A Highly Chemoselective, Diastereoselective, and Regioselective Epoxidation of Chiral Allylic Alcohols with Hydrogen Peroxide, Catalyzed by Sandwich-Type Polyoxometalates: Enhancement of Reactivity and Control of Selectivity by the Hydroxy Group Through Metal—Alcoholate Bonding.

ChemInform ◽  
2003 ◽  
Vol 34 (27) ◽  
Author(s):  
Waldemar Adam ◽  
Paul L. Alsters ◽  
Ronny Neumann ◽  
Chantu R. Saha-Moeller ◽  
Dorit Sloboda-Rozner ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Hydroxy Group ◽  
Allylic Alcohols ◽  
Sandwich Type ◽  
And Control ◽  
Sandwich Type Polyoxometalates

A New Highly Selective Method for the Catalytic Epoxidation of Chiral Allylic Alcohols by Sandwich-Type Polyoxometalates with Hydrogen Peroxide

Synlett ◽  
2002 ◽  
pp. 2011-2014 ◽  
Author(s):  
Rui Zhang ◽  
Waldemar Adam ◽  
Paul L. Alsters ◽  
Ronny Neumann ◽  
Chantu R. Saha-Möller ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Allylic Alcohols ◽  
Selective Method ◽  
Catalytic Epoxidation ◽  
Sandwich Type ◽  
Sandwich Type Polyoxometalates

The role of copper ions in hydrogen peroxide bleaching: Their origin, removal, and effect on pulp quality

TAPPI Journal ◽  
2012 ◽  
Vol 11 (7) ◽  
pp. 37-46 ◽  
Author(s):  
PEDRO E.G. LOUREIRO ◽  
SANDRINE DUARTE ◽  
DMITRY V. EVTUGUIN ◽  
M. GRAÇA V.S. CARVALHO
Keyword(s):  
Hydrogen Peroxide ◽  
Copper Ions ◽  
Peroxide Bleaching ◽  
Metals Removal ◽  
Peroxide Decomposition ◽  
Equipment Corrosion ◽  
And Performance ◽  
And Control ◽  
Main Effects

This study puts particular emphasis on the role of copper ions in the performance of hydrogen peroxide bleaching (P-stage). Owing to their variable levels across the bleaching line due to washing filtrates, bleaching reagents, and equipment corrosion, these ions can play a major role in hydrogen peroxide decomposition and be detrimental to polysaccharide integrity. In this study, a Cu-contaminated D0(EOP)D1 prebleached pulp was subjected to an acidic washing (A-stage) or chelation (Q-stage) before the alkaline P-stage. The objective was to understand the isolated and combined role of copper ions in peroxide bleaching performance. By applying an experimental design, it was possible to identify the main effects of the pretreatment variables on the extent of metals removal and performance of the P-stage. The acid treatment was unsuccessful in terms of complete copper removal, magnesium preservation, and control of hydrogen peroxide consumption in the following P-stage. Increasing reaction temperature and time of the acidic A-stage improved the brightness stability of the D0(EOP)D1AP bleached pulp. The optimum conditions for chelation pretreatment to maximize the brightness gains obtained in the subsequent P-stage with the lowest peroxide consumption were 0.4% diethylenetriaminepentaacetic acid (DTPA), 80ºC, and 4.5 pH.

Rational Synthesis, Structure, Magnetism and Electrochemistry of Mixed Iron–Nickel-Containing Wells–Dawson-Fragment-Based Sandwich-Type Polyoxometalates

2009 ◽  
Vol 2009 (34) ◽  
pp. 5194-5204 ◽  
Author(s):  
Israel M. Mbomekalle ◽  
Pierre Mialane ◽  
Anne Dolbecq ◽  
Jérôme Marrot ◽  
Francis Sécheresse ◽  
...  
Keyword(s):  
Sandwich Type ◽  
Sandwich Type Polyoxometalates

scholarly journals Sandwich type polyoxometalates encapsulated into the mesoporous material: synthesis, characterization and catalytic application in the selective oxidation of sulfides

RSC Advances ◽  
2018 ◽  
Vol 8 (49) ◽  
pp. 28249-28260 ◽  
Author(s):  
Elham Naseri ◽  
Roushan Khoshnavazi
Keyword(s):  
Selective Oxidation ◽  
Mesoporous Material ◽  
Room Temperature ◽  
Material Synthesis ◽  
Catalytic Activities ◽  
Oxidation Of Sulfides ◽  
Catalytic Application ◽  
Sandwich Type ◽  
First Time ◽  
Sandwich Type Polyoxometalates

The A-type sandwich POMs of [(HOSnIVOH)3(PW9O34)2]12– (P2W18Sn3) and [(OCeIVO)3(PW9O34)2]12– (P2W18Ce3) were immobilized for the first time into the porous MIL-101 MOF. Their catalytic activities were examined in the oxidation of sulfides to sulfones at room temperature.

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