Banana Oil Synthesis

RUNNING HEAD: Synthesis of Banana Oil

Abstract

A reflux apparatus was assembled with a water-cooled condenser and a drying tube. Isopentyl alcohol, glacial acid sulfuric acid is added to a 25 milliliter round bottom flask and attached to the reflux apparatus. The mixture was boiled, the extracted first using water followed by aqueous sodium bicarbonate. The mixture was dried using anhydrous granular sodium sulfate. After dried, the sample was placed in a distillation apparatus and heated. This resulted in 1.8g of pure isopentyl acetate, a 44% yield.

Introduction

Isopentyl acetate is yielded by combining isopentyl alcohol with acetic acid using sulfuric acid as a catalyst. The product is isopentyl acetate also known as banana oil. Banana oil is an ester. Esters can be found in fruits and flowers’ scents. When water is added to an ester, the process can be reversed and a carboxylic acid can be formed.

In order for a substance to be boiling for a long period of time, a reflux apparatus should be used in order for liquid not to be loss. As vapors rise from the boiling mixture, they are immediately cooled as they rise towards the water-cooled condenser.

Extraction is where a solute is transferred from one solvent to another. For the solute to transfer to the other solvent, both solvents must not be miscible forming two separate layers. An important characteristic of extraction involves intermolecular interactions, dipole with dipole, ionic with h-bonds, etc. Alike molecules will attract, while not like molecules will remain. Extraction will not result in a pure sample, so another technique is needed to yield a pure result.

Distillation is a technique that can either result in a pure substance or bring a mixture closer to a pure substance. The process works by heating a sample to boiling which causes vapors to rise and pass through a condenser and cool back to a liquid into a receiving flask. Only if the heated sample is pure a temperature reading will be constant. If the mixture has two different boiling points a drastic change in temperature will be visible. If the mixture consists of two substances with similar boiling points, the temperature will slowly increase in regards to the vapor rising. With two similar boiling points a fractional distillation technique would be best to use, but a simple distillation technique the most commonly used with two different boiling points. The graph at the right demonstrates how the temperatures correspond to the composition of the product. As sample B is heated and vapors are condensed, the result is not a pure sample but a sample containing more of sample A than what it started with (Pavia, Lampman, Kriz, Engel, 2005).

Procedure

A 25 milliliter round-bottom flask is filled with 5 milliliters of isopentyl alcohol and 7 milliliters of glacial acetic acid. There is also 1 milliliter of sulfuric acid added to the mixture and once the sulfuric acid is added, the flask should be swirled to assist the reaction. A corundum boiling stone is also placed inside the flask.

Once the reaction mixture is made it should be attached to a reflux apparatus with a water-cooled condenser and a drying tube with calcium chloride surrounded by glass wool. Once the apparatus is setup, the water began circulating and the mixture was heated under a heating mantle for an hour.

After an hour or so passed the mixture was transferred to a 125 milliliter separatory funnel and cooled to room temperature. Then 10 milliliters of water is added to the separatory funnel and mixed. After shaking and mixing, the gasses are vented from the funnel. After the phases separate, the water solution is extracted. Then 5 milliliters of 5% aqueous sodium bicarbonate is added and mixed. After the phases separate, the sodium bicarbonate solution is drained out. The remaining crude ester is poured into a 25 milliliter Erlenmeyer flask and dried with 1 gram of anhydrous granular sodium sulfate. The mixture is mixed around and dried once more with about .5 grams of the sodium sulfate.

Once