Arsenic oxide production

An effective method for destruction of other organic wastes is ultraviolet irradiation of a water solution or slurry containing also hydrogen peroxide. It should effectively destroy arsenicals or products therefrom insofar as they can be brought into solution in water. Capture of the arsenical oxidation products would be necessary before any release into the environment. 

Early catalysts for acrolein synthesis were based on cuprous oxide and other heavy metal oxides deposited on inert siHca or alumina supports (39). Later, catalysts more selective for the oxidation of propylene to acrolein and acrolein to acryHc acid were prepared from bismuth, cobalt, kon, nickel, tin salts, and molybdic, molybdic phosphoric, and molybdic siHcic acids. Preferred second-stage catalysts generally are complex oxides containing molybdenum and vanadium. Other components, such as tungsten, copper, tellurium, and arsenic oxides, have been incorporated to increase low temperature activity and productivity (39,45,46). 

Fire Hazards - Flash Point Not flammable Flammable Limits in Air (%) Not flammable Fire Extinguishing Agents Not pertinent Fire Extinguishing Agents Not To Be Used Not pertinent Special Hazards of Combustion Products Poisonous, volatile arsenic oxides may be formed in fires Behavior in Fire Not pertinent Ignition Terrqterature Not pertinent E/cc/nca/Hazard Not pertinent Burning Rate Not pertinent. 

Reactivity Hydrolysis products Hydrochloric acid and chlorovinyl arsenous oxide, a vesicant. The latter is a nonvolatile solid that is not readily washed away by rains. Strong alkalies destroy these blister-forming properties. 

Vesicants produce acidic products including hydrogen chloride (HC1), hydrogen bromide (HBr), or hydrogen fluoride (HF), and ethanolamines, thioglycols, or thioethers when hydrolyzed. Arsenous oxide decomposition products from HL (C03-A010) are toxic and may also have vesicant properties. HL will also produce acetylene at higher pH. 

Volatile decomposition products may include HC1, HBr, HF, and nitrogen oxides (NO ) or sulfur oxides (SO ). Decomposition vapors from nitrogen vesicants may form explosive mixtures in air. In addition, a corrosive and toxic residue may remain. HL (C03-A010) will also produce toxic arsenic oxides. 

Volatile decomposition products may include HC1, HBr, and arsenic oxides. In addition, a corrosive or toxic residue or both may remain. 

Volatile decomposition products include arsenic oxides. Arsine may decompose to hydrogen gas and arsenic metal if heated in a sealed container. 

Arsine is highly volatile and there is little risk of direct residual contamination. However, potential persistent decomposition products include arsenic and arsenic oxides. Wash the remains with soap and water. Pay particular attention to areas where agent may get trapped, such as hair, scalp, pubic areas, fingernails, folds of skin, and wounds. If remains are heavily contaminated with residue, then wash and rinse waste should be contained for proper disposal. Once the remains have been thoroughly decontaminated, no further protective action is necessary. Body fluids removed during the embalming process do not pose any additional risks and should be contained and handled according to established procedures. Use standard burial procedures. 

L-Amino acid oxidase has been used to measure L-phenylalanine and involves the addition of a sodium arsenate-borate buffer, which promotes the conversion of the oxidation product, phenylpyruvic acid, to its enol form, which then forms a borate complex having an absorption maximum at 308 nm. Tyrosine and tryptophan react similarly but their enol-borate complexes have different absorption maxima at 330 and 350 nm respectively. Thus by taking absorbance readings at these wavelengths the specificity of the assay is improved. The assay for L-alanine may also be made almost completely specific by converting the L-pyruvate formed in the oxidation reaction to L-lactate by the addition of lactate dehydrogenase (EC 1.1.1.27) and monitoring the oxidation of NADH at 340 nm. 

It oxidizes in air at elevated temperatures producing arsenic oxides, the products and yields of which depend on the air supply. In alkali metal sulfide solutions arsenic pentasulfide forms thioarsenate anion, [AsS4] and its alkali metal salts, e.g., NasAsS4. 

Arsenic, when gently heated in the presence of air or oxygen, exhibits phosphorescence 7 which, as with phosphorus and sulphur, is accompanied by oxidation, arsenious oxide containing about 3 per cent, of arsenic oxide being produced. No ozone is formed, nor is there ionisation, as in the phosphorescence of the two elements mentioned. The arsenic oxide appears to be a primary product formed directly from the arsenic, as the lower oxide does not yield it under such conditions. Arsenious oxide is formed slowly below 200° C. without luminescence, but between 250° and 310° C. the glow appears suddenly 8 so long as the pressure is between certain limits,9 outside of which no luminescence is observed. The lower limit, 4 to 10 mm. Hg, falls with increasing temperature, while the upper limit, 200 to 700 mm. Hg, rises... 

Barium Arsenates.—Barium orthoarsenate, Ba3(As04)2, is formed as large colourless plates when a mixture of barium oxide, alkali chloride and alkali hydrogen orthoarsenate is fused and allowed to cool.6 It is also said to be formed7 by the action of ammonia on an aqueous solution of barium hydrogen arsenate the product, however, varies in composition, barium ammonium arsenate sometimes being formed and... 

Pharmaeosiderite may be obtained artificially 5 by heating ferric orthoarsenate and water in a sealed tube at 200° C. or by boiling the ferric salt with ammonium acetate solution acidified with acetic add. The product contains considerably more water than the natural mineral, but loses it when strongly heated. The mineral loses 5 molecules of water up to 233 1° C., when decomposition begins, the products being ferric and arsenic oxides.8... 

Jackson et al. (2003) studied the oxidation reaction rates of a gersdorffite specimen with the composition of Ni0.68Fe0.19Co0.14As1.08S0.92- The oxidation rate of the mineral was more than 10 times greater in aerated water than air, and arsenic was more reactive than sulfur. As-, As+, As3+, and As5+ were detected in the surface oxidation products in the presence of either air or aerated water. After 5 hours of exposure to air, As+ and As3+ were measured on the surface of the gersdorffite. As5+ was finally detected after a total of 10 hours of air exposure (Jackson et al., 2003), 899. In aerated distilled water, As3+ and As5+ were the dominant arsenic surface oxidation products after only 15 minutes (Jackson et al., 2003), 897. 

Many factors affect the oxidation rates of sulfide minerals and the chemistry of their oxidation products. A few of the important factors are briefly introduced in this section and discussed in further detail in this and later chapters. As a result of the complex interactions between these different factors, high-arsenic rocks and mining wastes will not automatically produce high-arsenic weathering products and aqueous solutions (Piske, 1990). 

Both Reactions 3.50 and 3.51 indicate that sulfur oxidizes before iron and that As(I-) and As(0) in arsenopyrite oxidize to As(III). Nevertheless, (Craw, Falconer and Youngson (2003), 81) warn that higher than expected pH readings in their experimental data suggest that at least Reaction 3.50 may be a too simplistic description of arsenopyrite oxidation. Some of the arsenic from arsenopyrite may fully oxidize to As(V) rather than existing as H3As03° as predicted by Reaction 3.50. Using X-ray photoelectron spectroscopy (XPS), Nesbitt and Muir (1998) confirmed that As(III) is not the only arsenic species in surface oxidation products on arsenopyrite. As(V) and even traces of As(I) are also present. 

Organic constituents that may be found in ppb levels in WP/F smoke include methane, ethylene, carbonyl sulfide, acetylene, 1,4-dicyanobenzene, 1,3-dicyanobenzene, 1,2-dicyanobenzene, acetonitrile, and acrylonitrile (Tolle et al. 1988). Since white phosphorus contains boron, silicon, calcium, aluminum, iron, and arsenic in excess of 10 ppm as impurities (Berkowitz et al. 1981), WP/F smoke also contains these elements and possibly their oxidation products. The physical properties of a few major compounds that may be important for determining the fate of WP/F smoke in the environment are given in Table 3-3. 

Oxidation Products of the Elements of Group V. Treat 0.5 gram each of (a) red phosphorus, (b) powdered arsenic, (c) powdered antimony, and (d) powdered bismuth with... 

Dioxirane (RR C02) compounds are relatively new in the arsenal of the synthetic chemist, however since the isolation of dimethyldioxirane by Murray and Jeyaraman in 1985,146 it has become a very important oxidant for preparative oxygen transfer chemistry.147 The dioxiranes are ideal oxidants in that they are efficient in their oxygen atom transfer, exhibit high chemio- and regio-selectivities, act catalytically, are mild towards the substrate and oxidized product, and perform under strictly neutral conditions. The compounds are prepared from peroxymonosulfate and ketones under neutral to mildly alkaline conditions (Figure 2.46). 

The product from Step 2 (1.0 mmol), diphenylphosphoryl azide (1.2 mmol), triethylamine (5 mmol), phenanthrene-9,10-dione (0.7 mmol) and triphenyl arsen oxide (0.05 mmol) were dissolved in 12 ml toluene and heated 3 hours at 60 °C. The product was purified by chromatography on silica gel using CH2Cl2/hexane, 2 1, re-crystallized in CH2Cl2/hexane, and the product isolated in 100% yield. H- and C-NMR data supplied. 

Hydrolysis Product Chlorovinyl arsenous oxide Combustion Products C2H2CIASO 3088-37-7 ... 

Lewisite in soil may rapidly volatilize or may be converted to lewisite oxide due to moisture in the soil (Rosenblatt et al, 1975). The low water solubility suggests intermediate persistence in moist soil (Watson and Griffin, 1992). Both lewisite and lewisite oxide may be slowly oxidized to 2-chlorovinylarsonic acid (Rosenblatt et al, 1975). Possible pathways of microbial degradation in soil include epoxidation of the C=C bond and reductive deha-logenation and dehydrohalogenation (Morrill et al, 1985). Due to the epoxy bond and arsine group, toxic metabolites may result. Additionally, residual hydrolysis may result in arsenic compounds. Lewisite is not likely to bioaccumulate. However, the arsenic degradation products may bioaccumulate (Rosenblatt et al, 1975). 

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