In this lab, 4-methylcyclohexene was synthesize from 4-methylcyclohexanol with phosphoric acids via the E1 mechanism. With a fair percent yield of 52.16%, success of our reaction was verified by IR spectroscopy analysis and unsaturation tests.
Our IR showed C-H vinyl stretches near 3050 cm-1, aliphatic C-H stretches near 2900 cm-1, C=C stretches near 1650 cm-1, C-H bending vibrations near 1455 cm-1, and no broad absorption peak at 3200-3700 cm-1, where the OH functional group of the original 4-methylcyclohexanol should show itself.
Success of the alcohol dehydration was further verified with unsaturation tests. When the first ten Br2 drops were added, the product ...view middle of the document...
542 g 4-methylcyclohexene. This was only a 52.16% yield due to random error. It may be attributed to random laboratory errors such as losing product during transfer, boiling off product during distillation, and incorrect measurements.
Experimental IR: Literature IR:
C-H vinyl stretch
IR spectroscopy was performed on the isolated 4-methylcyclohexene sample. As shown above, the experimental IR (Appendix 2) corresponds quite well to the literature IR. It is important to note the presence of the C=C stretch in the mid-1600 range because it proved the formation of an alkene. The C-H vinyl stretches to the left of 3000 indicate an aromatic ring. Also, there are no C-O or O-H stretching vibrations as are seen in the literature IR spectrum for the reactant, 4-methylcyclohexanol between 1300-1000 and 3650-3000, respectively.
Unsaturation Test Data:
Br2 2 drops, turned brown 10 drops,...