Epoxidation of Styrene by Anhydrous t-Butyl Hydroperoxide over Au/TiO₂Catalysts

Thiolate‐Protected Aun Nanoclusters as Catalysts for Selective Oxidation and Hydrogenation Processes

“…Briefly, the Au 25 (SR) 18 nanoclusters (1 nm in diameter, where R stands for ÀCH 2 CH 2 Ph or long-chain alkyl groups such as ÀC 6 H 13 and ÀC 12 H 25 ) were synthesized through a kinetically controlled synthetic approach starting with HAuCl 4 . [12,13] The Au 38 (SR) 24 clusters (1.3 nm in diameter) were synthesized by two-phase thiol etching of Au n (SG) m clusters (where, ÀSG ¼ glutathionate) at elevated temperature (80 8C). [14] Both Au 25 (SR) 18 and Au 38 (SR) 24 clusters have been characterized well in our previous work.…”

“…[12,13] The Au 38 (SR) 24 clusters (1.3 nm in diameter) were synthesized by two-phase thiol etching of Au n (SG) m clusters (where, ÀSG ¼ glutathionate) at elevated temperature (80 8C). [14] Both Au 25 (SR) 18 and Au 38 (SR) 24 clusters have been characterized well in our previous work.…”

“…The ultrasmall Au 25 (SR) 18 , Au 38 (SR) 24 , and Au 144 (SR) 60 nanoclusters may be described as superatoms. [17][18][19][20][21] These Au n (SR) m superatoms possess a non-crystallographic atomic packing structure (i.e., no translational symmetry in the metal core, [13] which is in contrast with larger face-centered cubic (fcc) crystalline Au nanoparticles.…”

“…This structure apparently possesses a non-closed exterior shell, that is, only twelve of the twenty faces of the icosahedral core (Au 13 ) are capped by twelve Au atoms, leaving eight faces open; these sites may act as catalytically active sites. Although the crystal structures of both Au 38 (SR) 24 and Au 144 (SR) 60 have not been attained so far, theoretical predictions have been made recently. [22,23] The lowest-energy structure of Au 38 (SR) 24 is predicted to be composed of a face-fused bi-isocahedral Au 23 core protected by six Au 2 (SR) 3 extended motifs and three RSÀAuÀSR simple motifs; [22] among the motifs, the six Au 2 (SR) 3 are evenly distributed on the two icosahedral Au 13 subunits, while the three Au(SR) 2 motifs bridge the two icosahedral units.…”

Zeolite-Y encapsulated VO[2-(2′-hydroxyphenyl)benzimidazole] complex: investigation of its catalytic activity towards oxidation of organic substrates

“…Similarly, styrene oxidation holds substantial interest in academic as well as industrial research owing to its imperative products such as styrene oxide, benzaldehyde or phenylacetaldehyde which are otherwise synthesized by using strong oxidants such as peroxyacids, manganese dioxide, chromic acid, potassium dichromate or selenium dioxide, producing large amounts of undesired and/or toxic wastes, most significantly when applied to industrial processes [8][9][10][11][12][13][14]. On the other hand, oxidation of cyclohexane to cyclohexanol and cyclohexanone (K/A oil) has achieved much attraction in industries as the two are strategic intermediates in the production of adipic acid (to make Nylon-66) and caprolactam (to make Nylon-6).…”