- Kinetic Studies of the Continuous Wave Laser-Induced Cyclization of Hexafluoro-1,3-butadiene
-
Kinetics of the isomerisation of hexafluoro-1,3-butadiene have been studied in the past by standard pyrolysis and by shock tubes, with conflicting results.The present study indicates that the pyrolysis results are correct and also indicates that vibrational-translational energy in hexafluoro-1,3-butadiene occurs through a vibrational mode that is nearly harmonic.
- Zitter, R. N.,Koster, D. F.,Cheung, K.
-
-
Read Online
- A T-shaped Ni[κ2-(CF2)4-] NHC complex: Unusual Csp3-F and M-CF bond functionalization reactions
-
A T-shaped octafluoronickelacyclopentane-NHC complex is prepared and characterized. While the solid-state structure includes a weak isopropyl-CH3 agostic interaction, the reactivity of this complex with Lewis- and Bronsted acids is clearly enhanced by its low coordination number. Reaction with Me3SiOTf, for example, yielded a rare metal-heptafluorocyclobutyl complex whereas carboxylic acids gave substitution at the α-carbon and/or Ni-CF bond protonolysis to afford thermally robust 4H-octafluorobutyl Ni complexes.
- Andrella, Nicholas O.,Sicard, Alexandre J.,Gorelsky, Serge I.,Korobkov, Ilia,Baker, R. Tom
-
-
Read Online
- Method for producing fluorine-containing cyclic sulfur compounds
-
A method for producing a fluorine-containing cyclic sulfur compound is disclosed. The method includes mixing a perfluoroolefin having from 4 8 carbon atoms with sulfur. In addition, the method is F. 2 The present invention relates to a method for producing a fluorine-containing cyclic sulfur compound.
- -
-
Paragraph 0049-0050; 0054-0062
(2021/10/27)
-
- MANUFACTURING METHOD OF PERFLUOROCYCLOALKENE COMPOUND
-
PROBLEM TO BE SOLVED: To obtain a perfluorocycloalkene compound high in conversion ratio of a reaction at high yield and high selectivity. SOLUTION: A perfluorocycloalkene compound represented by (1), where R1 to R4 are same or different, and represent a fluorine atom or a perfluoroalkadiene compound, is obtained by conducting a cyclization reaction of a perfluoroalkanediene compound represented by CR12=CR2-CR3=CR42, where R1 to R4 are same or different and represent a fluorine atom or a perfluoroalkyl group. The cyclization reaction can be conducted in presence of a catalyst, by a gas phase continuous flow type, or by the gas phase continuous flow type in presence of the catalyst. SELECTED DRAWING: None COPYRIGHT: (C)2020,JPOandINPIT
- -
-
Paragraph 0083-0091
(2020/05/14)
-
- Synthesis of hydrohalocyclobutenes through dechlorination of hydrohalocyclobutanes in amide solvents
-
In this study, we synthesized hydrohalocyclobutenes through the dechlorination of hydrohalocyclobutanes in N,N-dimethylformamide and N,N-dimethylacetamide. The structure of the reaction site ?CClR1?CClR2– (R1 = H, F; R2 = H, F, Cl) of the reactants was critical for the efficient reductive dechlorination from the 1- and 2- positions. The reaction proceeded efficiently at the –CFCl–CFCl–, –CFCl?CCl2–, and ?CHCl?CHCl– groups. Conversely, the –CFCl?CHCl– group could hardly afford the dechlorinated product. Based on these results, we propose a rational reaction mechanism.
- Guo, Qin,Lu, Fengniu,Quan, Hengdao,Zhang, Chengping,Zhang, Wenni
-
-
- Preparation method of halogenation cycloolefin
-
The invention relates to a preparation method of halogenation cycloolefin and belongs to the field of chemical synthesis. According to the preparation method, in an amide or alkylamine solvent, with halogenation cycloparaffin as a raw material, a dehalogenation reaction is conducted, and the target product halogenation cycloolefin is obtained. According to the method, the reaction conditions are mild, the yield of the halogenation cycloolefin is high, dangerous reduction agents such as metal or hydrogen do not need to be used, the technology is safe and reliable, solid waste such as metal halide is not generated, and a common distillation means can be used for effective industrial separation.
- -
-
Paragraph 0054-0057; 0072-0075
(2019/08/20)
-
- Structural assignment of fluorocyclobutenes by19F NMR spectroscopy – Comparison of calculated19F NMR shielding constants with experimental19F NMR shifts
-
Although the optimized reduction of perfluorocyclo-butene with LiAlH4 gave a quantitative yield of the target 3,3,4,4-tetrafluorocyclobut-1-ene, unoptimized reductions led to complex inseparable mixtures of fluorocyclobutenes. These mixtures showed highly complex19F NMR spectra, the assignment of which was quite tedious. Hence, we accomplished a series of single-reference computations of the19F NMR magnetic shieldings of the corresponding fluorine atoms. Surprisingly, various DFT approaches, including both traditional and advanced functionals, gave highly diverse results with poor correlations between the experimental and computed19F chemical shifts, and the individual fluorocyclobutenes could not be identified. In contrast, the domain-based local pair natural orbital coupled clusters (DLPNO-CCSD) method, developed recently as a part of the ORCA computational package, gave shielding values that enabled the assignment of all structures observed, albeit with some systematic errors. Slightly better magnetic shielding values were obtained by a simple Hartree–Fock (HF) method with a specially tailored IGLO-III basis set. The method developed was successfully employed for the assignment of the19F NMR shifts of unknown fluorocyclobutenes.
- Ku?nirová, Kate?ina,?im?nek, Ond?ej,Rybá?ková, Markéta,Kví?ala, Jaroslav
-
p. 3867 - 3874
(2018/10/20)
-
- Full-PVC butanone synthetic method
-
The invention relates to a synthetic method of perfluorocyclobutanone. According to the method, trifluorochloroethene (I) undergoes thermal polymerization to obtain a dimer (II); then, dechloridation is carried out to obtain hexafluorocyclobutene (III); and hexafluorocyclobutene is oxidized to obtain perfluorocyclobutanone (IV). According to the technology, a trifluorochloroethene synthesis route is used such that perfluorocyclobutanone is easier to prepare. In addition, the technology is safer and more stable; impurities are less; and yield and product quality are also increased correspondingly. The synthetic method is suitable for large-scale production.
- -
-
Paragraph 0024; 0052
(2017/08/02)
-
- Hexafluoropropylene-2-butyne synthesizing method
-
The invention discloses a hexafluoropropylene-2-butyne synthesizing method. Hexachlorobutadiene (CCl2=CCl-CCl=CCl2) is taken as the raw material to generate hexafluoropropylene-2-butyne under the action of a catalyst, the raw material hexachlorobutadiene is easy to obtain and low in cost. The gaseous-phase circulating fluorination method is adopted, the discharge level of three industrial wastes is low, the yield of products is high, and production cost is reduced greatly; the gaseous-phase circulating fluorination method is conducted at normal temperature, the traditional high-pressure telomerization process route is avoided, and risks in industrial safety production are reduced greatly; meanwhile, the method has the advantage that operation is easy and is totally suitable for industrial production.
- -
-
Paragraph 0051; 0052; 0053; 0054
(2016/10/08)
-
- Catalytic synthesis of polyfluoroolefins
-
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.
- Stepanov,Delyagina,Cherstkov
-
experimental part
p. 1290 - 1295
(2011/01/04)
-
- Method of preparing perfluoroalkadiene
-
Disclosed herein is a method of preparing a perfluoroalkadiene. A dihaloperfluorocarbon used as a starting material is added dropwise to a nonpolar organic solvent, a metal powder and an organic metal compound. The dihaloperfluorocarbon is slowly added dropwise in a temperature range from 30° C. to 150° C. for a certain period of time. Moreover, the nonpolar organic solvent used may be benzene, toluene, xylene, etc., and the organic metal compound is used by being dissolved in ethyl ether or tetrahydrofuran at a concentration of 1 to 3M. The metal powder used may be Mg, Zn, Cd, etc.
- -
-
Page/Page column 3
(2009/04/24)
-
- Solvents for use in fluorination reactions
-
A method of fluorinating an organic compound comprising reacting an organic compound with a fluorinating agent characterized in that a perfluorocarbon compound is present in the reaction medium. The perfluorocarbon compound may replace an amount of a solvent which would otherwise be required for the reaction to proceed efficiently. The perfluorocarbon compound is readily recoverable after reaction and may be re-used in subsequent reactions. Additives to the reaction medium, such as 18-crown-6, may increase the amoun of solvent which may be replaced. The method is beneficial where solvent consumption would otherwise be large, or where solvent recovery would otherwise be difficult.
- -
-
-
- Perfluorocarbon fluids as solvent replacements
-
Perfluoroperhydrophenanthrene 1 may be used as a 'bulking agent' to minimise the problem of solvent recovery in halogen exchange ('Halex') reactions for the preparation of octafluorocyclopentene 8, and chlorofluoro-pyridine, -pyrimidine and -benzene derivatives. New 'one-pot' procedures for the syntheses of hexafluorobut-2-yne 3, octafluorobut-2-ene 11 and hexafluorocyclobutene 7 are described.
- Chambers, Richard D.,Edwards, Andrew R.
-
p. 3623 - 3627
(2007/10/03)
-
- IR Multiphoton Dissociation Dynamics of Octafluorocyclopentene: Time-Resolved Observation of Concerted Products :CF2 and Hexafluorobutadiene
-
Real time observation of :CF2 and hexafluorobutadiene (HFBD) generated simultaneously in the concerted IR multiphoton dissociation of octafluorocyclopentene (OFCP) is reported.The formation rate of both the transients, i.e., hot HFBD and :CF2, which have an overlapping absorption at 250 nm, fits to a single exponential, with a rate constant (2.0 +/- 0.1) x 106s-1.The fast exponential decay of the transient signal up to 100 μs is assigned to electrocyclic isomerization of HFBD to hexafluorocyclobutene with a rate constant k = (5.7 +/- 0.2) x 104s-1, whereas the slower decay on the millisecond time scale suggests :CF2 dimerization to form C2F4, with a bimolecular rate constant (4.5 +/- 0.1) x 107M-1s-1.RRKM calculation for the unimolecular dissociation of OFCP and isomerization of HFBD gives an average energy of OFCP as 383 +/- 10kJ/mol and of nascent HFBD as 202 +/- 5 kJ/mol, corresponding to the experimental rates.The nascent vibrationally hot HFBD exhibits a red shift of 50 nm in the transient absorption spectrum.
- Chowdhury, P. K.
-
p. 12084 - 12089
(2007/10/02)
-
- Thermal reactions of hexafluorobutadiene and hexafluorocyclobutene with elemental sulphur
-
Hexafluorobuta-1,3-diene and hexafluorocyclobutene interact with elemental sulphur under conditions of mutual conversion (>/= 280 deg C) to give the same products, hexafluoro-3,6-dihydro-1,2-dithiine (1), hexafluorothiolene-3 (2) and hexafluorothiolanethione (3).The product composition and ratio depend on the reaction conditions.Dithiine 1 and thiolene 2 were formed in competitive reactions.Their thermal stability and the retrocycloaddition reaction of dithiine 1 have been studied.The latter reaction results in thiolene 2 in addition to the formation of hexafluorocyclobutene.This is consistent with a stepwise mechanism for the retrocycloaddition as well as the cycloaddition reaction.
- Kazmina, N. B.,Mysov, E. I.,Aerov, A. F.,Kagramanova, E. M.
-
p. 203 - 208
(2007/10/02)
-
- Thermal reactions of hexafluoro-1,3-butadiene. Part I. Primary products and their thermal transformations
-
Depending on the temperature, the thermal reactions of hexafluoro-1,3-butadiene include intra- and/or intermolecular cycloaddition and give hexafluorocyclobutene, - and -cycloadducts as primary products.The latter react with hexafluorobutadiene to give its trimers while the -cycloadduct, being generated as two isomers, undergoes some thermal rearrangements in addition.Thus, cis-perfluorodivinylcyclobutane is isomerized at 150 deg C to perfluorotricyclo2,5>- and -2,6>octanes together with unstable, easily polymerized, cis,trans-perfluoro-1,5-cyclo-octadiene.The trans isomer is isomerized at 200 deg C to perfluorovinyl-4-cyclohexene and perfluorotricyclo2,6>octane.Possible schemes for the formation of the latter are discussed.Racemic trans,trans-perfluoro-1,5-cyclo-octadiene is argued to be a precursor of perfluorotricyclo2,6>octane in the isomerizations of both the cis- and trans--cycloadducts.
- Kazmina, Nataliya B.,Antipin, Mikhail Yu.,Sereda, Sergei V.,Struchkov, Yuri T.,Mysov, Evgeni I.,Leites, Larisa A.
-
-
- Real Time Optical Observation of Nascent Hexafluorobutadiene in the IR Multiphoton Dissociation of Decafluorocyclohexene
-
Real time observation of retro-Diels-Alder dissociation of decafluorocyclohexene into tetrafluoroethylene and hexafluorobutadiene induced by transversely excited atmospheric pulsed CO2 laser is reported.The formation rate and the red-shifted absorption spectra of nascent hexafluorobutadiene suggest substantial internal energy incorporation, which appears to be sufficient for its undergoing electrolytic transformation to hexafluorocyclobutene at a rate corresponding to the decay kinetics.When the above IR multiphoton dissociation of decafluorocyclohexene occurs in presence of oxygen, UV light emission due to COF2* is observed.
- Chowdhury, Pradyot Kumar
-
p. 3455 - 3461
(2007/10/02)
-
- LASER-DRIVEN OXIDATION OF SOME HALOOLEFINS
-
CW CO2 laser-photosensitized (SF6) oxidation of hexafluoropropene, chlorotrifluoroethene, 1,1-dichlorodifluoroethene, 1,2-dichlorodifluoroethene and hexafluoro-1,3-butadiene with molecular oxygen at total pressure 13-26.5 kPa leads with all but the last to the formation of carbonyl halides.The distribution of these products suggests that the oxidation occurs via a cleavage of intermediary dioxetanes.The reactivities of the olefins towards oxygen at mean effective temperature 710 K are nearly equal.
- Pola, J.,Chvatal, Z.
-
p. 197 - 214
(2007/10/02)
-
- Infrared Multiphoton-Induced Concerted :CF2 Elimination in Octafluorocyclopentene by a Pulsed CO2 Laser
-
On infrared multiphoton excitation, octafluorocyclopentene (OFCP) undergoes a ring-opening reaction to give difluorocarbene and hexafluorobutadiene as unstable primary products which undergo further reactions; the former dimerizes to tetrafluoroethylene, and the latter isomerizes to its thermodynamically stable cyclic isomer.The multiphoton dissociation (MPD) yield of OFCP shows a strong fluence dependence, with a threshold of 0.3 J/cm2 for the 10R(32) line of the CO2 laser for inducing the reaction.Two characteristic peaks in the MPD spectra have been observed, both red-shifted from the ν20 ring deformation mode absorption peak of OFCP.Increase in pressure of OFCP or foreign gas addition has shown to deteriorate the MPD yield.
- Chowdhury, Pradyot K.,RAO, K. V. S. Rama,Mittal, J. P.
-
p. 2877 - 2882
(2007/10/02)
-
- Reactions Involving Fluoride Ion. Part 30. Preparation and Reactions of Epoxides Derived from Perfluoroalkyl Substituted Alkenes
-
Reactions of alkenes that are oligomers of tetrafluoroethene or hexafluorocyclobutene with sodium hypochlorite give epoxides which show remarkable overall stability.Ring-opening reactions, induced by fluoride ion, yield alkenes, ketones, and acid fluorides.
- Bryce, Martin R.,Chambers, Richard D.,Kirk, Julian R.
-
p. 1391 - 1395
(2007/10/02)
-
- REACTIONS INVOLVING FLUORIDE ION. PART 24 . SYNTHESES FROM PERFLUOROCYCLOBUTENE
-
Passage of perfluorocyclobutene, in a flow system, over caesium fluoride at 590-600 deg C provides a synthesis of hexafluoro-2-butyne in high yield.In a similar process, using glass tubes, tricyclo2,6>octane and bicyclo -2-heptene were obtained.
- Chambers, Richard D.,Jones, Colin, G. P.,Taylor, Graham,Powell, Richard L.
-
p. 407 - 412
(2007/10/02)
-
- Cyclization of Perfluorobutadiene. Studies with a Single-Pulse Shock Tube
-
The perfluorobutadienes -> perfluorocyclobutene isomerization was studied, highly diluted in argon, behind reflected waves in a single-pulse shock tube.The temperature range covered was 630-725 K at pressures p1 ranging from 100 to 400 torr.Under these conditions no side products are obtained and the unimolecular reaction is in its high-pressure limit.The first-order rate constant obtained is kuni = 2.86 X 1014exp(-42.0 X 103/RT)S-1.It is suggested that the rate constant obtained at lower temperatures, which shows lower activation energy and lower preexponential factor, was influenced by some heterogeneous processes.The temperature range covered in this study is very low for the single-pulse shock tube technique.Details of the gas dynamic procedure are reported.
- Lifshitz, Assa,Kahana, Paz
-
p. 2827 - 2829
(2007/10/02)
-
