Tiangco Lab 6 Fischer Esterification Chem 253 PDF

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Lab Report...

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Wyatt Tiangco Partner: Megan Wehrbier Chem 253 – TA: Somayeh Mousavi Lab 6: Fischer Esterification 9/22/2020

Purpose The purpose of this lab was to synthesize the ester, Isopentyl Acetate, commonly known as banana oil. The way this was done was by creating a reaction with carboxylic acid and alcohol with a catalyst, also known as using the Fischer Esterification method.

Theory To begin with, Esters are known as the main compounds known to provide most tastes and smells that are considered pleasant to most. The way that esters are formed are by reacting carboxylic acids, which are also known for tastes and smells of things, with alcohols. Multiple Esters are used to create artificial flavorings found in most foods. Isopentyl acetate, the ester found in this lab, is a main substance in banana oil. Fischer Esterification utilizes and acid catalyst to add and alcohol, that is nucleophilic, to the Carbon/Oxygen bond in the carboxylic acid. The resulting product is water, which is extracted, and the carbonyl oxygen is deprotonated, in which the ester forms.

Reaction

(From Gas Chromatograph) Area of Peak A (Isopentyl Alcohol): 366.62 Area of Peak B (Isopentyl Acetate): 9893.09 Total Area: 10259.71

% of Peak A: 366.62/10259.71 = .036 = 3.6% % of Peak B: 9893.09/10259.71 = .964 = 96.4%

Ratio: 9893.09/366.62 = 26.9 = 27 Percentage of Isopentyl Acetate: 96.4%

Methods/Procedures The procedures were followed verbatim from the handout given to us during the lab and were no exceptions made in this lab for our particular run of the experiment. Acetic acid and sulfuric acid, which were used in this experiment, can cause serious burns when directly applies to the skin or eyes. Acetic acid is also flammable. Also, isopentyl acetate and isopentyl alcohol can irritate the eyes, respiratory system when breathed in, and skin.

Observations/Results During the separation part of the experiment where it was required to shake, there was some built up pressure that ended up in a little bit of the solution leaking out, but not much. All other errors would have been due to human or procedure error that was unknown to us, the people doing the procedure. Most of the lab we were able to smell apple, but at the end when we had our final solution, in smelled more of banana (laffy-taffy almost). The yield was very clear, with maybe a slight yellow tint, but again not much, and has a watery viscosity.

Discussion/Conclusion We were able to successfully synthesize the isopentyl acetate from the acetic acid and isopentyl alcohol. Because we were able to do all of the procedures correctly and well, we got a very good amount of yield of isopentyl acetate in our distillate. I calculated our percent at 96%, which was very good considering the minor slip up that we had during the experiment.

Exercises 1 – CO2 is removed during the washing part of the procedure CH3COOH + NaHCO3  CH3COONa + H2O + CO2 CH3COOH + (CH3)2CHCH2CH2OH  CH3COOCH2CH2CH(CH3)2 + H2O 7 – Raoult’s law explains how the pressure of a solution is proportional to the mole fraction of the solution. So, when the pressure is low, its boiling temperature raises. When NaCl is mixed in with water, the mole fraction of water decreases which then decreases the pressure, and making NaCl have the higher boiling point.

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