The Effect Of Distillation On Boiling Points And Vapor Pressure

1708 WordsApr 9, 20177 Pages
Distillation is a technique used in chemistry to isolate/purify a mixture of liquid chemicals based on boiling points and vapor pressure.1 In this experiment, various isomers of methylcyclohexene were synthesized from 2-methylcyclohexanol via an alcohol dehydration E1 elimination reaction. This reaction is in an equilibrium state, and therefore, distilling and then condensing the product as the reaction progresses allows for a higher yield due to Le Chatelier 's principle. Simple distillation was preformed due to time constraints, and the two chemicals varied in boiling points by approximately 60 oC. This technique is very common in organic chemistry, for it allows a mixture of miscible liquids with different boiling points to be…show more content…
IR spectroscopy is able to determine if starting material was co-distilled due to 2-methycyclohexanl’s alcohol functional group that creates a distinct signal in the 3200 cm-1 to 3600 cm-1 range, which does not appear for the methylcyclohexene products. Also, GC is an adept method to analyze a mixture of compounds and determine the proportion of chemicals in a solution. This allows for the identification of all three products and the potential to identify impurities due to co-distillation. Both of these analytical tests are more beneficial than HNMR spectroscopy, which would not provide as much of an insight to the composition of the distillate solution and the relative amounts of each chemical that is present. The synthesis of the methylcyclohexene products from 2-methylcyclohexanol occurs through an E1, unimolecular elimination reaction. The first step in this reaction mechanism involves the protonation of the alcohol group in the starting material. The oxygen of this alcohol performs a nucleophilic attack on a hydrogen from the phosphoric acid and gains a positive charge. Then, the pronated alcohol, which is now a good leaving group, leaves the cyclohexane ring and creates a positive charge on the carbon to which it was
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