kaolin-so3h as a new solid acid is prepared via reaction of kaolin and chlorosulfonic acid. this natural based catalyst is very inexpensive and easy available. imidazoles are an important class of heterocycles being the core fragment of different natural products and biological systems such as anti-allergic, anti-inflammatory, analgesic, antifungal, antimycotic, antibiotic, antiulcerative, anti...

A highly reactive and acidic chiral Brønsted acid catalyst, chiral N-triflyl phosphoramide, was developed. Highly enantioselective Diels-Alder reaction of alpha,beta-unsaturated ketone with silyloxydiene was demonstrated using this chiral Brønsted acid catalyst.

3,4-ِdihydropyrano[c]chromene derivatives were synthesized using sulfonic acid functionalized silica (sio2-pr-so3h) as a highly efficient heterogenous solid acid catalyst via one-pot three-component condensation of aromatic aldehydes with malononitrile and 4-hydroxycoumarin in excellent yields.

Previous studies on hydroformylation of methyl oleate with rhodium and triphenylphosphine or triphenylphosphite have led to a laboratory process for recycling the precious metal catalyst. Another catalyst recycling process has now been studied as the basis for converting commercially available oleic acid into the enol ether of methyl formylstearate. The process involves one-step esterification-...

14-aryl- and 14-alkyl-14-h-dibenzo [a,j]xanthenes are prepared from the reaction of aromatic- and aliphaticaldehydes with β-naphthol in the presence of catalytic amounts of 4-dodecylbenzenesulfonic acid(dbsa) as asurfactant-type brønsted acid catalyst in toluene and under solvent-free conditions in excellent yields and shortreaction times. the catalyst was recovered and reused for five successi...

Nano silica sulfuric acid as a solid acid, was described to be an effective catalyst for one-pot three-component reaction of kojic acid, aryl aldehydes and indoles for the preparation of 2-substituted aryl (indolyl) kojic acid derivatives. The catalyst was prepared by combination of chlorosulfonic acid to nano silica gel. The size of nanoparticles were observed with SEM.All prepared compounds w...

A series of arylidine barbituric acid derivatives was synthesized by Knoevenagel condensation reaction of aromatic aldehydes with barbituric acid or thiobarbituric acid using dodecylbenzenesulfonic acid as a Brønsted acid-surfactant catalyst in aqueous media. Regardless of the nature of the substitution (electron-donating and -withdrawing), all the reactions were completed within 15-65 min in w...

the catalytic oxidation of toluene to benzoic acid in the liquid phase has been studied in an un-stirred tank reactor. low concentration of acetic acid was added in order to increase the solubility of the catalyst in toluene. the dependence of the rate of reaction on the concentration of toluene catalyst and oxygen pressure was studied. it has been suggested that liquid phase oxidation of tolue...

Mesoporous MCM-41 was coated on Fe3O4 nanoparticles and then functionalized with sulfurochloridic acid to provide a core-shell solid acid nano-catalyst. The catalyst was characterized by transmission electron microscopy (TEM), infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TG), Brunauer-Emmet-Teller analysis (BET) and vibrating sample magnetometery (VSM). The...