If I have cyclohexene in a hydroboration-oxidation reaction to form cyclohexanol how can I find percentage yield?
I have NaBH4 (0.0610) and boron triflouride etherate (0.0162) and they are in a 4 to 3 ratio to form b2h6 (diborane) so diborane number of moles is based on boron triflouride etherate as its the limiting reagent so then I plug in to the overall reaction 3cyclohexene (0.0594mol) + b2h6 to form 3cyclohexanol. so according to the overall reaction b2h6 is the limiting reagent so will use that to form cyclohexanol using ratio 1:3?
% yield = (actual yield/theoretical yield)*100 = ?
The actual yield is what the problem tells you the reaction produces. The theoretical yield is what you calculate is formed from the stoichiometry.
To calculate the percentage yield of cyclohexanol in the hydroboration-oxidation reaction, you would need the actual yield of cyclohexanol and the theoretical yield. Let's go step-by-step to find the theoretical yield and calculate the percentage yield:
Step 1: Determine the limiting reagent:
You correctly identified that boron trifluoride etherate (BF3·Et2O) is the limiting reagent because it is present in a lower quantity compared to NaBH4. Since the reaction occurs in a 4:3 ratio, we need 4 moles of cyclohexene for every 3 moles of diborane (B2H6). Since you have 0.0162 moles of BF3·Et2O, the number of moles of diborane formed can be calculated using the ratio:
0.0162 moles BF3·Et2O x (3 moles diborane / 4 moles BF3·Et2O) = 0.01215 moles B2H6
Step 2: Calculate the theoretical yield:
Since the reaction occurs in a 1:3 ratio (1 mole of cyclohexene produces 3 moles of cyclohexanol), we can use the number of moles of cyclohexene to determine the theoretical yield of cyclohexanol. You have 0.0594 moles of cyclohexene, so:
0.0594 moles cyclohexene x (3 moles cyclohexanol / 1 mole cyclohexene) = 0.1782 moles cyclohexanol
Step 3: Calculate the percentage yield:
The percentage yield is the actual yield divided by the theoretical yield, multiplied by 100. However, you haven't provided the actual yield of cyclohexanol. The actual yield is determined through experimental measurement.
Once you have the actual yield of cyclohexanol, divide it by the theoretical yield and multiply by 100:
Percentage yield = (actual yield / theoretical yield) x 100
For example, if the actual yield of cyclohexanol is 0.140 moles, then the percentage yield would be:
Percentage yield = (0.140 moles / 0.1782 moles) x 100 = 78.5%
Please note that the actual yield can vary depending on the efficiency of the reaction, purity of reagents, and other experimental factors.