Teflon Enclosed Steel Spiral as Column Packing
As n srtbatitnte for a. tantallm wire spiral as fractionat,ing loo column packing we have used st,eel wire enclosed in Teflon spaghetti tubing. In addition to the advantage.; of tant,ah~m, i.e., chemical inertness, low holdup, ease of insertion and reU 90 moval, heat resistance and eare of clenning, the packing described here is ahout m e t h i r d t,he cost of tsnt.almn. The efficiency of the spiral is somewhat less ihan st,ainless steel $ FJ spongeas illnst.t.ated in the graph. For a. 19-em fractionating colomn accompanying a 'O 19/22 organic kit, 53 in. of 22 gauge hard steel wire (IR0.07/ 100 f t ) is inserted into 1 mm i d . Teflon spaghetti t,ltbing (Prince ilnhher and Plastics Co., Inc., 1675 Niagara Street., Buffalo, N.Y. 14207, $7.00/100 ft), requiring ahont 1 min. MiLLUER5 OF DISTILLATE The wire is of the type used for making hairpins and was fnr.. F"ction'"on of a mixture of lo m1 nished by a local wire mannfactmer. The tubing ends are Ond l o m' Of water. allowed to protrode ahont one cm over each end of the wire. A spiral is achieved by winding aronnd a 7-mm ~ n ~ ; ~O ~ glass rod or, mare easily, on a lathe. The Teflon ends are sealed by placing them in a. micro bnrner flame for one or two seconds and pinching with a pliers. On spirling some "shrinkage" of t,he wire into the tubing occurs leaving a flexible tail that may extend into the boiling mixture and serve as an ehnlator.
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464
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Journal of Chemical Education
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