Preparation of Synthetic Banana Oil
The main purpose of this experiment was to synthesize banana oil (isopentyl acetate. ) Ester are often prepared by the Fischer esterification method, which involves heating a carboxylic acid with an alcohol in the presence of an acid catalyst. Theory: Synthesize isopentyl acetate by combining isopentyl alcohol with acetic acid and sulfuric acid and then heating the reaction mixture under reflux for an hour. The alcohol is the limiting reactant, so it should be weighed/ the acids can be measured by volume.
The esterification reaction is reversible, and it has an equilibrium constant of approximately 4. 2. A pure component can be obtained from a mixture by separating it from all other components of the mixture, using procedures that take advantage of differences in solubility, boiling points, acid-base properties, and other characteristics of the components. Because isopentyl acetate is a liquid, the separation and purification operations will differ from those used previously for solid products.
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The water that forms during the reaction will be separated from the ester along with the wash liquids.
Any traces of water that remain are then removed by a drying agent, either magnesium sulfate or sodium sulfate. Because isopentyl alcohol has a lower boiling point than that of isopentyl acetate, and the by-products have higher boiling points, it should be possible- in principle- to remove the alcohol and by-products from the ester by distillation. Isopentyl alcohol should distill first, followed by the ester, and any by-products should remain behind in the pot-the vessel in which the reaction mixture is boiled. Reaction: Reaction:
Acetic acid + isopentyl alcohol isopentyl acetate + water 17 mL150 mmol Weigh 150 mmol of isopentyl alcohol into a round bottom flask of appropriate size, and add boiling chips. Under a hood, add 17 mL of glacial acetic acid, and then carefully mix in 1. 0 mL of concentrated sulfuric acid while stirring. Connect a West condenser to the reaction flask, turn on the cooling water, start the stirrer, and heat the reaction mixture under reflux for one hour after boiling begins. Reflux apparatus When the reaction time is up, allow the reaction mixture to cool to about room temperature.
Turn off the cooling water and remove the reflux condenser. Transfer the reaction mixture to a separatory funnel. Leaving the boiling chips behind, and washes the mixture with 50 mL of water. Drain the aqueous layer, and leave the organic layer in the separatory funnel. Then carefully wash the organic layer with two successive portion of 5% aqueous sodium bicarbonate, draining the aqueous layer after each washing. During the first washing, stir the layers until gas evolution subsides before you stopper the separatory funnel, and vent it frequently thereafter.
Dry the crude isopentyl acetate with anhydrous magnesium sulfate or sodium sulfate, and filter I by gravity. Using standard-taper glassware, assemble an apparatus for standard scale simple distillation. Be sure the thermometer is straight up as shown in the picture below. Distill the crude product, collecting any liquid that distills between 137oC and 143oC. Record the actual boiling range. Wait until the entire thermometer bulb is moist with condensing vapors, liquid is distilling into the receiver, and the temperature is stable.
The final weight obtained of the product is 4. 28 g because the reactant, both have one to one mole, and the percentage yield of the product is 32. 4%. Discussion/Conlusion: Isopentyl acetate was achieved through the method implemented in this experiment. With the use of isopentyl alcohol and acetic acid under the reaction method help to obtain the predicted product. One one this experiment could be developed is to specific precise amount of each compound need to be used in the reaction in order to obtain a better yield of the product.
Procedure required circumspect handling while synthesizing, the sources of the errors that caused the discrepancy may have been from washing and drying the product. A few part of the organic layer might have been removed in the process of removing the aqueous layer, water and sodium bicarbonate. Too much anhydrous sodium sulfate might have been added because the procedure was not specific as to what quantity should be added. Exercise