431-06-1Relevant articles and documents
METHOD FOR PRODUCING 1-CHLORO-1,2-DIFLUOROETHYLENE
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Paragraph 0015; 0075; 0076; 0081; 0084, (2016/12/22)
PROBLEM TO BE SOLVED: To provide a method for efficiently and economically producing 1-chloro-1,2-difluoroethylene that can industrially be performed. SOLUTION: The method for producing 1-chloro-1,2-difluoroethylene comprises bringing 1,2-dichloro-1,2-difluoroethane into contact with an alkali aqueous solution in the presence of a phase transfer catalyst to thereby subject 1,2-dichloro-1,2-difluoroethane to dehydrochlorination reaction. COPYRIGHT: (C)2015,JPO&INPIT
PROCESS FOR THE FLUORINATION OF HALOOLEFINS
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Page/Page column 6-7, (2012/02/02)
A process for the fluorination of haloolefins with elemental fluorine in the presence of anhydrous HF proceeds with high yield and selectivity in the product deriving from the addition of fluorine to the carbon-carbon double bond.
High-resolution FTIR study of the v2 fundamental of cis-CHF=CHF
Visinoni,Giorgianni,Baldan,Nivellini
, p. 4242 - 4246 (2007/10/03)
The high-resolution FTIR spectrum at room temperature of cis-1,2-difluoroethylene has been analyzed in the v2 fundamental region from 1670 to 1760 cm-1. This vibration of A1 symmetry, corresponding to the C=C stretching, gives rise to a strong b-type band approximately centered at 1719 cm-1. The rovibrational analysis led to the assignment of many transitions in the P, Q and R branches with J′ ≤ 70, Ka′ ≤ 30, Kc′ ≤ 69. From a simultaneous fit of the ground state combination differences coming from the present work and the previously analyzed v4 and v10 fundamentals, together with a few literature microwave data, a set of ground state parameters, including all the quartic and four new sextic centrifugal distortion coefficients, was derived. Using the Watson's A-reduction Hamiltonian in the Ir representation, from the final fit of about 3600 assigned transitions, accurate rovibrational constants for the upper state were obtained with a standard deviation of about 8 × 10-4 cm-1.
Bioactivation of S-(2,2-dihalo-1,1-difluoroethyl)-L-cysteines and S- (trihalovinyl)-L-cysteines by cysteine S-conjugate β-lyase: Indications for formation of both thionoacylating species and thiiranes as reactive intermediates
Commandeur, Jan N. M.,King, Laurence J.,Koymans, Luc,Vermeulen, Nico P. E.
, p. 1092 - 1102 (2007/10/03)
The covalent binding of reactive intermediates, formed by β-elimination of cysteine S-conjugates of halogenated alkenes, to nucleophiles was studied using 19F-NMR and GC-MS analysis. β-Elimination reactions were performed using rat renal cytosol and a β-lyase model system, consisting of pyridoxal and copper(II) ion. S-(1,1,2,2-Tetrafluoroethyl)-L-cysteine (TFE-Cys) was mainly converted to products derived from difluorothionoacetyl fluoride, namely, difluorothionoacetic acid, difluoroacetic acid, and N- difluorothionoacetylated TFE-Cys. In the presence of o-phenylenediamine (OPD), as a bifunctional nucleophilic trapping agent, the major product formed was 2-(difluoromethyl)benzimidazole. This product results from initial reaction of difluorothionoacetyl fluoride with one of the amino groups of OPD, followed by a condensation reaction between the thionoacyl group and the adjacent amino group of OPD. In incubations with S-(2-chloro-1,1,2- trifluorofluoroethyl)-L-cysteine (CTFE-Cys) and S-(2,2-dichloro-1,1- difluorofluoroethyl)-L-cysteine (DCDFE-Cys), formation of thionoacylated cysteine S-conjugates was also observed by GC-MS analysis, indicating formation of the corresponding thionoacyl fluorides. However, according to 19F-NMR analysis, chlorofluorothionoacyl fluoride-derived products accounted for only 10% of the CTFE-Cys converted. In the presence of OPD, next to the corresponding 2-(dihalomethyl)benzimidazoles, 2- mercaptoquinoxaline was identified as the main product in incubations with CTFE-Cys. When chlorofluorothionoacylating species were generated from the unsaturated S-(2-chloro-1,2-difluorovinyl)-L-cysteine (CDFV-Cys), 2- (chlorofluoromethyl)benzimidazole and 2-mercaptoquinoxaline were also found as OPD adducts. However, with CDFV-Cys the ratio of 2- (chlorofluoromethyl)benzimidazole to 2-mercaptoquinoxaline was 12-fold higher than in the case of CTFE-Cys. These results suggest an important second mechanism of formation of 2-mercaptoquinoxaline with CTFE-Cys. The formation of 2-mercaptoquinoxaline could also be explained by reaction of OPD with 2,3,3-trifluorothiirane as a second reactive intermediate for CTFE-Cys. Comparable results were obtained when comparing OPD adducts from DCDFE-Cys and TCV-Cys. Both DCDFE-Cys and TCV-Cys form dichlorothionoacylating species. However, DCDFE-Cys forms 21-fold more 2-mercaptoquinoxaline than TCV-Cys, which may be explained by its capacity to form 3-chloro-2,2-difluorothiirane next to dichlorothionoacyl fluoride. In order to explain the apparent differences in the preference of thiols to form different reactive intermediates, free enthalpies of formation (Δ(f)G) of thiolate anions and their possible rearrangement products, thionoacyl fluorides and thiiranes, derived from TFE-Cys, CTFE-Cys, and DCDFE-Cys, were calculated by ab initio calculations. For TFE-thiolate, formation of difluorothionoacetyl fluoride is energetically favored over formation of the thiirane. In contrast, the thiirane pathway is favored over the thionoacyl fluoride pathway for CTFE- and DCDFE-thiolates. The results of these quantum chemical calculations appear to be consistent with the experimental data.
The chlorination of 1,2-difluoroethane (HFC-152)
Nappa, Mario J.,Sievert, Allen C.
, p. 111 - 118 (2007/10/02)
The photochlorination of CH2FCH2F yields CH2FCCl2F and CHClFCHClF, both of which were considered to be potential replacements for CFC-113 (CCl2FCF2Cl) based on their boiling points (48 deg C and 59 deg C, respectively).The CHClFCHClF/CH2FCCl2F ratio can be controlled by the choice of solvents.In aromatic solvents, the reactivity of the chlorine radical is reduced, increasing the amount of CH2FCCl2F produced.Relative rates in CCl4 and in the presence of water were compared to rates in aromatic solvents.Both CH2FCCl2F and CHClFCHClF failed in early toxicity tests and will thus not be pursued as HCFC replacements for CFC-113.
REACTIONS OF HALOGEN FLUORIDES. X. FLUORINATION OF CHLORINE-SUBSTITUTED ALKANES WITH BROMINE TRIFLUORIDE
Kartashov, A. V.,Chuvatkin, N. N.,Boguslavskaya, L. S.
, p. 2276 - 2278 (2007/10/02)
Bromine trifluoride in Freon 113 readily substitutes the chlorine atoms in monochloroalkanes by fluorine, while in the presence of catalytic amounts of certain Lewis acids it is also capable of substituting the chlorine atoms in polychloroalkanes with the formation of the corresponding fluorides.Additions of tin tetrachloride make it possible not only to increase the reaction rate but also to increase the selectivity of fluorination.In some cases substitution of a primary chlorine atom is accompanied by hydride transfers.
FLUORINATION OF HYDROGEN-CONTAINING OLEFINS WITH ELEMENTAL FLUORINE
Conte, L.,Gambaretto, G. P.,Napoli, M.,Gervasutti, C.
, p. 319 - 326 (2007/10/02)
The hydrohalo-olefins cis and trans CHCl=CHCl, CHCl=CCl2, CHCl=CH-CH2Cl and CH2=CCl-CH2Cl have been fluorinated with elemental fluorine to give good yields of hydrohalofluoroalkanes.The best operational conditions for F2 addition to the double bond rather than hydrogen and/or chlorine atom substitution, dimerization and oligomerization of radical intermediates have been studied.Pleriminary studies on the reaction of Freon 12 and Freon 22 towards elemental fluorine have also been carried out.
REACTIONS OF HALOGENS FLUORIDES. VIII. SUBSTITUTIVE FLUORINATION OF BROMINE-CONTAINING ALKANES AND ESTERS WITH BROMINE TRIFLUORIDE
Chuvatkin, N. N.,Kartashov, A. V.,Morozova, T. V.,Boguslavskaya, L. S.
, p. 237 - 242 (2007/10/02)
The conditions were found for selective liquid-phase substitutive fluorination of bromine-substituted alkanes and esters with pure bromine trifluoride, in which all three fluorine atoms of the BrF3 molecule are used effectively in the fluorination.The exchange of bromine for fluorine in monobromohalogenoalkanes is nonstereospecific and is in a number of cases accompanied by skeletal rearrangements, hydride shifts, and migration of the halogen.A carbocationic mechanism of fluorination is discussed.
REACTIONS OF HALOGEN FLUORIDES. VII. FLUORINATION OF UNSATURATED COMPOUNDS WITH BROMINE TRIFLUORIDE AND AN EQUIMOLAR MIXTURE OF BROMINE TRIFLUORIDE WITH MOLECULAR BROMINE
Boguslavskaya, L. S.,Chuvatkin, N. N.,Kartashov, A. V.,Ternovskoi, L. A.
, p. 230 - 236 (2007/10/02)
The reactions of bromine trifluoride and an equimolar mixture of bromine trifluoride and bromine with halogen-substituted alkenes and methyl α-substituted acrylates were investigated.With sufficient dilution of the substrate by Freon 113 (20-25:1) it is possible to obtain the bromofluoro and difluoro adducts with good yiels.The best results (overall yields of fluorination products 80-83percent) were obtained with alkenes containing a halogen at the multiple bond; in the case of more reactive substrates the reaction becomes nonpreparative.The bromofluorination of E- and Z-1,2-dichloroethylenes and E- and Z-1,3-dichloropropenes with pure bromine trifluoride is antistereospecific.The bromofluorination of E- and Z-1,2-dichloroethylenes by the BrF3-Br2 system gives a mixture of diastereomeric bromofluoro adducts as a result of isomerization of the initial olefins in the presence of the bromine.The formation of the difluorides of the halogenated olefins is nonstereospecific and is accompanied by migration of the halogens.
REACTIONS OF CHLORINE MONOFLUORIDE. REGIOSPECIFICITY AND STEREOCHEMISTRY OF THE SUBSTITUTION OF BROMINE ATOMS BY FLUORINE IN HALOGEN-SUBSTITUTED ALKANES AND ESTERS
Boguslavskaya, L. S.,Chuvatkin, N. N.,Panteleeva, I. Yu.,Ternovskoi, L. A.
, p. 814 - 820 (2007/10/02)
Under mild conditions without catalysts chlorine monofluoride substitutes bromine atoms for fluorine in bromine-substituted alkanes and esters.Electron-donating substituents promote the substitution reaction.The following sequence is observed in the reactivity of the bromine atoms at the carbon: tertiary > secondary > primary.Halogen atoms (Cl, F) at a carbon containing a bromine also promotes substitution of the latter by fluorine.The reactivity of the bromine atoms decreases in the following order: CCl2Br(CClFBr) > CHClBr(CHFBr) > CH2Br.An alkoxycarbonyl group at a carbon containing bromine prevents substitution.In a number of cases substitutive fluorination is accompanied by skeletal rearrangements and by migration of chlorine atoms.The stereochemistry of substitutive fluorination was studied for the case of the reaction of erythro- and threo-1-bromo-2-fluoro-1,2-dichloroethanes and 1,2-dibromo-1,3-dichloropropanes with chlorine monofluoride.The probable mechanism of the reaction is discussed.
