Sulfuric acid, atmosphere

Attention has been focused recently on sedimentary microbial reduction of sulfate. This process neutralizes atmospheric sulfuric acid deposited into soft-water lakes (8-10) through the production of two equivalents of alkalinity per mole of sulfate reduced (11). 

Bromal (25.0 g 89.1 mmol) and (S)-citramalic acid (11.0 g 74.2 mmol) were cooled to 0°C under inert atmosphere. Sulfuric acid/acetic acid (1/1 25 ml) was added dropwise with stirring. After 2 h the contents were a yellow solution with a white precipitate. The ice bath was removed and the reaction mixture was stirred overnight at room temperature. The reaction mixture was diluted with ice and extracted 4 times with ethyl acetate. The organic layer was back extracted with water and then was dried with MgS04. After filtration, the filtrate was concentrated to an oil. The product was obtained as a white solid after crystallization from toluene/hexanes. Yield 23.2 g (77%) mp 151°C (sublime). 

S02 is oxidized to sulfuric acid both by homogeneous gas-phase reactions and by multiphase processes when a precursor gas is dissolved in water and then subsequently oxidized. The routes to atmospheric sulfuric acid production have been studied extensively for decades. The most important gas-phase mechanism is oxidation by OH radicals ... 

Investigating Atmospheric Sulfuric Acid-Water-Ammonia Particle Formation Using Quantum Chemistry... 

Sulfuric acid is stable but very corrosive and hygroscopic. It will draw moisture from the atmosphere. Sulfuric acid should be stored in a tightly closed container in an explosion-proof area. Containers should be stored out of direct sunlight and away from heat. Avoid heat and moisture. Isolate from incompatible materials. See also Section 12. 

The few observations of nucleation in the free troposphere are consistent with binary sulfuric acid-water nucleation. In the boundary layer a third nucleating component or a totally different nucleation mechanism is clearly needed. Gaydos et al. (2005) showed that ternary sulfuric acid-ammonia-water nucleation can explain the new particle formation events in the northeastern United States through the year. These authors were able to reproduce the presence or lack of nucleation in practically all the days both during summer and winter that they examined (Figure 11.16). Ion-induced nucleation is expected to make a small contribution to the major nucleation events in the boundary layer because it is probably limited by the availability of ions (Laakso et al. 2002). Homogeneous nucleation of iodine oxide is the most likely explanation for the rapid formation of particles in coastal areas (Hoffmann et al. 2001). It appears that different nucleation processes are responsible for new particle formation in different parts of the atmosphere. Sulfuric acid is a major component of the nucleation growth process in most cases. 

The burning of high-sulfur fuels has been shown to cause the phenomenon of "acid rain." When a high-sulfur fuel is burned, the sulfur is converted to sulfur dioxide (SO2) and sulfur trioxide (SO3). When sulfur dioxide and sulfur trioxide gas dissolve in water in the atmosphere, sulfurous acid and sulfuric acid are produced, respectively. Write the unbalanced chemical equations for the reactions of sulfur dioxide and sulfur trioxide with water. 

When exposed to SO2 followed by hydrogen peroxide, H2SO3 is irreversibly oxidized to the strong acid sulfuric acid, thereby taking the pH below 3. (SO2 is also oxidized to H2SO4 in the atmosphere.) Sulfuric acid is not volatile, so it does not diffuse back into the air. The pH remains low when the electrode is held in the air. 

Where data on both zinc and steel corrosion are available, they are given separately, notably in Tables 2.8-2.11 (ASTM and DIN tests) or as ratios (Fig. 2.3) however, generally lower corrosion rates are found in recent tests and reflect the recent lessening of atmospheric sulfur acidity, notably in the historic industrial countries (Fig. 2.4 and Table 2.7). Most of the results from work in countries of the former Soviet Union and Eastern Europe are given in Section III.2. 

Atmospheric corrosion of steel is a function of location. In country air the products of corrosion are either oxides or carbonates. In industrial atmosphere sulfuric acid is present, and near the ocean some salt is in the air. Corrosion is more rapid in industrial areas because of the presence of the acid, and it is higher both near cities and near the ocean because of the higher electrical conductivity of the rain and the tendency to form soluble chlorides or sulfates, which cause the removal of protective scale. 

Sulfuric acid is produced in the upper atmosphere of Venus by the Sun s photochemical action on carbon dioxide, sulfur dioxide, and water vapor. Ultraviolet photons of wavelengths less than 169 nm can photodissociate carbon dioxide into carbon monoxide and atomic oxygen. Atomic oxygen is highly reactive. When it reacts with sulfur dioxide, a trace component of the Venusian atmosphere, the result is sulfur trioxide, which can combine with water vapor, another trace component of Venus s atmosphere, to yield sulfuric acid. In the upper, cooler portions of Venus s atmosphere, sulfuric acid exists as a liquid, and thick sulfuric acid clouds completely obscure the planet s surface when viewed from above. The main cloud layer extends from 45-70 km above the planet s surface, with thinner hazes extending as low as 30 km and as high as 90 km above the surface. The permanent Venusian clouds produce a concentrated acid rain, as the clouds in the atmosphere of Earth produce water rain. 

The 1982 eruption of the southern Mexico volcano El Chicon showed the importance of the type of particulate matter in determining effects on climate. The matter given off by this eruption was imusually rich in sulfur, so that an aerosol of sulfuric acid formed and persisted in the atmosphere for about 3 years, during which time the mean global temperature was lowered by several tenths of a degree due to the presence of atmospheric sulfuric acid. By way of contrast, the eruption of Mt. St. Helens in Washington State in the U.S. 2 years earlier had little perceptible effect on climate, although the amount of material blasted into the atmosphere was about the same as that from El Chicon. The material from the Mt. St. Helens eruption had comparatively little sulfur in it, so the climatic effects were minimal. 

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