Efficient and clean epoxidation of methyl oleate to epoxidized methyl oleate catalyzed by external surface of TS-1 supported molybdenum catalysts

Preparation of Methyl Acrylate through Catalytic Aldol Condensation over Cs/TS-1 Catalysts

“…The Ti 2p 3/2 XPS spectra of the Cs-modified TS-1 samples further confirm the validity of such an interaction between Ti species and Cs species (Figure ). For TS-1 and Cs/TS-1-HNO 3 , the Ti 2p 3/2 signal appears at 460.4 eV assigned to the framework tetrahedral Ti species. , For Cs/TS-1 and Cs/TS-1-H 2 O, a significant negative shift of −1.0 eV is observed for the Ti 2p 3/2 signals compared to TS-1 and Cs/TS-1-HNO 3 . This indicates that Cs species addition influences the local chemical state of TiO 4 species due to the formation of Ti–O–Cs linkages and a partial electron transfer from Cs to Ti species alone. , Such a negative shift of XPS signals has also been observed for other alkali metal-modified zeolites .…”

CeOx‐induced oxygen vacancy‐enhanced Pt‐based titanium silicalite‐1 catalysts for selective conversion of levulinic acid

“…As shown in Figure 4B, the absorption peaks around wavenumbers of 1,450 cm −1 and 1,607 cm −1 can be attributed to the adsorption of pyridine molecules on the Lewis acid centers, and the weak absorption peaks around wavenumbers of 1,540 cm −1 , 1,597 cm −1 , and 1,639 cm −1 can be attributed to the adsorption of pyridine ions on the Brønsted acid centers. The peaks observed at 1493 cm −1 and 1,577 cm −1 wavenumber can be assigned to the adsorption of both pyridine ions and pyridine molecules on the Brønsted‐Lewis acid sites 40,41 . The Lewis acid centers possessed by the material are derived from the tetra‐coordinated skeletal titanium, and the formation of the Brønsted acid centers is related to hydroxyl defects on the defective zeolite 41 .…”

“…The peaks observed at 1493 cm À1 and 1,577 cm À1 wavenumber can be assigned to the adsorption of both pyridine ions and pyridine molecules on the Brønsted-Lewis acid sites. 40,41 The Lewis acid centers possessed by the material are derived from the tetra-coordinated skeletal titanium, and the formation of the Brønsted acid centers is related to hydroxyl defects on the defective zeolite. 41 Different types of acid sites play distinct and crucial roles in the lactonization of the intermediate 4-HVA.…”

Bulky olefin epoxidation under mild conditions over Mo-based oxide catalysts

“…A literature survey for Mo-containing silica/silicates tested in the epoxidation of MeOle or MeLin, indicated two previous studies. 104,105 Gao et al 105 reported the epoxidation of MeOle with H 2 O 2 , in the presence of molybdenum supported on the external surface of TS-1, which led to ca. 65% MeOleEp selectivity at ca.…”