Not Quite Perfect

The next day, we went up to the lab after the solution had 20 hours to reflux to find that during the night, we had an air leak and all of our solvent had boiled away. Nothing was left except a black residue on the inside of the flask and all over the stir bar. We got this cleaned up and decided to start the reaction again on Thursday.

On Thursday 9-29-11 we set the reaction up in the same way except for two differences: we used a smaller flask so that the contents would have more volume in the bottom of the flask (hopefully this would prevent the solvent from boiling away too fast) and we used a two neck flask instead of a three neck flask.

This would have one less way for the solvent to escape, so the reaction has one less way to fail. We didn't want to leave the reaction to run overnight again in case it would fail, so we set it up at the end of lab, and one of us could come in on Friday morning to turn the heat on.

On Friday 9-30-11 we turned the heat on at about 10:30 AM and let it go all day until 4 PM. The heating mantle was turned to 3 this time instead of 4. We still got the black residue on the inside of the flask, but we could tell that we still had solvent in the flask because nothing had bubbled up through the joints and there was still liquid dripping from the condenser back into the flask.

On Monday 10-3-11 we started a second round of heating at 11 AM and didn't turn it off again until 5. The total cook time at this point was 11.5 hours, which is less than the 20 hours we originally decided to do but we decided to do an IR spectrum of the solution the next day during lab to see if the reaction had proceeded at all, or whether it had failed again.