On Thursday 10-20-11 we had our Challenge Booth in honor of National Chemistry Week, which went well. People were educated about tooth decay (and a little freaked out about the fact that we used real teeth), but they mainly enjoyed the free gum we handed out at the booth! The other group's booths and demos were really interesting and we had a ton of fun with the Challenge. Here's a picture of our poster that we made for the occasion:
We had to get back to work after the Challenge, so we started another reaction for our project. The last reaction that we did was benzene, and that worked really well, so we decided to change our arene to N,N-diethylaniline. We set up the reaction the same way as we did before: we vacuum-filled and argon-filled the flask and then added the two solvents, dibutyl ether and THF, into the flask with a stir bar. We then measured out the Cr(CO)6 and the N,N-diethylaniline and added them into the flask. Once we started heating the solution, it turned yellow and then got darker as it kept heating. When the heating was stopped, the solution got lighter in color:
We set up the solution the Thursday before fall break, which caused the reaction to take a lot longer than it should have because it had to sit without heating over the weekend. It stirred and heated for 11.5 hours and then we tested it via IR to see that the two peaks in the CO region that corresponded to our desired solution. After this, we had to evaporate off the solvent, so we let it sit out in the hood for a week. We had light green crystals once the solvent had evaporated.
On Thursday 11-3-11 we tried to do a C13 NMR of our product in deuterated DMSO, but even with 512 scans the final scan was very noisy. It is a good thing that the IR is such a helpful way to identify the products, because we have had a lot of trouble with the NMR giving us good data.
While this one was sitting in the hood evaporating, we started another reaction, this time with methyl-3,5-dimethoxybenzoate. Again, we set up the two-necked flask, vaccum-filled and argon-filled it, and added the dibutyl ether and THF with a stir bar. We measured out the Cr(CO)6 and the arene and added them both to the flask. This time, because the reaction had to stir for 70 hours, we started it on Thursday at the end of lab and let it stir through Friday over the weekend until Monday morning. As soon as we started to heat the reaction, it turned light yellow. When we went back on Friday morning, we really couldn't see the reaction because the flask was blackened on the inside. The only problem was that we didn't have the data for this complex, so we didn't have anything to compare our IR to. We got a brown solid, and then we washed this with methylene chloride to get a yellow liquid. We then put this in the hood to evaporate off the solvent. After the solvent evaporated off, we had a light yellow powder in the beaker. We haven't had a chance to do an NMR on this yet, but we think we will try this next week.
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