This week the chemistry done was rather interesting.
On monday, 9/25 I did a peroxide test on the various ethers my professor had lying around. I expected all of them to be negative, but two came back positive. The peroxide test is potassium iodide in acid; in the presence of an oxidizer the iodine is oxidized to form a yellow (bad) or deeper color solution (worse). Our dimethoxy methane went bad and the test came back orange. Orange is borderline an explosion hazard, so I rectified it with aqueous washing with sodium sulfite (and accidentally dissolved half our product in water). Starting with 600mL of the ether, I finished with a pale yellow iodine test and 300mL of my ether. Overall, my professor was happy we caught this early, because it absolutely would have cooked off and blown up my lab if allowed to further peroxidize.
On Tuesday I worked with copper cyanide (CuCN) and N-N,Dimethylacetamide (DMAc) to stick a cyanide group on [10-bromo-1-methyl-1,2,3,4-tetrahydrobenzo[h]quinoline] to make [1-methyl-1,2,3,4-tetrahydrobenzo[h]quinoline-10-carbonitrile]. If you need a visualization, put it in ChemDraw since I can't post images. Essentially, the bromine is swapped with a cyanide group, and this involves working with copper cyanide. This reaction needed anhydrous DMAc and our DMAc had been in storage for much too long, and had picked up a signifigant amount of water. Doing a small scale distillation of the DMAc was an absolute nightmare, the distillation bumped violently at least 5 times, but after signifigant modifications to the distillation setup it worked. DMAc also dissolves rubber vacuum hose, and I had to re-do the distillation after I shut off the vacuum and accidentally back-filled the clean distillate with liquified hose.
Wednesday was an "administrative" day where I just cleaned glassware and ended up cleaning up a lab member's reaction after they needed to go to a lecture.
Thursday I ran an NMR of an unknown organic solvent to determine what its was. NMR interpretation with the help of ChemDraw told me it was an 8:1 ratio of isoamyl nitrite to isoamyl alcohol. I also finished the cyanide reaction by first vacuum distilling the DMAc out under high vacuum (~1mmHg) and then quenching it with an aqueous solution of iron (III) cloride and HCl in water, stirred overnight. I also vacuum distilled our recovered DMAc in an attempt to purify it, and the 600mL distillation only violently bumped once! The distillation came out a lot better than I thought it would. I came back after my physics lab to clean up the distillation apparatus and wash the glassware, where I found that the tar from the DMAc distillation could not be removed by any organic solvent. I also set up a sublimator to purify the [5-methyl-5,6,7,8-tetrahydrophenanthrene-4-carbaldehyde] that I made earlier that month. The water cooling in the sublimator overheated so I connected an ice bath and micro heat exchanger tube to cool the condenser column of the sublimator. I got a good product crystallizing out.
On friday I came in to clean up and work up all the unfinished reactions of the week. The cyanide reaction was cleaned, separated out with methylene chloride, and the aqueous waste was processed. The product was scraped out and weighed, with a few samples kept for x-ray crystallography and the rest being used for NMR experiments. Our final yield of the aldehyde was 13.5% adjusting for the sublimated mass. Interestingly enough, it weakly fluoresces orange when the column had it fluorescing teal. I suspected the teal is actually contamination by very similar chemicals.
Now I have become a chemist, holder of grudges on a chemical.