79-35-6Relevant academic research and scientific papers
A two-fluorine bromine acetate preparation method (by machine translation)
-
Paragraph 0026; 0028; 0031; 0033; 0036; 0038; 0041; 0043, (2019/01/22)
The invention provides a two-fluorine bromine acetate preparation method, comprises the following steps: (1) in order to CF2 X - CHCl2 As raw materials, through the dehydrochlorination cancels out the reaction, bromine addition reaction CF2 Br - CClXBr, wherein X is H or Cl; (2) step (1) in the CF2 Br - CClXBr optical oxidation or with sulfur trioxide oxidation reaction, reaction to obtain the CF2 Br - COCl; (3) the step (2) in the CF2 Br - COCl alcohol in the esterification reaction, after separation, distillation, thus obtaining the product 2, 2 - difluoro - 2 - [...] ester. The invention two fluorine bromine acetate preparation method, so that the 1, 1 - difluoro - 2, 2 - dichloroethane or 1, 1 - difluoro - 1, 2, 2 - trichloroethane two by-product that is utilized, reduce their pollution of the environment, but also the production two fluorine bromines acetate process is environment-friendly, two fluorine bromines acetate yield and safety are relatively high. (by machine translation)
Catalytic synthesis of polyfluoroolefins
Stepanov,Delyagina,Cherstkov
experimental part, p. 1290 - 1295 (2011/01/04)
A catalytic synthesis of polyfluoroolefins was developed proceeding from polyfluorochlorocarbons with the use of industrially produced nickel-chromium catalyst. Three ways of the catalytic synthesis of fluoroolefins were implemented: the cleavage of vicinal chlorine atoms from polyfluorochlorocarbons, the replacement of vinyl chlorine atoms by hydrogen in fluorochloroolrfins, and the reductive dimerization of polyfluorochlorocarbons containing a trichloromethyl group. The condition of a prolonged operation of the nickel-chromium catalyst was found consisting in the application of quartz for absorption of the hydrogen fluoride formed as a side product.
Process for activation of AIF3 based catalysts and process for isomerising hydrochlorofluorocarbons
-
Page 8-9, (2008/06/13)
An activated AlF3 based catalyst is produced by treating a crude AlF3 for more than 5 hours with a gas stream at a temperature from 300°C to 450°C.
Synthesis and Diels-Alder cycloaddition reactions of [(2,2-dichloro-1- fluoroethenyl)sulfinyl] benzene and [(2-chloro-1,2-difluoro ethenyl)sulfinyl] benzene
Sridhar, Madabhushi,Leela Krishna,Madhusudana Rao, Jampani
, p. 3539 - 3545 (2007/10/03)
Synthesis of [(2,2-dichloro-1-fluoroethenyl)sulfinyl] benzene and [(2- chloro-1,2-difluoro ethenyl)sulfinyl] benzene and their Dieis-Alder cycloadditions with cyclopentadiene, furan and 1,3-diphenylisobenzofuran under thermal and microwave irradiation conditions are described. 2000 Elsevier Science Ltd.
Process for the purification of chlorofluorohydrocarbons
-
, (2008/06/13)
The invention relates to a process for removing olefinic impurities from hydrogen-containing chlorofluorohydrocarbons (HCFCs) in which the contaminated HCFCs are passed in the gas phase at 200° to 400° C. over a zeolite.
Deuterium isotope studies of the hydrofluorination of chloroethenes over chromia catalysts
Kavanagh, David M. C.,Ryan, T. Anthony,Mile, Brynmor
, p. 167 - 176 (2007/10/02)
The mechanism of the catalytic fluorination of chloroalkenes over a chromia catalyst has been investigated by examining the effects of substituting DF for HF as the fluorine source for reaction with tetrachloroethene and trichloroethene.At a temperature of 250 degC and a HF (DF)/alkene molar ratio of 4.2:1, the rate of conversion of tetrachloroethene is increased by using DF and there is a concomitant increase in the selectivity to some chlorofluoroalkanes and a decrease in the selectivity to chlorofluoroalkenes.The opposite behaviour observed for the halogenated alkenes and alkanes indicates that the alkenes are not important intermediates in the production of the alkanes by a series of hydrofluorination and dehydrochlorination reactions.For tetrachloroethene, the main reaction pathway to the alkanes is a direct chlorine/fluorine exchange over a heavily fluorinated chromia surface with minimal C-H/C-D cleavage of intermediates.Substitution of DF for HF causes no change in the product selectivities from reaction with trichloroethene over chromia catalysts.However, the presence of dideutero - and monodeutero - products shows that both chlorine/fluorine exchange and HF addition / HCl elimination pathways are occurring for the less-substituted alkene.
Threshold Energies and Substituent Effects for Unimolecular Elimination of HCl (DCl) and HF (DF) from Chemically Activated CF2ClCH3 and CF2ClCD3
Jones, Yukari,Holmes, Bert E.,Duke, David W.,Tipton, Debbie L.
, p. 4957 - 4963 (2007/10/02)
Chemically activated CF2ClCH3-d0 and -d3 were prepared with 101 and 102 kcal/mol of internal energy, respectively, by the combination of CF2Cl with methyl-d0 and -d3 radicals at 300 K.The CF2ClCH3 reacts by loss of HCl and HF with rate constants of (2.5 +/- 0.4) x 109 and (0.10 +/- 0.02) x 109 s-1, respectively, a branching ratio of 25:1 in favor of HCl.The CF2ClCD3 has rate constants of (0.78 +/- 0.12) x 109 for loss of DCl and 0.033 +/- 0.005 x 109 sec-1 for loss of DF.The combined primary and secondary isotope effect was 3.2 +/- 0.9 for HCl/DCl elimination and 3.0 +/- 0.9 for loss of HF/DF.RRKM theory was used to model these unimolecular rate constants to determine the threshold energy barriers, E0's, for the four-centered elimination reactions.The E0's were 55 +/- 2 kcal/mol for dehydrochlorination and 69.5 +/- 2 kcal/mol for dehydrofluorination.These threshold barriers are in sharp disagreement with prediction based on trends in the E0's for a series of mono-, di-, and trisubstituted chloroethanes and a similar series of fluoroethanes.An analysis of the E0's for the chloroethanes, fluoroethanes, and chlorodifluoroethane suggests that the carbon-halogen bond in the transition state changes from a nearly neutral C-Cl bond for HCl loss to a C-F bond that has much greater charge separation when HF is eliminated.
STATE-DEPENDENT PHOTOCHEMISTRY OF HIGHLY FLUORINATED BICYCLOOCTA-2,4-DIENES
Roberts, Bryan E.,Goldman, Glenn D.,Lemal, David M.
, p. 353 - 360 (2007/10/02)
A series of 1,2,3,4,5,6-hexafluorobicycloocta-2,4-dienes was subjected to direct irradiation with ultraviolet light and to triplet sensitization.While all of the dienes cyclized smoothly upon direct irradiation to tricyclo2,5>oct-3-enes, their behavior when triplet sensitized was strongly dependent upon the substituents in the 7- and 8-positions.Responses included no reaction, cyclization to tricyclooctene, and fragmentation to hexafluorobenzene plus olefin.Fragmentation occurred only when geminal chlorines were present at the 7-position.This observation is consistent with the view that the four-membered ring opens homolytically at the C6-C7 bond, and only if sufficient stabilization is available for a radical center at the 7-position.
