Fluorinated methanes

See Bromine pentafluoride Hydrogen-containing materials Chlorine Hydrocarbons Chlorine trifluoride Methane Fluorine Hydrocarbons Iodine heptafluoride Carbon, etc. 

Of course, the overall AH for the 1 reaction of an alkane with chlorine, must also take into account the AH of this sea Step whfeh is-3 49 +243= lO kJ mol-1, making chterirtetoon mudi more exothermic than brommation. u naf(On continues the trend, and methane-fluorine mixtures are. explosive. For iodine, on the other hand, the first step becomes so endothermic, even for formation of atertiary redical, thatthe second step (AH= -234 +151=-83 kj mol-1) is not exothermic enough to make reaction favourable overall. Radical lodinatlons therefore do not take place. 

From studies of the concentration profiles through dichlorodifluoro-methane/fluorine flames at low pressures, Homann and MacLean have proposed a chain mechanism involving fluorine and chlorine atoms as chain carriers [151(b)]. 

Mercury-photosensitised decompositions have been reported for fluorinated methanes , fluorinated ethanes , fluorinated ethylenes , perfluorocyclobu-tene and perfluorobuta-1,3-diene , chlorofluoromethane , dichloromethane (ref. 939), and octafluorobut-2-ene . Acetone has been used for sensitising the decomposition of 1,4-dichlorobutane , chlorobutenes , and allylic halides (the last to cyclopropyl halides) other studies have involved the use of hexafluoroacetone and benzene as sensitisers. 

Representing a two electron covalent bond by a dash (—) the Lewis structures for hydrogen fluoride fluorine methane and carbon tetrafluoride become... 

A similar analysis for fluorination of methane gives AH° = -426 kJ for its heat of reaction Fluori nation of methane is about four times as exothermic as chlorination A reaction this exothermic if it also occurs at a rapid rate can proceed with explosive violence... 

The physical properties of hydrofluorocarbons reflect their polar character, and possibly the importance of intermolecular hydrogen bonding (3). Hydrofluorocarbons often bod higher than either their PFC or hydrocarbon counterparts. For example, l-C H F bods at 91.5°C compared with 58°C for n-Q and 69°C for Within the series of fluorinated methanes, the boiling point reaches a maximum for CH2F2, which contains an equal... 

Properties. The physical properties of aHphatic fluorine compounds containing chlorine are similar to those of the PECs or HECs (3,5). They usually have high densities and low boiling points, viscosities, and surface tensions. The irregularity in the boiling points of the fluorinated methanes, however, does not appear in the chlorofluorocarbons. Their boiling points consistently increase with the number of chlorines present. The properties of some CECs and HCECs are shown in Tables 3 and 4. 

Flammability (e.g. hydrogen, acetylene, methane), toxicity (e.g. carbon dioxide, fluorine), or chemical reactivity (fluorine, oxygen). 

Strong acids or superacid systems generate stable fluorinated carbocations [40, 42] Treatment of tetrafluorobenzbarrelene with arenesulfonyl chlorides in nitro-methane-lithium perchlorate yields a crystalline salt with a rearranged benzo barrelene skeleton [43] Ionization of polycyclic adducts of difluorocarbene and derivatives of bornadiene with antimony pentafluonde in fluorosulfonyl chloride yields stable cations [44, 45]... 

Hydrogen fluoride Fluorine Methane Carbon tetrafluoride... 

Write the balanced chemical equation for the complete fluorination of methane to tetrafluoromethane. Using bond enthalpies, estimate the enthalpy of this reaction. The corresponding reaction using chlorine is much less exothermic. To what can this difference be attributed ... 

Tab.3 - Calculated energies (hartree) of ground and carbon hole states for fluorinated methanes and optimized scale factors.

Tab.4 - Binding energies (eV) of carbon core electrons in fluorinated methanes.

This element can never be controlled. Fluorine reacts violently with solid methane at -190°C. With liquid hydrocarbons at -210°C, the reaction is dangerous. All hydrocarbons react dangerously, from the first homologues to anthracene as well as lubricants. In the gaseous state, there is ignition with small quantities, and detonation with large quantities and when the mixture is made quickly. There is immediate detonation with alkenes and alkynes. With benzene, when fluorine is incorporated bubble by bubble and at a low temperature, this causes ignition on the surface. If the flow rate is substantial, there is immediate detonation. 

Chlorine dioxide Copper Fluorine Hydrazine Hydrocarbons (benzene, butane, propane, gasoline, turpentine, etc) Hydrocyanic acid Hydrofluoric acid, anhydrous (hydrogen fluoride) Hydrogen peroxide Ammonia, methane, phosphine or hydrogen sulphide Acetylene, hydrogen peroxide Isolate from everything Hydrogen peroxide, nitric acid, or any other oxidant Fluorine, chlorine, bromine, chromic acid, peroxide Nitric acid, alkalis Ammonia, aqueous or anhydrous Copper, chromium, iron, most metals or their salts, any flammable liquid, combustible materials, aniline, nitromethane... 

Few SF5-substituted saturated hydrocarbons have been reported. On the basis of the methane and ethane derivatives in Scheme 7.22, it appears as if the equatorial b-fluorines of the ab4 system are much more... 

Violent explosions occur when fluorine directly contacts liquid hydrocarbons, even at —210 with anthracene or turpentine, or solid methane at — 190°C with liquid fluorine. Many lubricants ignite in fluorine [1,2]. Contact and reaction under carefully controlled conditions with catalysis can now be effected smoothly [3], Gaseous hydrocarbons (town gas, methane) ignite in contact with fluorine, and mixtures with unsaturated hydrocarbons (ethylene, acetylene) may explode on exposure to sunlight. Each bubble of fluorine passed through benzene causes ignition, but a rapid stream may lead to explosion [4],... 

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