Technical: From a technical standpoint the purpose of this lab is to understand all of the technical procedures needed to synthesize, isolate, and purify in a lab in order to create an ester.
Educational: From an educational standpoint the purpose of the lab is to teach us how to practically apply concepts that we have learned in the classroom, by the end of this lab I should understand what reactions need to take place before a
Assuming lab procedure is done correctly when im making ethyl acetate the final smell should be an ester that smells like bananas. And assuming during the second run through of the lab I am even better at lab procedure I should have an even stronger orangey ester, called octyl acetate.
Acetic acid, CH3COOH, 17.4 M, 12 mL
Distilled or deionized water, 5 mL
Ethyl alcohol, CH3CH2OH, 10 mL
Sodium carbonate, Na2CO3•10H2O, 4.5 g
Sulfuric acid, H2SO4, 18 M (conc.), 15 drops
Beaker, 600-mL
Beaker, 50-mL
Boiling stones
Pipet
Clamps, 2
Condenser and plastic tubing
Condenser outlet adapter
Erlenmeyer flask, 125-mL
Ground glass joint grease
Hot plate
Ring stands, 2
Round-bottom flask, 125-mL
Separatory funnel or test tube,
18 × 125-mm, and test tube stopper
Thermometer, 0–100 °C, and adapter
Three-way adapter
Measured out 12 mL of 17.4 M glacial acetic acid.
Measured out 10 mL of ethyl alcohol.
Placed a 125-mL round-bottom flask in the fume hood.
Added the acetic acid and ethyl alcohol to the round-bottom flask.
Added 15 drops of concentrated sulfuric acid to the flask as a catalyst.
Added a boiling stone to the flask to prevent boiling over.
Set up a water bath with a 600-mL beaker filled with 450 mL of water and 3 boiling stones.
Placed the round-bottom flask in the water bath on a hot plate, while making sure the reaction mixture was below the water line.
Assembled a reflux apparatus with a condenser attached to the round-bottom flask.
Slowly ran cold water through the condenser while heating the water bath.
Heated the mixture under reflux for 15 minutes, keeping the reaction mixture at a gentle boil.
Turned off the hot plate and removed the water bath to allow the reaction mixture to cool.
Prepared a saturated solution of sodium carbonate by dissolving 4.5 g of sodium carbonate in 15 mL of distilled water.
Poured the reaction mixture into a separatory funnel and added the sodium carbonate solution.
Stoppered the funnel, inverted it gently, and vented it 15–20 times to extract the aqueous layer.
Allowed the two layers to separate; the top layer contained the ethyl acetate, and the bottom layer contained the aqueous waste.
Drained the aqueous layer into a waste beaker and transferred the ester (ethyl acetate) layer to a clean, dry round-bottom flask.
Set up a distillation apparatus using a three-way adapter, condenser, and thermometer.
Slowly ran cold water through the condenser.
Heated the round-bottom flask in a water bath, distilling the ethyl acetate.
Recorded the temperature at the beginning and end of distillation.
Collected the distilled ethyl acetate in a pre-weighed 125-mL Erlenmeyer flask.
Weighed the flask with the ethyl acetate to determine the mass of the ester.
Compared the experimental yield of ethyl acetate to the theoretical yield.
Smelled the distilled ethyl acetate and recorded its fragrance.
Disposed of waste materials following proper lab safety protocols.
Cleaned all glassware and equipment thoroughly.
Isolation (Separatory Funnel):
An isolation of Ethyl Acetate is performed during this experiment, in this isolation we use a separatory funnel to separate to compounds from each other. This is done by taking a separatory funnel and mixing the two compounds with diffrent density's and separating the compounds from each other. The proper procedure is visually shown in the link but at a glace you hold the funnel and flip it upside down and relieve the pressure each flip by oping the stopcock while its upside down or opening the cap when its right side up, after 15-20 flips you can let the funnel rest and wait for the two layers to fully separate.
Purification (Distillation):
A distillation purification of an ester is performed during this experiment. In this process, we use a distillation setup to separate the ester from any impurities based on their boiling points. The distillation apparatus consists of a round-bottom flask, a condenser, and a receiving Erlenmeyer flask. The mixture is heated in the round bottom flask, as the temperature goes up, the ester evaporates first because of its lower boiling point than the impurities. The gas then travels through the condenser, where it cools and condenses back into a liquid, which is collected in the receiving flask. You will also need to watch the temperature to make sure you don't start to cause the impurity's to evaporate as well.
Boiling point range — ethyl acetate: 77.1°C
Boiling point — beginning of distillation: 70.9°C
Boiling point — end of distillation: 73.6°C
Mass of Erlenmeyer flask: 71.13g
Mass of Erlenmeyer flask plus ethyl acetate: 83.71g
Mass of ethyl acetate: 12.58g
Theoretical yield of ethyl acetate: 15.11g
Percent yield of ethyl acetate: 83.25%
Fragrance: Nail Polish remover
In this experiment, I successfully synthesized both ethyl acetate and octyl acetate through esterification reactions involving acetic acid with ethyl alcohol and octanol, respectively. The hypothesis was shown as both esters were produced, but the smells differed from expectations, showing there were errors along the way and not enough was produced. Ethyl acetate had a distinct nail polish remover odor, and octyl acetate smelled more like citrus cleaning products rather than the fruity scent expected. I learned that while the esterification process is straightforward, getting perfect yields and perfect product characteristics is hard due to factors such as incomplete reactions and material loss during transfers. Refining the reflux time and improving separation techniques could enhance yield and purity in future attempts. Despite these challenges, the experiment provided valuable insights into ester synthesis, isolation, and purification.
The lab taught the importance of accuracy and also attention to detail in synthesizing esters. After working with ethyl acetate and octyl acetate, it had shown that minor changes in procedure make a difference in the results, like the unexpected nail polish remover and citrus cleaning product like smell. The steps of isolation and purification that the esters went through really put into perspective how important each step is in attempting to get the highest yield and purity. This also allowed me to be fully involved within the experiment and to really reinforce such concepts as reflux and separation. It was a great practical experience that really made me understand esterification and also aspects of problem-solving required in the laboratory.