The bell-shaped pH rate profile for the reaction of tetrahydrofolic acid with formaldehyde to form 5, lo-methylene tetrahydrofolic acid has been shown to result from a change in rate-determining step with changing acidity. In alkaline solution, the rate-determining step is the acid-catalyzed dehydration of hydroxymethyl tetrahydrofolic acid and its conjugate base. This step is subject to genera...

In this study, three raw Brazilian clays from Joao Pessoa, Paraiba State (Aco AP, AVL and Verde Lodo) were characterized before after purification acid activation. Several instrumental techniques used, the classified as dioctahedral smectites with different compositions, where sample had highest content of montmorillonite. addition, analyses showed modification in clay mineral mainly due to rem...

Glucose is one of the primary derivative products from lignocellulosic biomass, which abundantly available. has excellent potential to be converted into valuable compounds such as ethanol, sorbitol, gluconic acid, and levulinic acid (LA). Levulinic an exceptionally promising green platform chemical. It comprises two functional groups, ketone carboxylate, acting highly reactive electrophiles for...

1-Methyl-3-(2-oxyethyl)-1H-Imidazol-3-ium-Borate Sulfonic Acid ([MOEI]-BSA) was easily prepared and used as a new and highly efficient solid acid catalyst for the synthesis of benzimidazole derivatives with high isolated yields. Various substituted benzimidazoles were synthesized by a combination of o-phenylenediamines and aldehydes in the presence of [MOEI]-BSA with excellent yields in water a...

The methods of thermal analysis – thermogravimetry, differential were used to study the catalytic system phosphor-molybdenum heteropoly acid–aluminum oxide. It is shown that modification aluminum oxide has a direct effect on state acid. On surface ƞ-Al2O3, phosphomolybdic acid destroyed by interaction with strong Lewis’s sites carrier, while γ-Al2O3 it retains individuality, probably due multi...

2,5 hexadione is produced from cellulose using ZrW in the presence of hydrogen while lactic acid is the main product in helium atmosphere. FTIR and kinetics studies strengthened the proposed mechanism which involves as important elementary steps hydroxyls abstractions and hydride transfers promoted by the Lewis acid sites of ZrW. Moreover the important increase of cellulose conversion in the pr...

Methyl benzoate (MB) compounds are prepared by reacting various benzoic acids with methanol using an acidic catalyst. In this study, the solid of zirconium metal solids fixed substances were studied. We determined that catalysts Ti had best activity. The catalytic synthesis a series MB titanium was direct condensation acid and metallic Lewis without other auxiliary Bronsted is reported for firs...

Silica Vanadic Acid, SVA, (oxo-vanadium has been supported on silica) as a dual Lewis and Bronsted acid ability was prepared and efficiently catalyzed one-pot multi-component condensation of enolizable ketones or alkyl acetoacetates with aromatic aldehydes, acetonitrile and acetyl chloride. The described reaction was produced β-acetamido ketone or ester derivatives in high to excellent yields i...