A pH-dependence of the Brønsted acid-catalyzed oxidation of sulfides to the corresponding sulfoxides with H₂O₂ is reported for the first time based on our systematic investigation of the catalytic performance of a series of Brønsted acids. For all of the Brønsted acids investigated, the catalytic performances do not depend on the catalyst loading (mol ratio of Brønsted acid to substrate), but r...

The silica boron sulfuric acid nanoparticles (SBSANs) as an efficient heterogeneous solid acid catalyst with both Brønsted and Lewis acidic sites catalyzed the preparation of bis-4-hydroxycoumarin derivatives using reaction of aldehydes and 4-hydroxycoumarin under mild and solvent-free condition at room temperature. This new and efficient methodology has advantages in comparison with currently ...

In this account, we summarized our recent efforts to develop molecular transformations under Brønsted base catalysis on the basis of own guiding principles for designing reaction systems, that include “the generation and application anionic species which are difficult utilize in conventional systems” employment organosuperbases possessing much higher basicities than organic bases as a catalyst”...

A highly efficient and simple method for the preparation of α,α´-bis(arylidene)cycloalkanones under solvent-free conditions has been developed. The crossed-aldol condensation of cycloalkanones (1 eq.) with arylaldehydes (2 eq.) in the presence of 2.5 mol% of ionic liquid 1,3-disulfonic acid imidazolium hydrogen sulfate {[Dsim]HSO4} afforded the title compounds in high yields and short reaction ...

For the synthesis of Mequinol (4-methoxy phenol), two acidic ionic liquids based on imidazolium cation (BMSIL and IMSIL) synthesized and characterized by FT-IR, 1H NMR, and CHNS analyses. Tan, the Baeyer–Villiger oxidation of para-anisaldehyde was studied with these ionic liquids, as the catalysts. The results showed that the BMSIL with more Brønsted acidic functions had higher c...

We report on the spectroscopy and photodynamic characterization of Brønsted and Lewis acid sites within solids with respect to the behavior of Nile Red (NR) upon interaction with single- and multi-metal(X)-doped MCM41 materials (X = Ti and/or Al) in dichloromethane (DCM) suspensions. The steady-state results show that the H-bonding ability of doped MCM41-based materials leads to different NR po...