Zone freezing, as a particular application of zone refining, is proposed for the purification of liquid organic materials. Thermoelectric refrigerators were used for producing frozen zones. The apparatus allowed the passage of three freezing zones through the sample during a single run. Fluorescence analysis indicated that the concentration of impurities in benzene could be lowered to 0.5 p. p. m. by several passages through the three-zone column. The segregation coefficients of several impurities in benzene were determined. The separation of xylene isomers and the concentration of alcohol in aqueous solution are also discussed.
