A Air condenser B Jacketed condenser C Centrifuge tube, 15m L D Drying tube E Hickman distillation head F Connecting adapter G Claisen adapter H Spin vane, triangular I Syringe, polyethylene J Flask, pear-shaped, 5mL K Flask, round-bottom, 10mL L Micro conical vial, 0. 1 mL M Micro conical vial, 3 mL N Micro conical vial, 5 mL O Thermometer adapter P Compression cap, 20-400 Q O-ring (EP, size 112) R Septum, PTFE/silicone S Universal inlet/vacuum adapter (Not Shown)

1. Cleaning of glassware

Since every student has a limited amount of glassware, proper housekeeping is very important. This not only means to keep the workspace organized and free of clutter, but also means to clean the glassware when it is not needed anymore.

There are various ways to clean glassware properly. The best policy generally is to clean the glassware immediately. This way it is usually easier and everybody gets exposed to fewer chemicals as well. Like in real life, letting the dirty dishes sit around for a week in the sink does not make it any easier to clean them, and often they start to smell bad as well due to food residues that go bad. In the lab, in many cases some soap and a brush will do just fine. In other cases, it is advisable to use some acetone first to rinse out the majority of the organic material before applying water and soap. In most cases, these simple techniques provide clean enough glassware already. In more difficult cases, acids or bases have to be used for cleaning. If a lubricant is used, the joints have to be degreased thoroughly as well using a non-polar solvent like petroleum ether or hexane.

In either case, the glassware should be rinsed with deionized water (if available), a little acetone and then briefly dried in an air stream. Even though it is relatively important to have reasonably clean glassware, it should not take too long to get it. Or in other words, do not spend one hour to do the cleaning, because you will run into problems later on to finish your experiment in a timely fashion. You are in the lab to conduct experiments and not to clean glassware for the better part of the time.


2. Lubrication or not?

Many of the joints do not perfectly match. In most cases, lower yields are due to these small leaks and can be reduced by placing an O-ring on the top of the joints to provide a better seal. In more critical applications high-vacuum grease has to be applied to the joints to provide a better seal. Generally, a small amount on the top part of the male joint is sufficient (If the male joint is rotated inside the female joint, and the top part is clear all the way around, enough grease was applied). Too much grease does not necessarily provide a better seal. It often ends up in the product since it dissolves relatively well in most organic solvents i.e. diethyl ether, THF, hydrocarbons, etc. It also can cause a lot of problems in the purification of the crude product as well, particularly if the product is a solid. Therefore, the exposure to the solvent should be minimized as much as possible. Therefore, it should be used sparingly, in the right places and only if really necessary. Both connecting joints also have to be cleaned properly before being lubricated.