Experiment 22 – Synthesis of 4-Methylcyclohexene – Name
OH
H3PO4, H2SO4 (cat)
heat
CH3
CH3
1. Data Table: Fill in the appropriate spaces in the data table below. Under the Amount
column, use g for solids, mL for liquids. The abbreviation na stands for not applicable. A
mmol is 1/1000th of a mole.
Reagent
Amount
(g or mL)
mmol
4-methylcyclohexanol
Phosphoric Acid
(85% by wt. in water)
Sulfuric Acid
(18 M, 96%)
4-methylcyclohexene
bp (oC)
observed
na
na
na
2. Percent Yield (show calculations on a separate sheet and attach to this page)
Percent yield of distilled product
%
3. Mechanism. On a separate sheet (attach to this report), write a step-by-step
mechanism for the reaction of 4-methylcyclohexanol with sulfuric acid to form 4methylcyclohexene.
4. Questions. On a separate sheet (attach to this report) provide answers to the
following questions.
A.) A by-product, 1-methylcyclohexene, may be formed in fairly small amounts. Give a
stepwise mechanism which would account for the formation of this by-product. Hint:
carbocation rearrangement.
B.) Draw the structure(s) of the major organic product(s) formed in the reaction of
racemic (±) 4-methylcyclohexene with bromine. Provide a complete stepwise
mechanism for the reaction (you only need to show one mechanism). How many
different stereoisomeric products are actually formed?