Catalysts for Cyclohexanone Ammoximation Based on TS-1 Titanosilicates Prepared by Controlled Hydrolysis

Among the approaches to the synthesis of crystalline titanosilicates, particular attention is given to the search for the simplest and most efficient methods for controlling the hydrolysis and condensation of silicon and titanium sources. An approach is presented for controlling the physicochemical and catalytic properties of TS-1 titanosilicate prepared by acid-catalyzed co-hydrolysis by varying the H+/Si molar ratio. Increasing the acid concentration leads to the development of a more pronounced porous structure, with the fraction of mesopores increasing by nearly 1.5 times, and alters the coordination state of titanium without promoting the formation of extraframework titanium. The resulting samples were compared with a sample synthesized in the presence of an equimolar amount of base used as a catalyst for the hydrolysis of the silicon and titanium sources. The samples prepared by acid-catalyzed co-hydrolysis exhibit higher activity in solvent-free cyclohexanone ammoximation, with a ketone conversion of 89% and an oxime selectivity of 98%.