]] and benzophenone to produce dry, oxygen-free toluene.
The mixture is still not blue yet indicating that the reaction is not complete.
The intense blue coloration due to the benzophenone ketyl radical shows that the toluene is considered free of air and moisture.
After the toluene has been thoroughly dried by the sodium and benzophenone, it is distilled at atmospheric pressure under a slight positive pressure of nitrogen to prevent contamination by air into the receiving Schlenk flask.
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2006-09-04 18:03 Rifleman 82 1600×1200× (333246 bytes) Reaction complete! Air free and moisture free toluene, with [[sodium]]-[[benzophenone indicator.]] Taken on 4 Sep 2006.