A Homemade, High Pressure Gas Cell
Figure 2. Variable temperature high pressure IR cell.
High pressure gas cells for infrared spectroscopicstudies fabricated of metal are commercially available. However, in the study of reactions between gases, metal surfaces may prove deleterious to the process or processes occurring. We have therefore constructed static as kell as variable temperature all glass infrared cells capable of operating a t internal pressure of up t o 7 stm. The static temperture cell (A) (Fig. 1) consists of medium wall 12 mm id Pyrex or Vycor tubing worked to the dimensions shown. The windows ( B )(NaCI andlor KRr) are polished, optically flat 12 X 20 mm plugs (available from the Harshaw Chemical Com~anv. . ..Solon. Ohio) which are held in dace hv two brass facenlates 1CI cut toallow pnsape of radiarwn and drdledaruund the peribhery t("1 toallow placement of -crews lo h & lthe fncp plate 10 the lrrassrheath ilJl.'l'heu.indous rest on tvflcm O.ringi ( E l withm the cell at the constriruun ( A ' )and un Vltm O-rings in a g w w c on the ibrass
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In operation, the cell is assembled, attached to a vacuum rack at the standard taper 10130joint shown (A") and evacuated. Gases are introduced and frozen in the nipple (A"') and the cell sealed with atorch at the constriction below the ioint (A"). Asshown. the total volume of the cell is 10.0 f 0.2 ccand. while lareer cells i a v e heen fabricated: this size has proven mast useful and isconvenient for mounting in a speetrophotometrr by using a drilled and grooved block of wood. A variable temperature cell was also built (Fig. 2) by interposing a water-jacket Figure 1. Static temperature high pressure IR cell. between the glass reaction cell and the hrass sheath. The water-jacket, connected to a constant temperature bath has been used in the temperature range + 10 to +50°C a t total internal pressures of up to 5 atm. Although functional, the cells we describe do suffer the limitation of requiring reattachment of the standard taper 1OI3Ojoint after each use. However, this inconvenience must be borne if metal valves, connectors, ete. are to be avoided. John Tlerney and Davld R. Dabon Temple University Philadelphia. PA 19122
Volume 58
Number 10
October 1981
813
