Convenient, Degassable, Reusable Tubes for "Merry-Go-Round" Photochemistry and General Vacuum Line Techniques The recent note' concerning the use of reusable degassable tubes in "Merry-GoRound" photochemical reactors prompts us to report that we have found a satisfactory commercially available design that differs substantially from those described.' The reusable, degassable tuhes are purchased from the supplier2 and are ready for attachment to a vacuum line apparatus. The Reacti-ThermO tubes of size 19 X 100 mm will fit a commercially available a p p a r a t u s h i t h the rubber grommets removed. The vials are self-sealingthrough threadedTeflon seals and willmaintain reducedpressuresof 10-"10F rnm with ease. The Teflon seal protects the solution from amtamination. The degassing procedure previously described' is also recommended fur these tubes. We have designed and fabricated a special chamber that allows us to degass each tube systematically without the necessity for the use of ground glass joints. In the figure we shaw a clme-up of the chamber which is made from six commercially available %-in. compressh~n fittings that have Teflon ferrules and Nylon bushings to allow the glass side arm of each vial to be sealed by insertion and finger tightening of the compression fitting. The chamber was made from h e a v gauge circular brass tubing into which was sealed with silver solder six equally spaced compression fittings. The bottom was sealed with heavy gauge brass n1nt.e and soldered. The evacuation tube was made of heavy dutfJ/a-in. brass tubinr solr~~~~~ dered to brass plate which was then soldered to the tap uf ihe chamber. The tube arrangement is easily used for the freezing of one tube a t a time. The simultaneous degassing of all six tubes is more difficult because of the rigidity of the chamber. However, the glass side arms of the tubes may be cut shorter tuallow for a more compact arrangement that could he fitted into a large stainless steel Dewar fir simultaneous degassing. The tubes described earlier' have the advantage of allowing pipet access to the contents and they are less expensive than the Reaeti-Therma vials. These vials come in different sizes and the vacuum closures are simpler to operate and more secure than the comparable tubes with the O-ring closures. We appreciate the support of the Robert A. Welch Foundation for partial support of the chemical studies, Mr. Stacy Elkins for a beautiful machine tool fabrication, and Ikan C. Austin for the photography. ~
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'Wubbels, G. G., J. CHEM. EDUC., 54,49 (1977). *Pierce Chemical Company, Box 117, Rockford, 111.G1105. 3The Southern New England Ultraviolet Co., 954 Newfield St., Middletown, Conn. 06457. Trinity University S a n Antonio, Texas 78284
Benjamin F. Plurnmer
Volume 55. Number 1 I. November 1978 1 719
