Friday, February 2, 2007


And now some unnamed lab-equipment: the rotavap.

It is said that Lyman Creighton Craig (1906-1974) invented the rotavap. He described it in 1950 (Versatile Laboratory Concentration Device; Anal. Chem.; 1950; 22(11) pp 1462 - 1462)

They even thought of another purpose besides concentration.Walter Büchi improved the design and introduced it in 1957 on the market. See here for a little bit of Büchi history and an illustration of his first commercial rotavap. I could not find a patent of this design though. I found a later patent by Walter Büchi (GB1039709) though, in the old patent tongue. Another Walter Büchi patent contains some lovely handwriting. Recently I needed dry THF (quick and dirty did not work) and the commercial stuff was all used or wet and old. I had to distill some THF. Distillation equipment is not in excess out here so I used a Dean-Stark trap. When the distilling was going well, I saw I had the perfect distilling equipment standing next to me. I realized that with minor adaptions I could use it as the perfect reduced pressure Dean-Stark distillation equipment, venting with dry argon after distillation makes it very nice for distilling solvents to dry it.

I will call it the "een of andere vent apparatus".

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