Monday was an administrative day. I ran 2 proton NMRs, one on the formyl naphthalene derivative and one on the nitrile naphthalene derivative. The aldehyde (my professor calls it "formyl", I use them interchangably) NMR came out very clean and told us our product was very pure. The formyl group, however was stil causing some steric/electronic hinderance and as a result, the methylpiperidine ring did not interconvert (flop around) and the hydrogens in the meta position from the nitrogen were diastereotopic (chemically shifted differently and unique under NMR). The formyl group did not rotate either, and was locked in place somehow. The nitrile naphthalene NMR told us the sample was a nasty blend of starting material, product and other junk that needed to be filtered out.
Tuesday was a primary work day, and I set up the synthesis of 4-bromo-1,8-naphthalic anhydride for the senior in our lab. The bromination of 1,8-naphthalic anhydride took liquid bromine and 4 molar KOH. The reactants were heated to dissolve the anhydride, then the mix was cooled to 0 degrees celsius to add the bromine, then heated to 60 celsius under a reflux column and left for 18 hours.
I ran a column on the nitrile product from monday in an attempt to purify it. The column failed to adequately seperate it from the starting material, owing to the -CN: group being roughly similar to a halogen (-Br in our case). We are attempting recrystallization via solvent evaporation.
I synthesized copper (II) sulphate as a precursor material to make copper (I) sulphite. I used copper (II) carbonate w/ concentrated sulphuric acid in an aqueous solution to make the copper sulphate. In order to percipitate the copper sulphate out of the solution, I cooled acetone to -50 degrees Celsius and dumped it into the blue copper sulphate solution. The reaction produced very fine percipitates. Percipitates this fine required the use of a fritted glass funnel and our aspirator vacuum, since the aspiratior draws a vacuum 10 times stronger than the house vacuum (~11mmHg versus 100-130mmHg depending on central pump load). The synthesis went well and the product bottled after drying.
Wednesday would normally be an administrative day, but I had chosen to skip my biology and physics lecture to "study" for my organic chemistry II exam, and instead of studying I came to the lab to work a full day.
I first synthesized the copper (I) sulphite by mixing the copper sulphate with water, accidentally adding sodium sulphate instead of sodium sulphite and getting no reaction, but filtering the copper solution through a fritted funnel under the aspirator. The copper solution was a deep blue, and that's when I realized my mistake when my professor pointed out that the solution should be green and I had added the wrong chemical. I added sodium nitrite and the solution turned a verdant green with a precipitate that I can only describe as sh*t brown. I then proceeded (and fail) to vacuum filter this precipitate through our fritted funnel only to find out that this was so fine it would just pass through the sintered glass. I instead used the biggest büchner funnel and 1L vacuum flask our lab has to filter out the liter and a half of aqueous solution + precipitate we had. I had a brown sludge which I dried over vacuum.
I synthesized n-butyl nitrite by adding 1-butanol, water and sulphuric acid to a sodium nitrite solution at 0 degrees celsius. I failed to keep the temperature under control (acetone/ice slush) and the reaction shot up to 14 celsius, cooking my product and destroying my yield.
The synthesis of the 4-bromo-1,8-naphthalic anhydride was worked up with sulphuric acid, the product was vacuum filtered and washed with water, methanol and diethyl ether. NMR resulted in a 3:1 ratio of starting material to product, and with a final molar yield of 65%, this makes the true yield ~17% give or take.
Thursday was another primary work day, and I completed the synthesis of n-butyl nitrite, this time adding copious amounts of liquid nitrogen (LN2) into the acetone-water slush to really keep the temperature down. I still got a 50% yield (volumetric) when my professor got a 105% yield (volumetric) when he did this reaction earlier, so I don't know what I did wrong. We did have enough for the next reaction though, which was all we needed. Alkyl nitrites have a poor shelf life of a few months to a year, so synthesis needs to be done before use. Apparently nitrous acid is a vibrant blue, and I got to see some with my own eyes before it fell apart during the workup.
I synthesized a 1-8,napthotriazine from 1-8 diaminonapthalene and the n-butyl nitrite made earlier. The reaction was started at 10 celsius, warmed up well past 25 celsius and was cooled down with a room-temperature water bath and left overnight.
I refilled the 180 liter LN2 dewar from the NMR room since my professor informed me it had been emptied and needed filling, and I had finished all my lab work for the day.
Friday was also supposed to be an administrative day, but I had decided to make LN2 Ice cream after my professor got back from his department meeting, so I stayed for a few hours. I dried up the 1-8,naphthotriazine by vacuum filtration, keeping the solids. Water washing yielded plenty of extra naphthotriazine so I filtered that too, keeping the solids. Overall yield was 4.5 grams, which wasn't bad.
The LN2 ice cream was a vanilla pudding mixed with heavy cream, and was unbearably sweet due to all the heavy cream. It came out much too thick and next time, I'm gonna use less pudding and more cream, plus some half and half.