Preparation 4-Methylcyclohexene
Introduction: The goals in this lab were to have a reaction occur with 4-methylcyclohexanol and an acid catalyst to form our product of 4-methylcyclohexene via an E1 reaction. This reaction is accomplished by removing the –OH group on 4-methylcyclohexanol via dehydration and to have a double bond form via a loss of a hydrogen on a β-Carbon. Many techniques and skills were developed in this lab. Among them were dehydration, isolation, drying, and distillation. We used all of these techniques to get the product we were looking for. In addition to these experimental techniques we also verified our product via spectroscopy which is a new technique. Using IR spectroscopy we were able to specifically analyze the functional groups on our product.
Results and Discussions:
Reaction Equation:
Theoretical Yields: Based on limiting moles of product -Based on C7H14O 24 mL C7H14O x (0.910 g C7H14O/1 mL C7H14O) x (1 mol C7H14O/114.19 g C7H14O) = 0.191 mol C7H14O 0.191 mol C7H14O x (1 mol C7H12/1 mol C7H14O) = 0.191 mol C7H12 C7H14O is the Limiting Reagent -The acids are not counted as reagents in this reaction and serve only as catalyst.
Theoretical Yield = mol of limiting reagent x M.W. = 0.191 mol x 96.17 C7H12 = 18.39 g C7H12
Actual Yield: 10.27 g C7H12
Percent Yield: (Actual/Theoretical) x 100% = (10.27/18.39) x 100% = 55.83 %
Analytical Data: -Boiling Point: The liquid had a boiling point between 101°C and 102 °C. According to Paula, Lampman, Kriz, and Engel, Introduction to Organic Techniques, 2004 3rd Ed. Experiment 24: Preparation of 4-Methylcyclohexene, pg 193 the boiling point of the compound should be between 100 and 105 °C. Our value is very close indicating a pretty pure substance. Impurities in the desired substance can alter the boiling point. - Looking at the liquid