Xn:Harmful;75-69-4Relevant articles and documents
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Swarts
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Kinetics of tetrachloromethane fluorination by hydrogen fluoride in the presence of antimony pentachloride
Meissner, Egbert,Milchert, Eugeniusz
, p. 89 - 95 (2003)
Contradictory information concerning the kinetics of tetrachloromethane fluorination by anhydrous hydrogen fluoride in the presence of antimony pentachloride has been explained. The present studies were performed using a stainless steel autoclave. The exchange of the first chlorine atom was carried out in the temperature range of 35-95°C, with the molar ratio of HF/CCl4 varied within the range of 1.2-1.7 and at a constant molar ratio of SbCl5/Cl2 equal to 1.9. The degree of conversion of CCl4 to CCl3F and the reaction rate constant as a function of temperature fit to an Arrhenius straight line. The Arrhenius constants (pre-exponential factor) and the activation energy were determined. Studies concerning the exchange of the second chlorine atom, i.e. the conversion of CCl3F to CCl2F2 have been performed. The results of kinetic investigations were created in the same way. Based on these results it was found that the Arrhenius equation is fulfilled also in the second stage of the fluorination. The same slope of the straight lines confirms that the fluorination stages proceed according to the same mechanism with the same activation energy but with different pre-exponential factors. Several kinetic problems associated with the performance of the reactor can be solved on the basis of the equations derived. However, knowledge of CCl4 conversion as a function of time, temperature, catalyst concentration and the type of the reaction is required for this purpose. Such calculations enable the selection of the optimal process parameters.
PROCESSES FOR THE SYNTHESIS OF 3-CHLOROPERFLUORO-2-PENTENE, OCTAFLUORO-2-PENTYNE, AND 1,1,1,4,4,5,5,5-OCTAFLUORO-2-PENTENE
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Page/Page column 14, (2009/07/18)
Disclosed is a process comprising reacting CF3CF2CCI2CF2CF3 (CFC-41 -10mca) with hydrogen in the presence of a dehalogenation catalyst to produce CF3CF2CCI=CFCF3 (CFC-1419myx). Also disclosed herein is a process comprising reacting CF3CF2CCI=CFCF3 (CFC- 1419myx) with hydrogen in the presence of a dehalogenation catalyst to produce CF3CF2C≡CCF3 (octafluoro-2-pentyne). Also disclosed herein is a process comprising reacting CF3CF2CCI2CF2CF3 (CFC-41 -10mca) with hydrogen in the presence of a dehalogenation catalyst to produce CF3CF2C≡CCF3 (octafluoro-2-pentyne). In addition, a process for reacting CF3CF2C≡CCF3, in a pressure vessel, with a Lindlar catalyst and hydrogen to produce CF3CF2CH=CHCF3 (1,1,1,4,4,5,5,5-octafluoro-2- pentene) is disclosed.
Decomposition of dichlorodifluoromethane with simultaneous halogen fixation by vanadium oxide supported on magnesium oxide
Tamai, Tsukasa,Inazu, Koji,Aika, Ken-Ichi
, p. 1565 - 1574 (2007/10/03)
Dichlorodifluoromethane (CCl2F2, 1% in He) decomposition with simultaneous halogen fixation by vanadium oxide supported on magnesium oxide was studied at 723 K in a flow apparatus. The pretreatment condition and vanadium loading of supported vanadium oxide samples affected the CCl2F2 decomposition efficiency. Through characterization studies (XRD, IR, Raman, and XPS) and reference experiments, Mg 3(VO4)2 was revealed to be the active species to initiate CCl2F2 decomposition, leading to MgF 2, MgCl2, and CO2 formation. The model experiments also suggested a detailed mechanism that VOCl3 was formed from Mg3(VO4)2 by a reaction with CCl 2F2 or the major intermediate compound CCl4, and that VOCl3 reacted with MgO to regenerate Mg3(VO 4)2 and to promote chlorine fixation as MgCl2.
