Dudik O. Adsorption and chemical transformations of aliphatic amines with different structure on the fumed oxides' surface.

The thesis is devoted to the studying of the adsorption-desorption processes and chemical transformations of aliphatic and biologically active amines on the surface of dispersed oxides. This is due to the presence of bridge acidic sites on the surface of mixed oxides. Adsorption of amines on the silica surface increases symbatically with increase in their basicity in aqueous solutions. The stepwise mechanism of desorption of amines from the silica surface has been established by thermogravimetric and TPD MS methods. Amine is desorbed in a molecular form in the first and second stages. Third - a high-temperature stage, occurs with the release of deamination product - the corresponding alkene, the fourth stage is due to desorption of ammonia. The linear correlation "structure-reactivity" between the Taft's substituent constants and the activation energy of the reaction of alkenes' formation from primary aliphatic amines on the silica surface has been obtained (E?=-56,5·??*+125, R2=0,990). Thermolysis stages have been identified, kinetic parameters have been calculated and mechanisms of thermal transformation of the primary amines using TPD MS have been proposed. The thermolysis stages for anaesthetics in condensed state and on silica surface have been identified. It has been established that the maximum values of the adsorption of anesthetics are observed in the range of pH (~ 8.0) close to the value of pKa of anesthetics (pKa = 7.9 - for lidocaine, pKa = 8.9 - for novocaine), i.e. in the range of pH which is optimal for realization of biological effect of anesthetics.