2317-91-1Relevant articles and documents
EDTA-assisted hydrothermal synthesis of cubic SrF2 particles and their catalytic performance for the pyrolysis of 1-chloro-1,1-difluoroethane to vinylidene fluoride
Wang, Zhikun,Han, Wenfeng,Liu, Huazhang
, p. 1691 - 1700 (2019)
Uniform, free-standing and cubic SrF2 microparticles were successfully fabricated by a facile hydrothermal method with ethylenediaminetetraacetic acid (EDTA) as the chelating agent. The influences of preparation conditions, such as the pH value, amount of EDTA and hydrothermal time, on the formation of SrF2 crystals were investigated. The formation mechanism of cubic SrF2 particles was proposed based on the experimental results. Following calcination in air at 500 °C, SrF2 particles were evaluated as the catalyst for the pyrolysis of 1-chloro-1,1-difluoroethane (HCFC-142b, CH3CClF2) to vinylidene fluoride (VDF, CH2═CF2) at 350 °C and a space velocity of 600 h?1. The results indicate that SrF2 cubes exhibit high catalytic activity with a HCFC-142b conversion of about 70% and a selectivity to VDF of 80-87%. No significant deactivation was observed within the time on stream of 30 h. With the reaction temperature increased to 450 °C, the conversion of HCFC-142b is close to 94%, while the selectivity to VDF remains almost unchanged. Although the SrF2 catalyst prepared by the conventional precipitation method also shows high conversion, its selectivity to VDF is only around 50-70%. We suggest that the surface acidity and specific surface area play major roles in the catalytic performance. Compared with the temperatures for industrial manufacture of VDF of 650-700 °C, the SrF2 catalysts provide a promising pathway to produce VDF at much lower temperatures.
Pyrolysis of 1,1-dichloro-1-fluoroethane in the absence and presence of added propene or CCl4: A computer-aided kinetic study
Huybrechts,Eerdekens
, p. 191 - 197 (2001)
The thermal dehydrochlorination CCl2FCH3→CClF double bond CH2+HCl has been studied in a static system between 610 and 700 K at pressures ranging from 14 to 120 torr. The experiments were performed in the absence and presence of an added inhibitor (0.5 to 7 torr of C3H6) or catalyst (2 to 8 torr of CCl4). The evolution of the reaction was followed by measuring the pressure rise in the quartz reaction vessel and analyzing the products by gas chromatography. All the experimental results can be explained quantitatively in terms of a reaction model both radical and molecular. The molecular dehydrochlorination has an activation energy of 52.05 kcal/mol and a preexponential factor of 1014.02 s-1.
CH3CF3-nCln haloalkanes and CH2=CF2-nCln halo-olefins on γ-alumina catalysts: reactions, kinetics and adsorption
Hess, A.,Kemnitz, E.
, p. 27 - 36 (1995)
The heterogeneously catalyzed reactions of the haloalkane, CH3CF(3-n)Cln, and halo-olefin, CH2=CF(2-n)Cl(n), series have been studied on a γ-alumina catalyst and the experimental results compared with calculated thermodynamic data.The main reactions occurring in this system can be explained by the following reaction paths: dehydrohalogenation, hydrohalogenation, F/Cl and Cl/F exchange with hydrogen halides.Dismutation reactions which are observed in other halocarbon series are unimportant in this system.A survey of the dominant reactions is given.In addition, the kinetic behaviour of CH3CF2Cl on the γ-alumina catalyst and the adsorption of various halocarbons have been investigated.The isosteric enthalpies of adsorption demonstrate that the interaction between the haloalkanes and the solid surface is more dominant than simple condensation. - Keywords: Chlorofluorocarbons; γ-Alumina catalysts; Heterogeneous catalysis; Kinetics; Adsorption; Enthalpy of adsorption
Dehalogenation of 1,1,2-trichloro-1-fluoroethane over ?±-Cr2O3 (101ì?12)
York, Steven C.,Cox, David F.
, p. 5182 - 5189 (2003)
The reaction of CFCl2CH2Cl over the stoichiometric Cr2O3 (1012) surface yields CFCl=CH2, HCa??CH, and surface halogen. The 1,2-dihalo-elimination reaction to CFCl=CH2 is initiated via C-Cl bond cleavage at the CFCl2-end of the molecule to give a -CFClCH2Cl haloalkyl surface intermediate. A rate-limiting ?2-chlorine elimination from the surface alkyl gives rise to the CFCl=CH2 product. Acetylene is formed by the subsequent reaction of CFCl=CH2 in series. The chlorine liberated from CFCl2CH2Cl binds at the five-coordinate surface Cr3+ sites on the stoichiometric surface and shuts down the dehalogenation chemistry by site blocking. No carbon buildup is observed on deactivated surfaces, and no evidence is seen for the replacement of surface lattice oxygen by halogen under the conditions of this study. At elevated temperatures, the thermal removal of surface chlorine is observed, and it is attributed to migration into the sample bulk.
METHOD FOR PRODUCING OLEFIN
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Paragraph 0150-0154; 0168-0171, (2017/11/01)
A method for producing at least one olefin compound selected from the group consisting of a compound of formula (51), a compound of formula (52), a compound of formula (53), and a compound of formula (54), the method including reacting an olefin compound of formula (21) with a olefin compound of formula (31) in the presence of at least one metal catalyst selected from the group consisting of a compound of formula (11), a compound of formula (12), a compound of formula (13), a compound of formula (14), and a compound of formula (15).
Method for producing fluorine-containing olefin
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Paragraph 0348; 0349; 0350; 0351; 0352; 0353, (2017/01/17)
A method for producing at least one compound selected from the group consisting of a compound represented by formula (10), a compound represented by formula (11), a compound represented by formula (12), and a compound represented by formula (13), by reacting a compound represented by formula (2) and a compound represented by formula (7) in the presence of at least one compound selected from the group consisting of a compound represented by formula (1), a compound represented by formula (3), a compound represented by formula (4), a compound represented by formula (8), and a compound represented by formula (9).
GASEOUS DIELECTRICS WITH LOW GLOBAL WARMING POTENTIALS
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, (2010/12/31)
A dielectric gaseous compound which exhibits the following properties: a boiling point in the range between about ?20° C. to about ?273° C.; non-ozone depleting; a GWP less than about 22,200; chemical stability, as measured by a negative standard enthalpy of formation (dHf0); a toxicity level such that when the dielectric gas leaks, the effective diluted concentration does not exceed its PEL; and a dielectric strength greater than air.
PURIFICATION METHOD, PRODUCTION PROCESS, AND USE OF, 1, 1-DIFLUOROETHANE
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Page/Page column 20-22, (2008/06/13)
Crude 1,1-difluoroethane containing at least one compound selected from the group consisting of unsaturated compounds each having two carbon atoms within the molecule and saturated chlorine-containing compounds each having two carbon atoms within the molecule is brought into contact with a zeolite and/or a carbonaceous adsorbent, or crude 1,1-difluoroethane containing hydrogen fluoride and, as impurities, at least one compound selected from the group consisting of unsaturated compounds each having two carbon atoms within the molecule is brought into contact with a fluorination catalyst in a gas phase state. High-purity 1,1-difluoroethane usable as a cryogenic refrigerant, or as an etching gas, can be produced in an industrially advantageous manner.
Substituent effects and threshold energies for the unimolecular elimination of HCl (DCl) and HF (DF) from chemically activated CFCl2CH3 and CFCl2CD3
McDoniel, J. Bridget,Holmes, Bert E.
, p. 3044 - 3050 (2007/10/03)
Combination of CFCl2 and methyl-d0 and -d3 radicals form CFCl2CH3-d0 and -d3 with 100 and 101 kcal/mol of internal energy, respectively. An upper limit for the rate constant ratio of disproportionation to combination, kd/kc, for Cl transfer is 0.07 ± 0.03 for collision of two CFCl2 radicals and 0.015 ± 0.005 for CH3 and CFCl2 radicals. The chemically activated CFCl2CH3 undergoes 1,2-dehydrochlorination and 1,2-dehydrofluorination with rate constants of 3.9 × 109 and 4.9 × 107 s-1, respectively. For CFCl2CD3 the rate constants are 8.7 × 108 s-1 for loss of DCl and 1.1 × 107 s-1 for DF. The kinetic isotope effect is 4.4 ± 0.9 for HCl/DCl and appears to be identical for HF/DF. Threshold energies are 54 kcal/mol for loss of HCl and 68 kcal/mol for HF; the E0's for the deuterated channels are 1.4 kcal/mol higher. Comparison of these threshold energies with other haloethanes suggests that for HF and HCl elimination the transition states are developing charges of different signs on the carbon containing the departing halogen and that chlorine and fluorine substituents exert similar inductive effects.
Room-temperature Catalytic Fluorination of C1 and C2 Chlorocarbons and Chlorohydrocarbons on Fluorinated Fe3O4 and Co3O4
Thomson, James
, p. 3585 - 3590 (2007/10/02)
A study of the room-temperature reactions of a series of C1 and C2 chlorohydrocarbon and chlorocarbon substrate molecules with fluorinated iron(II,III) oxide and cobalt(II,III) oxide has been conducted.The results show that fluorinated iron(II,III) oxide exhibits an ability to incorporate fluorine into the following substrates in the order: Cl2C=CCl2 > H2C=CCl2 > CH3CCl3 > CHCl3 > CH2Cl2 > CH2ClCCl3 > CCl4 > CHCl2CHCl2.The fluorinated cobalt(II,III) oxide gave the reactivity series CHCl3 > CCl4 > H2C=CCl2 > CHCl2CHCl2 > CH2Cl2 > CH3CCl3 > CCl2CCl2 > CH2ClCl3.Reactions of C1 chlorohydrocarbon or chlorocarbon probe molecules with fluorinated Fe3O4 gave predominately C1 chlorofluorohydrocarbon and chlorofluorocarbon products, respectively, whereas fluorinated cobalt(II,III) oxide produced predominately C2 chlorofluorohydrocarbon and chlorofluorocarbons.For fluorinated Co3O4 the distribution of C2 products obtained from C1 chlorohydrocarbon precursor molecules is consistent with the formation of radical intermediates at strong Lewis acid surfaces.C2 chlorohydrocarbons exhibit a fluorine for chlorine (F-for-Cl) exchange reaction through the catalytic dehydrochlorination of the substrate to the alkenic intermediate.The F-for-Cl exchange process was dependent upon the ability of the substrate material to undergo dehydrochlorination; the inability of a substrate to undergo dehydrochlorination results in the fluorination process proceeding through the formation of chlorocarbon or chlorohydrocarbon radical intermediates.
