Student Comments 2008: Synthesis of Isopentyl Acetate (Banana Oil) 

Make sure that when you pour your mixture (which was refluxed then cooled) from your flask into the separatory funnel, that you do not pour the boiling stones in the funnel as well.  They impede draining and your product gets stuck on the stones and may skew your results    -->   Kristina S.

When distilling, be sure not to let your distilling flask burn dry.  Take the heat off when there are still a few drops of liquid left in the bottom, but leave the rest of the apparatus put together for a while.  There will still be liquid in the distilling column, so you want to wait to take the receiving flask off until all of the gas/liquid in the column condenses and collects in the flask.  Otherwise you will not recover the product left in the column.  --Sarah Perz

When you initially mix the contents after refluxing and allow for two layers to seperate, it is difficult to tell if two layers actually do seperate because they are both clear layers. Do not think that the contents did not seperate; hold the sep. funnel up to a light source and this will help you find the line of seperation. --Patrick Hughes

If this lab is done again, perhaps different alcohols (ex. 1-propanol or 1-octanol) could be used for different students to produce more flavors (ex. pear or orange). Or maybe you could change both the alcohols and acids for even more flavors. I think that would make the end of the experiment more exciting because you would have to try and figure out what flavor you created instead of knowing ahead of time. --Megan Wasz

As Patrick stated, the seperation is very difficult to see.  Besides the dark coloring, I also had oily bubbles develop which made it even harder for me to observe the separation.  In order to better see the line of separation I employed a technique used in last semester's lab.  I took a stirring rod and slowly moved it around inside the sep. funnel.  This eliminated the oily bubbles and allowed me to distiguish between the dark colors.  Also, upon breaking a sep. funnel stopper I realized the importance of removing the stopper after shaking it and letting it sit; venting it is not enough, pressure still builds upon sitting. --Allison Kolman

When the mixture is being refluxed it turns a dark color.  This may be due to impurities in the alcohol (as stated on the last page). In order to test this, some of the mixture should be removed before refluxing completely. Chromic anhydride (CrO₃) should be added to a sulfuric acid solution to show when alcohol is present. Then the solution should turn from clear orange to bluish green. However this may not give you results as to how pure the compound is. An IR or a GC could be done to see what other compounds are present at this point in the experiment. Once this is done, the experiment may be revised to rid of these impurities. -Becki H

As stated earlier, it is very difficult to see the seperation. Since it was very hard to see the seperation, Dr.Friesen kept adding water until I had  two layers in my sep funnel. --Marie-France Likanje

This was the best lab ever, i am so glad we did this one in class. I would advise you to stop and sniff the final product, because it smells AMAZING, like a banana laffy taffy!!! I would also agree with Pat, if you cant tell the different layers apart, hold it up to a light source---ANDREA PROSPERI

This lab was absolutely the best lab ever...A+++++ for this lab. The smell was intoxicating, I wish i could have taken a sample home with me so i could wear it out as a perfume, im sure it would drive the boys CRAZY--  Make sure to watch closely for a speparation and if it is not very visible, add water until two layers formed or stirr the mixture slowly with a stirring rod and let the mixture sit for a min until two layers have formed!  Tamara Pike

If you plan on using different alcohols to react with the acetic acid, make sure that the ester formed has a boiling point which differs by at least 25 K, a simple distillation wont work of the all the organic constituents have about the same boiling point, it will all condense over and no purity will be acquired.

- Ricardo Rodriguez