Student Comments 2008: Steam Distillation of Essential Oils

When you start boiling the round-bottom be very careful to turn the heat up slowly. The liquid boils rather easily, so if you start it out at too high of a temperature the contents of your distilling flask will quickly boil over, travel through the distillation column and end in your receiving flask. Not only will you have to start over, but you will have to clean out the entire distillation apparatus as well. -Sarah Perz

Make sure you add enough water to the distilling flask in order to keep your spice from drying out and burning. It takes a while to clean out the round bottom flask if your spice does burn which may sound like tons of fun, but its not. --Megan Wasz

In addition to what Sarah mentioned above, I ran into trouble when I started boiling the contents in my distilling flask. My liquid boiled rather quickly, but instead of it ending up in my receiving flask, it formed bubbles inside my distilling flask and once they popped, my cloves ended up stuck onto the inside of the flask. This greatly reduced my percent yield because much of my contents did not get distilled properly. So, once again, if you see your contents starting to bubble, turn down the heat! --Patrick Hughes

One can become easily frustrated during the distillation of the essential oil, but it is important that one be patient. It takes a while for a substantial amount of liquid to accumulate in the recieving flask. However it is also important that the student not walk away because the distillation must be stopped before the initial spice begins to stick to the side of the distillation flask; this then becomes difficult to clean. --Allison Kolman

I would have to say to make sure you grind up your spice before attempting to boil. By doing this you will get a lager distill product--Kendall Moore

The apparatus set up for this lab is pretty involved. Many ring stands will need to be used because it is important to secure each piece of glassware to another piece and/or a clamp connected to a stand. By just connecting the glassware pieces (without blue clamps), an unstable apparatus is formed. A simple bump of the elbow can send the pieces flying in three directions and then your experiment is ruined, not to mention probably the glassware as well! Be sure to connect the pieces themselves with blue clamps and wherever possible, connect individual pieces to ring stands with metal clamps. -Becki H.

As Megan stated, you want to make sure there is enough water in the distilling flask so your spice does not dry out. I just kept adding water during the experiment to prevent the contents in the flask from drying out. Also don't forget to weigh your beaker before you collect the filtrate after adding magnesium sulfate. --Marie-France Likanje

Make sure you let the solution distill for the appropiate amout of time!!! If you want to increase your percent yield let the distillation process occur for a longer amount of time.You could also allow the solution to sit for a longer period of time when extracting the distillate with the dichloromethane and NaCl solutions. Having a longer time to separate will ensure that the maximum amount of product is recovered--Andrea Prosperi

You extract many times in part II. As a reminder from first semester lab, don't forget to vent the separatory funnel. --Melanie Bonifacio

Instructors/assistants: Clean up for this lab can be brutal. Use your glass sterilizing dishwasher if you have one, and put it on a high heat, long cycle. You may have to do two cycles. The leftovers are really difficult to get out of the round bottoms.

-Laura Volpe

The active ingridient in cloves essential oil is Euganol, but Euganol is a very small percent of the essential oil composition. So take care not to lose any product, because when it comes time to analyze the GC, Euganol will be represented by a very small peak. Take very close notice to the times of the Standard GCs and the experimental GCs. By the way, this lab is tweaked with excess Euganol to help those who are helpless lol.

Remember, when you gravity filter your product to place the magnesium sulfate dryign agent in the filter too.  Just because it might stick to the bottom of the flask does not mean that there is no product left in it.....by not filtering it you might jeopardize the percent yield you obtain--KS