Peroxides oxalates

Silver Acetylene, ammonium compounds, ethyleneimine, hydrogen peroxide, oxalic acid, sulfuric acid, tartaric acid... 

Scheme 2. Mechanism for hydrogen peroxide-oxalate ester generation of chemiluminescence. Ar = aryl B = a base.

Dimethyl peroxide Diethyl peroxide Di-t-butyl-di-peroxyphthalate Difuroyl peroxide Dibenzoyl peroxide Dimeric ethylidene peroxide Dimeric acetone peroxide Dimeric cyclohexanone peroxide Diozonide of phorone Dimethyl ketone peroxide Ethyl hydroperoxide Ethylene ozonide Hydroxymethyl methyl peroxide Hydroxymethyl hydroperoxide 1-Hydroxyethyl ethyl peroxide 1 -Hydroperoxy-1 -acetoxycyclodecan-6-one Isopropyl percarbonate Isopropyl hydroperoxide Methyl ethyl ketone peroxide Methyl hydroperoxide Methyl ethyl peroxide Monoperoxy succinic acid Nonanoyl peroxide (75% hydrocarbon solution) 1-Naphthoyl peroxide Oxalic acid ester of t-butyl hydroperoxide Ozonide of maleic anhydride Phenylhydrazone hydroperoxide Polymeric butadiene peroxide Polymeric isoprene peroxide Polymeric dimethylbutadiene peroxide Polymeric peroxides of methacrylic acid esters and styrene... 

Hydrogen peroxide, oxalates, and fluorides interfere with the precipitation of the phosphomolybdate and should therefore be absent. 

Incompal. Alcohol, arsenites, bromides, iodides, hydrochloric acid, charcoal organic substances generally ferrous or mercurous salts, hypophosphites, hyposulfites, sulfites, peroxides, oxalates. 

Catalytic activity of composites B-N-Fe and Si-N-Fe when applying UV radiation in presence of hydrogen peroxide, oxalic acid, and EDTA is determined by formation of photo-Fenton, ferric-oxalate, and Fe-EDTA systems in the solution which leads to generation of the super-oxidant-hydroxyl radicals. At the same time, solutions practically are not polluted by iron. High catalytic activity of the composites is determined by combination of heterogeneous and homogeneous catalyses. 

Gravimetric. Th is precipitated as a hydroxide, peroxide, oxalate, or other compound and ignited to Th02. 

Some typical redox systems are potassium persulfate-potassium metabisulfite [160] the monomer-soluble oxidizing agent tert-bwiyX perpivalate and potassium metabisulfite [161] hydrogen peroxide-sodium formaldehyde sulfoxylate [162] hydrogen peroxide-sodium formaldehyde sulfoxylate in the presence of cupric sulfate and EDTA [163] hydrogen peroxide-oxalic acid in the presence of ferrous sulfate [164] and persulfates and sodium formaldehyde sulfoxylate [165]. 

Several additional formulations with EDTA (or citric acid) and other materials have been proposed. Martin patented a mixture of hydrogen peroxide, oxalic acid, and an EDTA or citric acid-type complexer for removing copper deposits (iron oxides are removed by using an additional stage). An unusual aspect of this process is that it is performed at a pH of 3.0-6.0. To allow passivation of the steel to be effective, oxidative copper-removal processes usually are conducted at pH values of >9.0. 

Oxidative carbonylation of alcohols with PdCh affords the carbonate 572 and oxalate 573(512-514]. The selectivity of the mono- and dicarbonylation depends on the CO pressure and reaction conditions. In order to make the reaction catalytic, Cu(II) and Fe(III) salts are used. Under these conditions, water is formed and orthoformate is added in order to trap the water. Di-/-butyl peroxide is also used for catalytic oxidative carbonylation to give carbonates and oxalates in the presence of 2,6-dimetliylpyridine(515]. 

Peroxyoxalate. The chemical activation of a fluorescer by the reactions of hydrogen peroxide, a catalyst, and an oxalate ester has been the object of several mechanism studies. It was first proposed in 1967 that peroxyoxalate (26) was converted to dioxetanedione (27), a highly unstable intermediate which served as the chemical activator of the fluorescer (fir) (6,9). 

The first detailed investigation of the reaction kinetics was reported in 1984 (68). The reaction of bis(pentachlorophenyl) oxalate [1173-75-7] (PCPO) and hydrogen peroxide cataly2ed by sodium saUcylate in chlorobenzene produced chemiluminescence from diphenylamine (DPA) as a simple time—intensity profile from which a chemiluminescence decay rate constant could be determined. These studies demonstrated a first-order dependence for both PCPO and hydrogen peroxide and a zero-order dependence on the fluorescer in accord with an earher study (9). Furthermore, the chemiluminescence quantum efficiencies Qc) are dependent on the ease of oxidation of the fluorescer, an unstable, short-hved intermediate (r = 0.5 /is) serves as the chemical activator, and such a short-hved species "is not consistent with attempts to identify a relatively stable dioxetane as the intermediate" (68). 

Fig. 1. Time courses of the chemiluminescence intensity from oxalate—hydrogen peroxide systems in ethyl acetate as solvent, 0.7 mM TCPO. The curves correspond to the following concentrations of triethylamine (TEA) catalyst A, 0.05 mM B, 0.10 mM and C, 0.20 mM (70).

A modified oxalic ester reaction that is activated by air rather than hydrogen peroxide has been provided by combining a 9,10-dihydroxyanthracene or ben2oin with the ester and fluorescer (259). Oxygen from air is converted to hydrogen peroxide by the dihydroxyanthracene. 

Hydrogen peroxide has also been analy2ed by its chemiluminescent reaction with bis(2,4,6-trichlorophenyl) oxalate and perylene in a buffered (pH 4—10) aqueous ethyl acetate—methanol solution (284). Using a flow system, intensity was linear from the detection limit of 7 x 10 M to at least 10 M. 

Oxidation. Maleic and fumaric acids are oxidized in aqueous solution by ozone [10028-15-6] (qv) (85). Products of the reaction include glyoxyhc acid [298-12-4], oxalic acid [144-62-7], and formic acid [64-18-6], Catalytic oxidation of aqueous maleic acid occurs with hydrogen peroxide [7722-84-1] in the presence of sodium tungstate(VI) [13472-45-2] (86) and sodium molybdate(VI) [7631-95-0] (87). Both catalyst systems avoid formation of tartaric acid [133-37-9] and produce i j -epoxysuccinic acid [16533-72-5] at pH values above 5. The reaction of maleic anhydride and hydrogen peroxide in an inert solvent (methylene chloride [75-09-2]) gives permaleic acid [4565-24-6], HOOC—CH=CH—CO H (88) which is useful in Baeyer-ViUiger reactions. Both maleate and fumarate [142-42-7] are hydroxylated to tartaric acid using an osmium tetroxide [20816-12-0]/io 2LX.e [15454-31 -6] catalyst system (89). 

The plutonium extracted by the Purex process usually has been in the form of a concentrated nitrate solution or symp, which must be converted to anhydrous PuF [13842-83-6] or PuF, which are charge materials for metal production. The nitrate solution is sufficientiy pure for the processing to be conducted in gloveboxes without P- or y-shielding (130). The Pu is first precipitated as plutonium(IV) peroxide [12412-68-9], plutonium(Ill) oxalate [56609-10-0], plutonium(IV) oxalate [13278-81-4], or plutonium(Ill) fluoride. These precipitates are converted to anhydrous PuF or PuF. The precipitation process used depends on numerous factors, eg, derived purity of product, safety considerations, ease of recovering wastes, and required process equipment. The peroxide precipitation yields the purest product and generally is the preferred route (131). The peroxide precipitate is converted to PuF by HF—O2 gas or to PuF by HF—H2 gas (31,132). 

Cobalt salts are used as activators for catalysts, fuel cells (qv), and batteries. Thermal decomposition of cobalt oxalate is used in the production of cobalt powder. Cobalt compounds have been used as selective absorbers for oxygen, in electrostatographic toners, as fluoridating agents, and in molecular sieves. Cobalt ethyUiexanoate and cobalt naphthenate are used as accelerators with methyl ethyl ketone peroxide for the room temperature cure of polyester resins. 

Nitroparaffins Oxalic acid Oxygen Perchloric acid Peroxides, organic Phosphorus (white) Potassium chlorate Potassium perchlorate Potassium permanganate Silver... 

Before use, electrodes must be carefully cleaned to remove any previous deposits. Deposits of copper, silver, cadmium, mercury, and many other metals can be removed by immersion in dilute nitric acid (1 1), rinsing with water, then boiling with fresh 1 1 nitric acid for 5-10 minutes, followed by a final washing with water. Deposits of lead dioxide are best removed by means of 1 1 nitric acid containing a little hydrogen peroxide to reduce the lead to the Pb(II) condition ethanol or oxalic acid may replace the hydrogen peroxide. 

Discussion. With an acidic titanium(IV) solution hydrogen peroxide produces a yellow colour with small amounts oftitanium(up to 0.5 mg ofTiOz permL), the intensity of the colour is proportional to the amount of the element present. Comparison is usually made with standard titanium(IV) sulphate solutions a method for their preparation from potassium titanyl oxalate is described below. The hydrogen peroxide solution should be about 3 percent strength (ten volume) and the final solution should contain sulphuric acid having a concentration from about 0.75 to 1.75M in order to prevent hydrolysis to a basic sulphate and to prevent condensation to metatitanic acid. The colour intensity increases slightly with rise of temperature hence the solutions to be compared should have the same temperature, preferably 20-25 °C. 

The colour is unaffected by the presence of phosphate or fluoride. Titanium and molybdenum) VI) (which give colours with hydrogen peroxide) and tungsten interfere. Titanium may be removed by adding fluoride or hydrofluoric acid, which simultaneously remove the yellow colour due to iron(III). If titanium is absent, phosphate may be used to decolorise any iron(III) salt present. Oxalic acid eliminates the interference due to tungsten. In the presence of elements... 

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