Sulfur dioxide

Last updated
Sulfur dioxide
Sulfur-dioxide-2D.svg
Sulfur-dioxide-3D-vdW.png
Sulfur dioxide lewis structure.png
Names
IUPAC name
Sulfur dioxide
Other names
Sulfurous anhydride
Sulfur(IV) oxide
Identifiers
3D model (JSmol)
3535237
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.028.359
EC Number
  • 231-195-2
E number E220 (preservatives)
1443
KEGG
MeSH Sulfur+dioxide
PubChem CID
RTECS number
  • WS4550000
UNII
UN number 1079, 2037
Properties
SO
2
Molar mass 64.066 g mol−1
AppearanceColorless gas
Odor Pungent; similar to a just-struck match [1]
Density 2.6288 kg m−3
Melting point −72 °C; −98 °F; 201 K
Boiling point −10 °C (14 °F; 263 K)
94 g/L [2]
forms sulfurous acid
Vapor pressure 237.2 kPa
Acidity (pKa)1.81
Basicity (pKb)12.19
18.2·10−6 cm3/mol
Viscosity 12.82 μPa·s [3]
Structure
C2v
Digonal
Dihedral
1.62 D
Thermochemistry
248.223 J K−1 mol−1
−296.81 kJ mol−1
Hazards
GHS pictograms GHS-pictogram-acid.svg GHS-pictogram-skull.svg
GHS Signal word Danger
H314, H331 [4]
NFPA 704 (fire diamond)
Flammability code 0: Will not burn. E.g. waterHealth code 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no codeSulfur dioxide
0
3
0
Lethal dose or concentration (LD, LC):
3000 ppm (mouse, 30 min)
2520 ppm (rat, 1 hr) [5]
993 ppm (rat, 20 min)
611 ppm (rat, 5 hr)
764 ppm (mouse, 20 min)
1000 ppm (human, 10 min)
3000 ppm (human, 5 min) [5]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 5 ppm (13 mg/m3) [6]
REL (Recommended)
TWA 2 ppm (5 mg/m3) ST 5 ppm (13 mg/m3) [6]
IDLH (Immediate danger)
100 ppm [6]
Related compounds
Related sulfur oxides
Sulfur monoxide
Sulfur trioxide
Related compounds
Ozone

Selenium dioxide
Sulfurous acid
Tellurium dioxide

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)
Infobox references

Sulfur dioxide (also sulphur dioxide in British English) is the chemical compound with the formula S O
2
. It is a toxic gas responsible for the smell of burnt matches. It is released naturally by volcanic activity and is produced as a by-product of copper extraction and the burning of fossil fuels contaminated with sulfur compounds.

Contents

Structure and bonding

SO2 is a bent molecule with C2v symmetry point group. A valence bond theory approach considering just s and p orbitals would describe the bonding in terms of resonance between two resonance structures.

Two resonance structures of sulfur dioxide Sulfur-dioxide-resonance-2D.svg
Two resonance structures of sulfur dioxide

The sulfur–oxygen bond has a bond order of 1.5. There is support for this simple approach that does not invoke d orbital participation. [7] In terms of electron-counting formalism, the sulfur atom has an oxidation state of +4 and a formal charge of +1.

Occurrence

The blue auroral glows of Io's upper atmosphere are caused by volcanic sulfur dioxide. Io Aurorae color.jpg
The blue auroral glows of Io's upper atmosphere are caused by volcanic sulfur dioxide.

It is found on Earth and exists in very small concentrations and in the atmosphere at about 1 ppm. [8] [9] [ clarification needed ]

On other planets, it can be found in various concentrations, the most significant being the atmosphere of Venus, where it is the third-most significant atmospheric gas at 150 ppm. There, it condenses to form clouds, and is a key component of chemical reactions in the planet's atmosphere and contributes to global warming. [10] It has been implicated as a key agent in the warming of early Mars, with estimates of concentrations in the lower atmosphere as high as 100 ppm, [11] though it only exists in trace amounts. On both Venus and Mars, as on Earth, its primary source is thought to be volcanic. The atmosphere of Io, a natural satellite of Jupiter, is 90% sulfur dioxide [12] and trace amounts are thought to also exist in the atmosphere of Jupiter.

As an ice, it is thought to exist in abundance on the Galilean moons—as subliming ice or frost on the trailing hemisphere of Io, [13] and in the crust and mantle of Europa, Ganymede, and Callisto, possibly also in liquid form and readily reacting with water. [14]

Production

Sulfur dioxide is primarily produced for sulfuric acid manufacture (see contact process). In the United States in 1979, 23.6 million tonnes (26,014,547 US short tons) of sulfur dioxide were used in this way, compared with 150 thousand tonnes (165,347 US short tons) used for other purposes. Most sulfur dioxide is produced by the combustion of elemental sulfur. Some sulfur dioxide is also produced by roasting pyrite and other sulfide ores in air. [15]

An experiment showing burning of sulfur in oxygen. A flow-chamber joined to a gas washing bottle (filled with a solution of methyl orange) is being used. The product is sulfur dioxide (SO2) with some traces of sulfur trioxide (SO3). The "smoke" that exits the gas washing bottle is, in fact, a sulfuric acid fog generated in a reaction.

Combustion routes

Sulfur dioxide is the product of the burning of sulfur or of burning materials that contain sulfur:

S + O2 → SO2, ΔH = −297 kJ/mol

To aid combustion, liquefied sulfur (140–150 °C, 284-302 °F) is sprayed through an atomizing nozzle to generate fine drops of sulfur with a large surface area. The reaction is exothermic, and the combustion produces temperatures of 1000–1600 °C (1832–2912 °F). The significant amount of heat produced is recovered by steam generation that can subsequently be converted to electricity. [15]

The combustion of hydrogen sulfide and organosulfur compounds proceeds similarly. For example:

2 H2S + 3 O2 → 2 H2O + 2 SO2

The roasting of sulfide ores such as pyrite, sphalerite, and cinnabar (mercury sulfide) also releases SO2: [16]

4 FeS2 + 11 O2 → 2 Fe2O3 + 8 SO2
2 ZnS + 3 O2 → 2 ZnO + 2 SO2
HgS + O2 → Hg + SO2
4 FeS + 7O2 → 2 Fe2O3 + 4 SO2

A combination of these reactions is responsible for the largest source of sulfur dioxide, volcanic eruptions. These events can release millions of tonnes of SO2.

Reduction of higher oxides

Sulfur dioxide can also be a byproduct in the manufacture of calcium silicate cement; CaSO4 is heated with coke and sand in this process:

2 CaSO4 + 2 SiO2 + C → 2 CaSiO3 + 2 SO2 + CO2

Until the 1970s, commercial quantities of sulfuric acid and cement were produced by this process in Whitehaven, England. Upon being mixed with shale or marl, and roasted, the sulfate liberated sulfur dioxide gas, used in sulfuric acid production, the reaction also produced calcium silicate, a precursor in cement production. [17]

On a laboratory scale, the action of hot concentrated sulfuric acid on copper turnings produces sulfur dioxide.

Cu + 2 H2SO4 → CuSO4 + SO2 + 2 H2O

From sulfite

Sulfite results from the reaction of aqueous base and sulfur dioxide. The reverse reaction involves acidification of sodium metabisulfite:

H2SO4 + Na2S2O5 → 2 SO2 + Na2SO3 + H2O

Reactions

Industrial reactions

Treatment of basic solutions with sulfur dioxide affords sulfite salts (e.g. sodium sulfite):

SO2 + 2 NaOH → Na2SO3 + H2O

Featuring sulfur in the +4 oxidation state, sulfur dioxide is a reducing agent. It is oxidized by halogens to give the sulfuryl halides, such as sulfuryl chloride:

SO2 + Cl2 → SO2Cl2

Sulfur dioxide is the oxidising agent in the Claus process, which is conducted on a large scale in oil refineries. Here, sulfur dioxide is reduced by hydrogen sulfide to give elemental sulfur:

SO2 + 2 H2S → 3 S + 2 H2O

The sequential oxidation of sulfur dioxide followed by its hydration is used in the production of sulfuric acid.

2 SO2 + 2 H2O + O2 → 2 H2SO4

Laboratory reactions

Sulfur dioxide is one of the few common acidic yet reducing gases. It turns moist litmus pink (being acidic), then white (due to its bleaching effect). It may be identified by bubbling it through a dichromate solution, turning the solution from orange to green (Cr3+ (aq)). It can also reduce ferric ions to ferrous. [18]

Sulfur dioxide can react with certain 1,3-dienes in a cheletropic reaction to form cyclic sulfones. This reaction is exploited on an industrial scale for the synthesis of sulfolane, which is an important solvent in the petrochemical industry.

Cheletropic reaction of butadiene with SO2.svg

Sulfur dioxide can bind to metal ions as a ligand to form metal sulfur dioxide complexes, typically where the transition metal is in oxidation state 0 or +1. Many different bonding modes (geometries) are recognized, but in most cases, the ligand is monodentate, attached to the metal through sulfur, which can be either planar and pyramidal η 1. [19]

Uses

Precursor to sulfuric acid

Sulfur dioxide is an intermediate in the production of sulfuric acid, being converted to sulfur trioxide, and then to oleum, which is made into sulfuric acid. Sulfur dioxide for this purpose is made when sulfur combines with oxygen. The method of converting sulfur dioxide to sulfuric acid is called the contact process. Several billion kilograms are produced annually for this purpose.

As a preservative

Sulfur dioxide is sometimes used as a preservative for dried apricots, dried figs, and other dried fruits, owing to its antimicrobial properties, and is called E220 [20] when used in this way in Europe. As a preservative, it maintains the colorful appearance of the fruit and prevents rotting. It is also added to sulfured molasses.

In winemaking

Sulfur dioxide was first used in winemaking by the Romans, when they discovered that burning sulfur candles inside empty wine vessels keeps them fresh and free from vinegar smell. [21]

It is still an important compound in winemaking, and is measured in parts per million (ppm) in wine. It is present even in so-called unsulfurated wine at concentrations of up to 10 mg/L. [22] It serves as an antibiotic and antioxidant, protecting wine from spoilage by bacteria and oxidation - a phenomenon that leads to the browning of the wine and a loss of cultivar specific flavors. [23] [24] Its antimicrobial action also helps minimize volatile acidity. Wines containing sulfur dioxide are typically labeled with "containing sulfites".

Sulfur dioxide exists in wine in free and bound forms, and the combinations are referred to as total SO2. Binding, for instance to the carbonyl group of acetaldehyde, varies with the wine in question. The free form exists in equilibrium between molecular SO2 (as a dissolved gas) and bisulfite ion, which is in turn in equilibrium with sulfite ion. These equilibria depend on the pH of the wine. Lower pH shifts the equilibrium towards molecular (gaseous) SO2, which is the active form, while at higher pH more SO2 is found in the inactive sulfite and bisulfite forms. The molecular SO2 is active as an antimicrobial and antioxidant, and this is also the form which may be perceived as a pungent odor at high levels. Wines with total SO2 concentrations below 10 ppm do not require "contains sulfites" on the label by US and EU laws. The upper limit of total SO2 allowed in wine in the US is 350 ppm; in the EU it is 160 ppm for red wines and 210 ppm for white and rosé wines. In low concentrations, SO2 is mostly undetectable in wine, but at free SO2 concentrations over 50 ppm, SO2 becomes evident in the smell and taste of wine.[ citation needed ]

SO2 is also a very important compound in winery sanitation. Wineries and equipment must be kept clean, and because bleach cannot be used in a winery due the risk of cork taint, [25] a mixture of SO2, water, and citric acid is commonly used to clean and sanitize equipment. Ozone (O3) is now used extensively for sanitizing in wineries due to its efficacy, and because it does not affect the wine or most equipment. [26]

As a reducing agent

Sulfur dioxide is also a good reductant. In the presence of water, sulfur dioxide is able to decolorize substances. Specifically, it is a useful reducing bleach for papers and delicate materials such as clothes. This bleaching effect normally does not last very long. Oxygen in the atmosphere reoxidizes the reduced dyes, restoring the color. In municipal wastewater treatment, sulfur dioxide is used to treat chlorinated wastewater prior to release. Sulfur dioxide reduces free and combined chlorine to chloride. [27]

Sulfur dioxide is fairly soluble in water, and by both IR and Raman spectroscopy; the hypothetical sulfurous acid, H2SO3, is not present to any extent. However, such solutions do show spectra of the hydrogen sulfite ion, HSO3, by reaction with water, and it is in fact the actual reducing agent present:

SO2 + H2O ⇌ HSO3 + H+

Biochemical and biomedical roles

Sulfur dioxide is toxic in large amounts. It or its conjugate base bisulfite is produced biologically as an intermediate in both sulfate-reducing organisms and in sulfur-oxidizing bacteria, as well. The role of sulfur dioxide in mammalian biology is not yet well understood. [28] Sulfur dioxide blocks nerve signals from the pulmonary stretch receptors and abolishes the Hering–Breuer inflation reflex.

It was shown that endogenous sulfur dioxide plays a role in diminishing an experimental lung damage caused by oleic acid. Endogenous sulfur dioxide lowered lipid peroxidation, free radical formation, oxidative stress and inflammation during an experimental lung damage. Conversely, a successful lung damage caused a significant lowering of endogenous sulfur dioxide production, and an increase in lipid peroxidation, free radical formation, oxidative stress and inflammation. Moreover, blockade of an enzyme that produces endogenous SO2 significantly increased the amount of lung tissue damage in the experiment. Conversely, adding acetylcysteine or glutathione to the rat diet increased the amount of endogenous SO2 produced and decreased the lung damage, the free radical formation, oxidative stress, inflammation and apoptosis. [29]

It is considered that endogenous sulfur dioxide plays a significant physiological role in regulating cardiac and blood vessel function, and aberrant or deficient sulfur dioxide metabolism can contribute to several different cardiovascular diseases, such as arterial hypertension, atherosclerosis, pulmonary arterial hypertension, stenocardia. [30]

It was shown that in children with pulmonary arterial hypertension due to congenital heart diseases the level of homocysteine is higher and the level of endogenous sulfur dioxide is lower than in normal control children. Moreover, these biochemical parameters strongly correlated to the severity of pulmonary arterial hypertension. Authors considered homocysteine to be one of useful biochemical markers of disease severity and sulfur dioxide metabolism to be one of potential therapeutic targets in those patients. [31]

Endogenous sulfur dioxide also has been shown to lower the proliferation rate of endothelial smooth muscle cells in blood vessels, via lowering the MAPK activity and activating adenylyl cyclase and protein kinase A. [32] Smooth muscle cell proliferation is one of important mechanisms of hypertensive remodeling of blood vessels and their stenosis, so it is an important pathogenetic mechanism in arterial hypertension and atherosclerosis.

Endogenous sulfur dioxide in low concentrations causes endothelium-dependent vasodilation. In higher concentrations it causes endothelium-independent vasodilation and has a negative inotropic effect on cardiac output function, thus effectively lowering blood pressure and myocardial oxygen consumption. The vasodilating and bronchodilating effects of sulfur dioxide are mediated via ATP-dependent calcium channels and L-type ("dihydropyridine") calcium channels. Endogenous sulfur dioxide is also a potent antiinflammatory, antioxidant and cytoprotective agent. It lowers blood pressure and slows hypertensive remodeling of blood vessels, especially thickening of their intima. It also regulates lipid metabolism. [33]

Endogenous sulfur dioxide also diminishes myocardial damage, caused by isoproterenol adrenergic hyperstimulation, and strengthens the myocardial antioxidant defense reserve. [34]

As a refrigerant

Being easily condensed and possessing a high heat of evaporation, sulfur dioxide is a candidate material for refrigerants. Prior to the development of chlorofluorocarbons, sulfur dioxide was used as a refrigerant in home refrigerators.

As a reagent and solvent in the laboratory

Sulfur dioxide is a versatile inert solvent widely used for dissolving highly oxidizing salts. It is also used occasionally as a source of the sulfonyl group in organic synthesis. Treatment of aryl diazonium salts with sulfur dioxide and cuprous chloride yields the corresponding aryl sulfonyl chloride, for example: [35]

Preparation of m-trifluoromethylbenzenesulfonyl chloride.svg

As a result of its very low Lewis basicity, it is often used as a low-temperature solvent/diluent for superacids like Magic acid (FSO3H/SbF5), allowing for highly reactive species like tert-butyl cation to be observed spectroscopically at low temperature (though tertiary carbocations do react with SO2 above about –30 °C, and even less reactive solvents like SO2ClF must be used at these higher temperatures). [36]

Proposed use in climate engineering

Injections of sulfur dioxide in the stratosphere has been proposed in climate engineering. The cooling effect would be similar to what has been observed after the large explosive 1991 eruption of Mount Pinatubo. However this form of geoengineering would have uncertain regional consequences on rainfall patterns, for example in monsoon regions. [37]

As an air pollutant

Sulfur dioxide is a noticeable component in the atmosphere, especially following volcanic eruptions. [38] According to the United States Environmental Protection Agency, [39] the amount of sulfur dioxide released in the U.S. per year was:

YearSO2
197031,161,000 short tons (28.3 Mt)
198025,905,000 short tons (23.5 Mt)
199023,678,000 short tons (21.5 Mt)
199618,859,000 short tons (17.1 Mt)
199719,363,000 short tons (17.6 Mt)
199819,491,000 short tons (17.7 Mt)
199918,867,000 short tons (17.1 Mt)

Sulfur dioxide is a major air pollutant and has significant impacts upon human health. [40] In addition, the concentration of sulfur dioxide in the atmosphere can influence the habitat suitability for plant communities, as well as animal life. [41] Sulfur dioxide emissions are a precursor to acid rain and atmospheric particulates. Due largely to the US EPA's Acid Rain Program, the U.S. has had a 33% decrease in emissions between 1983 and 2002. This improvement resulted in part from flue-gas desulfurization, a technology that enables SO2 to be chemically bound in power plants burning sulfur-containing coal or oil. In particular, calcium oxide (lime) reacts with sulfur dioxide to form calcium sulfite:

CaO + SO2 → CaSO3

Aerobic oxidation of the CaSO3 gives CaSO4, anhydrite. Most gypsum sold in Europe comes from flue-gas desulfurization.

Sulfur can be removed from coal during burning by using limestone as a bed material in fluidized bed combustion. [42]

Sulfur can also be removed from fuels before burning, preventing formation of SO2 when the fuel is burnt. The Claus process is used in refineries to produce sulfur as a byproduct. The Stretford process has also been used to remove sulfur from fuel. Redox processes using iron oxides can also be used, for example, Lo-Cat [43] or Sulferox. [44]

Fuel additives such as calcium additives and magnesium carboxylate may be used in marine engines to lower the emission of sulfur dioxide gases into the atmosphere. [45]

As of 2006, China was the world's largest sulfur dioxide polluter, with 2005 emissions estimated to be 25,490,000 short tons (23.1 Mt). This amount represents a 27% increase since 2000, and is roughly comparable with U.S. emissions in 1980. [46]

Safety

US Geological Survey volunteer tests for sulfur dioxide after the 2018 lower Puna eruption 20180519 USGS Leilani Estates Hawaii Volcanic EruptionDSC 0411 medium.jpg
US Geological Survey volunteer tests for sulfur dioxide after the 2018 lower Puna eruption

Inhalation

Inhaling sulfur dioxide is associated with increased respiratory symptoms and disease, difficulty in breathing, and premature death. [47] In 2008, the American Conference of Governmental Industrial Hygienists reduced the short-term exposure limit to 0.25 parts per million (ppm). The OSHA PEL is currently set at 5 ppm (13  mg/m3) time-weighted average. NIOSH has set the IDLH at 100 ppm. [48] In 2010, the EPA "revised the primary SO2 NAAQS by establishing a new one-hour standard at a level of 75 parts per billion (ppb). EPA revoked the two existing primary standards because they would not provide additional public health protection given a one-hour standard at 75 ppb." [40]

A 2011 systematic review concluded that exposure to sulfur dioxide is associated with preterm birth. [49]

Ingestion

In the United States, the Center for Science in the Public Interest lists the two food preservatives, sulfur dioxide and sodium bisulfite, as being safe for human consumption except for certain asthmatic individuals who may be sensitive to them, especially in large amounts. [50] Symptoms of sensitivity to sulfiting agents, including sulfur dioxide, manifest as potentially life-threatening trouble breathing within minutes of ingestion. [51]

See also

Related Research Articles

Acid rain rain that is unusually acidic

Acid rain is a rain or any other form of precipitation that is unusually acidic, meaning that it has elevated levels of hydrogen ions. It can have harmful effects on plants, aquatic animals and infrastructure. Acid rain is caused by emissions of sulfur dioxide and nitrogen oxide, which react with the water molecules in the atmosphere to produce acids. Some governments have made efforts since the 1970s to reduce the release of sulfur dioxide and nitrogen oxide into the atmosphere with positive results. Nitrogen oxides can also be produced naturally by lightning strikes, and sulfur dioxide is produced by volcanic eruptions. Acid rain has been shown to have adverse impacts on forests, freshwaters and soils, killing insect and aquatic life-forms, causing paint to peel, corrosion of steel structures such as bridges, and weathering of stone buildings and statues as well as having impacts on human health.

Carbon dioxide Chemical compound

Carbon dioxide is a colorless gas with a density about 60% higher than that of dry air. Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms. It occurs naturally in Earth's atmosphere as a trace gas. The current concentration is about 0.04% (412 ppm) by volume, having risen from pre-industrial levels of 280 ppm. Natural sources include volcanoes, hot springs and geysers, and it is freed from carbonate rocks by dissolution in water and acids. Because carbon dioxide is soluble in water, it occurs naturally in groundwater, rivers and lakes, ice caps, glaciers and seawater. It is present in deposits of petroleum and natural gas. Carbon dioxide is odorless at normally encountered concentrations, but at high concentrations, it has a sharp and acidic odor. At such concentrations it generates the taste of soda water in the mouth.

Sulfur Chemical element with atomic number 16

Sulfur (in British English, sulphur) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent, and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula S8. Elemental sulfur is a bright yellow, crystalline solid at room temperature.

Sulfuric acid chemical compound

Sulfuric acid (alternative spelling sulphuric acid), also known as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with molecular formula H2SO4. It is a colorless, odorless, and viscous liquid that is soluble in water and is synthesized in reactions that are highly exothermic.

Hydrogen sulfide Poisonous, corrosive and flammable gas

Hydrogen sulfide is the chemical compound with the formula H
2
S
. It is a colorless chalcogen hydride gas with the characteristic foul odor of rotten eggs. It is very poisonous, corrosive, and flammable.

Sulfurous acid Chemical compound

Sulfurous acid (also sulphurous acid) is the chemical compound with the formula H2SO3. There is no evidence that sulfurous acid exists in solution, but the molecule has been detected in the gas phase. The conjugate bases of this elusive acid are, however, common anions, bisulfite (or hydrogen sulfite) and sulfite. Sulfurous acid is an intermediate species in the formation of acid rain from sulfur dioxide.

Nitric oxide Colorless gas with the formula NO

Nitric oxide is a colorless gas with the formula NO. It is one of the principal oxides of nitrogen. Nitric oxide is a free radical, i.e., it has an unpaired electron, which is sometimes denoted by a dot in its chemical formula. Nitric oxide is also a heteronuclear diatomic molecule, a historic class that drew researches which spawned early modern theories of chemical bonding.

Sulfite salt or ester of sulfurous acid

Sulfites or sulphites are compounds that contain the sulfite ion, SO2−
3
. The most important sulfite compounds are sodium sulfite and its derivative sodium metabisulfite. These compounds are used a food preservatives and in the production of paper.

Neutralization (chemistry) chemical reaction

In chemistry, neutralization or neutralisation is a chemical reaction in which an acid and a base react quantitatively with each other. In a reaction in water, neutralization results in there being no excess of hydrogen or hydroxide ions present in the solution. The pH of the neutralized solution depends on the acid strength of the reactants.

Flue-gas desulfurization

Flue-gas desulfurization (FGD) is a set of technologies used to remove sulfur dioxide from exhaust flue gases of fossil-fuel power plants, and from the emissions of other sulfur oxide emitting processes such as waste incineration.

Vanadium(V) oxide chemical compound

Vanadium(V) oxide (vanadia) is the inorganic compound with the formula V2O5. Commonly known as vanadium pentoxide, it is a brown/yellow solid, although when freshly precipitated from aqueous solution, its colour is deep orange. Because of its high oxidation state, it is both an amphoteric oxide and an oxidizing agent. From the industrial perspective, it is the most important compound of vanadium, being the principal precursor to alloys of vanadium and is a widely used industrial catalyst.

Sodium dithionite chemical compound

Sodium dithionite is a white crystalline powder with a weak sulfurous odor. Although it is stable in the absence of air, it decomposes in hot water and in acid solutions.

Potassium bisulfite chemical compound

Potassium bisulfite (or potassium hydrogen sulfite) is a chemical mixture with the approximate chemical formula KHSO3. Potassium bisulfite in fact is not a real compound, but a mixture of salts that dissolve in water to give solutions composed of potassium ions and bisulfite ions. It is a white solid with an odor of sulfur dioxide. Attempts to crystallize potassium bisulfite yields potassium metabisulfite, K2S2O5.

The sulfite process produces wood pulp thatis almost pure cellulose fibers by treating wood chips with solutions of sulfite and bisulfite ions. These chemicals cleave the bonds between the cellulose and lignin components of the lignocellulose. A variety of sulfite/bisulfite salts are used, including sodium (Na+), calcium (Ca2+), potassium (K+), magnesium (Mg2+), and ammonium (NH4+). The lignin is converted to lignosulfonates, which are soluble and can be separated from the cellulose fibers. For the prroduction of cellulose, the sulfite process competes with the Kraft process, which produces stronger fibers and is less environmental costly.

Calcium sulfite chemical compound

Calcium sulfite, or calcium sulphite, is a chemical compound, the calcium salt of sulfite with the formula CaSO3·x(H2O). Two crystalline forms are known, the hemihydrate and the tetrahydrate, respectively CaSO3·½(H2O) and CaSO3·4(H2O). All forms are white solids. It is most notable as the product of flue-gas desulfurization.

The Wellman–Lord process is a regenerable process to remove sulfur dioxide from flue gas without creating a throwaway sludge product.

Disulfite chemical compound

A disulfite, commonly known as metabisulfite or pyrosulfite, is a chemical compound containing the ion S
2
O2−
5
. It is a colorless dianion that is primarily marketed in the form of sodium metabisulfite or potassium metabisulfite. When dissolved in water, these salts release the bisulfiite HSO
3
ion. These salts act equivalently to sodium bisulfite or potassium bisulfite.

Sodium bisulfite chemical compound

Sodium bisulfite (or sodium bisulphite, sodium hydrogen sulfite) is a chemical mixture with the approximate chemical formula NaHSO3. Sodium bisulfite in fact is not a real compound, but a mixture of salts that dissolve in water to give solutions composed of sodium and bisulfite ions. It is a white solid with an odor of sulfur dioxide. Regardless of its ill-defined nature, "sodium bisulfite" is a food additive with E number E222.

Sulfoxylic acid chemical compound

Sulfoxylic acid (H2SO2) (also known as hyposulfurous acid or sulfur dihydroxide) is an unstable oxoacid of sulfur in an intermediate oxidation state between hydrogen sulfide and dithionous acid. It consists of two hydroxy groups attached to a sulfur atom. Sulfoxylic acid contains sulfur in an oxidation state of +2. Sulfur monoxide (SO) can be considered as a theoretical anhydride for sulfoxylic acid, but it is not actually known to react with water.

The topic of sulfite food and beverage additives covers the application of sulfites in food chemistry. "Sulfite" is jargon that encompasses a variety of materials that are commonly used as preservatives or food additive in the production of diverse foods and beverages. Although sulfite salts are relatively nontoxic, their use has led to controversy, resulting in extensive regulations. Sulfites are a source of sulfur dioxide (SO2), a bactericide.

References

  1. Sulfur dioxide, U.S. National Library of Medicine
  2. Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN   0-8493-0487-3.
  3. Miller, J.W. Jr.; Shah, P.N.; Yaws, C.L. (1976). "Correlation constants for chemical compounds". Chemical Engineering. 83 (25): 153–180. ISSN   0009-2460.
  4. https://echa.europa.eu/information-on-chemicals/cl-inventory-database/-/discli/notification-details/115657/1409763
  5. 1 2 "Sulfur dioxide". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  6. 1 2 3 NIOSH Pocket Guide to Chemical Hazards. "#0575". National Institute for Occupational Safety and Health (NIOSH).
  7. Cunningham, Terence P.; Cooper, David L.; Gerratt, Joseph; Karadakov, Peter B. & Raimondi, Mario (1997). "Chemical bonding in oxofluorides of hypercoordinatesulfur". Journal of the Chemical Society, Faraday Transactions. 93 (13): 2247–2254. doi:10.1039/A700708F.
  8. Owen, Lewis A.; Pickering, Kevin T (1997). An Introduction to Global Environmental Issues. Taylor copper extraction& Francis. pp. 33–. ISBN   978-0-203-97400-1.
  9. Taylor, J.A.; Simpson, R.W.; Jakeman, A.J. (1987). "A hybrid model for predicting the distribution of sulphur dioxide concentrations observed near elevated point sources". Ecological Modelling. 36 (3–4): 269–296. doi:10.1016/0304-3800(87)90071-8. ISSN   0304-3800.
  10. Marcq, Emmanuel; Bertaux, Jean-Loup; Montmessin, Franck; Belyaev, Denis (2012). "Variations of sulphur dioxide at the cloud top of Venus's dynamic atmosphere". Nature Geoscience. 6: 25–28. doi:10.1038/ngeo1650. ISSN   1752-0894.
  11. Halevy, I.; Zuber, M. T.; Schrag, D. P. (2007). "A Sulfur Dioxide Climate Feedback on Early Mars". Science. 318 (5858): 1903–1907. Bibcode:2007Sci...318.1903H. doi:10.1126/science.1147039. ISSN   0036-8075. PMID   18096802.
  12. Lellouch, E.; et al. (2007). "Io's atmosphere". In Lopes, R. M. C.; Spencer, J. R. (eds.). Io after Galileo. Springer-Praxis. pp. 231–264. ISBN   978-3-540-34681-4.
  13. Cruikshank, D. P.; Howell, R. R.; Geballe, T. R.; Fanale, F. P. (1985). "Sulfur Dioxide Ice on IO". Ices in the Solar System: 805–815. doi:10.1007/978-94-009-5418-2_55. ISBN   978-94-010-8891-6.
  14. Europa's Hidden Ice Chemistry – NASA Jet Propulsion Laboratory. Jpl.nasa.gov (2010-10-04). Retrieved on 2013-09-24.
  15. 1 2 Müller, Hermann. "Sulfur Dioxide". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a25_569.
  16. Shriver, Atkins. Inorganic Chemistry, Fifth Edition. W. H. Freeman and Company; New York, 2010; p. 414.
  17. WHITEHAVEN COAST ARCHAEOLOGICAL SURVEY. lakestay.co.uk (2007)
  18. http://publications.gc.ca/collections/collection_2017/rncan-nrcan/M34-20/M34-20-107-eng.pdf
  19. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN   978-0-08-037941-8.
  20. Current EU approved additives and their E Numbers, The Food Standards Agency website.
  21. "Practical Winery & vineyard Journal Jan/Feb 2009". www.practicalwinery.com. 1 Feb 2009. Archived from the original on 2013-09-28.
  22. Sulphites in wine, MoreThanOrganic.com.
  23. Jackson, R.S. (2008) Wine science: principles and applications, Amsterdam; Boston: Elsevier/Academic Press
  24. Guerrero, Raúl F; Cantos-Villar, Emma (2015). "Demonstrating the efficiency of sulphur dioxide replacements in wine: A parameter review". Trends in Food Science & Technology. 42: 27–43. doi:10.1016/j.tifs.2014.11.004.
  25. Chlorine Use in the Winery. Purdue University
  26. Use of ozone for winery and environmental sanitation, Practical Winery & Vineyard Journal.
  27. Tchobanoglous, George (1979). Wastewater Engineering (3rd ed.). New York: McGraw Hill. ISBN   0-07-041677-X.
  28. Liu, D.; Jin, H; Tang, C; Du, J (2010). "Sulfur dioxide: a novel gaseous signal in the regulation of cardiovascular functions". Mini-Reviews in Medicinal Chemistry. 10 (11): 1039–1045. doi:10.2174/1389557511009011039. PMID   20540708. Archived from the original on 2013-04-26.
  29. Chen S, Zheng S, Liu Z, Tang C, Zhao B, Du J, Jin H (Feb 2015). "Endogenous sulfur dioxide protects against oleic acid-induced acute lung injury in association with inhibition of oxidative stress in rats". Lab. Invest. 95 (2): 142–156. doi:10.1038/labinvest.2014.147. PMID   25581610.
  30. Tian H. (Nov 2014). "Advances in the study on endogenous sulfur dioxide in the cardiovascular system". Chin Med J. 127 (21): 3803–3807. PMID   25382339.
  31. Yang R, Yang Y, Dong X, Wu X, Wei Y (Aug 2014). "Correlation between endogenous sulfur dioxide and homocysteine in children with pulmonary arterial hypertension associated with congenital heart disease". Zhonghua Er Ke Za Zhi (in Chinese). 52 (8): 625–629. PMID   25224243.
  32. Liu D, Huang Y, Bu D, Liu AD, Holmberg L, Jia Y, Tang C, Du J, Jin H (May 2014). "Sulfur dioxide inhibits vascular smooth muscle cell proliferation via suppressing the Erk/MAP kinase pathway mediated by cAMP/PKA signaling". Cell Death Dis. 5 (5): e1251. doi:10.1038/cddis.2014.229. PMC   4047873 . PMID   24853429.
  33. Wang XB, Jin HF, Tang CS, Du JB (16 Nov 2011). "The biological effect of endogenous sulfur dioxide in the cardiovascular system". Eur J Pharmacol. 670 (1): 1–6. doi:10.1016/j.ejphar.2011.08.031. PMID   21925165.
  34. Liang Y, Liu D, Ochs T, Tang C, Chen S, Zhang S, Geng B, Jin H, Du J (Jan 2011). "Endogenous sulfur dioxide protects against isoproterenol-induced myocardial injury and increases myocardial antioxidant capacity in rats". Lab. Invest. 91 (1): 12–23. doi:10.1038/labinvest.2010.156. PMID   20733562.
  35. Hoffman, R. V. (1990). "m-Trifluoromethylbenzenesulfonyl Chloride". Organic Syntheses .; Collective Volume, 7, p. 508
  36. Olah, George A.; Lukas, Joachim. (1967-08-01). "Stable carbonium ions. XLVII. Alkylcarbonium ion formation from alkanes via hydride (alkide) ion abstraction in fluorosulfonic acid-antimony pentafluoride-sulfuryl chlorofluoride solution". Journal of the American Chemical Society. 89 (18): 4739–4744. doi:10.1021/ja00994a030. ISSN   0002-7863.
  37. Clarke L., K. Jiang, K. Akimoto, M. Babiker, G. Blanford, K. Fisher-Vanden, J.-C. Hourcade, V. Krey, E. Kriegler, A. Löschel, D. McCollum, S. Paltsev, S. Rose, P. R. Shukla, M. Tavoni, B. C. C. van der Zwaan, and D.P. van Vuuren, 2014: Assessing Transformation Pathways. In: Climate Change 2014: Mitigation of Climate Change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Edenhofer, O., R. Pichs-Madruga, Y. Sokona, E. Farahani, S. Kadner, K. Seyboth, A. Adler, I. Baum, S. Brunner, P. Eickemeier, B. Kriemann, J. Savolainen, S. Schlömer, C. von Stechow, T. Zwickel and J.C. Minx (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
  38. Volcanic Gases and Their Effects. Volcanoes.usgs.gov. Retrieved on 2011-10-31.
  39. National Trends in Sulfur Dioxide Levels, United States Environmental Protection Agency.
  40. 1 2 Sulfur Dioxide. United States Environmental Protection Agency
  41. Hogan, C. Michael (2010). "Abiotic factor" in Encyclopedia of Earth. Emily Monosson and C. Cleveland (eds.). National Council for Science and the Environment. Washington DC
  42. Lindeburg, Michael R. (2006). Mechanical Engineering Reference Manual for the PE Exam. Belmont, C.A.: Professional Publications, Inc. pp. 27–3. ISBN   978-1-59126-049-3.
  43. FAQ’s About Sulfur Removal and Recovery using the LO-CAT® Hydrogen Sulfide Removal System. gtp-merichem.com
  44. Process screening analysis of alternative gas treating and sulfur removal for gasification. (December 2002) Report by SFA Pacific, Inc. prepared for U.S. Department of Energy (PDF) . Retrieved on 2011-10-31.
  45. May, Walter R. Marine Emissions Abatement Archived 2015-04-02 at the Wayback Machine . SFA International, Inc., p. 6.
  46. China has its worst spell of acid rain, United Press International (2006-09-22).
  47. Sulfur Dioxide[broken link] U.S. Environmental Protection Agency
  48. "NIOSH Pocket Guide to Chemical Hazards".
  49. Shah PS, Balkhair T, Knowledge Synthesis Group on Determinants of Preterm/LBW Births (2011). "Air pollution and birth outcomes: a systematic review". Environ Int. 37 (2): 498–516. doi:10.1016/j.envint.2010.10.009. PMID   21112090.CS1 maint: multiple names: authors list (link)
  50. "Center for Science in the Public Interest – Chemical Cuisine" . Retrieved March 17, 2010.
  51. "California Department of Public Health: Food and Drug Branch: Sulfites" (PDF). Archived from the original (PDF) on July 23, 2012. Retrieved September 27, 2013.