Experiment 6 Full Report

Report sheet: Experiment 6: Preparation of n-Butyl Acetate. Name : Wei Sean Loy 20

Date : 2011-04-

Aim:  To prepare n-Butyl Acetate (Ester) by using the Fishcher-Speir etherification method and also to test the presence of the Ester by chemical test, smell test and infer-red test.

Method: As per lab manual (green, 2001)

Reaction undertaken: Reaction between Acetic Acid and Alcohol take place during the FisherSpier etherification process. This reaction is a reversible equation. The chemical reaction of Acetic Acid and n-Butanol will form n-Butyl Acetate (Ester) and water. Acetic Acid + n-Butanol



n-Butyl Acetate + water

CH3COOH + CH3CH2CH2CH2OH CH3CH2CH2CH2OH  CH3COOCH2CH2CH2CH3 CH3COOCH2CH2CH2CH3 + H2O

Observation: 1.  The round bottom flask which contains Acetic Acid, n-Butanol,

Dowex ion exchange resin and molecular sieves is heated and a clear liquid is formed at the end of the process. A sweet smell of  banana is detected from the liquid which is positive that it is the presence of n-Butyl Acetate. 2. When conducting the chemical test, a few drops of Ferric Nitrate

solution are added into the sample to test the presence of ester functional group. Upon the addition, a dark reddish brown mixture solution is formed, which is again positive to the presence of n-Butyl Acetate. 3. From the IR test, infra-red spectra of our sample are obtained. It is

compared with the n-Butyl Acetate’s IR spectra graph. From 1000 to

1900 cm-1 of frequency band is similar to the graph of Acetic Acid, while the band within 3000 to 3700 cm-1 frequency is coherent to the graph of Butanol.

Discussion: It is conform that Ester is formed. The clear liquid which we obtained from the round bottom flask has a pleasant smell of banana. The addition of  Ferric Nitrate solution into the sample shows a dark reddish brown colour also confirmed the presence of Ester.  The IR spectroscopy result of our sample is compared with the result of  pure n-Butyl Acetate. Both of the graphs show identical shapes of peaks and bands. In the 1350 cm-1 peak which present in both graph shows the presence of C-O group. The peak in 17000 cm-1 represented the C=O bond. While the peak at the band of 2750 to 3000 cm-1 shows the presence of C-H. Three of the distinctive functional group of Ester is shown from the graph. Thus, we can conclude that there is presence of  Ester functional group in the sample we obtained.  The slightly difference in shape of graph of the pure n-Butyl Acetate and the sample we have might be caused by a few factors, such as the overheating during the process. The longer time of heating would affect the absorbance of alcohol by the Acetic Acid. And also some human errors of inaccurate measuring may affect the mass of reactants causing some incomplete reacting between each substance. The addition of HCl may also affect the results. The acidity of HCl would interfere the pH value of  the sample. To compensate the acidity of HCl, Sodium Hydroxide is added into the sample to alter the pH of the sample.

Conclusion:  The entire conformation test conducted shows affirmation to the presence of the Ester functional group. We can smell pleasant banana smell from the sample, and also obtained a reddish brown solution when Ferric Nitrate solution is added. We obtained a highly similar results of graph from our sample comparing with the pure n-Butyl Acetate. As a conclusion, n-Butyl Acetate is successfully formed.

Reference: Green. A, 2011. CHM 1011 Laboratory lab manual, pp 35-39