Synthesis, characterization and catalytic performance of hierarchical TS-1 with carbon template from sucrose carbonization

Desilication of TS-1 zeolite for the oxidation of bulky molecules

“…This sample exhibits a catalytic activity for small molecules comparable to the original TS-1 (62% vs. 61% conversion), whereas for bulky organic molecules a 400% increase in the catalytic activity is observed. These results open the possibility to get promising mesoporous zeolites for the epoxidation of bulky molecules unlocking the potential of this catalyst in industrial applications, despite the lower crystallinity of the as-synthesized mesoporous TS-1 zeolites as compared with other hierarchical TS-1 obtained by desilication with NaOH [6,8,[14][15][16][17]22]. Taking into account that the oxidation activity of Ti-containing zeolites is correlated to the framework titanium content, the catalytic performance of our hierarchical zeolites in oxidation reactions confirm that: i) a part of the tetrahedral Ti species remain in the structure of the zeolite TS-1 after the desilication treatment, ii) these Ti-active centers are accessible to bulky organic molecules, and iii) in the absence of kinetic restrictions, these centers remain the intrinsic catalytic activity of the Ti sites in the original TS-1.…”

“…Catalytic activity of titanium-containing materials is related to the coordination of the Ti active sites and, more specifically, to the tetrahedrally coordinated Ti(IV) sites, which can be easily analyzed by UV-vis spectroscopy [16,[20][21][22]. The parent zeolite shows a band centered at 210-220 nm, which corresponds to isolated tetrahedrally coordinated Ti species, together with a broad shoulder between 250-290 nm associated with highly coordinated (oligomeric) Ti [6,[20][21][22]. The presence of extra-framework TiO 2 , usually observed at 330 nm and upwards, is negligible [22].…”

“…In order to minimize diffusional limitations in the microporous network of MFI zeolites, several approaches have been developed in the last few years to induce intra-crystalline mesoporosity including hard templating [4][5][6], soft templating [7,8], demetalation [9][10][11][12][13][14][15] and modified crystallization methods [16,17]. Unfortunately, several of these approaches provide structures which are not hydrothermally stable in a manner similar to nanocrystalline zeolites.…”

Effect of triethylamine treatment of titanium silicalite-1 on propylene epoxidation

“…Since titanium silicalite-1 (TS-1) was invented by Taramasso et al [4] in 1983, it has attracted much attention for its excellent catalytic performance in the selective oxidation of various organic compounds with dilute H 2 O 2 as oxidant under mild conditions, such as the oxidation of alkanes, the epoxidation of alkenes, the hydroxylation of aromatics, and the ammoxidation of ketones [5][6][7][8][9][10][11]. The invention of TS-1 also opened a new route for the manufacture of PO.…”

Synthesis of hierarchical structured porous MoS2/SiO2 microspheres by ultrasonic spray pyrolysis

“…Their multiscale porosity has advantages of rendering size and shape selectivity with microand mesopores and favouring the diffusion and accessibility to the active sites by large molecules with the macropores. A variety of hierarchical structured materials have been developed (Lin et al, 2010;Lemaire and Su, 2011;Stevens et al, 2011;Wang et al, 2011), and a recent excellent review summarised these results (Yang et al, 2011).…”