Water peroxide formation

Metbyl-l-pentene [763-29-1] M 84.2, b 61.5-62", d 0.680, n 1.395. Water was removed, and peroxide formation prevented by several vacuum distns from sodium, followed by storage with sodium-potassium alloy. 

Scheme 10.27 Catalytic cycle of HppE. Dashed arrows indicate electron transport. In this scheme HPP binds to iron1". After a one-electron reduction, dioxygen binds and reoxidizes the iron center. The peroxide radical is capable of stereospecifically abstracting the (pro-R) hydrogen. Another one-electron reduction is required to reduce one peroxide oxygen to water. Epoxide formation is mediated by the resulting ironlv-oxo species.

Two major pathways exist for this reaction, one bypassing hydrogen peroxide (first pathway) and the other involving intermediate peroxide formation via reaction (15.21) (second pathway). The peroxide formed is either electrochemically reduced to water via reaction (15.22) or decomposed catalytically on the electrode surface via reaction (15.23), in which case half of the oxygen consumed to form it reemerges [in both cases the overall reaction corresponds to Eq. (15.20)]. 

Dining an attempt to prepare an anhydrous 25% solution of peroxyacetic acid in acetic acid by dehydrating a water-containing solution with acetic anhydride, a violent explosion occurred. Mistakes in the operational procedure allowed heated evaporation to begin before the anhydride had been hydrolysed. Acetyl peroxide could have been formed from the anhydride and peroxyacid, and the latter may have detonated and/or catalysed violent hydrolysis of the anhydride [1], A technique for preparing the anhydrous acid in dichloromethane without acetyl peroxide formation has been described [2],... 

Final ozonides (FOZ), 716, 717, 718 cis and trans isomers, 719, 720 dialkyl peroxide formation, 706 IR spectroscopy, 719 mass spectrometry, 690 microwave spectroscopy, 721-3 molecular model, 750 NMR spectroscopy, 724-5 ozone water disinfection, 606 X-ray crystallography, 726-30 Fireflies... 

Risk labels, lATA/ICAO, 751-3 Risk phrases, 621, 748, 749 River water, peroxide determination, 642 RNA, ozone disinfection, 616 ROS see Reactive oxygen species Rose Bengal sensitized photooxidation, 890 Rotational barriers, regioselective allylic hydroperoxide formation, 836, 847-9 Rotational isomers, peroxynitrous add, 8-9 Rotational spectra, ozonides, 721, 722-3 RP-HPLC, hydrogen peroxide determination, 627... 

Lipid peroxidase inhibition. Water extract of the fresh root, administered intragastrically to infant mice at a dose of 50 mL/kg, was active. The treatment was administered for 7 successive days followed by a single dose of 20% v/v CCI4 in olive subcutaneously at 1 mL/kg on the last day, 1 hour after the administration of the carrot extract . Lipid peroxide formation inhibition. Fresh fruit juice, taken orally by human... 

Once SnCls and/or SnCl2 form, additional reactions involving moleciflar oxygen or water vapor may occur. SnCls can react exothermically with oxygen to form peroxide, while peroxide formation from SnCl2 is only lightly endothermic ... 

But, in addition, it was shown that the water vapor concentration was without the effect on hydrogen peroxide formation which should be expected from this mechanism. The suggestion was made that the reaction might perhaps be better represented by the mechanism suggested by Taylor and Marshall ... 

Ethylene glycol bis(B-aminoethylether)-V,V -tetraacetic acid (EGTA) [67-42-5] M 380.4, m >245 (dec). Dissolved in aq NaOH, pptd by addn of aq HCl, washed with water and dried at 100° in vacuo. ueous 5% Na2CO3, dried with MgSO4 and stored with chromatographic alumina to prevent peroxide formation. 

This experiment was performed on XAD-4 quaternary resin in the OH- form, and desorption was by ethyl ether only (i.e., HC1 saturated ether not used). Calcium hypochlorite [Ca(OCl)2] was used to provide the required 2-ppm chlorine concentration. Millipore Super-Q water was salted according to the general procedure and passed over a 10-mL bed volume of resin (approximate dry weight = 6 g at 150 bed volumes/h. The resins were blown with nitrogen (3 lb/in2) for 10 s to remove residual water and eluted with 3 X 50-mL portions of ethyl ether. Peroxide formation was suppressed by the addition of 2% (v/v) ethanol. 

The main products were hydrogen peroxide, methanol, formaldehyde, acetaldehyde, and water. The change in mole ratio of propane and oxygen in feed from 2 to 8 had almost no influence upon the hydrogen peroxide formation. The yields of methanol, formaldehyde, and acetaldehyde increased and that of water decreased with decreasing mole ratio... 

Tetrahydrofuran can be stored for at least half a year without oxidation by adding 25 vof% H20. [J. Zhao and P. W. Carr, The Magic of Water in Tetrahydrofuran—Preventing Peroxide Formation, LCGC 1999,17, 346.]... 

The primary contaminants in commercial THF are water and organic peroxides (THF is notoriously prone to peroxide formation and should not be exposed to air after purification). Molecular sieves reduce the water content to 28 ppm [52] but do not destroy peroxides. Modern organic laboratories typically purify THF by distillation from sodium benzophenone ketyl under a nitrogen atmosphere, which has the virtue of destroying both peroxides and water [63]. This is the method of choice for obtaining high-quality THF. 

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