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In this study, various ionic liquids immobilized onto montmorillonite clay (IL-MMT) were prepared by ion-exchange reaction between the ionic liquids and ions in the clay interlayer. Tetra-alkyl ammonium chlorides were used as the ionic liquid precursors. The IL-MMTs were characterized by elemental analyses (EA), BET, XRD, 13 C NMR, FT-IR, and SEM. The surface areas and d -spacings of the IL-MMTs increased with increasing alkyl chain lengths. The IL-MMTs showed good catalytic activity for the synthesis of the cyclic carbonate from alkyl glycidyl ether (AGE) and carbon dioxide. The effects of the IL cation structure, and reaction parameters such as temperature and CO 2 pressure on the reactivity of IL-MMTs were also discussed. The catalyst could be reused in up to four consecutive runs without a significant reduction in the initial activity.

Mesoporous CrSBA-15 catalysts synthesized with a variety of n Si / n Cr ratios by pH-aDH method were used in the production of enones by the liquid-phase oxidation of benzylic compounds. To investigate the leaching of chromium species on the silica surface, CrSBA-15(8) was chemically treated with ammonium acetate solution while the Cr-containing mesoporous silica catalysts used for these reactions were regenerated by washing and calcinations. The treated catalysts such as washed CrSBA-15 and regenerated CrSBA-15 catalyst were used/reused in these reactions to find their catalytic activities. Furthermore, the influences of various reaction parameters such as temperature, time, ratios of reactant and solvents on the synthesis of tetraline (T O) have been systematically investigated. Based on the catalytic investigations, CrSBA-15(8) catalyst is found to be a highly active, recyclable and promising heterogeneous catalyst for the selective synthesis of enones, and it has superior catalytic activity in the oxidation of benzylic compounds than CrMCM-41.

Two-dimensional mesoporous SBA-15 catalysts synthesized by different hydrothermal methods have been used, for the first time, in the liquid-phase oxidation of α-pinene with t -butyl hydrogen peroxide (TBHP) for the synthesis of verbenone (V O). The recyclable CrSBA-15 catalysts have also been reused in this reaction to find their catalytic activities. To investigate the leaching of chromium species on the silica surface, CrSBA-15(8) has been treated with ammonium acetate solution, and it has been also treated with boiling water for the investigation of hydrothermal stability. The treated CrSBA-15(8) catalyst has been used in the catalytic reaction for finding the effects of catalytic stability. The influences of various reaction parameters such as temperature, time, ratios of reactant (α-pinene-to-TBHP) have been extensively investigated for the synthesis of V O. In addition, the liquid-phase oxidation of α-pinene has been conducted with different solvents to find the best solvent with a good catalytic activity. On the basis of all investigations with a hypothetical reaction pathway of α-pinene oxidation, the CrSBA-15(8) catalyst is found to be a highly active, recyclable and promising heterogeneous catalyst in the liquid-phase oxidation of α-pinene for highly selective synthesis of V O. Furthermore, CrSBA-15(8) catalyst has higher selectivity of V O (88.2%) than other CrSBA-15 and CrMCM-41.

Mesoporous TiSBA-15 catalysts have been synthesized using Pluronic P123 as a structuring agent under pH-adjusting direct hydrothermal (pH-aDH) method. The mesoporous TiSBA-15 catalysts characterized by sophisticated instrumental techniques via. ICP-AES, XRD, N 2 adsorption, FE-SEM, TEM, UV–vis DRS and 29 Si MAS NMR show their two-dimensional mesostructures with tetrahedral titanium on the silica surface. The highly ordered TiSBA-15 catalysts have been used in the liquid-phase oxidation of 2-methyl-1-naphthol (2M1N-OH) with hydrogen peroxide (H 2 O 2 , 30%), for the synthesis of vitamin K 3 (2-methyl-1,4-naphthoquinone). The recyclable TiSBA-15 catalysts have also been reused to find their catalytic activities. The influences of various reaction parameters such as temperature, time, ratios of reactant (2M1N-OH: H 2 O 2 ) have been then investigated in this catalytic reaction for the highly selective synthesis of vitamin K 3 . In addition, the liquid-phase oxidation of 2M1N-OH has been carried out with different solvents to find the best solvent with a good catalytic activity. Based on the all catalytic studies, TiSBA-15(6) catalyst is found to be a highly active and eco-friendly heterogeneous catalyst for the selective synthesis of vitamin K 3 . Furthermore, TiSBA-15(6) catalyst has higher 2M1N-OH conversion (100%) and vitamin K 3 selectivity (93.2%) than other TiSBA-15 and TiMCM-41(40).

Mesoporous GaSBA-15 molecular sieves with different n Si /n Ga ratios have been directly synthesized using Pluronic 123 triblock polymer as a structure-directing agent by pH-adjusting method. The mesoporous materials have been characterized using ICP-AES, XRD, N 2 adsorption, 71 Ga-MAS NMR, SEM and TEM. ICP-AES studies show a high amount of gallium incorporation on the silica pore walls. The structural and textural properties of calcined GaSBA-15 are characterized by XRD and N 2 adsorption. 71 Ga MAS NMR results demonstrate that a high amount of tetrahedral-gallium could be substituted for Si in the framework of SBA-15. TEM and FE-SEM images show the uniform pore diameter and rope-like hexagonal mesoporous structure of GaSBA-15. These GaSBA-15 materials have been used as catalysts for vapour-phase t-butylation of 1,2-dihydroxybenzene (DHB) for selective synthesis of 4-t-butylcatechol (4-TBC) under different reaction conditions. GaSBA-15(10) gave the highest 93.2% conversion of DHB and 95.7% selectivity of 4-TBC as compared with other GaSBA-15 catalysts.