Hydrocarbons reaction with halogens

A consequence of the presence of reactive halogen species in the troposphere is that because the rate constants for halogen atom, particularly Cl, reactions with hydrocarbons are significantly larger than those for the corresponding OH + HC reactions, hydrocarbons can be effectively removed by reaction with halogen atoms. 

NaCl-soln. 2-phenyl-l-propylmercuric chloride. Y 97%. F. e., also with dialkyl-boranes, s. R. C. Larock and H. C. Brown, Am. Soc. 92, 2467 (1970) anti-Markownikoff hydrohalogenation (cf. Synth. Meth. 24, 560) by reaction with halogen, also reduction to hydrocarbons (cf. Synth. Meth. 15,69) cf. J. J. Tufariello and M. M. Hovey, Am. Soc. 92, 3221 (1970). 

Tetraethyl- and tetramethyl-lead are removed from internal combustion engines by scavenging, i.e., a reaction with halogenated hydrocarbon gasoline ad-... 

Methods of producing B —C bonds include hydroboration, nucleophilic displacement at a boron atom in BX., (X = halogens or B(0R>3) by e.g. a Grignard reagent, and a psewiio-Friedel-Crafts reaction with an aromatic hydrocarbon, BX3, and AICI3. 

This realization led me to study related possible intermolecular electrophilic reactions of saturated hydrocarbons, Not only protolytic reactions but also a broad scope of reactions with varied electrophiles (alkylation, formylation, nitration, halogenation, oxygenation, etc.) were found to be feasible when using snperacidic, low-nucleophilicity reaction conditions. 

Reaction with Organic Compounds. Aluminum is not attacked by saturated or unsaturated, aUphatic or aromatic hydrocarbons. Halogenated derivatives of hydrocarbons do not generally react with aluminum except in the presence of water, which leads to the forma tion of halogen acids. The chemical stabiUty of aluminum in the presence of alcohols is very good and stabiUty is excellent in the presence of aldehydes, ketones, and quinones. 

Reactions other than those of the nucleophilic reactivity of alkyl sulfates iavolve reactions with hydrocarbons, thermal degradation, sulfonation, halogenation of the alkyl groups, and reduction of the sulfate groups. Aromatic hydrocarbons, eg, benzene and naphthalene, react with alkyl sulfates when cataly2ed by aluminum chloride to give Fhedel-Crafts-type alkylation product mixtures (59). Isobutane is readily alkylated by a dipropyl sulfate mixture from the reaction of propylene ia propane with sulfuric acid (60). 

The most versatile method of preparing ethers is the Williamson ether synthesis, particularly in the preparation of unsymmetrical alkyl ethers (12,13). The reaction of sodium alcoholates with halogen derivatives of hydrocarbons gives the ethers ... 

Additions of halogen fluorides to the more electrophilic perfluonnated olefins generally require different conditions Reactions of iodine fluoride, generated in situ from iodine and iodine pentafluoride [62 102 103, /05] or iodine, hydrogen fluoride, and parapeiiodic aud [104], with fluormated olefins (equations 8-10) are especially well studied because the perfluoroalkyl iodide products are useful precursors of surfactants and other fluorochemicals Somewhat higher temperatures are required compared with reactions with hydrocarbon olefins Additions of bromine fluoride, from bromine and bromine trifluonde, to perfluonnated olefins are also known [lOti]... 

Such a molecule, containing alternating single and double bonds, would be expected to be quite reactive. Actually, benzene is quite unreactive, and its chemical properties resemble those of the alkanes much more than those of the unsaturated hydrocarbons. For example, the characteristic reaction of benzene with halogens resembles that of the reaction of the alkanes ... 

We have already seen that triphenylmethyl radical reacts both with itself to form Chichibabin s hydrocarbon (formula II, not the diradical) and with halogens and oxygen. The reactions of the stable radical are important because of the expectation that radicals too unstable to isolate will betray their presence by giving similar products. 

Pyridine ylide/LFP studies of 83-85 in pentane or isooctane afforded carbene lifetimes of 21-24 ns (k 4 to 5 x 107 s 1), similar to the lifetime of dimethylcarbene under these conditions. Unfortunately, these lifetimes are limited by reactions with the hydrocarbon solvents the lifetime of 83 is 1.5 times longer in cyclohexane-d12 than in cyclohexane. The observation that the lifetimes of 55-CI ( 1000 ns) and 55-F (—7000 ns) are considerably longer than those of 83 and 84 could reflect the superior stabilization provided by the halogen spectator substituents of 55, but this conclusion is tentative in the absence of definitive intramolecularly controlled lifetimes for 83-85. 

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