User:Milton Beychok/Sandbox: Difference between revisions
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At high temperature (about 1000 °[[Celsius (unit)|C]]) and with the use of a [[catalyst]], sulfur dioxide will react with hydrogen sulfide to form elemental sulfur and water (in the form of [[steam]]). This is commonly accomplished by the [[Claus process]], the primary method of converting hydrogen sulfide into elemental sulfur. | At high temperature (about 1000 °[[Celsius (unit)|C]]) and with the use of a [[catalyst]], sulfur dioxide will react with hydrogen sulfide to form elemental sulfur and water (in the form of [[steam]]). This is commonly accomplished by the [[Claus process]], the primary method of converting hydrogen sulfide into elemental sulfur. | ||
Hydrogen sulfide is readily soluble in water, amounting to 4.1 grams per litre of water at 20 °C which is equivalent to 0.41 weight %. When it is in solution in water, the H<sub>2</sub>S forms a weak acid (sometimes referred to as hydrosulfuric acid) containing hydrosulfide and sulfide [[ion]]s (HS<sup>−</sup> and S<sup>2−</sup>). The solubility is further enhanced in alkaline solutions due to increased ionization. | Hydrogen sulfide is readily soluble in water, amounting to 4.1 grams per litre of water at 20 °C which is equivalent to 0.41 weight %.<ref>[http://www.atsdr.cdc.gov/toxprofiles/tp114.pdf Toxicological Profile for Hydrogen Sulfide] July 2006, [[U.S. Department of Health and Human Services]], [[Agency for Toxic Substances and Disease Registry]] (ATSDR)</ref> When it is in solution in water, the H<sub>2</sub>S forms a weak acid (sometimes referred to as hydrosulfuric acid) containing hydrosulfide and sulfide [[ion]]s (HS<sup>−</sup> and S<sup>2−</sup>). The solubility is further enhanced in alkaline solutions due to increased ionization. | ||
Hydrogen sulfide reacts with metal ions to form metal [[sulfide]]s, which may be considered the [[salt]]s of hydrogen sulfide. Some [[Mineral deposit|minerals]] are sulfides. | Hydrogen sulfide reacts with metal ions to form metal [[sulfide]]s, which may be considered the [[salt]]s of hydrogen sulfide. Some [[Mineral deposit|minerals]] are sulfides. | ||
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Hydrogen sulfide is considered a broad-spectrum poison, meaning that it can poison several different systems in the body, although the [[nervous system]] is most affected. | Hydrogen sulfide is considered a broad-spectrum poison, meaning that it can poison several different systems in the body, although the [[nervous system]] is most affected. | ||
* 0.00047 [[parts-per notation| | * 0.00047 [[parts-per notation|ppmv]] is the recognition threshold, the concentration at which 50% of humans can detect the characteristic foul odor of hydrogen sulfide.<ref>[http://www.extension.iastate.edu/Publications/PM1963A.pdf Odor perception and physiological response]</ref> | ||
* At 100–150 ppm the [[olfactory nerve]] is paralyzed after a few inhalations, and the sense of smell disappears, often together with awareness of danger.<ref>USEPA; Health and Environmental Effects Profile for Hydrogen Sulfide p.118-8 (1980) ECAO-CIN-026A ???</ref><ref>Zenz, C., O.B. Dickerson, E.P. Horvath. ''Occupational Medicine.'' 3rd ed. St. Louis, MO., 1994, p.886 /publisher.ISBN???</ref> | * At 100–150 ppm the [[olfactory nerve]] is paralyzed after a few inhalations, and the sense of smell disappears, often together with awareness of danger.<ref>USEPA; Health and Environmental Effects Profile for Hydrogen Sulfide p.118-8 (1980) ECAO-CIN-026A ???</ref><ref>Zenz, C., O.B. Dickerson, E.P. Horvath. ''Occupational Medicine.'' 3rd ed. St. Louis, MO., 1994, p.886 /publisher.ISBN???</ref> | ||
* 320–530 ppm leads to [[pulmonary edema]] with the possibility of death. | * 320–530 ppm leads to [[pulmonary edema]] with the possibility of death. | ||
Revision as of 17:46, 2 March 2011
Hydrogen Sulfide
Hydrogen sulfide (or hydrogen sulphide) is a chemical compound with the formula H2S. It is a colorless, highly toxic, flammable gas with a characteristic foul odor.
Hydrogen sulfide is present in very large amounts in raw natural gas and also occurs in large amounts during the refining of petroleum crude oil. In fact, the vast majority of the 66,000,000 metric tons of elemental sulfur produced worldwide in 2006 was by-product sulfur from petroleum refining and natural gas processing plants.[1] It is also present in volcanic gases and some water well sources
It also occurs in swamps and sewers as a result of the bacterial breakdown of organic matter in the absence of oxygen, which is known as anaerobic digestion.
Chemical properties
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Hydrogen sulfide is a highly toxic and flammable gas (flammability range: 4.3 to 46 volume % in air). It is heavier than air and tends to accumulate at the bottom of poorly ventilated, confined spaces.
Hydrogen sulfide and oxygen burn to form sulfur dioxide (SO2) and water. In general, hydrogen sulfide acts as a reducing agent.
At high temperature (about 1000 °C) and with the use of a catalyst, sulfur dioxide will react with hydrogen sulfide to form elemental sulfur and water (in the form of steam). This is commonly accomplished by the Claus process, the primary method of converting hydrogen sulfide into elemental sulfur.
Hydrogen sulfide is readily soluble in water, amounting to 4.1 grams per litre of water at 20 °C which is equivalent to 0.41 weight %.[4] When it is in solution in water, the H2S forms a weak acid (sometimes referred to as hydrosulfuric acid) containing hydrosulfide and sulfide ions (HS− and S2−). The solubility is further enhanced in alkaline solutions due to increased ionization.
Hydrogen sulfide reacts with metal ions to form metal sulfides, which may be considered the salts of hydrogen sulfide. Some minerals are sulfides.
Hydrogen sulfide reacts with alcohols to form thiols.
Toxicity
Hydrogen sulfide is considered a broad-spectrum poison, meaning that it can poison several different systems in the body, although the nervous system is most affected.
- 0.00047 ppmv is the recognition threshold, the concentration at which 50% of humans can detect the characteristic foul odor of hydrogen sulfide.[5]
- At 100–150 ppm the olfactory nerve is paralyzed after a few inhalations, and the sense of smell disappears, often together with awareness of danger.[6][7]
- 320–530 ppm leads to pulmonary edema with the possibility of death.
- 530–1000 ppm causes strong stimulation of the central nervous system and rapid breathing, leading to loss of breathing.
- 800 ppm is the lethal concentration for 50% of humans for 5 minutes exposure (LC50).
- Concentrations over 1000 ppm cause immediate collapse with loss of breathing, even after inhalation of a single breath.
References
- ↑ Sulfur production report by the United States Geological Survey
- ↑ Carl L. Yaws (June 25, 2001). Matheson Gas Data Handbook, 7th Edition. McGraw-Hill. ISBN 0-07-135851-4.
- ↑ Air Liquide Gas Encyclopedia
- ↑ Toxicological Profile for Hydrogen Sulfide July 2006, U.S. Department of Health and Human Services, Agency for Toxic Substances and Disease Registry (ATSDR)
- ↑ Odor perception and physiological response
- ↑ USEPA; Health and Environmental Effects Profile for Hydrogen Sulfide p.118-8 (1980) ECAO-CIN-026A ???
- ↑ Zenz, C., O.B. Dickerson, E.P. Horvath. Occupational Medicine. 3rd ed. St. Louis, MO., 1994, p.886 /publisher.ISBN???