Sulfur dioxide

• Sulphur ( IV) oxide
• Sulfur dioxide

A colorless, pungent, poisonous gas

Gaseous

-75.5 ° C

-10 ° C

0.33 MPa ( 20 ° C)

Hydrolysis in water

1.63305 D ( 5.4473 · 10-30 C · m)

1.000686 (0 ° C, 101.325 kPa)

Risk

1.3 mg · m-3

2520 ppm · h 1 ( LC50, rat, inh. )

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Sulfur dioxide, SO2, is the anhydride of sulfurous acid H2SO3. Sulphur dioxide is a colorless, mucous membrane irritant, pungent and sour -tasting, poisonous gas. It is very good ( physically ) in water and forms with water very slightly sulphurous acid. It is mainly produced in the combustion of sulfur-containing fossil fuels such as coal or oil products which contain up to 4 percent sulfur. Thus, it contributes to a significant degree of air pollution. It is the reason for acid rain, where the sulfur dioxide is first oxidized by oxygen to form sulfur trioxide and then with water to form sulfuric acid ( H2SO4) is implemented. To prevent this, there are various methods for flue gas desulfurization. In addition, sulfur dioxide is found in the environment of high temperature areas and active volcanoes.

Production

Sulphur dioxide can be prepared by various methods:

• By burning sulfur or hydrogen sulfide

• By the roasting of sulfidic ores, such as pyrite:

• Of sulphites by the stronger acids

Properties

Sulfur dioxide is a pungent, colorless gas. It has good water solubility, solutions are slightly acidic. The molecule is bent:

Sulfur dioxide is resonance-stabilized:

Use

Liquid sulfur dioxide dissolves many substances and therefore has established itself as a valuable aprotic polar solvent.

In the food industry, sulfur dioxide is used as a preservative, anti-oxidant and disinfectant use, especially for dried fruit, potato dishes, fruit juices, jams and wine. Wine and beer barrels are ausgeschwefelt to disinfect before use by treatment with SO2 gas.

Sulfur dioxide destroys the vitamin B1; also found in laboratory experiments evidence of destruction of B12 vitamins. In the EU it is approved as a food additive under the E number 220 for "organic " products. It is also used for the preparation of sulphuryl chloride and thionyl chloride SOCl2 SO2Cl2.

Further, sulfur is an important starting material for the production of sulfur trioxide, followed by concentrated sulfuric acid to produce, for example, with the contact method.

Sulphur dioxide is also used for the preparation of many chemicals, medicines and dyes and bleaching of paper and textiles. It can fade the ink.

Use in concentration camps

In experiments with poison gases, which were conducted in the Croatian concentration camp Stara Gradiška, sulfur dioxide came alongside Zyklon B, used in Serbian, Jewish and Roma women, and children.

Pollution

Sulfur dioxide damage in high concentrations, human, animals and plants. The oxidation products lead to " acid rain " which attacks sensitive ecosystems such as forests and lakes at risk as well as buildings and materials. However, the SO2 emissions from developed industrial countries could be greatly reduced in the last two decades through the use of low-sulfur or sulfur-free fuels and fuels and means of flue gas desulphurisation.

Of all modes of international shipping transport makes the highest emission contribution. There, the maximum permissible sulfur content in the fuel is currently at 4.5 percent. The IMO has, however, reduced the limit: By 2012, it should be lowered to 3.5 by 2020 and to 0.5 percent. This limit applies already for California's coastal waters. In the Baltic and North Sea there are sulfur emission control areas (English SECA ), in which the limit is 1.5 percent today. From July 1, 2010, he is on 1 percent and 1 January 2015, it is to be lowered to 0.1 percent.

The Max Planck Institute for Meteorology showed in a study that, in the vicinity of the busy ports of Rotterdam, Antwerp and Milford Haven an even thicker cloud cover prevails than in the surrounding areas. Sulfur dioxide and nitrogen oxides act as condensation nuclei and stimulate the formation of clouds. The reinforced through this cloud cover albedo resulted in a reduction of solar radiation in the underlying areas.

Safety

A sulfur dioxide concentration that is above the TLV can humans cause headaches, nausea and dizziness. At higher concentrations, the gas damaged heavily the bronchi and lungs.

Exposure to high concentrations of sulfur dioxide over a prolonged period can lead by the destruction of important for the formation of blood vitamin B12 anemia.