Via the one-pot condensation reaction of ethyl acetoacetate, aromatic aldehydes, 2,4-dinitrophenylhydrazine, and β-naphthol; new pyrazolone derivatives were synthesized in the presence of three Brønsted acid catalysts. These Brønsted acid catalysts are Silica sulfuric acid (SSA), tetra-n-butyl ammonium hydrogen sulfate (TBAHSO4) and [2,2′-Bipyridine]-1,1′-diium tricyanomethanide {[2,2′-BPyH][C(...

A novel study of external Brønsted acid-assisted thiourea catalysts in the asymmetric FriedelCrafts alkylation of indoles with nitroalkenes is reported. The final 3-substituted indoles derivatives are synthesized with better results by cooperative effect between chiral thiourea and a Brønsted acid additive (1a·HA), than those obtained with sole thiourea catalyst 1a. The effect of diverse catal...

The grafting of titania on SBA-15 followed by its phosphation was presented to prepare a mesoporous Lewis–Brønsted bifunctional solid acid catalyst for the tandem conversion glucose via fructose 5-hydroxymethylfurfural (HMF). Titania dispersed as an amorphous surface layer containing abundant coordinatively unsaturated tetrahedral Ti ions, which reactive and readily transformed upon into new ti...

Solution phase titrations are made easy by multi-nuclear FlowNMR spectroscopy with automated, continuous titre addition to give accurate insights into Brønsted acid/base, hydrogen bonding, Lewis acid/base and metal/ligand binding equilibria under native conditions.

The characterization and catalytic performance of Zn/ZSM-5 Zn-B/ZSM-5 catalysts in the n-hexane aromatization was reported. Catalysts were prepared by post-synthesis ion exchange thoroughly characterized means XRD, Py-FTIR, N2 adsorption, 27Al 11B MAS NMR spectroscopy electron microscopy techniques. incorporation zinc reduces Brønsted acid site density increases Lewis acidic sites final ZSM-5 b...

Lactic acid is an important platform molecule in the synthesis of a wide range of chemicals. However, in aqueous solutions without alkali, its efficient preparation via the direct catalysis of sugars is hindered by a side dehydration reaction to 5-hydroxymethylfurfural due to Brønsted acid, which originates from organic acids. Herein, we report that a previously unappreciated combination of com...

Incorporating a hydrophobic Brønsted acid ionic liquid (HBAIL) inside the nanospaces of SBA-15-Pr-SO(3)H led to a hydrophobic super Brønsted acid catalyst, which showed excellent catalytic performance in direct esterification of alcohols and carboxylic acids at ambient temperature under solvent-free conditions.

5-Hydroxymethylfurfural (HMF) synthesis from glucose over in-situ phosphated titania catalysts is presented. Phosphates were incorporated into framework forming a titanium phosphate surface layer, where the coordinatively unsaturated tetrahedral TiO 4 units act as water-tolerant Lewis acid site (LAS) and adjacent protonated Brønsted (BAS), together Lewis-Brønsted pairs at molecular-level proxim...