Authors:C. Ribeiro, M. Crespi, L. Guinesi, C. Guerreiro, and H. Zorel
Tin(II) complexes with 8-hydroxyquinolinate in solid state have been obtained by adding aqueous ammonium to a solution containing
stannous chloride and 8-hydroxiquinoline in medium of HCl and acetone up to pH 5 and 9, respectively. The products obtained
show the same composition, Sn(C9H6ON)2; however there are some differences regarding both the thermal behaviour in an oxidant atmosphere and morphology. These products
were characterised by elemental and complexometric analysis, TG and DTA curves, infrared and X-ray diffractometry. TG curves
show, above 448 K, the partial oxidation on air atmosphere of Sn(II) complexes to Sn(IV) complexes, SnO(C9H6ON)2. This behaviour does not depend only on pH in which the compounds were obtained but also on the heating rate in TG curves.
Sn(II) complexes volatilise almost completely on nitrogen atmosphere and partially on air atmosphere depending on the oxidation
degree of the compound.
Jntti introduced a method to reduce the time required for the stepwise measurement of adsorption isotherms. After each pressure
change he measured the adsorbed mass three times and calculated its equilibrium value at the new pressure. In the present
paper, we discuss the applicability of this method in a broader scope without starting from a given combination of sorptive
and adsorbent and the influence of measuring inaccuracies. The method is applied to detect whether the adsorption process
is based on more than one adsorption mechanism or not.