15869-96-2Relevant articles and documents
Alkyl cyclobutane fuels
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Page/Page column 6-9, (2020/04/15)
A method for making an alkyl cyclobutane fuel, which includes obtaining a solution of at least one alpha olefin. A catalyst is added to the solution, thereby generating a mixture of dimers. The mixture is hydrogenated, thereby converting the dimers to hydrogenated dimers. The mixture is purified to produce an alkyl cyclobutane fuel.
Addition reactions of organometallic reagents to nitrogen trifluoride and enhanced alkyl-alkyl coupling by NF3
Belter, Randolph K.
, p. 110 - 113 (2015/04/27)
A survey of the reaction of nitrogen trifluoride (NF3) with various organometallic reagents finds that organomagnesium (Grignard) reagents are the most useful for producing N,N-difluoroaminoalkanes. Alkyl-alkyl coupling is a persistant side reaction. Organolithiums are marginally effective. Organocopper, organozinc reagents undergo primarily alkyl-alkyl coupling catalyzed by the presence of NF3. Organocalcium and organoaluminum reagents are unreactive.
Ultrasound promoted Wurtz coupling of alkyl bromides and dibromides
Vandenburg, Daniel,Price, Gareth J.
experimental part, p. 5 - 8 (2012/04/04)
Sonochemically enhanced Wurtz coupling using lithium metal has been investigated for a number of isomeric alkyl bromides under a variety conditions. The products result from direct coupling of short lived radicals formed at the metal surface rather than the secondary radicals which can be formed during coupling of aromatic halides and thus give rise to a single major product. Coupling has been extended to dibrominated aryl and alkyl compounds as well as showing that aryl-alkyl coupling is possible. Dibrominated alkyls were found to give low molecular weight oligomers although no reaction occurred for 1,2-isomers. The growth of oligomers in THF may be solubility limited. A simple model is proposed to explain these findings.
Ring opening of decalin via hydrogenolysis on Ir/- and Pt/silica catalysts
Haas, Andreas,Rabl, Sandra,Ferrari, Marco,Calemma, Vincenzo,Weitkamp, Jens
experimental part, p. 97 - 109 (2012/07/13)
The catalytic conversion of cis-decalin was studied at a hydrogen pressure of 5.2 MPa and temperatures of 250-410 °C on iridium and platinum supported on non-acidic silica. The absence of catalytically active Br?nsted acid sites was indicated by both FT-IR spectroscopy with pyridine as a probe and the selectivities in a catalytic test reaction, viz. the hydroconversion of n-octane. On iridium/silica, decalin hydroconversion starts at ca. 250-300 °C, and no skeletal isomerization occurs. The first step is rather hydrogenolytic opening of one six-membered ring to form the direct ring-opening products butylcyclohexane, 1-methyl-2-propylcyclohexane and 1,2- diethylcyclohexane. These show a consecutive hydrogenolysis, either of an endocyclic carboncarbon bond into open-chain decanes or of an exocyclic carboncarbon bond resulting primarily in methane and C9 naphthenes. The latter can undergo a further endocyclic hydrogenolysis leading to open-chain nonanes. All individual C10 and C9 hydrocarbons predicted by this direct ring-opening mechanism were identified in the products generated on the iridium/silica catalysts. The carbon-number distributions of the hydrocracked products C9- show a peculiar shape resembling a hammock and could be readily predicted by simulation of the direct ring-opening mechanism. Platinum on silica was found to require temperatures around 350-400 °C at which relatively large amounts of tetralin and naphthalene are formed. The most abundant primary products on Pt/silica are spiro[4.5]decane and butylcyclohexane which can be readily accounted for by the well known platinum-induced mechanisms described in the literature for smaller model hydrocarbons, namely the bond-shift isomerization mechanism and hydrogenolysis of a secondary-tertiary carboncarbon bond in decalin.
Hydrogen Atoms as Convenient Synthetic Reagents: Mercury-Photosensitized Dimerization of Functionalized Organic Compounds in the Presence of H2
Muedas, Cesar A.,Ferguson, Richard R.,Brown, Stephen H.,Crabtree, Robert H.
, p. 2233 - 2242 (2007/10/02)
Hydrogen atoms are generated by mercury photosensitization in an unexceptional apparatus that makes them readily available for organic chemistry on a preparatively useful scale at 1 atm of pressure and temperatures from 0-150 °C. The H atoms add to CH2=CH-CH2X to give the intermediate radical CH3-(?CH)-CH2X, which dimerizes to give CH3CH(CH2X)-CH(CH2X)CH3. The saturated substrates CH3CH2CH2X undergo H abstraction to give CH3CH2(?CH)X as intermediates and CH3CH2CH(X)-CH(X)CH2CH3 as final products. The reaction shows a tolerance for different functional groups, X, which may be an alkyl or fluoroalkyl chain or contain vinyl, epoxy, ester, ketone, nitrile, and silyl groups. Radical disproportionation products are also formed but are easily separated. H atoms attack the weakest C-H bonds of the substrates with high selectivity. In our earliest direct mercury photosensitization, Hg* often failed to attack the substrate C-H bonds to give dimers; the presence of H2 strongly suppresses direct Hg* chemistry. H atoms are not sensitive to steric or polar effects Radical fragmentation is avoided by using "high" pressures (1 atm). Intramolecular radical additions to C=C bonds and methyl group 1,2-shift were also seen in some cases. Exceptional product ratios are observed for cross-reactions involving hydroxyalkyl radicals where H-bonding favors the homodimers in certain cases. Several bond strengths of C-H bonds α to CO were determined: EtCO2Me, 94.5; i-PrCO2Me, 92.7; cyclopentanone, 94.3; (i-Pr)2CO, 91.9 kcal/mol.
Making Mercury-Ptotosensitized Dehydrodimerization into an Organic Synthetic Method: Vapor Pressure Selectivity and the Behavior of Functionalized Substrates
Brown, Stephen H.,Crabtree, Robert H.
, p. 2935 - 2946 (2007/10/02)
Mercury-photosensitized dehydrodimerization in the vapor phase can be made synthetically useful by taking advantage of a simple reflux apparatus (Figure 1), in which the products promptly condense and are protected from further conversion.This vapor pressure selectivity gives high chemical selectivity even at high conversion and on a multigram scale.Mercury absorbs 254-nm light to give the 3P1 excited state (Hg*), which homolyses a C-H bond of the substrate with a 3o>2o>1o selectivity.Quantitative prediction of product mixtures in alkane dimerization and in alkane-alkane cross-dimerizations is discussed.Radical disproportionation gives alkene, but this intermediate is recycled back into the radical pool via H atom attack, which is beneficial both for yield and selectivity.The method is very efficient at constructing C-C bonds between highly substituted carbon atoms, yet the method fails if a dimer has four sets of obligatory 1,3-syn methyl-methyl steric repulsions, as in the unknown 2,3,4,4,5,5,6,7-octamethyloctane.We have extended the range of substrates susceptible to the reaction, for example to higher alcohols, ethers, silanes, partially fluorinated alcohols, and partially fluorinated ethers.We see selectivity for dimers involving C-H bonds α to O or N and for S-H over C-H.An important advantage of our experimental conditions in the case of alcohols is that the aldehyde or ketone disproportionation product (which is not subject to H. attack) is swept out of the system by the stream of H2 also produced, so it does not remain and inhibit the rate and lower the selectivity. kdis/krec is estimated for a number of radicals studied.The very hindered 3o 1,4-dimethylcyclohex-1-yl radical is notable in having a kdis/krec as high as 7.1.
One-Electron Chemical Reductions of Phenylalkylsulfonium Salts
Beak, Peter,Sullivan, Thomas A.
, p. 4450 - 4457 (2007/10/02)
Twenty-two arylalkylsulfonium salts have been reduced with potassium in graphite in tetrahydrofuran and the sulfide products identified.Two trialkylsulfonium salts did not reduce under these conditions.Comparison of the sulfides from a series of monophenylalkylsulfonium salts reveals a leaving-group propensity of benzyl > secondary > primary > methyl > phenyl in a ratio of 28:(6.0 +/- 0.3):1.0:(0.53 +/- 0.09): 0.05.The cleavage ratio is shown to be independent of the electron source and the homogeneity of heterogeneity of the reaction in two cases.Multiplicative transitivity of the above ratios is not observed, although the same qualitative order is found for other comparisons.These results are interpreted in terms of the initial formation of a ?-ligand radical anion sulfonium cation, which undergoes cleavage to a carbon radical and a sulfide.This appears to be the first evidence for this type of structure in a sulfur system.Leaving-group propensities different from the above order are observed in reductions of diphenylsulfonium and benzo-fused sulfonium salts, and rationales are offered.The intermediates in these reactions appear to be different from those involved in radical additions to, or displacements on, sulfur.
