Studies of the interaction between CuCl and HY zeolite for preparing heterogeneous Cu I catalyst

Abstract

The interaction between CuCl and HY (Si/Al=20) zeolite under inert nitrogen gas atmosphere has been studied by TG/TGA, XRD, 27 Al MAS NMR, and 29 Si MAS NMR spectra. CuCl is easy to sublimate and disperse on the surface of the zeolite. But if CuCl was adsorbed on the cage of the zeolite, it was unlikely to be desorbed from the zeolite at over 800°C. The ion-exchange of Cu I in solid CuCl with H + in HY zeolite occurred at over 300°C and the maximum ion-exchange rate was reached at 340°C under a heating rate of 10°C/min, with the consequent release of HCl gas. And it was found that CuCl promotes the dealumination of framework aluminium of the HY zeolite and probably reacted with the extra framework aluminium to form (AlO)Cl. During the heating treatment, the unique structure of the Y zeolite was kept and CuCl crystalline phase was unlikely to disappear because the powder XRD pattern of CuCl crystalline phase was still observed when the CuCl/HY sample was treated at 350°C for 60 h and 650°C for 5 h. Over 100% ion-exchanged degree of the Cu I with H + in HY zeolite was obtained at high treatment temperature (650°C or over) due to the reaction between defect –Si–OH and CuCl to form –Si–OCu.