Chloro fluoromethanes

Disodium hexafluorosilicate converts phthaloyl chloride into phthaloyl fluoride in 51.5 % yield.15 Disodium and barium hexafluorosilicate can be used for the preparation of chloro-fluoromethanes. Thus, heating carbon tetrachloride with disodium hexafluorosilicate or barium hexafluorosilicate in an autolave under high pressure gives a mixture where dichlorodi-... 

Reactions of Of D) Atoms with H2, 02, N20, H20, CH4, atul Chloro-fluoromethanes. O( D) + H2 (276). No physical quenching was found (791). DeMore (276) has studied the photolysis at 2537 A of mixtures of 03-H2 dissolved in liquid argon at 87 K. The quantum yield of ozone decomposi-... 

The disproportionation of chlorofluoromethanes is also catalyzed by iron(lll) halides,21 chromium oxyfluorides and other metal halides. With tron(III) chloride on activated carbon at temperatures above 300 C, for example, the compounds carbon Iclrafluoride, chloro-fluoromethane, trtchlorofluoromclhanc and carbon tetrachloride are obtained from dichloro-fluoromethane (Scheme 3) ... 

Chloro fluoromethane 298.15 K 343.82 literature summary 138-427 K 2.28xl0-3-5700 Xiang 2002... 

Chloro fluoromethane 296 37xl0-15 Howard Evenson 1976a... 

Molina, M. J., and Rowland, F. Sherwood (1974). Stratospheric Sink for Chloro-fluoromethanes Chlorine Atom Catalyzed Destruction of Ozone. Nature 249 810-812. 

Molina, M.J. Rowland, F.S. Stratospheric sink for chloro-fluoromethanes chlorine atom-catalysed destruction of ozone. Nature 1974, 28, 810-812. 

D) + CliloroJIuoromelhones. The reactions of 0( D) with chloro-fluoromethanes have been studied by Donovan et al. (316), Gillespie and Donovan (396), and Fletcher and Husain (362). The reactions yield predominantly CIO radicals... 

Because of the slow diffusion process of chlorofluoromethanes through the tropopause into the stratosphere and a slow photodissociation process of chlorolluoromethanes by sunlight in the stratosphere the maximum reduction of O, is estimated to occur 10 years after the release of chloro-fluoromethanes at ground level [Rowland and Molina (843)]. 

Popkie, H. E., and Kaufman, Joyce J., "Molecular Calculations with the MODPOT, VRDDO and MODPOT/VRDDO Procedures. V. Ab-Initio and MODPOT LCA0-M0-SCF Calculations on the Chloro-fluoromethanes," Int. J. Quantum Chem. (1977), Sll, 33- 3-... 

Klesper et al. first demonstrated, in 1962, SFC by the separation of nickel porphyrins using supercritical chloro-fluoromethanes as mobile phases. Sie and Rijnders and Giddings, in 1966, developed the technique further, both practically and theoretically, as well as many applications. A few years later, Gouw and Jentof reviewed the general aspects of SFC, including different mobile phases, solute retention, selectivity, and applications. ... 

TFE undergoes free radical addition reactions typical of other olefins. It readily adds Br, Cl, and I, halogen halides IBr and ICl, and nitrosyl halides such as NOCl and NOBr. Additional reactions of chloro-fluoromethanes and chloromethanes in the presence of catalysts like aluminum chloride have been reported [48]. A variety of other compounds such as alcohols, primary amines and ammonia can be reacted with TFE to prepare tetrafluoroethers (HCF CF OR), difluoroacetamide (HCF CONHR) and substituted triazines. Oxygen can be added to TFE to produce polymeric peroxide or TFE epoxide. In the absence of hydrogen, sodium salts of alcohols will react with TFE to yield trifluorovinylethers (ROCF = CF ), which can be homo- and copolymerized. 

In a series of comparative studies Dolle et al. examined the nucleophilic aromatic substitution of a number of nitropyridine derivatives [104—106], The results, as summarized in Scheme 13.14, show that under microwave-enhanced conditions the 2-N02 and 2-+NMe3 groups led to excellent fluorine incorporation whilst the 2-iodo compound was virtually unreactive. Under thermal conditions no fluorination was observed for the 2-chloro and 2-bromo compounds. In a separate study Banks et al. [107] again observed the beneficial effects of nitro and trimethylamino substitution (Scheme 13.15). The authors also developed a novel microwave-enhanced method of producing [18F]-fluoromethane [108]. 

While the boiling points of chloro- and bromomethanes always increase according to the number of halogen atoms, this correlation does not exist in the case of fluoromethanes. The bp increases from CH4 to CH2F2 and then decreases until CF4 (Table 1.4). Indeed, a parallelism exists between boiling points and dipolar moments. A partially fluorinated compound will exhibit nonnegligible intermolecular interactions according to the importance of the dipolar moment (Table 1.5). ... 

Freon—12 or "F-12 . See Dichlorodi-fluoromethane in Vol 5 of Encycl, p D1209-L "Freon—13 , " F—13 ot Monocblorotriffaro-methane. See Chloro tri fluoro me thane in this... 

The dipole moments of the fluoromethanes follow a pattern that is different from those of the chloro- and bromomethanes the halogen is now the high- (O) but low-k fluorine. CH2F2 has the highest dipole moment (1.93D) of the fluoromethanes, because of the... 

Photochlorination of cyclopropane gave chlorocyclopropane (la) and 1,3-dichloro-propane. The latter was the major product at low temperature. Photochlorination with tert-h Ay hypochlorite gave mostly chlorocyclopropane (la). Methylcyclopropane reacted with chlorine to give predominantly l-chloro-2-methylcyclopropane (lb), but small amounts of acyclic products such as 2-chlorobutane, 1,3-dichlorobutane, and 1,3-dichloro-2-methyl-propane were also obtained. With ferr-butyl hypochlorite 4-chlorobut-l-ene was isolated as the only acyclic product. Photochlorination of 1,1-dimethylcyclopropane in trichloro-fluoromethane atO°C gave the chloromethylcyclopropane derivative 2 in 67% yield after immediate workup. 

A general definition of the Quantum Molecular Similarity Measure is reported. Particular cases of this definition are discussed, drawing special attention to the new definition of Gravitational-like Quantum Molecular Similarity Measures. Applications to the study of fluoromethanes and chloro-methanes, the Carbonic Anhydrase enzyme, and the Hammond postulate are presented. Our calculations fully support the use of Quantum Molecular Similarity Measums as an efficient molecular engineering tool in order to predict physical properties, lMok>gical and pbarraacdogical activities, as well as to interpret complex chemical problems. 

Fluoromethane (CH3F, = 1.81 D) hag a smaller dipole moment than chloro-methane (CH3C1, - 1.87 D) even though fluorine is more electronegative than chlorine. Explain. 

Table 4. The lowest ionization potential and approximate maxima of the UV absorption bands of lowest frequency of chloro- and bromo-fluoromethanes. [Reproduced from Sandotfy, C. Atmospheric Environment 10, 343 (1976), with permission of Pergamon Press Ltd.]...

Fluoromethane Bromoethane 2-Iodopropane 2-Chloro-2-methylpropane Dihromomethane Trichloromethane Bromoethene 3-Chloropropene... 

Argon nitrogen carbon dioxide Trichloro fluoromethane Difluorodichloromethane Dichlorofluoromethane l-chloro,2-2 difluoroethane... 

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