Yazar "Yurdakoç, Mehmet Kadir" seçeneğine göre listele

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    Öğe
    Acidity of silica-alumina catalysts by amine titration using Hammett indicators and FT-IR study of pyridine adsorption
    (1999) Yurdakoç, Mehmet Kadir; Akçay, Mehmet; Yurdakoç, Mürüvvet; Tonbul, Yalçın
    In this study, characterization and surface acidity of Siral ($SiO_2-Al_2O_3$) compounds were investigated with Hammett acidity functions, the n-butylamine titration method and FTIR analysis of the spectra of pyridine adsorption. All the samples had an acid strength of $H_oleqle$+2.8. The calculated total amount of acid of the samples increased with the increase in $SiO_2$ content up to Siral 40 and then decreased sharply in the case of Siral 80. Maximum amount of acidity was observed in the case of Siral 40 as 1.37mmole/g. No evidence was found for a band at 1540 $cm^{-1}$ on Pural indicating that there were no Bronsted sites on the surface strong enough to react with pyridine. As a result, we can say that the Lewis sites predominate in all the silica-aluminas.
  • [ X ]
    Öğe
    Thermogravimetric investigation of the dehydration kinetics of KSF, K10 and Turkish bentonite
    (2001) Tonbul, Yalçın; Yurdakoç, Mehmet Kadir
    The kinetic parameters for the dehydration of bentonite from Turkey, KSF and K10 were determined by using dynamic TG techniques. The Ozawa method is better for the dehydration of the clay samples than the first order equation of Coats and Redfern. The former function calculates consistently higher activation energies than the latter. The mean values of the activation energies in the $alpha$ range 0.1-0.7, are 56-66 kJ mol-1 in the Ozawa method.