Radiocarbon14C study of the catalytic activity of the CaY-CO2, CaY′-CO2, and CaNdY′-CO2 systems in benzene alkylation by ethylene and the interaction of CO2 with zeolites

1.	By14C labeling, it has been shown that carbon dioxide will adsorb differently on various synthetic Ca2+-ion-containing zeolites (CaNaY, and dealuminated CaNaY and CaNdNaY) on which benzene is being alkylated by ethylene. The promoting action of CO2 is due to the presence of a weakly adsorbed form of the compound which can be readily displaced by N2 at the reaction temperature.
2.	The CO2 content of the catalyst and its time variation are dependent on the zeolite composition, the re-action temperature, and the moisture content of the CO2.
3.	Under fixed operating conditions, the CO2 content of zeolite 0.67CaNaY and its time variation are the same for C6H6 alkylation by ethylene and for toluene disproportionation.