Volatile toxicants

Trimethyl arsine [593-88-4] C H As, has been identified as the toxic volatile arsenical, once known as "Gosio gas," produced by the reaction of certain molds that grow on wallpaper paste and react with inorganic arsenic compounds present in the paper. A number of microorganisms can methylate arsenic trioxide and other arsenic-containing compounds to yield trimethylarsine. These microorganisms include Scopulariopsis brevicaulis Candida humicola and Gliocladium roseum (72). 

Toxic Volatile Ratio of Equilibrium Vapor Concentration over the Acute Substances Toxic Concentration (in ppm) is greater than 1000... 

Fig. 3. A model integrated adsorption/electrothermal regeneration/cryogenic vapor recovery system for volatile organic compounds [91]. Reprinted from Gas Sep. Purif, Volume 10, Lordgooei, M., Carmichael, K. R., Kelly, T. W., Rood, M. J. and Larson, S. M., Activated carbon cloth adsorption cryogenic system to recover toxic volatile organic compounds, pp. 123-130, Copyright 1996, with permission from Elsevier Science.

Livingston, A.G., Freitas dos Santos, L.M., Extraction and Biodegradation of a Toxic Volatile Organic Compound (1,2 dichloroethane) from Wastewater in a Membrane Bioreactor, Applied Microbiology and Biotechnology, v.42, pp.421-431, 1994. 

The compounds of Se, Te and Po should all be treated as potentially toxic. Volatile compounds such as H2Se, H2Te and organo derivatives are particularly dangerous and maxirnum permissible limits for air-bome concentrations are 0.1 mg m (cf. lOmgm for HCN). The elements are taken up by the kidneys, spleen and liver, and even in minute concentrations cause headache, nausea and irritation of mucous membrane. 

Cyanomethane, commonly known as acetonitrile, CH3CN, is a toxic volatile liquid that is used as a solvent to purify steriods and to extract fatty acids from fish oils. Acetonitrile can be synthesized from methyl isonitrile by the isomerization reaction CH,NC(g) - CH3CN(g). 

Transmethylation is important not only in the biosynthesis of cellular components but also in detoxification. Although the resulting metabolites are less toxic to the cell, they are often more lipophilic and may have serious adverse effects on other biota. Toxic volatile arsenic compounds... 

STABREX is easier and simpler to use compared to any other oxidant available for industrial water treatment. The product is pumped directly from returnable transporters (PortaFeed Systems)17 with standard chemical feed equipment. Previously, the only practical ways to apply bromine were to oxidize bromide solutions on-site with chlorine in dual liquid feed systems, or with one of the solid organically-stabilized bromine products applied from sidestream erosion feeders. The former is cumbersome and complex, and the latter is prone to dusting and difficult to control. Other oxidants require complex handling and feed of toxic volatile gases, unstable liquids, multiple-component products, or reactive solids. Simplicity in use results in reduced risk to workers and to the environment. 

The plant produced pesticides. An intermediate compound in this process is methyl isocyanate (MIC). MIC is an extremely dangerous compound. It is reactive, toxic, volatile, and flammable. The maximum exposure concentration of MIC for workers over an 8-hour period is 0.02 ppm (parts per million). Individuals exposed to concentrations of MIC vapors above 21 ppm experience severe irritation of the nose and throat. Death at large concentrations of vapor is due to respiratory distress. 

Toxic Volatile Ratio of Equilibrium Vapor Concentration over the Acute... 

Toxic Volatile Dispersion modeling of credible worse case scenarios indi-... 

Elimination of releases of toxic volatile organic compounds to the environment that can occur with pump-and-treat-aerobic processes (D103640, p. 2)... 

Addition of hydrogen cyanide to aldehyde and ketone forms cyanohydrin. The reaction is usually carried out using sodium or potassium cyanide with HCl. Hydrogen cyanide is a toxic volatile liquid, and a weak acid. Therefore, the best way to carry out this reaction is to generate it in situ by adding HCl to a mixture of aldehydes or ketones and excess sodium or potassium cyanide. Cyanohydrins are useful in organic reaction, because the cyano group can be converted easily to an amine, amide or carboxylic acid. 

Caution. Since metal carbonyls and their derivatives are toxic volatile compounds, all operations must be performed in an efficient hood. 

Secondary prevention and mitigation, by themselves, are unable to eliminate the risk of serious or catastrophic chemical accidents, although improved process safety management can reduce their probability and severity. Most chemical production involves transformation processes, which are inherently complex and tightly coupled. Normal accidents are an unavoidable risk of systems with these characteristics [11]. However, the risk of serious, or catastrophic, consequences need not be. Specific industries use many different processes. In many cases, alternative chemical processes exist which completely or almost completely eliminate the use of highly toxic, volatile, or flammable chemicals [12]. 

With the exception of the neutral halo complexes, which are prepared by direct reaction of the halogen with the metal, and a number of complexes generated by the direct reaction of the metal with a strong acid, coordination complexes of Os are prepared directly or indirectly from [0s04] (2). The latter is a toxic, volatile solid, normally purchased in 1-g ampuls and opened within the reaction mixture contained in a fume hood to prevent escape of the toxic vapor (3) and loss of the reactant. It is also available as an aqueous solution of osmic acid, which is suitable for some reactions. 

Nickel tetracarbonyl is a highly toxic volatile colorless liquid that is shipped in cylinders pressurized with carbon monoxide.8 Its vapor is about six times as dense as air. Purification of nickel by the Mond process is based on the decomposition of Ni(CO)4, the reverse of Eq. 15.3. The yellow-red iron pentacarbonyl slowly decomposes in air and is sensitive to light and heal. In feet. Fe-jfCOJy, an orange solid, is prepared by photolysis of Fe(CO). ... 

Caution. Pentacarbonyliron(O) is a toxic, volatile liquid. It is sensitive to light and heat and can be pyrophoric in air. Carbon monoxide is evolved during the course of the synthesis. Diphenylphosphine, methyldiphenylphos-phine, and tributylphosphine are malodorous, air-sensitive, and toxic liquids. All manipulations must be carried out in a well-ventilated fume hood. 

The tnicroencapsululion of pesticides (qv) and herbicides active area of development that has produced several commercial products. The function of the microcapsules is to prolong activity while reducing mammalian toxicity, volatilization losses, phytotoxicity. environmental degradation, and movement in the soil. Ideally, encapsulation would also reduce the amount of agrochemical needed. 

Carbon monoxide is a colorless, odorless, flammable, almost insoluble, very toxic gas that condenses to a colorless liquid at — 90°C. It is not very reactive, largely because its bond enthalpy (1074 kj-mol ) is the highest for any molecule. However, it is a Lewis base, and the lone pair on the carbon atom forms covalent bonds with d-block atoms and ions. It is also a Lewis acid, because its empty antibonding tr-orbitals can accept electron density from a metal (Fig. 14.39). This dual character makes carbon monoxide very useful for forming complexes, and numerous metal carbonyls are known. An example of this behavior is its reaction with nickel to give nickel carbonyl, a toxic, volatile liquid ... 

Hydrogen Cyanide and Cyanides Hydrogen cyanide is a highly toxic, volatile substance (bp 26°C) produced when metal cyanide solutions are acidified ... 

Selective Response of Polymeric-Film-Coated Optical Waveguide Devices to Water and Toxic Volatile Compounds... 

Human toxicity Volatile organic component emissions below expected future legal limits... 

Caution HCN is a highly toxic, volatile liquid (bp 27 °C) that is also susceptible to explosive polymerization in the presence of base catalysts. It should be handled only in a well-ventilated fume hood and by teams of at least two technically qualified persons who have received appropriate medical training for treating HCN poisoning. Sensible precautions include having available proper first aid equipment and HCN monitors. Uninhibited HCN should be stored at a temperature below its melting point (-13 °C). Excess HCN maybe disposed by addition to aqueous sodium hypochlorite, which converts the cyanide to cyanate. 

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