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This paper details an experiment which serves as an introduction to organic laboratory research. The reaction is the dehydration of a cis, trans mixture of 2-methylcyclohexanols. At intervals of times the reactant mixture is sampled for the cis and trans reactants. At those same intervals of times the receiver flasks of product cyclohexanes being collected are changed, such that sequential fractions of material are obtained. The reactant aliquots are quantitatively assayed by proton NMR, measuring each hydroxyl proton of the isomeric alcohols against the hydroxyl proton of an internal standard amount of cyclohexanol. The product fractions are analyzed for the relative amounts of the three cyclohexene isomers formed, again by proton NMR, this time measuring the vinyl hydrogens of one isomer against another.
The resultant data are then analyzed, such that k and kt are obtained for the kinetic part of the experiment and six relative rate constants, for example f t (1-ene) , are obtained for the regiochemical part of the experiment. Finally six specific rate constants, for example k t (1-ene) are obtained so that the student may rationalize the rate of reaction of a specific alcohol conformer, for example diaxial trans 2-methylcyclohexanol, leading to a particular isomeric cyclohexene, for example 1-methylcyclohexene.
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