New types of Lewis acids as water-stable catalysts have been developed. Metal salts such as rare earth metal triflates can be used in carbon–carbon bond-forming reactions in aqueous media. These salts can be recovered after the reactions and reused. Furthermore, Lewis acid–surfactant-combined catalysts, which can be used for reactions in water without using any organic solvents, have been also ...

Protic ionic liquids are synthesized via proton transfer from acids to organic bases. One of the key issues associated with conventional protic ionic liquids is the thermal instability resulting from temperature-induced decomposition via reverse proton transfer. This shortcoming significantly hampers the use of these protic ionic liquids in separations, electrochemical capacitors, fuel cells, a...

Frustrated Lewis pair (FLP) chemistry enables a rare example of alkyne 1,2-hydrocarbation with N-methylacridinium salts as the carbon Lewis acid. This 1,2-hydrocarbation process does not proceed through a concerted mechanism as in alkyne syn-hydroboration, or through an intramolecular 1,3-hydride migration as operates in the only other reported alkyne 1,2-hydrocarbation reaction. Instead, in th...

glucose. The influence of the solution acidity on the deconstruction of Miscanthus giganteus was examined by varying the 1-butylimidazole to sulfuric acid ratio. Increased acidity led to shorter preteatment times and resulted in reduced hemicellulose content in the pulp. Addition of water to the ionic liquid resulted in enhanced saccharification yields. The ability to tune acidity through the u...

Convenient procedure for the synthesis of corresponding pyrano[2,3-d]pyrimidine derivatives were developed via one-pot three-component reaction of aryl aldehyde derivatives, malononitrile with barbituric acids in the presence of copper (II) chloride dihydrate (CuCl2.2H2O) as highly efficient Lewis acid catalyst. This protocol has advantages such as readily and inexpensive catalyst, high reactio...

In this study, multi component Hantzsch reaction was carried out between various  Aromatic Aldehyde with Dimedone,Ethyl acetateand ammonium acetate to produce polyhydroquinolinederivatives under solvent-free conditions at 110oC by a (Zinc oxide  nanocatalyst) as effective Lewis acid. The remarkable advantages offered by this method compared with other methods are a green catalyst, simple work-u...

The grafting and sulfation of zirconia conformal monolayers on SBA-15 to create mesoporous catalysts of tunable solid acid/base character is reported. Conformal zirconia and sulfated zirconia (SZ) materials exhibit both Brönsted and Lewis acidity, with the Brönsted/Lewis acid ratio increasing with film thickness and sulfate content. Grafted zirconia films also exhibit amphoteric character, whos...

Two enantioselective cyanation reactions, the Strecker reaction of ketoimines and the Reissert reaction of pyridine derivatives, promoted by Lewis acid–Lewis base bifunctional asymmetric catalysts are described.

Known as a Lewis acid which acts as a natural catalyst, bentonite can be used to produce several arylidene  (thio) barbituric  acid  derivatives  through  conducting  a  Knoevenagel  reaction  between aromatic aldehydes and (thio) barbituric acid. Water is considered as the medium for this reaction and the results are at arange of good to excellent over a reasonable reaction time. This method i...

Rate coefficients for terminal acetate (g-O2CCH3) substitution from the [Mo3(l3-O)2(l-O2CCH3)6 (g-O2CCH3)3] anion were examined in polar protic (D2O and methanol-d4), polar aprotic (DMSO-d6 and DMF-d7) and acidic solvents (acetic acid-d4). Reaction rates were determined using variable-temperature H NMR and found to span orders of magnitude depending on the solvent (k K (s!1) = 7.2 " 10!6 for D2...