Acids and Oxides of Nitrogen

Nitrosylsulfuric acid hydrolyzes in water forming sulfuric acid and oxides of nitrogen as shown above. 

D. Oxidation with Nitric Acid and Oxides of Nitrogen.329... 

Among the oxidative procedures for preparing azo compounds are oxidation of aromatic amines with activated manganese dioxide oxidation of fluorinated aromatic amines with sodium hypochlorite oxidation of aromatic amines with peracids in the presence of cupric ions oxidation of hindered aliphatic amines with iodine pentafluoride oxidation of both aromatic and aliphatic hydrazine derivatives with a variety of reagents such as hydrogen peroxide, halogens or hypochlorites, mercuric oxide, A-bromosuccinimide, nitric acid, and oxides of nitrogen. 

Characters and Tests.—Colourless, heavy, oily, intensely acid liquid. Sp. gr. 1 843. Mixed with water, much heat is evolved. Diluted with five or six times its volume of water, it gives, with barium chloride, a white precipitate (barium sulphate), which is insoluble in nitric acid it should yield no precipitate or darkening of colour with hydrosulphuric acid, indicating the absence of lead. When a solution of ferrous sulphate is carefully poured upon the sur ce of the acid, there should be no brown colour developed where the two liquids unite, showing the absence of nitric acid and oxides of nitrogen. The acid should leave no residue on evaporation. 

The amine ends also react with atmospheric contaminants, such as SO2 and oxides of nitrogen and ozone, under ambient storage conditions (50). This phenomenon is referred to as aging and results in reduced acid dye affinity. 

Aluminum nitrate is available commercially as aluminum nitrate nonahydrate [7784-27-2], A1(N02)3 9H20. It is a white, crystalline material with a melting point of 73.5°C that is soluble in cold water, alcohols, and acetone. Decomposition to nitric acid [7699-37-2], HNO, and basic aluminum nitrates [13473-90-0], A1(0H) (N03) where x + = 3, begins at 130°C, and dissociation to aluminum oxide and oxides of nitrogen occurs above 500°C. 

Beryllium Nitrate. BeryUium nitrate tetrahydrate [13516-48-0], Be(N02)2 4H2O, is prepared by crystallization from a solution of beryUium hydroxide or beryllium oxide carbonate in a slight excess of dilute nitric acid. After dissolution is complete, the solution is poured into plastic bags and cooled to room temperature. The crystallization is started by seeding. Crystallization from more concentrated acids yields crystals with less water of hydration. On heating above 100°C, beryllium nitrate decomposes with simultaneous loss of water and oxides of nitrogen. Decomposition is complete above 250°C. 

Acid rain erodes buildings, particularly those constructed from limestone. It has been reported that the Acropolis in Athens has suffered more deterioration in the last 20 years than in the previous 2000. Acidic gases are produced directly by the combination of oxides of sulfur and oxides of nitrogen with water and also by more complex processes involving unburned hydrocarbons and ozone in the atmosphere. 

Other acid gases such as hydrogen chloride and oxides of nitrogen produce similar corrosion problems. The corrosion effects produced by acid condensate are amplified by the motion of the gas stream (typically 20-53 m/s) and erosion effects due to entrained solids and impingement at bends, damper plates, reheaters, etc. 

Titov claims that the free radical mechanism applies for nitration of aliphatic hydrocarbons, of aromatic side chains, of olefins, and of aromatic ring carbons, if irf the latter case the nitrating agent is ca 60—70% nitric acid that is free of nitrous acid, or even more dil acid if oxides of nitrogen are present... 

H2S, trace (NH3, HCN, COS, CS2, phenols, aromatics, fatty acids, tars, oxides of nitrogen and sulfur)... 

CASRN 75-18-3 molecular formula C2H0S FW 62.14 Photolytic. Sunlight irradiation of a mixture of methyl sulfide (initial concentrations 0.2-2.5 ppm) and oxides of nitrogen (86-580 ppb) in an outdoor chamber at various time intervals (2-7 h) yielded nitrogen dioxide, ozone, sulfur dioxide, nitric acid, formaldehyde, and methyl nitrate, a sulfate aerosol, and methane sulfonic acid (Grosjean, 1984a). 

Acid deposition or, acid rain, occurs when SO2 and oxides of nitrogen (NOx) react with water, oxygen, and oxidants to form acidic compounds. It is deposited in dry form (gas, particles) or wet form (rain, snow, fog), and can be carried by wind hundreds of miles across state and national borders. Acid rain harms lakes and streams, damages trees, crops, historic buildings, and monuments. 

Lead does not evolve hydrogen readily with acids. Nitric acid attacks the metal readily, forming lead nitrate and oxides of nitrogen ... 

The environmental effects of acid deposition that have been most thoroughly studied are probably those on lakes, ponds, and other bodies of fresh water. When acid and oxides of sulfur and nitrogen are added to such bodies of water, the pH of the lake or pond tends... 

Standard Cu. In a fume hood, add 15 mL of water and 3 mL of 70% nitric acid to 0.5 - 0.6 g of accurately weighed reagent Cu wire in a 100 mL volumetric flask and boil gently to dissolve the wire. Add 1.0 g of urea or 0.5 g of sulfamic acid and boil 1 min to destroy HN02 and oxides of nitrogen that would interfere with the iodometric titration. Cool to room temperature and dilute to 100 mL with 1.0 M HC1. 

Historically, the major acids believed to contribute to acid deposition in the troposphere have been sulfuric and nitric acids, formed by the oxidation in air of S02 and oxides of nitrogen, respectively. However, there is an increasing recognition that organic acids may contribute significantly to the total acid burden and indeed may represent the major acidic species even in polluted urban environments. In addition, since nitrous acid (HONO) is formed whenever N02 and water are present (see Chapter 7.B.3), its contribution to the total acidity, particularly to indoor air environments, has become of interest and concern. 

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