene and 1,1-difluoroethane and a preparation method thereof The oxide of an active component A and the oxide of an active component B form the former body of the catalyst, wherein A is one or more than one of Mg, Y, Sm and La, B is one or two of Al and Zn, the mol ratio between A and B is 1:9-99, and the catalyst is obtained through the pretreatment of inert gas and the fluorination pretreatment The catalyst is prepared by a precipitation method or an immersion method The former body of the catalyst is obtained after the treatment at a certain temperature, and the catalyst is then obtained through the treatment of inert gas and anhydrous hydrogen fluoride The catalyst which has the advantages of low cost, simple preparation process, high activity, high stability and the like is particularly suitable for the gas phase fluorination production of fluorothene and 1,1-difluoroethane through an acetylene method

Catalyst for preparing fluoroethylene and 1,2difluoroethane, and preparation method

The invention relates to a catalyst for fluorination, especially a catalyst for producing HFC-134a in gas phase fluorination and the manufacturing method. Aiming at the lack of prior technology, the invention provides a catalyst for producing HFC-134a in gas phase fluorination with high activity and high stability and the manufacturing method. The catalyst comprises carrier and active component. The carrier adopts Y compound and the active component adopts Cr compound. The preparing process for the catalyst for producing HFC-134a in gas phase fluorination is that soluble Cr and Y salts are taken to be dissolved by water according to the proportion; it is mixed in uniformity; precipitant is added to make them precipitate; then the filter solution is neural after centrifugal separation and washing; it is dried; the dried precipitate is formed by tablet mould; the precursor of fluorination catalyst is obtained by baking; after it is treated dry by nitrogen, it is treated by HF without water; finally the catalyst is obtained.

Vapor-phase fluorination catalysts for producing HFC-134a and the preparing method

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