Alkanes hexafluorophosphate

The kinetics and mechanism of iV-nitration reactions have been reviewed and the nitration of alkanes with nitronium hexafluorophosphate in CH2CI2 or EtN02 has been shown to involve direct electrophilic insertion of NO2+ into C-H and C-C a-bonds. ... 

ILs based on the l-alkyl-3-methyIimidazoIium cation, [C CiIm] , or tetra-alkylammonium cation, [(C )4N]l are among the most popular and commonly studied or used in technological improvements. As for the anions, l7is(trifluoromethylsulfonyl)imide, [Tf2N], and alkylsulfate, [C S04] (n = 1, ll 8), are much superior compared to the more commonly investigated hexafluorophosphate, [PFg] , and tetrafluoroborate, [BF4], being hydrolytically stable and less viscous. Comparing the results of the solubility of ILs in typical solvents from different publications, it can be concluded that the miscibility gap in the liquid phase increases in the order alcohol < aromatic hydrocarbon < cycloalkane < n-alkane [50-54,66,78,79,95-100,127-136]. 

A further step towards optimised conditions in the catalytic transfer hydrogenation of alkenes was achieved with the introduction of the ionic liquid N-butyl-N -methylimidazolium hexafluorophosphate (BMIMPFg) as a solvent. The reduction of alkenes with formates and Pd/C in BMIMPF6 leads to saturated hydrocarbons in high yields. With an alkyne, a mixture of cis/trans alkenes and the saturated alkane was obtained (Scheme 4.5). Sufficiently pure products were isolated by a simple liquid-liquid... 

The iodide salt is insoluble in benzene, alkanes, carbon tetrachloride, or diethyl ether but is easily soluble in water, methanol, acetone, or methylene chloride. It can be recovered from methylene chloride in nearly quantitative yield by precipitation with ether. The hexafluorophosphate dissolves in the same solvents as does the iodide, with, the exception of cold water, in which it is only slightly soluble (about 0.01 M). The cation is stable in aqueous HC1 or NaOH but rapidly loses trimethyl-amine in pyridine solution. It can be chlorinated or brominated on boron by the elements in methylene chloride. The hexa-... 

A solution of a stable nitronium salt (generally the hexafluorophosphate NOa PF but also the hexafluoroantimonateNO SbFft ortetrafiuoroborate NO2BF4) in methylene chloride-tctramethylene sulfone solution was allowed to react with the alkane (cycloalkane), with usual precautions taken to avoid moisture and other impurities. Reactions were carried out at room temperature (25°C) in order to avoid or minimize the possibility of radical side reactions and/or protolytic cleavage reactions (tertiary nitroalkanes particularly readily undergo protolytic cleavage, even if the system initially is acid free but nitration forms acid). Data obtained are summarized in Table XXI. 

The employment of suitable organic solvents, such as acetonitrile and acetic acid, with oxidation-resistant supporting electrolytes permits the anodic formation of reactive radical cations from many organic materials. Most aromatic compounds and olefins, as well as those alkanes which have particularly weak C—H bonds, are oxidised in acetonitrile containing fluoroborate or hexafluorophosphate electro-lytes. °" 2 Some aromatic radical cations can be further oxidised to dications within the available potential range. Radical cations in general either deprotonate or attack nucleophiles present in the medium reactions with pyridine, methanol, water, cyanide ion, acetate ion or acetonitrile itself produce addition or substitution products. The complete reactions involve a second electron transfer and coupled chemical... 

Acetonitrile has a very anodic decomposition potential. Exchange of the perchlorate anion against tetrafluoroborate or hexafluorophosphate shifts the anodic decomposition potential (ImAcm" ) of acetonitrile from 2.48 to 2.91 or 3.02 V vs Ag/Ag, respectively. In acetonitrile/TEABF4 some half-wave potentials have been determined to be 3.0 V for i-pentane, 3.01 V for 2-methylpentane, 3.28 V for 2,2-dimethyl-butane and >3.4V for n-octane, n-heptane and n-hexane. The half-wave potentials of some alkanes have also been obtained by the use of ultramicroelectrodes in acetonitrile without any supporting electrolyte the values range from 3.87 V for methane to 3.5 V for n-heptane vs Ag/Ag. These values correlate well with the ionization potentials of the alkanes". Controlled potential electrolyses were carried out on saturated solutions of four alkanes in acetonitrile 0.1 M TBABF4 to yield acetamidoalkanes (Table 5). ... 

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