Hydrogen selenide

Chemical Safety Data Sheet SD-53, Hydrogen Peroxide, pp 5, 30-31. Washington, DC, MCA, Inc, 1969 

Hygienic Guide Series Hydrogen Peroxide (90%). Am Ind Hyg Assoc 18 275-276, 1957 

Woodbury CM Hydrogen peroxide. In Encyclopaedia of Occupational Health and Safety, 3rd ed, rev, Vol 1, A-K, pp 1088-1090. Geneva, International Labour Office, 1983 

Oberst FW, Comstock CC, Hackley EB Inhalation toxicity of ninety per cent hydrogen peroxide vapor—acute, subacute, and chronic exposures of laboratory animals. AMA Arch Ind Hyg Occup Med 10 319-327, 1954 

Speit G, Vogel W, Wolf M Characterization of sister chromatid exchange induction by hydrogen peroxide. Environ Mutagen 4 135-142, 1982 

The low-temperature properties of H2Se were studied by Kruis and Clusius [37KRU/CLU] who found that the solid phase was characterised by two phase transitions at 80 to 87 K and at 172.5 K, respectively. The temperature span of the lower transition is indicative of a higher order transition, and the higher transition takes place between two isotropic phases. The heats of transformation for the two transitions are (1.574 + 0.002) and (1.116 + 0.002) kJ-mol, respectively. H2Se(cr) melts at (207.430 + 0.018) K with an enthalpy of fusion of  

Rawling and Toguri [66RAW/TOG] (see Appendix A) presented an expression for the temperature dependent equilibrium constant  

This expression also closely describes the data in [I899BOD] and [69YUS/DEV]. 

The experimental data presented by Rawling and Toguri in the temperature range of 800 to 900 K have been analysed by the third-law method using the selected heat capacity functions for H2Se(g), H2(g) and Se(cr, I). The derived enthalpy of formation for H2Se(g) from this analysis is Af//°(H2Se, g, 298.15 K) = (29.5 1.5) kJ-mol.  

X (7 X 10 7 - 0.2)). This equation was covered by experimental data in the temperature range 500 to 1450 K. A corresponding third-law analysis using this expression yielded the value Af//° (H2Se, g, 298.15 K) = (28.0 1.5) kJ-mol .  

Chemical Name Synonyms Chemical Formula CAS number Molecular Weight Boiling point (1 atm) 

Melting point Triple point temperature Triple point pressure Vapor pressure (21.1°C) Absolute density (25°C, 1 atm) Relative density (25°C, 1 atm) Critieal temperature Critieal pressure Latent heat of fusion (-65.7°C) 

HjSe is an eye, skin and mucous membrane irritant Poisoning may affect lungs, liver and spleen. Exposure may cause coughing, labored breathing, olfactory fatigue, nausea, vomiting, weakness, headache, bronchial pneumonia, delayed pulmonary edema and death. 

Can form flammable and explosive mixtures with air. Avoid oxidizers. 

Self contained breathing apparatus in positive pressure mode. Impervious clothing and gloves to avoid contact with gas. Face shield and splash proof goggles to prevent eye exposure. 

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Hydrogen selenide (selenium hydride), HjSe, and hydrogen telluride (tellurium hydride), HjTe... 

Elemental selenium has been said to be practically nontoxic and is considered to be an essential trace element however, hydrogen selenide and other selenium compounds are extremely toxic, and resemble arsenic in their physiological reactions. 

Hydrogen selenide in a concentration of 1.5 ppm is intolerable to man. Selenium occurs in some solid in amounts sufficient to produce serious effects on animals feeding on plants, such as locoweed, grown in such soils. Exposure to selenium compounds (as Se) in air should not exceed 0.2 mg/m3 (8-hour time-weighted average - 40-hour week). 

Thus a second method was envisaged, the reaction of a nitrile, hydrogen selenide, and an a-halogenated ketone in the presence of a condensation catalyst, which can be POCl, or POCI3 with a Lewis acid such as PCI3 or anhydrous ZnCl. The use of fresh AICI3 leads to the formation of tarry side-products. 

The maximum yield of 2-alkylseIenazole is 25%. In this way. 4-methylselenazole (7) was obtained starting from hydrogen cyanide, hydrogen selenide and chloroacetone. It is the only known selenazole not substituted in the 2-position. The yield relative to chloroacetone is very low (2.5%) (Scheme 2). 

The selenoureas needed for condensation can usually be prepared by addition of hydrogen selenide to a solution of the corresponding cyanamides or carbodiimides. They can be less dangerously and quite... 

The advantage of this method is that it avoids the use of hydrogen selenide, necessary for the preparation of selenourea from cyanamide (14). Benzoylselenourea is synthesized by the method of Douglass (24) by the action of potassium selenocyanate On benzoyl chloride in acetone solution. 

The first involves the reaction of aziridine with an aldehyde or a ketone and the treatment of the resulting carbinol with hydrogen selenide (Scheme 69) (Methode I). 

Seienazolidines can also be obtained by first treating aziridine with hydrogen selenide and condensing the intermediate product with a carbonyl compound (Scheme 70) (Methode II). 

Selenium heterocycles receive far less mention in the literature than do such homologs as oxazole, thiazole, or imidazole. In fact, preparative methods of selenium heterocycles are much more limited than for the other series, mainly because of manipulatory difficulties arising from the toxicity of selenium (hydrogen selenide is even more toxic) that can produce severe damage to the skin, lungs, kidneys, and eyes. Another source of difficulty is the reactivity of the heterocycle itself, which can easily undergo fission, depending on the reaction medium and the nature of the substituents. 

Hydrogen selenide Hydrogen peroxide, nitric acid... 

Selenium is an essential element and is beneficial at low concentrations, serving as an antioxidant. Lack of selenium affects thyroid function, and selenium deficiencies have been linked to Keshan Disease (34). Selenium at high levels, however, is toxic. Hydrogen selenide (which is used in semiconductor manufacturing) is extremely toxic, affecting the mucous membranes and respiratory system. However, the toxicity of most organ oselenium compounds used as donor compounds for organic semiconductors is not weU studied. 

Bina Selenides. Most biaary selenides are formed by beating selenium ia the presence of the element, reduction of selenites or selenates with carbon or hydrogen, and double decomposition of heavy-metal salts ia aqueous solution or suspension with a soluble selenide salt, eg, Na2Se or (NH 2S [66455-76-3]. Atmospheric oxygen oxidizes the selenides more rapidly than the corresponding sulfides and more slowly than the teUurides. Selenides of the alkah, alkaline-earth metals, and lanthanum elements are water soluble and readily hydrolyzed. Heavy-metal selenides are iasoluble ia water. Polyselenides form when selenium reacts with alkah metals dissolved ia hquid ammonia. Metal (M) hydrogen selenides of the M HSe type are known. Some heavy-metal selenides show important and useful electric, photoelectric, photo-optical, and semiconductor properties. Ferroselenium and nickel selenide are made by sintering a mixture of selenium and metal powder. 

Contact with elemental selenium does not injure the skin. Selenium dioxide, however, upon contact with water, sweat, or tears, forms selenous acid, a severe skin irritant. Selenium oxyhaHdes are extremely vesicant and cause bums when in contact with human skin (91,92). Hydrogen selenide affects the mucous membranes of the upper respiratory tract and the eyes (93). 

Other gas-treating processes involving sulfolane are (/) hydrogen selenide removal from gasification of coal, shale, or tar sands (qv) (108) (2) olefin removal from alkanes (109) (J) nitrogen, helium, and argon removal from natural gas (110) (4) atmospheric CO2 removal in nuclear submarines (5) ammonia and H2S removal from waste streams (6) H2S, HCl, N2O, and CO2 removal from various streams (111—120) and (7) H2S and SO2 removal from... 

Trialkyl- and triarylarsine sulfides have been prepared by several different methods. The reaction of sulfur with a tertiary arsine, with or without a solvent, gives the sulfides in almost quantitative yields. Another method involves the reaction of hydrogen sulfide with a tertiary arsine oxide, hydroxyhahde, or dihaloarsorane. X-ray diffraction studies of triphenylarsine sulfide [3937-40-4], C gH AsS, show the arsenic to be tetrahedral the arsenic—sulfur bond is a tme double bond (137). Triphenylarsine sulfide and trimethylarsine sulfide [38859-90-4], C H AsS, form a number of coordination compounds with salts of transition elements (138,139). Both trialkyl- and triarylarsine selenides have been reported. The trialkyl compounds have been prepared by refluxing trialkylarsines with selenium powder (140). The preparation of triphenylarsine selenide [65374-39-2], C gH AsSe, from dichlorotriphenylarsorane and hydrogen selenide has been reported (141), but other workers could not dupHcate this work (140). 

The comparatively ready accessibility of selenocarboxamides has encouraged the use of this procedure for the synthesis of selenazoles (1889LA(250)294). Reaction of the a-chloro-carbonyl compound (73) with the selenocarboxamide (74) provided a ready synthesis of a variety of substituted selenazoles (75). Useful variations of this general procedure are described in detail in Chapter 4.20, and particularly attractive is the reaction of hydrogen selenide with a mixture of a nitrile and the a-halogenoketone to afford the selenazole (48YZ191, 79S66). 

Thermolysis of the aziridine (446) in the presence of diphenylketene gave a mixture of the pyrrolidone (447 minor product) and the oxazolidine (448 major product). In this instance the preferential addition to the C=0 bond is explained in terms of steric effects (72CC199). Similar addition to diphenylacetaldehyde takes place with the same orientation and the oxazolidine (448a) was obtained. When the reaction of the aziridine with the aldehyde was carried out in the presence of hydrogen selenide a selenazolidine was obtained (72BSB295). 

Cautionl Hydrogen selenide is very toxic. This preparation should be carried out in a well-ventilated hood. The operator should wear rubber gloves. The apparatus should be screened from any bright light. 

Hydrogen cyanide Calcium cyanide Potassium cyanide Sodium cyanide Hydrogen fluoride as F Hydrogen peroxide Hydrogen selenide as Se Hydrogen sulphide Hydroquinone... 

Hydrogen fluoride Hydrogen selenide Hydrogen sulphide... 

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