Isothermal kinetics of titanium-oxo-alkoxy clusters formation

Abstract

In this article, the influences of titanium tetraisopropoxide Ti(OR)4 (R = Pri) concentration, molar ratio, h = [H2O]/[Ti(OR)4], and temperature, on the formation kinetics of the titanium-oxo-alkoxy clusters (TOAC), were studied. The TOAC formation isothermal kinetics was monitored by measuring absorbance changes versus time in the reaction mixture at predefined wavelength λ = 350 nm. It was determined that the isothermal rate of clusters formation is a power law function of titanium tetraisopropoxide concentration and the molar concentration of water (cw). The kinetic parameters α and β were calculated. The apparent activation energy Ea values in the clusters formation reaction has been calculated and correlated with the change of titanium tetraisopropoxide concentration and molar ratio. The model for mechanism of TOAC formation is proposed.

U ovom radu ispitivani su uticaji koncentracije, titan izopropoksida Ti(OR)4 (R = Pri), molskog odnosa, h = [H2O]/[Ti(OR)4], i temperature,na kinetiku formiranja titan okso-alkoksi klastera (TOAC). Izotermna kinetika formiranja TOAC praćena je snimanjem promene apsorbanse sa vremenom u reakcionoj smeši, na predefinisanoj talasnoj dužini λ = 350 nm. Utvrđeno je da je brzina izotermnog formiranja klastera stepena funkcija koncentracije titan izopropoksida i molarne koncentracije vode (cw). Kinetički parametri α i β su izračunati. Vrednosti prividne energije aktivacije Ea u reakciji formiranja klastera su izračunate i povezane sa promenama koncentracije titan izopropoksida i molskog odnosa h. Predložen je model mehanizma formiranja TOAC.