Matheson highest purity tank chlorine was passed through a tube of resublimed ** f into an evacuated Pyrex system where it was condensed with liquid air. It was then distilled at least three times from a trap at - 78 ` to a liquid air trap with only a small middle fraction being retained in each distillation. The purified product was stored at - 78 ` in a tube equipped with a break seal.

Of several methods employed for tagging chlorine with radiochlorine, the exchange of inactive chlorine with tagged aluminum chloride at room temperature was found to be the most satisfactory. To prepare the latter, silver chloride was precipitated from a solution containing ** f obtained from the Oak Ridge National Laboratory. The silver chloride was fused under vacuum in the presence of aluminum chips with the resultant product of ** f which was sublimed into a flask on the vacuum line. Previously purified chlorine was subsequently admitted and the exchange was allowed to take place. The radiochlorine was stored at - 78 ` in a tube equipped with a break seal.

Liter quantities of Mallinckrodt, low sulfur, reagent grade carbon tetrachloride were saturated with ** f and ** f and illuminated for about 50 hours with a 1000 watt tungsten lamp at a distance of a few inches. The mixture was then extracted with alkali and with water following which the carbon tetrachloride was distilled on a Vigreux column, a 25% center cut being retained which was then degassed under vacuum in the presence of ** f. Purified inactive chlorine was then added from one of the tubes described above and the mixture frozen out and sealed off in a flask equipped with a break seal. This chlorine carbon tetrachloride solution was illuminated for a day following which the flask was resealed onto a vacuum system and the excess chlorine distilled off. The required amount of carbon tetrachloride was distilled into a series of reaction cells on a manifold on a vacuum line. The desired amounts of inactive chlorine and radioactive chlorine were likewise condensed in these cells on the vacuum line following which they were frozen down and the manifold as a whole was sealed off. The contents of the manifold for liquid phase experiments were then mixed by shaking, redistributed to the reaction tubes, frozen down, and each tube was then sealed off. The reactants for the gas phase experiments were first frozen out in a side arm attached to the manifold and then allowed to distill slowly into the manifold of pre-cooled reaction cells before sealing off. This method in general solved the problem of obtaining fairly equal concentrations of reactants in each of the six cells from a set.