Thermogravimetric evidence of nickel or copper isomorphously substituted into a zeolite

The synthesis of pure silica ZSM-5 has been modified to produce highly crys talline material in the protonated form, necessary for catalytic activity, directly from a low water fluoride gel. Tetrahedrally co-ordinated divalent species of nickel and copper have been synthesised as salts of large organ ic cations and increasing mole fractions incorporated into the zeolite gels . The products have been analysed and characterised using simultaneous ther mogravimetric and derivative thermogravimetric analysis (TG-DTG). The therm al decomposition under nitrogen of the metal associated cations, tetraethyl ammonium (TEA(+)), occluded within the zeolite channels is indicative and c haracteristic of the incorporation of heteroatoms into the zeolite framewor k. Anomalous losses in the systems can be explained by Jahn-Teller distorti ons. The mass losses increased with increased metal loading and were consis tent with those reported in full water system, analysis also confirmed that the material was hydrophobic and thermally stable. Analysis by X-ray diffraction (XRD), scanning electron microscope (SEM), X- ray fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR) and Atomic Absorption Spectroscopy (AAS) has confirmed the reliability of TG-DT G as a diagnostic tool. The maximum levels of substitution achieved were (m ass%) Ni 3.93 and Cu 4.38.