Wednesday, 8 June 2011

Esterification


Students prepared Esters in chemistry today.
Esters are chemical compounds derived by reacting a carboxylic acid with an alcohol under reflux. Esters are ubiquitous. Many naturally occurring esters are fats and oils. Esters are the flavourings and smells found in essential oils and pheromones. There are also synthetic esters used in clothing such as polyesters.
Preparation of the Ester
First students assembled reflux glassware


Students refluxed 1-butanol and ethanoic acid for 30 minutes to produce their ester. They also added about 1mL of conc. sulphuric acid and It was important for them to use anti bump granules while refluxing. 

Collecting chemicals from the fume cupboard
As the students were using the first year undergraduate chemistry labs they got to use heating mantles rather than bunsen burners like in high schools. This allowed the students to have better control over the heating process and produce good results.
Students then allowed the ester to cool before using a separating funnel.







Students then added sodium carbonate solution to the separating funnel until no more effervescence occurred. The students then then collected the organic layer and washed it with about 20 mL of distilled water.

The final step for todays lesson was to dry the organic layer with fused calcium chloride.




 Chemicals
Boiling Point ( oC)
Densityg/cm3
ethanoic acid
118
1.05
1-butanol
116-118
0.810
prepared ester
126.2   
0.8826
sulfuric acid
142


            Today in Chemistry 
Mr. Chad Gramola, chemistry tutor from 
Mt. Compass High School supported the class.



















Exchange student from Italy - Fabio Melis enjoying chemistry in SMAF in Adelaide Australia



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