Uticaj kobalta na nosaču kopolimeru poli-4-vinilpiridina i divinilbenzena na oscilatornu evoluciju reakcije Brej-Liebhafski

Abstract

Bray˗Liebhafsky (Brej˗Liebhafski) reakcija je najstarija poznata homogena oscilatorna reakcija u kojoj se vodonik˗peroksid katalitički razlaže na kiseonik i vodu u prisustvu kalijum˗jodata i sumporne kiseline. Iako na prvi pogled jednostavna, ova reakcija je predmet intenzivnog ispitivanja dugi niz godina, i po eksperimentalno primećenim fenomenima čini jedan od dinamički najbogatijih hemijskih sistema. Zahvaljujući bogatstvu informacija sadržanih u ispoljenim fenomenima dinamike, kao i zbog ekstremne osetljivosti na spoljne uticaje (perturbacije), Bray˗Liebhafsky oscilatorna reakcija se pokazala kao pogodna analitička matrica za testiranje aktivnosti polimera kako u uslovima zatvorenog, tako i u uslovima otvorenog reaktora. U ovoj tezi su realizovana istraživanja u cilju utvrđivanja mogućnosti korišćenja Bray˗Liebhafsky (BL) reakcije kao matrice za testiranje aktivnosti kobalt˗(II)˗nitrata ugrađenog na makroporozni poli˗4˗vinilpiridin kopolimerizovan sa divinilbenzenom. BL matrica je realizovana u zatvorenom, izotermskom i dobro˗mešajućem reaktoru. Ispitivanja obuhvataju dinamiku i kinetiku reakcionih sistema različitih temperatura, koje su činili BL matrica konstantnog sastava i promenljivog sadržaja kobalta na nosaču kopolimeru poli˗4˗vinilpiridina i divinilbenzena (perturbatora). Dinamička i kinetička stanja perturbovane BL matrice su kvalitativno i kvantitativno analizirana na osnovu strukture i kinetičkih parametara (broja oscilacija ˗ n, predoscilatornog perioda ˗ τ1 i dužine oscilograma ˗ τend) jodidnih oscilograma dobijenih potenciometrijskom metodom.

The Bray˗Liebhafsky reaction is the oldest known oscillatory homogeneous reaction in which hydrogen peroxide is catalytically broken down into water and oxygen in the presence of potassium iodate and sulfuric acid. Although apparently simple, this reaction is the subject of intense studies for many years, also recording to a series of experimentally observed phenomena it represents one of the richest dynamic chemical systems. Thanks to the wealth of information contained in the dynamics of the demonstrated phenomena, as well as because of the extreme sensitivity to external influences (perturbations), the Bray˗Liebhafsky oscillatory reaction proved to be a suitable analytical matrix for testing the activity of polymers in terms of both batch and open reactor conditions. In this thesis, the research carried out in order to determine the possibilities of using the Bray˗Liebhafsky (BL) reaction as a matrix for testing the activity of cobalt (II) nitrate supported on macroporous poli˗4˗vinilpiridin copolymerized with divinylbenzene. BL matrix is realized in a batch, isothermal and well stirred reactor. Studies include the dynamics and the kinetics of reaction systems at different temperatures, which consisting of constant composition of the BL matrix and variable content of cobalt supported on copolymer of poly˗4˗vinylpyridine and divinylbenzene (perturbation). Dynamic and kinetic states of perturbed BL matrix was analyzed qualitatively and quantitatively based on the structure and the kinetic parameters (the number of oscillation ˗ n, induction period ˗ τ1 and the length of the oscillogram ˗ τend) of the iodide oscillograms obtained by the potentiometric method.