The Concentration of C13

Abstract

The chemical exchange method has been applied to the separation of the isotopes of carbon. Various exchange reactions have been tested, using counter‐current flow in packed fractionation columns, and of these, the exchange between hydrogen cyanide gas and a solution of sodium cyanide in water has been found to be most efficient. In this exchange, the isotope of carbon of atomic weight 13 (ordinarily present to the extent of 1.06 percent) is concentrated in the gas phase. Suitable conditions for the exchange have been determined, and a satisfactory apparatus has been devised. Using two fractionation units in a cascade arrangement, sodium cyanide, containing carbon of 25 atom percent C¹³, has been produced at a rate of 2.5 grams per day. This corresponds to a transport of 0.15 grams of C¹³ per day. In all, more than 20 grams of carbon, containing 25 percent of C¹³, and additional quantities of less concentrated material, have been obtained in this way.