2 : 3-Dimethylbutane Compound

Hexane refers to the straight-chain hydrocarbon, C H branched hydrocarbons of the same formula are isohexanes. Hexanes include the branched compounds, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, and the straight-chain compound, / -hexane. Commercial hexane is a narrow-boiling mixture of these compounds with methylcyclopentane, cyclohexane, and benzene (qv) minor amounts of and hydrocarbons also may be present. Hydrocarbons in commercial hexane are found chiefly in straight-mn gasoline which is produced from cmde oil and natural gas Hquids (see Gasoline AND OTHER MOTOR fuels Gas,natural). Smaller volumes occur in certain petroleum refinery streams. 

Higher molecular compounds, such as benzene, cyclopentane, methylcyclo-pentane, cyclohexane, methylcyclohexane, isopentane, and 2,3-dimethylbutane... 

A careful examination of the results given in Tables 7 and 8 reveal that with the exception of 2,3-dimethyl-2-butene (in the case of 47) only cyclic guest molecules are taken up into the lattices of the host compounds 46-48, but not the respective open-chain analogues. Saturated 2,3-dimethylbutane, as a compound for comparison, is not accommodated either, either by 46 or by 47. Moreover, only cycles with distinct ring sizes (five- to eight-membered rings) are effective, indicating the presence... 

Rearrangements may also proceed via intermediates that are essentially cations, anions, or radicals, though those involving carbocations, or other electron-deficient species, are by far the most common. They may involve a major rearrangement of the carbon skeleton of a compound, as during the conversion of 2,3-dimethylbutan-2,3-diol (pinacol, 42) into 2,2-dimethylbutan-3-one (pinacolone, 43, cf. p. 113) ... 

Alkenes with a 1,1-disubstitution pattern form tertiary carbocations upon treatment with a Brpnsted acid. Consequently, such compounds are often easily reduced (Eq. 72). An example of this is the formation of 2-methylpentane in 93% yield after only 5 minutes when a dichloromethane solution of 2-methyl-1-pentene and 1.4 equivalents of triethylsilane is treated with 1.4 equivalents of trifluoromethanesulfonic acid at —75°.216 Similar treatment of 2,3-dimethyl-l-butene gives a 96% yield of 2,3-dimethylbutane.216... 

These reaction conditions also permit the chemoselective quantitative reduction of benzaldehyde to benzyl alcohol without any concomitant reduction of either acetophenone or 3,3-dimethylbutan-2-one present in the same reaction mixture.83 Additionally, this useful method permits the reduction of aldehyde functions in polyfunctional compounds without affecting amide, anhydride, eth-ylenic, bromo, chloro, or nitro groups.79,80,319... 

These compounds are 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane and 2,3-dimethylbutane, respectively. These four, along with the original n-hexane, are the only isomers. If you think you have another isomer, you have simply redrawn one of these. Try naming your answer and see if it matches one of these names. 

Photolytic. Major products reported from the photooxidation of 2,3-dimethylbutane with nitrogen oxides are carbon monoxide and acetone. Minor products included formaldehyde, acetaldehyde and peroxyacyl nitrates (Altshuller, 1983). Synthetic air containing gaseous nitrous acid and exposed to artificial sunlight (A. = 300-450 nm) photooxidized 2,3-dimethylbutane into acetone, hexyl nitrate, peroxyacetal nitrate, and a nitro aromatic compound tentatively identified as a propyl nitrate (Cox et al., 1980). 

Rank the following compounds in their entropies, from the lowest to the highest, and provide reasons for your ranking normal hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane. 

Use the structure-reactivity relationship approach to calculate the rate constants for the reactions of N03 with the following compounds and calculate the percentage difference from the recommended values in Table 6.3 (a) n-butane, (b) 2-methylbutane, (c) n-hexane, (d) 2,3-dimethylbutane, (e) n-octane, (f) n-non-ane. 

The exchange of a number of compounds in this category with deuterium has been examined by Burwell and his colleagues. n-Heptane has been exchanged over nickel-keiselguhr (43), reduced nickel oxide (29), a series of nickel catalysts of varying crystallite size (37), and over palladium supported on 7-alumina (43). Less extensive studies were also made with 2,3-dimethylbutane (29, 43) and n-hexane (42). 

Fig. 5. Rate of H—D exchange versus ionization potential of alkanes and aromatic compounds 1 = methane 2 = ethane 3 = propane 4 = n-butane 5 = n-pentane 6 = n-hexane 7 = cyclopentane 8 = cyclohexane 9 = benzene 10 = naphthalene 11 = phenanthrene 12 = 2,2-dimethylbutane (see text) 13 = 1,1-dimethylpropy I benzene (see text) 14 = 2-methylpropane 15 = 2-methylbutane 16 = 2,2-dimethylpropane 17 = 2-methylpentane 18 = 3-methylpentane 19 = 2,3-dimethylbutane 20 = 2,2-dimethylbutane.

Dimethylbutane and 2,3-dimethylbutane in Magic Acid—S02C1F solution at —78°C give the same distribution of products, a roughly 3 2 mixture of dimethyl-isopropylcarboxonium ion (19) and protonated acetone (20)67 (Scheme 9.5). This clearly demonstrates that, in contrast with the transformation of the abovementioned compounds, ozonation in this case proceeds via the intermediate carbocation 18. 

Cyclobutanes are less reactive compounds, undergoing ring opening according to the 1,2-dicarbene mechanism through a,a,(3, (3-tetraadsorbed intermediates (40) when CH2—CH2 bonds are present.297,298 One particular exception is cis-1,2-dimethylcyclobutane, which always yields 2,3-dimethylbutane as the main product. This was interpreted to occur via a jr-adsorbed alkene that is readily formed from the cis compound [Eq. (11.83)] due to the presence of vicinal cis hydrogens, but not from the trans isomer ... 

The halogen compounds used were methylene dichloride, chloroform, carbon tetrachloride, ethylene dichloride, ethyl bromide, ethylene dibromide, bromoform, methyl iodide, and ethyl iodide. The hydrocarbons selected for their interesting combustion properties were hexane, 2-methylpentane, 2,2-dimethylbutane, hex-l-ene, heptane, methylcyclo-hexane, isooctane, diisobutylene, benzene, toluene, m-xylene, and ethylbenzene. 

Woodall453 also examined the Hg-sensitized decomposition of z-C4H10, n-C4H10, and 2,2-dimethylbutane. In the presence of NO, the first compound yielded (CH3)3C=NO the latter two compounds yielded oximes, presumably via isomerization of the appropriate precursor nitroso compounds. 

Free rotation generally occurs around C—C single bonds (see Section 1-1E). Thus the following structural formulas are of the same compound, 2,3-dimethylbutane, because rotation about the central C—C bond makes the structures identical ... 

Identifying this monochloride derivative gives us the carbon skeleton. The starting alkane (compound A) must be 2,2-dimethylbutane. Its free-radical halogenation gives three different monochlorides ... 

Treatment of 3-iodo-2,2-dimethylbutane with alcoholic potassium hydroxide should bring about E2 elimination to regenerate the starting alkene. Hence, compound A is 3-iodo-2,2-dimethylbutane. 

Reaction with ketone and imine functionalities was studied in detail for silylene 85. Reaction of this silylene with ketones such as benzophenone, 3,3-dimethylbutan-2-one, and 2-adamantan-2-one afforded the disilaoxetane compounds 139 in high yields (Scheme 15). The formation of these products most likely occurs via a [2+1] cycloaddition to form a short-lived oxasilacyclopropane intermediate 140, which further reacts with a second silylene to form the final product C19970M4861, 1997PS537>. 

The synthesis was performed according to Scheme 9.3. 1,2-Bis (2-methyl-1-ben-zothiophen-3-yl)perfluorocyclopentene (9a) was formylated with dichloromethyl methyl ether to give diformyl compound 14, which treated with 2,3-bis(hydroxy-amino)-2,3-dimethylbutane sulfate followed by sodium periodate. Compound 10a was obtained and purified by column chromatography and gel permeation chromatography (GPC). Recrystallization from hexane-CH2Cl2 gave dark-blue plate crystals of 10a. 

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