Student Comments 2008: Eucalyptus Oil -- invite key = ochemrules

Getting your product to recrystallize here can be quite difficult, simply scratching probably isn't enough.  The procedure reccomended dipping the glass rod in the mixture, letting it dry, and then scratching.  The best way to do it is to dip it in, let it dry, and then keep dipping it in and letting it dry until you see a solid start to form on the rod.  Then start scratching and crystals should appear.  Be patient.  --Sarah Perz

Like Sarah said, you have to be really patient with this process. It can be tedious. However, to speed things along, you can always use the AIR in the fume hood to dry the glass rod faster each time instead of just letting it set out to dry like the lab indicates. Otherwise, you will be there forever...or at least close to forever!  -- Megan Wasz

Many students had more maleic anhydride in the GC data than the diene.  Proper care must be taken to use the correct amount of maleic anhydride and be sure to let the reaction run its full course to obtain the diene.  Also, though it looks like harmless chunks of white wax, do not touch the maleic anhydride. --Peter Nani

An instance happened in my lab period where, during recrystallization, the ethanol caught fire and started a slight scare in the lab. It is necessary to take proper precaution during recrystallization because the ethanol is highly flammable. When heating it over the thermwell, be careful that you do not drop the flask or spill any of the ethanol. -- Patrick Hughes

As Patrick discussed above, ethanol was the culprit of a small fire during our lab period.  In addition to being careful when handling the ethanol, it would also be a good idea to completely move the thermwell before detaching the round bottom flask from the reflux apparatus.  This will ensure that any ethanol the condensed into the apparatus does not drip out onto the heat source.--Allison Kolman

A good tip is when doing purification not to heat for a prolong period of time because you product could dry up and you would be letf with nothing.--Kendall Moore

Water should not be present anywhere in this experiment. Maleic anhydride as well as all the Diels-Alder products can be hydrolyzed by water. The glassware should be dried completely either in an oven or if necessary by the AIR nozzle. If heated in the oven, let it cool before beginning the experiment. Hydrolyzation could definitely disrupt your yield so be careful! - Becki H.

Since this lab uses eucalyptus oil, I thought it would be nice to add a fun fact. DId you know that eucalyptus oil is a rich source of cineole which is an antiseptic used to kill bad breath.--Marie-France Likanje

Don't catch this lab on FIRE. More importantly, if you do start a fire in lab, dont freak out and throw the flaming flask! This lab made me want to reintroduce myself with the safety rules for chem class!!! SAFETY FIRST because a safe lab is a happy lab--Andrea Prosperi

This lab was one of the most memorable organic chem labs.  An incident occured where my flask started on fire and almost burned my face and my lab partner.  One of the main precautions to take in performing this lab is to completely remove the heat source from where the flask which contains ETHANOL( HIGHLY FLAMMABLE)  and also to be careful not to spill any ethanol outside the flask near the heat source.  As Andrea commented SAFETY FIRST because a safe lab is a happy lab!  Tamara (I'am on fire) Pike

Remember when interpreting your GC, you can't ever lose a reactant.  Matter cannot be created nor destroyed.  --Melanie Bonifacio

When recrystallizing, it is important to use a MINIMUM amount of solvent. If you use too much solvent, you risk running the possibility that what ends up recrystallizing is the solvent itselft.

-Ricardo Rodriguez

While it said this in the lab write up, I still feel that it is important to mention again....If you are going to use air to attempt to speed up recrystallization, DO NOT turn the air up too high.  You not only lose your product but it is a pain to clean (you know, not that I did that....cough, cough)--K.S.

Make sure the round bottom flask is secured with the clamp before refluxing, otherwise the flask can easily slip off into the hot water bath, then you will have to restart the experiment. Alica P