Fourth Day

So today I didn't do a lot of research online. When I arrived in the morning, the Prof. told me that it didn't look like we were coming up with a lot of information online, so he suggested that we move on and go into the lab. So he's thinking about doing a liquid-liquid extraction of methanol/1-octanol/water or ethanol/1-octanol/water; or a gas absorption of CO2 using air. However, these "solutions" poised another problem: we couldn't find any literature for most of these chemicals, based on my research online and in the library from the past three days. So Prof. Wainright has decided that he going to send me into the lab to get the data for him. I will be making mixtures with different compostions of the chemicals for each of the three experiments I mentioned above. I'll be using Gas Chromatography to find the equilibrium data, and probably the Henry's Law constant for the chemicals. So the professor gave me a short lecture about Gas Chromatography, and we talked to Dr. Virnelson, who is in charge of the labs, about the experiments and asked for chemicals and equipment.

So a Gas Chromatograph (GC) is this "not so big" machine that has coiled tubes of approximately 25m in length. The machine is connected to a tank of an inert gas which is used as a carrier gas (in our case, Helium). So the Gas Chromatography involves injecting a tiny drop of the solution as a vapor into the tube. The vapor is then helped to move along the coiled tube by the Carrier Gas. As the vapor contains gases of different molecular masses, the lighter molecules will move quicker than the heavier gases. The heavier molecules will also tend to adsorb to the walls of the tube because they interact more with the walls, and therefore the tube has to be warmed up in order to increase the kinetic energy of the gas and help it move along. The GC is connected to a detector which will detect the chemicals as they elute out of the tube. The graphs that the detector makes will show different peaks as the detector will detect the gases at different times. Then we can be able to use the information from these graphs to work out the data for our chemicals.

So, I have never done this kind of experiment before...and I only had a 10 minute lecture on Gas chromatography today. And the lab is for senior students, so Chem. E undergrads don't usually come across labs like these which makes me feel that I am learning a lot! I will be in the lab starting tomorrow, and I hope all goes well. Each experiment takes quite some time as you have to make up solutions and wait for them to separate, heat the GC and wait for it to warm up, inject the solution and wait for the molecules to move along the tube and be detected by the attached detector...So it will probably take me the whole of next week to do all the experiments.

I am very excited though, because it is all interesting and I just cannot wait to be in a lab coat, and do "real" Chem. E labs!