2 : 3-Dimethylbutane

Using the procedure described above as your model, design and execute an experimental protocol for monochlorinating 2,3-dimethylbutane and determining the ratio of chlorodimethylbutanes produced. Also describe how you would analyze the mixture for the presence of polychloro isomers. Check with your instructor before undertaking any experimental work. 

Combine all of the aqueous solutions. If the resulting solution is acidic, neutralize it carefully with solid sodium carbonate and flush it down the drain with a large excess of water. Rinse the glasszvool from the gas trap with aqueous 0.5 M sodium carbonate and discard it in the trash. Put the sodium sulfate in a container for solids contaminated with alkyl halides. 

Define and provide a specific example of each of the following terms propagation step initiation step bond homolysis limiting reagent 

What is the fundamental difference between a reaction mechanism that uses single-headed arrows vs. one that uses half-headed (fish-hook) arrows  

Using curved arrows to symbolize the flow of electrons, write the complete mechanism for the formation of 1,3-dichlorobutane from 1-chlorobutane using ABCN (1) and sulfuryl chloride. Clearly label each step as to whether it is part of the initiation, propagation, or termination steps. 

PROPERTIES RESEARCH GRADE PURE GRADE TECHNICAL GRADE 

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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. 

Gas separation performances (H2/n-butane, n-hexane/2-2 dimethylbutane) have been measured using a sweep gas (countercurrent mode) in order to increase the permeation driving force (no differential pressure was used) permeate and retentate compositions (see Figure 2) were analysed using on line gas chromatography. 

When introducing a mixture of n-hexane and 2-2 dimethylbutane (45/55 molar ratio), almost only n-hexane permeates the permeate contains up to 99.5% of the linear isomer (Figure 10). 

Figure 10. N-hexane ( ) / 2-2 dimethylbutane ( ) separation with the composite zeolite-alumina membrane (fluxes in the permeate as a function of the temperature). A mixture of n-hexane. 2-2 dimethylbutane and nitrogen (5 6 89) was fed in the tube (Fig. 2) with a flow rate of 2 1/h. Sweep gas (N2), countercurrent mode, flow rate 0.5 1/h.

Molecular sieving effect of the membrane has been evidenced using a mixture of two isomers (i.e. no Knudsen separation can be anticipated), n-hexane and 2-2 dimethylbutane (respective kinetic diameters 0.43 and 0.62 nm). Figure 10 shows the permeate contains almost only the linear species, due to the sieving effect of the zeolite membrane (pore size ca 0.55 nm). This last result also underlines that the present zeolite membrane is almost defect-fi ee. 

Comparing the product selectivity at low conversion in the hydrogenolysis of 2,2-dimethylbutane for the two catalysts is noteworthy. Zirconium hydride supported on siUca does not produce neopentane, but only isopentane (10%) as a Cs product in agreement with a /1-alkyl transfer as a key step for the carbon-carbon cleavage (no neopentane can be formed through this mechanism, Scheme 25). 

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