Isopentyl Acetate Synthesis

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Isopentyl Acetate Synthesis

Results:

Crude % Yield Calculation

Reaction:

H2SO4
C2H4O2(aq) + C5H12O(aq) ----> C7H14O2(aq) + H2O(l)

(1 mole of acetic acid reacts with 1 mole of isopentyl alcohol to make 1 mole of isopentyl acetate and 1 mold of water)

Volume of isopentyl alcohol (d=0.809g/mL; MW=88.15g/mol): 2.5mL
Moles of isopentyl alcohol: (2.5mL)(0.809g/1mL)(1mol/88.15g) = 0.02294mol

Volume of glacial acetic acid (d=1.06g/mL; MW=60g/mol): 3.5mL
Moles of glacial acetic acid: (3.5mL)(1.06g/1mL)(1mol/60g) = 0.06183mol

Therefore, the acetic acid is in excess, which makes the isopentyl alcohol the limiting reagent.

The theoretical yield is:

Molecular weight of isopentyl acetate is 130.19g

(0.02294mol isopentyl alcohol)(1 mol isopentyl acetate/1mol isopentyl alcohol)(130.19g/1mol)=2.9866g

The observed yield is:

Weight of 3mL conical vial: 20.0005g
Weight of 3mL conical vial with crude ester product: 21.6993g Weight of crude ester product: 1.6988g

Therefore, the crude % yield is:

Crude % yield = (observed/theoretical)x100%
= (1.6988g/2.9866g)x100%
= 56.88%

Discussion:
The synthesized product, isopentyl acetate, is made by the reaction of isopentyl alcohol and glacial acetic acid with sulfuric acid (H2SO4) as the catalyzing agent. The crude ester produced in lab was isopentyl acetate, because first, the product smelled of bananas and second, the IR spectrum for the product shows that the product is isopentyl acetate. As for the purity of the product, the distillation of the crude ester showed that its boiling point was supposed to be 130°C - 140°C and the boiling points of the impurities that could have been in the crude ester have lower boiling points. Therefore, since the crude product had a boiling point of 124°C, it indicated that there were some impurities in the crude product. When looking at the IR spectrum, it can be seen that there is no spike around 3235cm-1, which...
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