Chromium-exchanged zeolite (CrE-ZSM-5) as catalyst for alcohol oxidation and benzylic oxidation with t-BuOOH

Lounis, Zoubida; Riahi, Abdelkhalek; Djafri, Fatiha; Мuzart, Jacques

doi:10.1016/j.apcata.2006.05.015

Cited by 54 publications

(36 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In recent years, synthetic and natural zeolites have become increasingly important due to the wide range of their chemical and physical properties and have been studied for the liquid adsorption of dissolved pollutants in water and/or wastewater. A lot of studies have focused on the adsorption of methylene blue a cationic dye by synthesized and natural zeolites [23][24][25][26][27][28][29][30][31][32][33]. The results showed that the adsorption kinetics and isotherms could be well described by the pseudo-second-order model and the two-parameter model (i.e.…”

Section: Introductionmentioning

confidence: 96%

Removal of methylene blue from colored effluents by adsorption onto ZnAPSO-34 nanoporous material

Abbad

Lounis

2014

Desalination and Water Treatment

View full text Add to dashboard Cite

A B S T R A C TThe effects of equilibrium time, solution pH, and sorption temperature of cationic methylene blue (MB) adsorption on nanoporous metallosilicoaluminophosphate ZnAPSO-34 were studied using a batch equilibration method. UV-Vis spectroscopy was used to obtain the adsorption isotherms at 20˚C. The optimum period for adsorption was 300 min. In fact, MB removal increased from 82 to 95% when we double the amount of adsorbent from 0.05 to 0.1 g l À1 . The equilibrium adsorption data were analyzed using Langmuir, Freundlich, and Temkin isotherm models. Langmuir isotherm was found to be the best-fitting model and the process followed pseudo-second-order kinetics. The results showed that ZnAPSO-34 could be employed as an alternative for the removal of dyes and colorants from aqueous solutions.

show abstract

Section: Introductionmentioning

confidence: 96%

Removal of methylene blue from colored effluents by adsorption onto ZnAPSO-34 nanoporous material

Abbad

Lounis

2014

Desalination and Water Treatment

View full text Add to dashboard Cite

show abstract

“…Recently, several studies were reported on synthesis and characterization of chromiumcatalysts supported by mesoporous molecular sieves and zeolites. In them, cation exchange properties of the supports were found to play a fundamental role [4][5][6].…”

Section: Introductionmentioning

confidence: 98%

Chromium removal from water using LTA zeolites: Effect of pH

Basaldella

Vázquez

Iucolano³

et al. 2007

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

“…Among the many synthetic procedures devised for the preparation of aromatic ketones, esters and amides [32][33][34][35][36][37], including Friedel-Crafts acylation, esterification and amidation of benzoic acid derivatives [38][39][40][41][42][43][44][45][46], the oxidation of benzylic methylene compounds stands out as a simple approach that has attracted much attention in the last decades. Many reagents (KMnO 4 , iodine(V) species, t BuOOH, m-CPBA, H 2 O 2 , NHPI, inter alia) can oxidize the activated benzylic position of aromatic alkanes, benzyl ethers, and amines to provide the corresponding arylcarbonyl moiety (Scheme 1) by a process opposite to Clemmensen, Wolf-Kisnerr and related reduction reactions [47][48][49][50][51][52][53][54][55][56][57][58][59][60][61]. Although good yields and selectivities have been obtained in most cases, stoichiometric amounts of relatively harmful or unsafe oxidizing agents are required.…”

Section: Introductionmentioning

confidence: 99%

Recent Advances in Homogeneous Metal-Catalyzed Aerobic C–H Oxidation of Benzylic Compounds

et al. 2018

View full text Add to dashboard Cite

Csp 3 -H oxidation of benzylic methylene compounds is an established strategy for the synthesis of aromatic ketones, esters, and amides. The need for more sustainable oxidizers has encouraged researchers to explore the use of molecular oxygen. In particular, homogeneous metal-catalyzed aerobic oxidation of benzylic methylenes has attracted much attention. This account summarizes the development of this oxidative strategy in the last two decades, examining key factors such as reaction yields, substrate:catalyst ratio, substrate scope, selectivity over other oxidation byproducts, and reaction conditions including solvents and temperature. Finally, several mechanistic proposals to explain the observed results will be discussed. relevant parameters such as reaction yields, substrate:catalyst ratio, selectivity towards target carbonyl compounds, reaction media, and other experimental conditions. Considering that metal complexes and combination of metal salts and ligands have been described as catalysts or precatalysts in this field, this review is organized according to the metal core involved in the reaction. Although mechanism for this transformation is far from being completely elucidated, several proposals will be discussed. Catalysts 2018, 8, x FOR PEER REVIEW 2 of 21Following the pioneering works by Ishii [63-66], cobalt(II) salts combined with N-hydroxyphtalimide (NHPI) derivatives have been amply used for the aerobic C-H oxidation of methylene compounds at atmospheric pressure. An in situ-generated phthalimide-N-oxyl radical (PINO) is proposed to play a key catalytic role as hydrogen atom abstracting species in the reaction, and other N-hydroxylated ligand/additives prone to form related radical species have also been evaluated and compared with NHPI. Among other transition metals, cobalt salts have been defined as promoters Catalysts 2018, 8, 640 3 of 21for the formation of PINO. Nolte and coworkers published the use of 0.5 mol% of Co(OAc) 2 ·4H 2 O combined with NHPI (10 mol%) in acetic acid to perform benzylic oxidation of 2-(hetero)arylacetic esters to the corresponding α-ketoesters at relatively low temperatures (40-80 • C). Lower yields (<30%) were obtained from some o-alkoxylated and brominated substrates, as well as from all the heteroaromatic esters. Finally, with regard to the oxidation of ethylbenzene to acetophenone, several N-hydroxy-phthalimides were evaluated as co-catalysts, achieving good conversion rates (except for nitro-substituted NHPIs) and relatively good acetophenone:1-phenylethanol ratios (59-88:2-5) [94].The solvent-free oxidation of several alkylbenzenes to the corresponding ketones using di-n-decyl-di-methyl ammonium bromide (DDAB) and other phase transfer agents was explored by Patil et al. A 0.5 mol% of the latter quaternary ammonium salt was required along with NHPI (3 mol%) and CoCl 2 ·6H 2 O (1 mol%) to perform the oxidation under oxygen gas flow rate of 110 mL/min at 65 • C, although other metal sources (MnCl 2 (H 2 O) 4 and CrCl 3 (H 2 O) 6 ) and ammonium phase transfer catal...

show abstract

Chromium-exchanged zeolite (CrE-ZSM-5) as catalyst for alcohol oxidation and benzylic oxidation with t-BuOOH

Cited by 54 publications

References 31 publications

Removal of methylene blue from colored effluents by adsorption onto ZnAPSO-34 nanoporous material

Removal of methylene blue from colored effluents by adsorption onto ZnAPSO-34 nanoporous material

Chromium removal from water using LTA zeolites: Effect of pH

Recent Advances in Homogeneous Metal-Catalyzed Aerobic C–H Oxidation of Benzylic Compounds

Contact Info

Product

Resources

About