Organic Chemistry - Steam Distillation

Last Monday the lab titled 'Steam Distillation' was performed (semi-microscale procedure). Basically, 10g of ground cloves were put into a flask with water and the mixture was boiled to extract the essential oil, eugenol. This process is called steam distillation, and is used because the normal boiling point of eugenol is 254 degrees C. This way, when water boils, the cloves boil, and eugenol drips out.

The whole lab smelled like gingerbread cookies or besamim. The TA said it reminded her of an alcoholic drink from Sweden, probably glogg.

So here is a diagram of the set-up - somewhat modified simple distillation, since a small separatory funnel had to be used to add water to the boiling mixture (so that the concentrations would remain the same and you wouldn't wind up getting eugenol diluted with a lot of water).


Here's the set-up as it was actually done:

Locked and loaded:

Joints greased - check.
Rubber bands tight - check.
Sep funnel loaded - check.
500 mL flask loaded - check.
Condenser water on - check.
Heating Mantle on - check.

Raise Mantle... BOIL!

Ever so slowly, the condensation line crept up the Claisen connecting tube and then the distilling head, and then began to trickle down into the Erlenmeyer flask as a whitish liquid.


When about 105 mL had been collected the heating mantle was lowered. Now came the solvent extraction, which we are by now familiar with. The white liquid was mixed with ether and the layers separated out. This time, ether was on top, visible here as a bit of a layer on the surface.

Draining of the ether layer:

Eugenol was now dissolved in the ether rather than mixed with water. It was dried out with sodium sulfate, after which it looked like this...

...and then 'twas evaporated with rotary evaporator. Afterwards, just a bit of (hopefully) pure eugenol was left.

Cleanup and completion of procedure:


Post-lab: Find a store that carries glogg. :)

Organic Chemistry lab - Extraction

This semester I am taking Organic Chemistry, and concomitantly the lab that goes with it. Last week Solvent Extraction was done. Here are some pictures from the lab:


First, you take a separatory funnel and put it on a ring stand. Then you add a mixture of acetanilide, p-toluic acid, and p-tert-butylphenol to some TBME, and pour it in. Then you add 10 mL of sodium bicarbonate, and after some venting to release CO2, the layers separate, like so.



Add HCl to precipitate p-toluic acid. As this is done, foaming occurs with some pretty cool effects. Once that's complete, vacuum filtration follows, with a vacuum hose, Buchner funnel, and Erlenmeyer flask. The vacuum created in the flask pulls the liquid in a solution through the funnel, leaving crystals behind.



Much later, NaOH extract has HCl added to it to precipitate p-tert-butylphenol. Crystals form, seen here as the white mass in the beaker. I think too much HCl was added; was it supposed to test out to a pH of 1.5?


During separation of acetanilide from ether, ether is evaporated using a rotary evaporator and a round-bottom flask. This leaves a small bead of orange liquid in the beaker, left to dry for a week.


Here's a real world application of solvent extraction, lest you think this is all fun and games. :)

Andrographis

Andrographis paniculata is an herb used in Scandinavia to treat colds and the flu. After reading this page I think I will try to grow it this year, at home and in the greenhouse. As far as I know no one has tried to grow it in Houston. Let's see how things turn out.

Why hack a calculator?

So that's the face behind brandonw on UnitedTI.

Case Study: petition for HON 2301 to replace PHIL 1305

If you are an Honors College student at the University of Houston, whose major is Biotechnology, you should know that there is no need to take PHIL 1305, since you have a Humanities credit from HON 2301. However, a petition is still required to have this approved. Do not follow the path of your predecessors. Rather, go to the main office of the College of Technology and tell them your situation directly. They will help you fill out the petition, with the correct options (17 - other - in my case), and smooth the bumps out.

UH is known for occasionally losing petitions in trans-departmental mail. This is what happened when I gave the first petition to the COT in early summer. It was labeled "degree exception". They sent it to the Department of Philosophy, but it was lost in the mail. This I discovered, to my chagrin, a few weeks before the fall semester was due to begin, and subsequently dropped the Philosophy class. After filing a second petition, this time to the Department of Philosophy, I waited the requisite 4-6 weeks, and came in to find no record of the petition, which in the meantime had been sent back to the COT. It took about 10 minutes to resolve the problem after visiting the office.

Thank you to COT front desk staff.