Sulfur dioxide

Sulfur dioxide is a natural component of air. It is produced when trees, brush, and other organic matter burn, and it is present in volcanic gases. It is also released during the normal metabolic reactions of some living organisms, especially marine plankton and bacteria. The compound is also produced in large amounts by human activities. All fossil fuels (coal, oil, and natural gas) contain small amounts of sulfur as impurities. When those fuels burn, the sulfur they contain is converted to sulfur dioxide, which becomes a component of air pollution. 

Sulfur dioxide. Red atoms are oxygen and yellow atom is sulfur. P U L I S H E R S RESOURCE CROUP 

Sulfur dioxide can be prepared by several methods, the most common of which is the combustion of sulfur or pyrites (FeS2). A variety of furnaces have been developed for carrying out this reaction. Each type of furnace produces sulfur dioxide of different purities. After production, the sulfur dioxide is normally cooled and compressed to convert it to liquid form. Liquid sulfur dioxide is more easily stored and transported than the gaseous form. Sulfur dioxide is also obtained as the byproduct of a number of industrial operations, especially the smelting of metallic ores. Smelting is the process by which a metal is extracted from its ore by heating in air. Since many ores are sulfides, this process often results in the formation of sulfur dioxide, which can be captured as a byproduct of the operation. Finally, sulfur dioxide can be produced by the direct combustion of sulfur itself  

Sulfur dioxide was first studied in detail by the English physicist and chemist Joseph Priestley (1733-1804), who invented a method for collecting gases over water. 

The ancient Greeks and Romans fumigated their homes by burning sulfur. The sulfur dioxide formed 

Sulfur dioxide is usually measured in terms of its concentration in air in units of Precise methods are available to monitor continuously the 

There are two widely used methods for determining the sulfur dioxide (SO ) concentration in the atmosphere of interest Both employ the affinity of lead oxide to react with gaseous SO to form lead sulfate. The most common method used in corrosion work is the sulfation. These devices can be either purchased or prepared in the laboratory. They consist of small disks of lead oxide that are exposed facing the ground under a small shelter to prevent the reactive paste from being removed by the elements [15]. 

The disk surface is thus exposed only to gaseous SO, not particulates. The American Society for Testing of Materials (ASTM) procedure suggests a 30-day exposure, followed by a standard sulfate analysis [16]. The other method sometimes used is the peroxide candle, similar in its function to the chloride candle, but again using lead peroxide to capture SOy In this procedure, a lead peroxide paste is applied to a paper thimble in the laboratory, and allowed to dry thoroughly before exposure. The thimble is then exposed in an instrument shelter to the test yard environment. In both cases, the SOj deposited results are appropriately reported in terms of deposition rate on the surface in units of mg/m /day. 

Source—burning of coal and oil, especially high-sulfur coal from the eastern U.S. industrial processes (paper, metals). 

Health effects—breathing problems, may cause permanent damage to lungs. 

Environmental effects—O2 is an ingredient in acid rain (acid aerosols), which can damage trees and lakes. Acid aerosols can also reduce visibility. 

Property damage—acid aerosols can eat away stone used in buildings, statues, monuments, etc. 

Source—leaded gasoline (being phased out), paint (houses, cars), smelters (metal refineries) manufacture of lead storage batteries. 

LABORATORY CHEMICAL SAFETY SUMMARY SULFUR DIOXIDE 

Vapor Density Vapor Pressure Flash Point Toxicity Data 

Sulfur dioxide has not been shown to be carcinogenic or to have reproductive or developmental effects in humans. Chronic exposure to low levels of sulfur dioxide has been shown to exacerbate pulmonary disease. 

Sulfur dioxide is a noncombustible substance (NFPA rating = 0). 

Contact with some powdered metals and with alkali metals such as sodium or potassium may cause fires and explosions. Liquid sulfur dioxide will attack some forms of plastics, rubber, and coatings. 

Presented here are general descriptions of preservatives and sterilants as well as filtration options that can be used at different stages during the winemaking process. A variety of additives may be used to control the growth of microorganisms. These include sulfur dioxide, lysozyme, dimethyl dicarbonate, and sorbic acid. The use of other additives such as fumaric acid, nisin, carbon monoxide, and particular plant extracts has also been explored. Additional antimicrobial chemicals that are used in a winery as sanitizers are discussed in Chapter 9. 

Sulfur dioxide is widely recognized in both the wine and food industries for its antioxidative and antimicrobial properties. The current legal limit for SO2 in wines in the United States is 350 mg/L, a concentration well above levels normally used by winemakers. Nevertheless, wines that contain greater than 10 mg/L must disclose this information on the label. Because SO2 is a metabolite of yeasts during fermentation (Section 1.5.2), wines will usually contain some sulfite even though additions were not made during processing. 

Once dissolved in water, sulfur dioxide exists in equilibrium between molecular SO2 (S02 H20), bisulfite (HSO3 ), and sulfite (SOs ) species as illustrated below  

This equilibrium is dependent on pH, with the dominant species at wine pH (3 to 4) being the bisulfite anion (Fig. 5.1). Besides being in equilibrium with the molecular and sulfite species, bisulfite also exists in free and bound forms. Here, the molecule will react with carbonyl compounds (e.g., acetaldehyde), forming addition products or adducts such as hydroxysulfonic acids. 

Relative abundance of molecular SOj, bisulfite, and sulfite at different pH 

The use of porphyrin complexes for the electrocatalytic detection of 8O2 is limited. Iron and titanium porphyrin peroxo complexes (TPPFe-O-FeTPP or TiP(02)) interact with 8O2 to give sulfato complexes of the porphyrins or to give free sulfate Carballo et al. showed that NiPPIX polymerized on GCE catalyzed the oxidation of 8O2, and the modified electrode was stable under hydro-dynamic conditions of a flow cell .  

Selective noncatalytic reduction systems make use of the tendency of certain compounds, ammonia (NH3) and urea (CO[NH2]2) in particular, to react with and reduce oxides of nitrogen  

When either ammonia or urea is injected into flue gases at temperatures of about 870°C-1,100°C for ammonia and 900°C-1,150°C for urea, removal can reach as high as 50 percent. 

Sulfur dioxide is a colorless gas with a sharp, pungent odor, like that of a burning match. Most people are able to detect this highly characteristic odor at concentrations of about 0.5 ppm or greater. Its chemical formula is SO2. Sulfur dioxide is readily soluble in water, forming the weak acid sulfurous acid (H2SO3). Sulfur dioxide is formed when sulfur or a sulfur-containing compound is burned  

Sulfur dioxide is an irritant to the eyes, the respiratory system, and, in some cases, the skin. One factor in producing this effect is the interaction of sulfur dioxide with water to form sulfuric acid, a 

Sulfur dioxide is produced by both natural and anthropogenic sources. The most important of the natural sources are volcanic eruptions, which account for about 40 percent of all natural emissions of the gas. Since volcanic eruptions are episodic events, the amount of sulfur dioxide attributable to this source in any one year varies widely. Other natural sources of the gas are forest fires and other natural burns, biological decay, and certain metabolic processes carried out by living organisms, especially marine plankton and bacteria. Natural sources release about 27.5 million short tons (25 million metric tons) of sulfur dioxide per year. 

Air pollutants, in Casarett Doull s Toxicology, The Basic Science of Poisons, 2nd ed., John Doull, Curtis D. Klassen, and Mary O. Amdur, eds., Macmillan, New York, 1980. 

Pocket Guide to Chemical Hazards, Department of Human Health Services, NIOSH, Bethesda, MD, p. 38, 90-117, 1990. 

Cullen, E.I. Eger, Cardiovascular effects of carbon dioxide in man. Anesthesiology. 41 345, 1974. 

Williams, Carbon dioxide poisoning report of eight cases and two deaths. Brit. Med. J. 2 1012, 1958. 

Gurman, S.E. Harris, E. Braun, Toxicological interactions between carbon monoxide and carbon dioxide. Toxicology 47 135, 1987. 

Although sulfite may not be as inhibitory to native yeasts as once believed, prefermentation additions are, nevertheless, crucial in the control of native lactic acid bacteria (LAB) and acetic acid bacteria (AAB). Failure to utilize the agent, at least in the recent history of some California red wine fermentations, has been one step implicated in rapid proliferation of spoilage LAB, the metabolites of which are strongly inhibitory toward both indigeneous and inoculated strains of Saccharomyces sp. (see Sec 1.4.1). 

As discussed in Chapter 5, oxygen present in carefully handled must and juice is stimulatory to early growth of wine yeast. In this regard, the utilization of SO2 (which rapidly consumes oxygen), as an inhibitor of prefermentation enzymatic activity may be secondarily important to yeast activity. 

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SULFUR DIOXIDE 203-356 -4 4074E4>02 4 9426E4 03 -2 931lE-01 8 774SE40I 1 45718-04... 

SULFUR DIOXIDE -2 1296E 02 6.6886E 03 -2.9S18E-02 4.1984E401... 

Product removal during reaction. Sometimes the equilibrium conversion can be increased by removing the product (or one of the products) continuously from the reactor as the reaction progresses, e.g., by allowing it to vaporize from a liquid-phase reactor. Another way is to carry out the reaction in stages with intermediate separation of the products. As an example of intermediate separation, consider the production of sulfuric acid as illustrated in Fig. 2.4. Sulfur dioxide is oxidized to sulfur trioxide ... 

Example 4.4 Butadiene sulfone (or 3-sulfolene) is an intermediate used for the production of solvents. It can be produced from butadiene and sulfur dioxide according to the reaction ... 

This is an exothermic, reversible, homogeneous reaction taking place in a single liquid phase. The liquid butadiene feed contains 0.5 percent normal butane as an impurity. The sulfur dioxide is essentially pure. The mole ratio of sulfur dioxide to butadiene must be kept above 1 to prevent unwanted polymerization reactions. A value of 1.2 is assumed. The temperature in the process must be kept above 65°C to prevent crystallization of the butadiene sulfone but below lOO C to prevent its decomposition. The product must contain less than 0.5 wt% butadiene and less thM 0.3 wt% sulfur dioxide. 

Organic compounds containing sulfur are very important. Calcium sulfur, ammonium sulfate, carbon disulfide, sulfur dioxide, and hydrogen sulfide are but a few of the many important compounds of sulfur. 

Carbon disulfide, hydrogen sulfide, and sulfur dioxide should be handled carefully. Hydrogen sulfide in small concentrations can be metabolized, but in higher concentrations it quickly can cause death by respiratory paralysis. 

It quickly deadens the sense of smell. Sulfur dioxide is a dangerous component in atmospheric air pollution. 

Similar halogenations have been done on 2-lithio-l-phenylsulfonylindole[2], 2-Lithio-l-phenylsulfonylindole is readily converted to the 2-(trimethylsilyl) derivative[2,3]. 2-Trialkylstannylindoles can also be prepared via 2-lithio-indoles[4,5], 2-Sulfonamido groups can be introduced by reaction of a 2-lithioindole with sulfur dioxide, followed by conversion of the sulfinic acid group to the sulfonyl chloride with A-chlorosuccinimide[6]. 

Thionyl chloride reacts with alcohols to give alkyl chlorides The inorganic byprod nets m the reaction sulfur dioxide and hydrogen chloride are both gases at room tern perature and are easily removed making it an easy matter to isolate the alkyl chloride... 

Temp. Hydrogen sulfide Methane Nitric oxide Nitrogen Oxygen Sulfur dioxide ... 

Sodium suifite, acid (saturated) dissolve 600 g of NaHS03 in water and dilute to 1 liter for the preparation of addition compounds with aldehydes and ketones prepare a saturated solution of sodium carbonate in water and saturate with sulfur dioxide. 

Sulfurous acid, H2SO3 saturate water with sulfur dioxide. 

Chlorates Ammonium salts, acids, metal powders, sulfur, flnely divided organic or combustible materials, cyanides, metal sulfldes, manganese dioxide, sulfur dioxide, organic acids... 

Lead dioxide Aluminum carbide, hydrogen peroxide, hydrogen sulfide, hydroxylamine, ni-troalkanes, nitrogen compounds, nonmetal halides, peroxoformic acid, phosphorus, phosphorus trichloride, potassium, sulfur, sulfur dioxide, sulfides, tungsten, zirconium... 

Nitric acid, fuming Organic matter, nonmetals, most metals, ammonia, chlorosulfonic acid, chromium trioxide, cyanides, dichromates, hydrazines, hydrides, HCN, HI, hydrogen sulflde, sulfur dioxide, sulfur halides, sulfuric acid, flammable liquids and gases... 

Sulfur dioxide Halogens, metal oxides, polymeric tubing, potassium chlorate, sodium hydride... 

When a suitable reaction involving the analyte does not exist it may be possible to generate a species that is easily titrated. Eor example, the sulfur content of coal can be determined by using a combustion reaction to convert sulfur to sulfur dioxide. 

Another important example of a redox titration for inorganic analytes, which is important in industrial labs, is the determination of water in nonaqueous solvents. The titrant for this analysis is known as the Karl Fischer reagent and consists of a mixture of iodine, sulfur dioxide, pyridine, and methanol. The concentration of pyridine is sufficiently large so that b and SO2 are complexed with the pyridine (py) as py b and py SO2. When added to a sample containing water, b is reduced to U, and SO2 is oxidized to SO3. 

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