Efficient deprotection of Boc group in amines and sulfamides using Dawson heteropolyacid catalyst

A series of sulfamides containing two protecting groups have been synthesized starting from N-benzoylaminoacids derivatives of (glycine, alanine, valine, leucine, phenylalanine), chlorosulfonylisocyanate and primary amines. Selective deprotection of the cyclic or linear sulfamides and amines has been achieved by treatment with heteropolyacid, which is easily recoverable and reusable. This method represents a reasonable alternative to the previous reported deprotection procedures

Wells-Dawson Polyoxometelates [HP2W18-nMonO62]Fe2.5, xH2O; n = 0, 6: Synthesis, spectroscopic characterization and catalytic application for dyes oxidation

International audienceThe synthesis, IR, 31P NMR and cyclic voltammetry characterizations of new Wells-Dawson-type heteropolyanions that contain iron, HFe2.5P2W18O62, 23H2O and HFe2.5P2W12Mo6O62, 22 H2O, are reported. The catalytic activity of these compounds was evaluated through the oxidation of methyl violet dye, by hydrogen peroxide. The influence of different parameters such as the initial pH, the initial H2O2 concentration, the catalyst mass, and the initial dye concentration have been studied

Synthese et proprietes d'heteropolyanions vanado-molybdo-tungsto-phosphoriques en vue d'une application en catalyse d'oxydation

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Catalytic oxidation of naphtol blue black in water: Effect of Operating Parameters and the Type of Catalyst

The main objective of this work is to study the oxidation of naphthol blue black (NBB) in aqueous solution by hydrogen peroxide using a recyclable Dawson type heteropolyanion [H1.5Fe1.5P2W12Mo6O61.23H2O] as catalyst.The effects of various experimental parameters of the oxidation reaction of the dye were investigated. The mineralization of the dye was investigated by the total organic carbon (TOC) measurement in optimum conditions. The influence of the catalyst nature (Dawson- type iron -substituted heteropolyanion) and (Dawson- type copper -substituted heteropolyanion) on the oxidation process was investigated. The catalytic oxidation using a recyclable heteropolyanions as catalysts is an economically and environmentally friendly process to remove the toxicity of the recalcitrant compounds in water

Effect of Heteropolyanions of Dawson Type on the Development of the Bacteria (Staphylococcus Aureus and Echerichia Coli)

The objective of this study is to test the inhibiting activity of new molecules of heteropolyanions synthesized such as (K6P2W18, H6P2W18, K6P2W12 MO6, H6P2W12 MO6) with respect to two bacterial strains (Staphylococcus aureus and Echerichia coli). The sensitivity of these two strains to the molecules of heteropolyanions is evaluated by the inhibiting minimal concentration (IMC) in liquid medium by the technique of the macro method. The tests of the latter proved a remarkable effectiveness

Complexation de l’aluminium par des hétéropolyanions lacunaires : Récupération par membrane liquide émulsionnée

L'objectif visé par cette étude est la dépollution des eaux à partir de la complexation d’un métal toxique, l’aluminium en solution, par des hétéropolyanions lacunaires (HPA) de type Dawson. Les complexes formés sont récupérés par membrane liquide émulsionnée (MEL).Les résultats de la complex1ation de l’aluminium pars deux hétéropolyanions : (α2P2W17O61)10- et (P2W15Mo2O61)10- se sont avérés très intéressants. Les constantes de stabilité des complexes formés Al3+ (α2P2W17O61)7- et Al<sup3+ (P2W15Mo2O61)7- sont respectivement : β1=6,12.107et β2 =1,28.106. En ce qui concerne la récupération des complexes formés, par (MEL), le rendement d'extraction est de 86% pour Al3+ (α2P2W17O61)7-, pour un temps de contact de 4min, et de 91 % pour Al 3+ (P2W15Mo2O61)7-, pour un temps de contact de 6min.Mots clés : hétéropolyanions; aluminium; complexation; extraction; membrane liquide émulsionné

Etude de l’oxydation d’un colorant organique AO7, par H2O2, en présence d’un catalyseur de type dawson-Well

Ce travail est consacré à l’application d’un hétéropolyanion de type Dawson, substitué au fer [H₁,₅Fe₁,₅P₂W₁₂Mo₆O₆₁,22H₂O] dans la réaction d’oxydation d’un colorant azoïque (l’acide orange 7) en présence de H2O2 . Les conditions opératoires favorisant la réaction d’oxydation de l’acide orange 7 (pour une concentration initiale égale à 30 mg/L) sont: pH initial de la solution: 3, masse du catalyseur [H₁,₅Fe₁,₅P₂W₁₂Mo₆O₆₁,22H₂O]: 0,006g, concentration en H2O2 : 0,05mmol, T=25°C .Mots clés: Oxydation- hétéropolyanions- acide orange7- colorants azoïquesEnglish Title: Oxidation study of an organic dye AO7 by H2O2, in the presence of a Dawson-Well type catalystEnglish AbstractThe main objective of this work was to study the degradation of Acid Orange 7 (AO7) dye in an aqueous solution by a homogeneous catalytic system based on hydrogen peroxide and a recyclable DAWSON type heteropolyanion [H₁,₅Fe₁, ₅P₂W₁₂Mo₆O₆₁,22H₂O]. Effects of various experimental parameters of the oxidation reaction of the dye were investigated. The studied parameters were the initial pH, the initial H2O2 concentration, the catalyst mass, temperature and the dye concentration.The optimal conditions for a maximum discoloration efficiency are:pH: 3, Catalyst mass: 0.006g, [H2O2]0 :0.05mmol, T=25°C .Keywords: oxidation, heteropolyanions, acid orange 7, azo dy