"Greening" Preparation of Banana Oil
Fall 2010 Oraganic Cemistry
Dr. Kenick
UNH-Manchester, NH
By: Suzanne Craft
email: ssm27@unh.edu or onmylilypad@comcast.net


Green Chemistry

Through out my semester long journey of organic chemistry with Dr. Kenick, she has taught us and encouraged us to think "green". The importance of using green chemistry is essiental when working with any chemical substance. Our environment is susceptible to everyday wastes and hazards. In order to preserve our planet Earth, that we all call home, it is of great value that we the people do in fact practice some form of adding green chemistry to our everyday lives. What is green chemistry you ask? Well it can be answered quite simply; it is the make up of chemical products and processes, that consists of reducing or eliminating hazardous substances. On our first day of organic chemistry we were given a piece of paper that contained the 12 principles of green chemistry. With this list now in hand, it was used a great deal while working in the lab and in class applying it to each chapter lesson.

My Project

~My semester long project consisted of doing an experiment (preparation of banana oil) and including the 12 principles of green chemistry to it. The chemicals that were involved in my experiment consisted of acetic acid, isoamyl alcohol, and sulfuric acid. At the end of my procedure my final product was purified banana oil. All of the left over chemicals were able to be disposed of properly due to the nature of neutralizing them with sodium bicarbonate. This is a way to use Prevention ( #1 on the list of 12 principle of green chemistry); I had reduced my waste and was able to dispose of it without hurting or causing any damage to the environment, or to human health.


Isoamyl acetate

C7H14O2


scan0001.jpg
The Rxn that is taking place




~Isoamyl acetate is an organic compound, that is an ester. It is formed when acetic acid and isoamyl alcohol reacts using sulfuric acid as its catalyst.
~ The process of this reaction is called a Fischer esterification reaction. It simply takes heating a carboxylic acid with an acid catalyst in an alcohol slovent. The ending product is an ester. (2)


scan0002.jpg
Shows how the OH- is the leaving group for this Rxn


Fischer Esterfication Reaction


scan0003.jpg
Fischer Esterfication Rxn




Uses of Banana Oil
  • Aroma therapy
  • For flavoring
    014.JPG
    ~Mixture heating and reacting on a hot plate~ photo taken by: Suzanne Craft
  • Perfumes/ Soaps
  • Extracting penicillin
  • Massage oils/ Bath oils
These are just some of the common uses for banana oil. (1)





Glassware:
  • 1-50ml beaker
  • 1-100ml beaker
  • 4-150ml beaker
  • 2-400ml beaker
  • 1-250ml Erlenmyer flask
  • 1-10ml graduated cylinder
  • 1-25ml graduated cylinder
  • 1-50ml graduated cylinder

Other Equipment:
  • 2-ringstands
  • 2-clamps
  • 1-small ring
  • 1-hot plate
  • 1-thermowell
  • 1-transformer
  • 1-therometer
  • 1-separatory funnel
  • 1-distillation apparatus
  • 1- mitt

Chemicals:

PPE:
  • Lab Coat
  • Googles
  • Closed-toe shoes
  • Proper protocol for experiment


Preparation of Banana Oil



1. Obtain a clean, dry 1000ml beaker and add water to fill the beaker roughly half-way
v Bring water to a boil on a hot plate
2. Obtain a clean 250ml Erlenmeyer flask.
v 1st add 24ml of acetic acid
v While working under a hood, slowly and cautiously add 10ml of concentrated sulfuric acid to the Erlenmeyer flask, swirl to mix. (the mixture will become hot)
v Lastly add 27ml of isoamyl alcohol to mixture, swirl again to mix.
3. Place the Erlenmeyer flask with the mixture into the bath of boiling water. Boil for 25 minutes
v Use a ring stand with a clamp to suspend the Erlenmeyer flask into the 1000ml beaker of water
4. While the mixture is heating and reacting place approximately 150ml of water into any clean beaker, and add ice to create an ice-water bath.
v Pour 75ml of this ice-water into a 250ml beaker and save the rest for the washes with the separatory funnel.
5. Once the mixture has reacted, carefully remove it from the bath of boiling water and pour it into the 250ml beaker containing the 75ml of ice-water.
v Pour the total mixture into the separatory funnel. Use a plastic stopper to close the opening (top) of the separatory funnel.
v Set up a ring stand with a small ring attached, to place the separatory funnel in.
6. Obtain a separatory funnel and check to ensure the stopcock is closed.
v Pour the total mixture into the separatory funnel. Use a plastic stopper to close the opening (top) of the separatory funnel.
v Set up a ring stand with a small ring attached, to place the separatory funnel in.

7. Gently shake the funnel for a few seconds, carefully turn the funnel upside down by supporting the stopper with one hand and slowly open the stopcock to remove any built up pressure. Be sure the stopcock is facing away from you and others.
v Repeat this procedure until the internal pressure is minimal, and then shake vigorously to ensure thorough contact of the two liquids.

8. Place the separatory funnel in a small ring held by a ring stand to allow the layers to separate
v Obtain a clean 400ml beaker, remove the stopper and open the stopcock, thereby draining the bottom aqueous layer into the 400ml beaker
v When collecting the bottom layer, close the stopcock just as the upper layer enters the stopcock bore.
v Use care as the bottom layer is acidic and must be neutralized and discarded once completely collected.
9. Wash the solution twice more with 25ml portions of the ice-water and collect the bottom layer in the 400ml beaker.
v Once completed, the collected bottom layer should be neutralized with sodium bicarbonate and can then be safely discarded in the sink with running water
10. Transfer the ester (top layer) to a clean, dry 100ml beaker containing approximately 2g anhydrous sodium carbonate
v Allow to stand with occasional swirling for 5 minutes to allow sodium carbonate to neutralize any traces of H2SO4 and absorb any water.
v Carbon dioxide evolution indicates that acid is being neutralized.
11. Pour only the liquid through a funnel placed in the distillation flask. The solid remains in the 100ml beaker
12. Assemble the distillation apparatus as shown
v Be sure all connections are made with rubber stoppers and are tight to prevent vapor leakage
v Also be sure the apparatus is securely supported.
13. Use a 100ml beaker that is clean and dry. Obtain the mass of the beaker for the next step.
14. After the distillation flask is attached to the condenser, increase the voltage to bring the liquid to a boil and collect any condensed liquid in a waste beaker.
v Adjust the voltage so that the temperature gradually rises, the liquid vaporizes, then condenses, and ultimately drips from the condenser at a rate of 1-2 drops per second
v Once the temperature reaches 135oC, carefully maintain this temperature by adjusting the voltage accordingly and begin collecting your product in the previously weighed and recorded 100ml beaker
v Continue to collect the product until the liquid in the distillation flask almost completely disappears
v At this point immediately lower the heating mantle away from the distillation flask
15. Weigh and record the mass of the beaker and the ester
v Weigh and record the mass of a clean, dry 10ml graduated cylinder
v Pour about 10ml of the ester into the cylinder, weigh and record its mass.
v Record the actual volume of the ester in the graduated cylinder
16. Pour the ester and any other distillation products in the proper labeled waste bottle
v Do not pour any chemicals down the sink
17. Properly clean and return all equipment
v Be careful when dismantling the distillation apparatus, as the glassware is expensive
18. Wash the glassware with warm water and soap
v Rinse 3 times with distilled water and then with acetone.


Adopted from:
http://sunny.moorparkcollege.edu/~chemistry/Chemistry_1A_labs/experiment_fourteen.pdf


























017.JPG
~after ice-water was added to mixture~ photo taken by Suzanne Craft
018.JPG
~Separatory funnel used here to seperate the ester~ Photo taken by:Suzanne Craft


Observations that occured

Acetic Acid + Isoamyl Alcohol + Sulfuric Acid
Turned yellow in color and very hot to touch
After 5 minutes of boiling
Color of the liquid turned dark brown
After 10 minutes of boiling
Liquid is still a very dark brown color
After 25 minutes of boiling
Dark copper brown
Cold water was added
Light brown color on top of dark brown- steam seeping from beaker
Using separatory funnel
Clearly see the 2 layers; 1bottom layer acid, top layer ester
Adding sodium carbonate to ester
Light golden brown in color
Distillation flask used
Clear, liquid- smells like bananas


019.JPG
~Distillation apparatus used to collect purified banana oil~ photo taken by: Suzanne Craft


















References:
  1. http://gomestic.com/consumer-information/the-banana-oil/
  2. http://www.epa.gov/greenchemistry/pubs/principles.html
  3. Fundamental of Organic Chemistry; John McMurry; pp.339-340. 7th edition
  4. http://sunny.moorparkcollege.edu/~chemistry/Chemistry_1A_labs/experiment_fourteen.pdf
  5. http://www.sciencelab.com/
  6. http://www.osha.gov/
  7. http://www.epa.gov/greenchemistry/

Thank You for visting my page. For any question please do not hesitate to contact me.