Oxidation of 2,3,6-Trimethylphenol over Ti- and V-Containing Mesoporous Mesophase Catalysts: Structure–Activity/Selectivity Correlation

Titanium-monosubstituted polyoxometalates: relation between homogeneous and heterogeneous Ti-single-site-based catalysis

“…The oxidation of alkylphenols with H 2 O 2 over Ti,Siand Ti-POM-catalysts has been studied using 2,3,6-trimethylphenol (TMP) as model substrate [73][74][75][76][77]135,136]. For both types of catalysts we found the same products, 2,3,5-trimethyl-1,4-benzoquinone (TMBQ, vitamin E precursor) and 2,2´,3,3´,5,5´-hexamethyl-4,4´-biphenol (BP) (scheme 5).…”

“…The higher [TMP]/[Ti], the higher yield of BP [73,135]. Based on the product study, a homolytic oxidation mechanism that implicates the formation of phenoxyl radicals, the coupling of which gives BP, was assumed [73,135].…”

“…To overcome the steric limitation of TS-1, a considerable amount of research was focused on the preparation of titanium-containing materials with lager pores [29][30][31][32][33][34][35][36][37][38][39][40][41]63]. In the late 1990s, we also started our activity in the development of mesoporous Ti,Si-catalysts for selective oxidation of bulky organic substrates with H 2 O 2 [71][72][73][74][75][76][77][78][79]. For successful designing new catalysts and processes, we needed a basic knowledge about the mechanism of the formation of active titanium species and the mechanisms of their interaction with organic substrates.…”

Efficient Oxidation of 2,3,6-Trimethyl Phenol using Non-Exchanged and H+ Exchanged Manganese Oxide Octahedral Molecular Sieves (K-OMS-2 and H–K-OMS-2) as Catalysts

“…Fenton's reagent [13] (FeSO 4 /5% H 2 O 2 ) system afforded 100% conversion with 99.9% selectivity to TMQ after a 3 h reaction period. Ti-based catalysts have also been studied for the synthesis of TMQ in a one-step reaction with high conversion and selectivities after a 30 min reaction period [14][15][16][17][18][19].…”

Titanium-Doped Solid Core-Mesoporous Shell Silica Particles: Synthesis and Catalytic Properties in Selective Oxidation Reactions

“…Syntheses of mesostructured titanium-silicates, such as Ti-MCM-41 [13,14], Ti-HMS [15], Ti-TUD-1 [16], Ti-MMM-2 [17] and some other, can serve as an example of the successful utilization of such an approach. These materials have attracted considerable attention as catalysts for selective oxidation of bulky organic substrates using green oxidant-aqueous hydrogen peroxide [18][19][20][21][22][23][24].…”