A gas chromatographic method for the determination of mass‐transfer resistances in zeolite catalysts

The various mass‐transfer resistances that occur in a packed bed of zeolite granules contribute to the gas chromatographic “C” terms that determine the relative width (or second moment) of a gas chromatographic peak. It was assumed that mass transport in the micropores of the crystallites was independent of the nature of the carrier gas. From measurements with hydrocarbon pulses in hydrogen and nitrogen carrier gases, it was possible by the method of Giddings and Schettler to separate the gas phase resistances from the micropore resistances. Data are given for benzene, n‐octane and (in part) n‐decane on Na × zeolite at 370, 400 and 430°C. Experimental difficulties and precautions are discussed.