Kinetic Study and Modeling of Peroxypropionic Acid Synthesis from Propionic Acid and Hydrogen Peroxide Using Homogeneous Catalysts

2008 ◽  
Vol 47 (3) ◽  
pp. 656-664 ◽  
Author(s):  
Sébastien Leveneur ◽  
Tapio Salmi ◽  
Dmitry Yu. Murzin ◽  
Lionel Estel ◽  
Johan Wärnå ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Kinetic Study ◽  
Propionic Acid ◽  
Acid Synthesis ◽  
Homogeneous Catalysts

scholarly journals Kinetic study of the inactivation of ascorbate peroxidase by hydrogen peroxide

2000 ◽  
Vol 348 (2) ◽  
pp. 321 ◽  
Author(s):  
Alexander N.P. HINER ◽  
José Neptuno RODRÍGUEZ-LÓPEZ ◽  
Marino B. ARNAO ◽  
Emma LLOYD RAVEN ◽  
Francisco GARCÍA-CÁNOVAS ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Kinetic Study ◽  
Ascorbate Peroxidase

scholarly journals A Kinetic Study of the Reaction of isoPropoxy-methyl-phosphoryl Fluoride (Sarin) with Hydrogen Peroxide.

1958 ◽  
Vol 12 ◽  
pp. 723-730 ◽  
Author(s):  
Lennart Larsson ◽  
Börje Wickberg ◽  
Einar Stenhagen ◽  
Lars Gunnar Sillén ◽  
B. Zaar ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Kinetic Study

scholarly journals During Oxidative Stress the Clp Proteins of Escherichia coli Ensure that Iron Pools Remain Sufficient To Reactivate Oxidized Metalloenzymes

2020 ◽  
Vol 202 (18) ◽  
Author(s):  
Ananya Sen ◽  
Yidan Zhou ◽  
James A. Imlay
Keyword(s):  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Acid Synthesis ◽  
Growth Defect ◽  
Natural Environments ◽  
Intracellular Iron ◽  
Amino Acid Synthesis ◽  
Common Component ◽  
Content Type ◽  
Iron Pool

ABSTRACT Hydrogen peroxide (H2O2) is formed in natural environments by both biotic and abiotic processes. It easily enters the cytoplasms of microorganisms, where it can disrupt growth by inactivating iron-dependent enzymes. It also reacts with the intracellular iron pool, generating hydroxyl radicals that can lethally damage DNA. Therefore, virtually all bacteria possess H2O2-responsive transcription factors that control defensive regulons. These typically include catalases and peroxidases that scavenge H2O2. Another common component is the miniferritin Dps, which sequesters loose iron and thereby suppresses hydroxyl-radical formation. In this study, we determined that Escherichia coli also induces the ClpS and ClpA proteins of the ClpSAP protease complex. Mutants that lack this protease, plus its partner, ClpXP protease, cannot grow when H2O2 levels rise. The growth defect was traced to the inactivity of dehydratases in the pathway of branched-chain amino acid synthesis. These enzymes rely on a solvent-exposed [4Fe-4S] cluster that H2O2 degrades. In a typical cell the cluster is continuously repaired, but in the clpSA clpX mutant the repair process is defective. We determined that this disability is due to an excessively small iron pool, apparently due to the oversequestration of iron by Dps. Dps was previously identified as a substrate of both the ClpSAP and ClpXP proteases, and in their absence its levels are unusually high. The implication is that the stress response to H2O2 has evolved to strike a careful balance, diminishing iron pools enough to protect the DNA but keeping them substantial enough that critical iron-dependent enzymes can be repaired. IMPORTANCE Hydrogen peroxide mediates the toxicity of phagocytes, lactic acid bacteria, redox-cycling antibiotics, and photochemistry. The underlying mechanisms all involve its reaction with iron atoms, whether in enzymes or on the surface of DNA. Accordingly, when bacteria perceive toxic H2O2, they activate defensive tactics that are focused on iron metabolism. In this study, we identify a conundrum: DNA is best protected by the removal of iron from the cytoplasm, but this action impairs the ability of the cell to reactivate its iron-dependent enzymes. The actions of the Clp proteins appear to hedge against the oversequestration of iron by the miniferritin Dps. This buffering effect is important, because E. coli seeks not just to survive H2O2 but to grow in its presence.

A new method for the preparation of peroxymonophosphoric acid

2003 ◽  
Vol 81 (2) ◽  
pp. 156-160 ◽  
Author(s):  
Tian Zhu ◽  
Hou-min Chang ◽  
John F Kadla
Keyword(s):  
Hydrogen Peroxide ◽  
Acetic Acid ◽  
Carbon Tetrachloride ◽  
Glacial Acetic Acid ◽  
Acid Synthesis ◽  
Conversion Ratio ◽  
New Method ◽  
Phosphorous Pentoxide ◽  
Preparation Conditions ◽  
Peroxy Acids

A new method for the preparation of peroxymonophosphoric acid (H3PO5) has been developed. It utilizes a biphasic solution to moderate the vigorous reaction between phosphorous pentoxide (P2O5) and hydrogen peroxide (H2O2). P2O5 is suspended in carbon tetrachloride (CCl4), and concentrated H2O2 is slowly added while being vigorously stirred at low temperature. Careful control of the reaction temperature through the slow addition of H2O2 is critical. Using typical preparation conditions (P2O5:H2O2 = 0.5:1, H2O2 70 wt %, 2°C, 120–180 min), ~70% of the H2O2 is effectively converted to H3PO5. Increasing the concentration of H2O2, as well as the mole ratio of P2O5:H2O2, leads to an even higher % conversion of H2O2 to H3PO5. The addition of glacial acetic acid to the P2O5:H2O2 suspension at the end of the 120–180 min reaction (P2O5:H2O2:CH3COOH = 0.5:1:0.3) leads to the formation of peracetic acid in addition to H3PO5, and to an overall increase in the conversion ratio of total peroxy acids based on H2O2 (>95%).Key words: peroxymonophosphoric acid, synthesis, stability, conversion ratio.

Sign in / Sign up

Export Citation Format

Share Document