Alkanes cleavage

Alkanes cleavage with Na/Hg, other linkers for alkanes [112, 113, 120-122, 197[... 

O n hn- h Alkenes and alkanes cleavage by reducing media or bases [198]... 

Alkanes cleavage to give the most stable carbocations (Section 12-15A)... 

Reaction between 1-alkynes and trialkyl alanes goes uniquely in the sense of alkane cleavage if trialkylaminetrialkyl alanes are used. At 100°-120°C, trialkylaminedialkylalkynyl alanes are obtained in practically quantitative yield (31) ... 

Tertiary C-H tonds show the highest reactivity. C-C bonds are generally more reactive than secondary or primary C-H bonds, leading to preferential nitrolysis of n-alkanes(cleavage nitratlcn) The nitronium ion, which is linear itself, does not seem to exercise excessive steric hindrance in the transition states of the reactions, where it is substantially bent (indicated also from its behavior in electrophilic aromatic substitutions). Side products of the nitrolysis are methyl, ethyl, and isopropyl fluoride (formed by the reaction of PFg with the cleaved alkylcarbenium ions) or secondary alkylation products, themselves capable of undergoing reaction with the nitronium salt. 

We assess the relative stability of alkyl radicals by measuring the enthalpy change (AH°) for the homolytic cleavage of a C—H bond m an alkane... 

Some classes of compounds are so prone to fragmentation that the molecular ion peak IS very weak The base peak m most unbranched alkanes for example is m/z 43 which IS followed by peaks of decreasing intensity at m/z values of 57 71 85 and so on These peaks correspond to cleavage of each possible carbon-carbon bond m the mol ecule This pattern is evident m the mass spectrum of decane depicted m Figure 13 42 The points of cleavage are indicated m the following diagram... 

Alkyl halides can be reduced to alkanes by a radical reaction with tributyltin hydride, (C4H9)3SnH, in the presence of light (hv). Propose a radical chain mechanism by which the reaction might occur. The initiation step is the light-induced homolytic cleavage of the Sn— H bond to yield a tributyltin radical. 

Duffield and coworkers65 studied the El- induced mass spectra of five arene- (215-219) and four alkane sulfonylthioureas (220-223) and observed two rearrangement processes, namely loss of S02 from 215-219 and the elimination of ArS02 and RS02 with the thione sulfur atom from 215-223. The other fragmentations involved simple bond cleavages with and without hydrogen transfer (equation 48). The loss of H2S was evident for all the compounds studied except 221 and 222. It was, however, found to be a thermal and not an ionization process. 

Denig [118] has reported that the length and structure of the hydrocarbon chains of AOS may be determined by cleavage of the sulfo groups in presence of excess phosphorus pentoxide and hydrogenation of the hydrocarbons before determining the -alkanes and isoalkanes by pyrolysis gas chromatography. 

Nitration of alkanes can be carried out in the gas phase at 400°C or in the liquid phase. The reaction is not practical for the production of pure products for any alkane except methane. For other alkanes, not only does the reaction produce mixtures of the mono-, di-, and polynitrated alkanes at every combination of positions, but extensive chain cleavage occurs. A free-radical mechanism is involved. ... 

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