chemsample-infraredspectroscopy-dielsalder-yield

Conducted by: Student A + B
 * __Determining a Diels Alder product:__**

Because we got strange results on the melting temps for our Diels Alder Product we decided to use TLC to determine the purity of our product. We were not sure what eluent to try, so we experimented with a few.
 * [[image:newscan.png caption="newscan.png"]] ||
 * Results from TLC ||

We first tried the most polar (methanol) and the least polar (hexane). These TLC have not been preserved, but they clearly showed that the hexane was not polar enough to carry the products. The methanol seemed polar enough, except for the diene. We were made to understand that the diene did not absorb UV and therefore would not show up in the short wave UV light we were using. However, this proved to be untrue. After using an iodine chamber to have the diene show up, we realized that it was not there at all! The methanol had been too polar and pulled it right off the plate. So, we then tried a 50/50 methanol hexane mix. This produced all three samples, the two Diels Alder reactants and the product. However, there was not an effective separation. This means that we were unable to determine how much of the reactants were in the product. However, we did determine that there was some maliemide in the product, which we had  because of the melting temperatures that we measured. More time permitted, perhaps we could have tried different mixes of eluents that produced a better separation.

Conducted by: Student C + D
 * __Analysis of Diels-Alder Product via TLC Plating ~__**

Just as student A + B did above, we experimented with a few different eluents to run our Diels-Alder TLC plating process. First, we tried a relatively polar eluent in Toluene - however, we did not get any complete results from doing this [after 20, or so, minutes within an "iodine chamber" ... (just a glass bottle with iodine in it) ... no significant movement of the mol. was observed]. Therefore, we moved on to a different eluent ~ this time, methanol. A slightly less polar solvent that had produced good results for students A + B. See below ...



Though our plates are not labeled neatly, they were both set up in the same way: on the left, a drop of maleimide ... directly in the center of each plate, we placed 2,3 - Dimethyl ... and on the right, our Diels-Alder product. These are the results displayed from running the plates in methanol - and, cleary the samples made their way up the TLC plate; this is Good! //So//, looking closely, it's clear that both maleimide & our D. Alder product had similar traveling properties, indicating that there must be at least some chemical properties shared between the two ... even better, our TLC run (for once!) actually performed near what is termed "ideal response, in an ideal world!"

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