Poly hydrogen peroxide

Again, as with pyridopyrimidines, the main reaction is oxidation of di- or poly-hydro derivatives to fully aromatic structures, often merely by air or oxygen. In some cases the reagent of choice is mercury(II) oxide, whilst other reagents used include sulfur, bromine, chloranil, chromium trioxide-acetic acid, hydrogen peroxide, and potassium ferricyanide, which also caused oxidative removal of a benzyl group in the transformation (306) (307)... 

The catalytic activity of PCSs results from their semiconductor properties. The first studies in this field date from 1959—1961. Thus, we have demonstrated catalytic activity of products of the thermal transformation of PAN in the decomposition reactions of hydrogen peroxide, hydrazine hydrate, and formic acid270, 271. There is an indication of catalytic activity of poly(aminoquinone) in the reactions of the hydrogen peroxide decomposition272. ... 

PCSs obtained by dehydrochlorination of poly(2-dilorovinyl methyl ketones) catalyze the processes of oxidation and dehydrogenation of alcohols, and the toluene oxidation207. The products of the thermal transformation of PAN are also catalysts for the decomposition of nitrous oxide, for the dehydrogenation of alcohols and cyclohexene274, and for the cis-tnms isomerization of olefins275. Catalytic activity in the decomposition reactions of hydrazine, formic acid, and hydrogen peroxide is also manifested by the products of FVC dehydrochlorination... 

FIGURE 4-18 Permselective coatings flow injection response of a poly(l,2-diaminoben-zene)-coated electrode to the following a, hydrogen peroxide (1 mM) b, ascorbic acid (1 mM) c, uric acid (1 mM) d, L-cysteine (1 mM) and e, control human serum. (Reproduced with permission from reference 63.)... 

The presence of two hydroxyl groups per molecule in poly-(methyl methacrylate) and in polystyrene, each polymerized in aqueous media using the hydrogen peroxide-ferrous ion initiation system, has been established " by chemical analysis and determination of the average molecular weight. Poly-(methyl methacrylate) polymerized by azo-bis-isobutyronitrile labeled with radioactive has been shown to... 

Hydrogen peroxide, Poly(acrylamide) gel, etc. See Hydrogen peroxide 2-Ethoxyethanol, etc. See other PEROXIDISABLE compounds... 

Fig. 1.16 Schematic representation of the nanofibrous poly (acrylonitrile-co-acrylic acid) membrane containing MWCNTs, as well as the promoted electron transfer from hydrogen peroxide to the immobilized catalase through the PANCAA/MWCNTs nanofiber. Reprinted from [209] (reproduced by permission ofWiley-VCH).

Zeolite based ceramics as catalysts for wet hydrogen peroxide catalytic oxidation of phenol and poly-phenols... 

Electrosynthesis of polymers compares favorably with the thick film method providing addressable and controlled deposition. In terms of selectivity to hydrogen peroxide in the presence of interferents, the most promising results were obtained with poly-l,2-diaminobenzene (poly-1,2-DAB)-modified electrodes [125],... 

L.V. Lukachova, E.A. Kotel nikova, D. D Ottavi, E.A. Shkerin, E.E. Karyakina, D. Moscone, G. Palleschi, A. Curulli, and A.A. Karyakin, Electrosynthesis of poly-o-diaminobenzene on the Prussian Blue modified electrodes for improvement of hydrogen peroxide transducer characteristics. Bioelectrochemistry 55, 145-148 (2002). 

Recently, Kondo and coworkers reported on the polymerization of St with diphenyl diselenides (37) as the photoiniferters (Eq. 39) [ 162]. In the photopolymerization of St in the presence of 37a and 37b, the polymer yield and the molecular weight of the polymers increased with reaction time. The chain-end structure of the resulting polymer 38 was characterized. Polymer 38 underwent the reductive elimination of terminal seleno groups by reaction with tri-n-butyltin hydride in the presence of AIBN (Eq. 40). It also afforded the poly(St) with double bonds at both chain ends when it was treated with hydrogen peroxide (Eq. 41). They also reported the polymerization of St with diphenyl ditelluride to afford well-controlled molecular weight and its distribution [163]. 

The biomimetic protocol was invented by Julia and Colonna, and involves the use of polyamino acids (such as poly-(L)-leucine) as the catalysts for peroxide oxidation of chalcones, styryl alkyl ketones and conjugated alkenones. The substrate range is broad, especially when using immobilized catalysts and an organic solvent containing the substrate, urea-hydrogen peroxide and an organic base (Scheme 22)[101]. 

Scheme 22 Reagents and conditions i) poly-L-leucine, urea-hydrogen peroxide, THF, diazabicycloundecene.

Bentley et al.m recently improved upon Julia s epoxidation reaction. By using urea-hydrogen peroxide complex as the oxidant, l,8-diazabicyclo[5,4,0]undec-7-ene (DBU) as the base and the Itsuno s immobilized poly-D-leucine (Figure 4.2) as the catalyst, the epoxidation of a, (3-unsaturated ketones was carried out in tetrahydrofuran solution. This process greatly reduces the time required when compared to the original reaction using the triphasic conditions. 

In a lOmL round-bottomed flask equipped with a magnetic stirrer bar were placed tetrahydrofuran (0.8 mL) and immobilized poly-D-leucine (100 mg). (7 )-Benzylidene acetophenone (50 mg), l,8-diazabicyclo[5.4.0] undec-7-ene (90 mg), and urea-hydrogen peroxide (27 mg) were added to the mixture. The thick white reaction mixture was stirred vigorously for 30 minutes. 

Abstract In this chapter, the depression mechanism of five kinds of depressants is introduced respectively. The principle of depression by hydroxyl ion and hydrosulphide is explained which regulates the pH to make the given mineral float or not. And so the critical pH for certain minerals is determined. Thereafter, the depression by cyanide and hydrogen peroxide is narrated respectively which are that for cyanide the formation of metal cyanide complex results in depression of minerals while for hydrogen peroxide the decomposition of xanthate salts gives rise to the inhibitation of flotation. Lastly, the depression by the thio-organic such as polyhydroxyl and poly carboxylic xanthate is accounted for in detail including die flotation behavior, effect of pulp potential, adsorption mechanism and structure-property relation. 

In the early 1980 s Julia and Colonna published a series of papers which, to some extent, filled the gap left by the natural biocatalysts. The Spanish and Italian collaborators showed that a, -unsaturated ketones of type 1 underwent asymmetric oxidation to give the epoxide 2 using a three-phase system, namely aqueous hydrogen peroxide containing sodium hydroxide, an organic solvent such as tetrachloromethane and insoluble poly-(l)-alanine, (Scheme 1) [12]. The reaction takes place via a Michael-type addition of peroxide anion (the Weitz-Scheffer reaction). 

Methods A Immobilised poly-(L)-leucine, urea hydrogen peroxide, DBU, THE B Immobilised poly-(D)-leucine, urea hydrogen peroxide, DBU, THE... 

Scheme 18. Reagents and Conditions (i) Immobilised poly-(L)-leucine, urea hydrogen peroxide, DBU, THF, 12 h, 76%, 94% e.e. (ii) mCPBA, CH2CI2, 94%. (iii) HCl (g), CH2CI2, 66%. (iv) Amberlite IRA-420 ( OH), THF, 80%. (v) NaNj, MeOH, H20,94%. (vi) H2, Pd/C, EtOAc. (vii) NH3,MeOH. (viii) benzoyl chloride, (ix) trifluoroacetic acid, CH2CI2,74%...

Hydrogen peroxide, Poly(hydroxyacrylic acid lactone), etc., 4477... 

In 2003, Bernini and coworkers established a method for converting some flavonoid ketones into the corresponding lactones with hydrogen peroxide as oxidant catalyzed by MTO supported on poly(4-vinylpyridine) polymers (equation 82) °. Conversions and... 

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