Sulfur dioxide

The sulfur dioxide (or sulfur dioxide ) is a chemical Composé consisted of two Atome S of Oxygène and an atom of Soufre; its empirical formula is: S O ₂. SO₂ is a dense Gaz , colorless and toxic, its inhalation is strongly irritating.

Sulfur dioxide is used like disinfecting, disinfectant and anti-bacterial like like cooling gas, agent of preserving bleaching and like of food products, in particular the dry fruits, in the production of alcoholic drinks and more especially in the manufacture of the Vin.

In the wine, sulfur dioxide is present in hydrated free form: Sulfurous acid H₂S0₃ or , or in form combined with the Aldehyde S (éthanal), the Ketone S (acid alpha-cétoglutarique) and some Sugar S. Sulfur dioxide is also used for the Vinification because it inhibits or stops the development of the Levure S and Bactérie S, thus stopping the Fermentation at the desired time and ensures a sterilization of the wine. In fact during the wine making, the sulfur dioxide introduction makes it possible to select yeasts because those necessary to the wine making are more resistant to sulfur dioxide than other yeasts present. The body formed by combination between sulfur dioxide and the éthanal is the aldehyde-sulfurous or acid acid ethanolsulfonic, which is a strong acid, according to the following reaction:

CH₃CHO + NaH SO₃ → CH₃CHOH-O-SO₂Na

It is not possible to undoubtedly preserve a wine, i.e. to avoid the refermentations, the bacterial diseases or the Madérisation, without a repeated control of its content free sulfur dioxide, which is with the sulfur dioxide state SO2, and whose odor and taste are unpleasant.

In industry, sulfur dioxide especially serves for the sulphuric production of Acid. The sulphuric acid has innumerable applications and is the chemicals more used. Sulfur dioxide is obtained by combustion of sulfur or Pyrite S, then transformed into Trioxyde of sulfur (SO₃) very pure by oxidation with air, catalyzed by the Platine or of pentoxide of Vanadium. SO₃ thus obtained allows the direct manufacture of sulphuric acid very concentrated by simple hydration.

Environment

SO₂ is produced by the Volcan S and various industrial processes. The Coal of bad quality and the Pétrole contain sulfur compounds and generate sulfur dioxide at the time of their Combustion.

Sulfur dioxide can play a part cooling for planet, because its Albédo is raised enough, i.e. it reflects the rays of the sun without absorbing them. For certain scientists, a solution to stop total climate warming would be of " climatiser" the planet with sulfur dioxide. But that could also have dramatic consequences, because when it combines with the Eau and the atmospheric Oxygène, sulfur dioxide and with the Dioxide nitrogen is one of the leading causes of the acid rains, perturbing, even destroying fragile ecosystems. China is the first sulfur dioxide transmitter in the world.

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