Kinetics study of the perchloroethylene hydrofluorination into pentafluoroethane (Freon 125) over chromium-based catalyst

Решетников, С. И.; Zirka, A. A.; Петров, Р. В.; Иванов, Е. А.

doi:10.1016/j.cej.2011.05.109

Cited by 6 publications

(3 citation statements)

References 4 publications

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“…The gaseous product mixture was passed through a scrubber with dry alkaline metal carbonate in which HF and HCl were converted into CO 2 and H 2 O. The reaction components were identified on a Varian chromatograph CP-3800 with mass-spectrometer Saturn-2000 (Varian B.G., Inc.) [7].…”

Section: Methodsmentioning

confidence: 99%

Influence of the Catalyst Preparation on Properties of Chromium-Magnesium Catalysts for Freon 125 Synthesis

Zirka

Simonova

Kosova

et al. 2015

KEM

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The effect of the chromium-magnesium precursor preparation techniques on physicochemical properties (BET surface area, total pore volume, mean pore diameter) and catalysts activity in the gas-phase hydrofluorination of perchloroethylene to pentafluoroethane (Freon 125) was studied. Kinetics of the catalytic reactions was studied for the most active catalyst. Based on the experimental data, the pathway of perchloroethylene fluorination with HF was suggested.

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Section: Methodsmentioning

confidence: 99%

Influence of the Catalyst Preparation on Properties of Chromium-Magnesium Catalysts for Freon 125 Synthesis

Zirka

Simonova

Kosova

et al. 2015

KEM

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“…Pentafluoroethane (HFC-125) is an important component in some alternative refrigerants that are promising replacements for HCFC-22. − The fluorination of tetrachloroethene or 1,1,1-trifluoro-2,2-dichloroethane is the commercial process for manufacture of HFC-125, − and chloropentafluoroethane (CFC-115) is the primary byproduct during this process. Vapor–liquid equilibrium (VLE) data of the mixture of CFC-115 and HFC-125 are indispensable to design the purification process of HFC-125.…”

Section: Introductionmentioning

confidence: 99%

Measurements of Bubble Point Pressures for the Binary Mixture of Pentafluoroethane with Chloropentafluoroethane

et al. 2013

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Bubble point pressures for the binary mixture of pentafluoroethane (HFC-125) with chloropentafluoroethane (CFC-115) were measured at the temperature ranges from (243.15 to 333.15) K using a static apparatus. The uncertainties of measurements were estimated to be less than 20 mK in temperature, 1.2 kPa in pressure, and 0.001 in liquid-phase mole fraction. The experimental data were correlated with the Peng–Robinson equation of state with van der Waals mixing rules. The correlation results have a good agreement with the experimental results. The overall average absolute deviation was 0.36 % between measured pressures and calculated results from the Peng–Robinson (PR) equation of state. The interaction parameter k 12 was obtained for different temperatures, and the relationship between k 12 and the temperature was correlated with the deviation of ± 0.5 %. The azeotropic compositions and pressures at specified temperatures were calculated.

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“…Analysis of experimental data obtained on samples with different promoters (Tablе1) testified that despite the difference in the activity and selectivity the scheme the products formation is identical. The observed dependence shows that the process of perchlorethylene hydrofluorination proceeds via complex parallel-series scheme, which can be represented in a form similar to that given in [13,14] for the Cr-Mg catalyst: This scheme consists of ten reactions. It includes consecutive substitution of fluorine for chlorine, and by-product formation, as a result of reactions of the trifluorodichloroethane CHCl 2 -CF 3 and tetrafluorochloroethane CF 3 -CHFCl disproportionation.…”

Section: Samplementioning

confidence: 99%

Chromium-based catalyst for HFC-125 synthesis: promoters effect

Решетников

Simonova

Zirka

et al. 2016

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract.A variation of promoters, including rare-earth elements, allows to control of the specific surface and, perhaps, oxidation state of chromium and, consequently, catalyst activity and selectivity of chromium-based catalyst for HFC-125. To improve the catalytic properties of the 15% Cr 2 O 3 -85% -Al 2 O 3 oxide system were added promoters (Ni or Cu or Co) in an amount of 5 wt% in terms of oxides. It was found that additional promotion Cr-Al samples by nickel and copper allow to increase the specific surface area of about 25-40% and the activity increased about 2 times. Modification of cobalt resulted in a decrease of the surface by 20% and the activity decreased by about 2 times. IntroductionVarious rare-earth metal oxides were widely investigated as promoters of heterogeneous catalysts for enhancing their activity, selectivity, and stability [1]. In particular, the ceria-containing catalysts use for diesel soot combustion and the reduction NO x [2,3] hydrogen purification reactions, namely the water gas shift reaction [4] and etc. It is known, that the promoters affect the textural characteristics: specific surface area, pore diameter, and on the electronic state of the active component. Despite the large number of works, studying the role of promoters in the formation of the main characteristics of catalysts and their role in the formation of the active sites of the catalyst are still unclear.In recent decades, considerable efforts have been focused on the synthesis of chladones, having zero ozone depletion potential. The most promising in this regard are chladones of the ethane row, namely, pentafluoroethane CHF 2 -CF 3 (HFC-125), which is produced by the gas-phase catalytic hydrofluorination of perloroethylene Cl 2 C=CCl 2 . A fluorination catalyst based on of an amorphous Cr (III) compounds in combination with promoting and stabilizing admixtures of aluminum, magnesium, nickel, zinc and others [5,6]. Rare-earth metal oxides are used as promoters also, namely, lanthanum [7], scandium [8,9], and yttrium [10,11]. However, systematic studies of the mechanism of influence of promoters on the catalytic properties of chromium-containing fluorination catalysts are absent. These issues are of great scientific and practical interest.In this work, we studied chromium-containing catalyst (~15% Cr 2 O 3 -85% -Al 2 O 3 ) and the effect of promoters (~5% Ni, Cu and Co) on physicochemical and catalytic properties of the catalysts for the gas-phase hydrofluorination of perchloroethylene to pentafluoroethane (chladone HFC-125). Kinetic regularities of the reaction were also considered.

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Kinetics study of the perchloroethylene hydrofluorination into pentafluoroethane (Freon 125) over chromium-based catalyst

Cited by 6 publications

References 4 publications

Influence of the Catalyst Preparation on Properties of Chromium-Magnesium Catalysts for Freon 125 Synthesis

Influence of the Catalyst Preparation on Properties of Chromium-Magnesium Catalysts for Freon 125 Synthesis

Measurements of Bubble Point Pressures for the Binary Mixture of Pentafluoroethane with Chloropentafluoroethane

Chromium-based catalyst for HFC-125 synthesis: promoters effect

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