Day Eleven: Pyrotechnics and Argon

Dawned the morning of our scaled-up Grignard reaction.  Fortunately, it was sunny and low in humidity, so keeping moisture out of the lab was a much more feasible goal.  However, we still had to dry our glassware prior to starting the reaction, and we wanted to do what we could to maintain the dryness throughout the experimental run.

Enter a hair dryer, a flame torch, and a large tank of argon gas.

Even after removing my glassware from the oven, there was a significant amount of water in my round-bottomed flask.  Before assembling my reflux apparatus, I clamped the flask aloft and ran a hair dryer in a swirling motion below it.  Once most of the moisture was gone, I added the remaining pieces of glassware and stoppered the ends with dessicant tubes.  Then, I ignited a small flame torch and ran it lightly from bottom to top outside the apparatus, watching the condensation move up into the dessicant tubes:

After that, we connected gas tubing where the dessicant tubes had previously been via syringe needles poked through rubber septa.  It took some adjusting to infuse all three apparatuses with argon, but it was effective once we got it to work.  The problem that arose then was the amount of pressure due to the argon, even with the outlet tube.  Since my alkyl halide, benzyl chloride, is quite volatile, the reflux process caused a lot of my reaction solution to spit out of the RB flask instead of condensing and falling back down.  We promptly removed the argon and the heat from my apparatus, though, and the rest of the experiment proceeded without any other disruptions.

The product has been left to stir over the weekend and will be characterized and oxidized on Monday!