Decarboxylative Mechanism
Chem 205
I. Title and Equation: Unimolecular Elimination
+ 2 Isomers
II. Experimental Procedure :
In a flask, 0.081 mol of 2-methycyclohexanol and 3 mL of 85% H3PO4 were mixed. The mixture was boiled under a fractional distillation column, and 7 mL of the distillate was collected. The organic and aqueous layers were separated and the organic layer was dried with anhydrous sodium sulfate. The product was analyzed using GC.
III. Conclusion: In this experiment, 2-methylcyclohexanol was mixed with phosphoric acid with heat, to produce 3 isomers in one solution. This solution was run through a GC to calculate the product distribution. One isomer was such a rarity that it did not register on the GC. 1-methylcyclohexene accounted for 82.9% of the product solution. 17.1% was the 2-methylcyclohexene products.
IV. Questions:
1) What were the isomers of the methylcyclohexene produced from the reaction and what are their relative distribution?
2) Draw a detailed arrow mechanism illustrating how each of the anticipated products could be formed. Use your mechanisms to explain the product distribution represented by your GC analysis.
Most Favored Product
This product has the most substituted double bond and therefore the most favored product.
Second Most Favored Product
This product has the second most substituted double bond.
Least Favored Product
The terminal alkene is the least substituted and therefore the least favored.
3) The starting alcohol consisted of a mixture of stereoisomers. Draw all the possible stereoisomers of 2-methylcyclohexanol.
4) The reaction you carried out is considered to be reversible. Write an equation for the equilibrium constant (Keq) for the reaction in terms of the concentrations of reagents. Give 2 reasons why your reaction favored the formation of alkenes.
We were removing the water and therefore favored the dehydration of the alcohol. Also the
I. Title and Equation: Unimolecular Elimination
+ 2 Isomers
II. Experimental Procedure :
In a flask, 0.081 mol of 2-methycyclohexanol and 3 mL of 85% H3PO4 were mixed. The mixture was boiled under a fractional distillation column, and 7 mL of the distillate was collected. The organic and aqueous layers were separated and the organic layer was dried with anhydrous sodium sulfate. The product was analyzed using GC.
III. Conclusion: In this experiment, 2-methylcyclohexanol was mixed with phosphoric acid with heat, to produce 3 isomers in one solution. This solution was run through a GC to calculate the product distribution. One isomer was such a rarity that it did not register on the GC. 1-methylcyclohexene accounted for 82.9% of the product solution. 17.1% was the 2-methylcyclohexene products.
IV. Questions:
1) What were the isomers of the methylcyclohexene produced from the reaction and what are their relative distribution?
2) Draw a detailed arrow mechanism illustrating how each of the anticipated products could be formed. Use your mechanisms to explain the product distribution represented by your GC analysis.
Most Favored Product
This product has the most substituted double bond and therefore the most favored product.
Second Most Favored Product
This product has the second most substituted double bond.
Least Favored Product
The terminal alkene is the least substituted and therefore the least favored.
3) The starting alcohol consisted of a mixture of stereoisomers. Draw all the possible stereoisomers of 2-methylcyclohexanol.
4) The reaction you carried out is considered to be reversible. Write an equation for the equilibrium constant (Keq) for the reaction in terms of the concentrations of reagents. Give 2 reasons why your reaction favored the formation of alkenes.
We were removing the water and therefore favored the dehydration of the alcohol. Also the