Sulfur dioxide, hydrogen peroxide

Sulfur dioxide, hydrogen peroxide determination, 637 Sulfur peroxides, 1002-39 Sunflower oil... 

The chemiluminescence-redox detector (CRD) is based on specific redox reactions coupled with chemiluminescence measurement. An attractive feature of this detector is that it responds to compounds such as ammonia, hydrogen sulfide, carbon disulfide, and sulfur dioxide. Hydrogen peroxide, hydrogen, carbon monoxide, sulfides, and thiols that are not sensitively detected by flame ionization detection can be detected with the CRD detector. Compounds that typically constitute a large portion of the matrix of many industrial samples are not detected, thus simplifying matrix effects and sample cleanup procedures for some applications. 

The temperature and density structure of the troposphere, along with the concentrations of major constituents, are well documented and altitude profiles have been measured over a wide range of seasons and latitudes for the minor species water, carbon dioxide, and ozone. A few profiles are available for carbon monoxide, nitrous oxide, methane, and molecular hydrogen, while only surface or low-altitude measurements have been made for nitric oxide, nitrogen dioxide, ammonia, sulfur dioxide, hydrogen sulfide, and nonmethane hydrocarbons. No direct measurements of nitric acid and formaldehyde are available, though indirect information does exist. The concentrations of a number of other important species, such as peroxides and oxy and peroxy radicals, have never been determined. Therefore, while considerable information concerning trace constituent concentrations is available, the picture is far from complete. 

Aminopyrazine was oxidized by hydrogen peroxide in acetic acid at 20° to 3-aminopyrazine 1 -oxide and at 50° for 15 hours to 2-aininopyrazine 1,4-dioxide (51%) (also obtained by similar oxidation of 3-aminopyrazine 1-oxide) (1189). m-Chloroperoxybenzoic acid was also used for the oxidation of 2-aminopyrazine to its 1-oxide (1258). The following aminopyrazine TV-oxides have been prepared by oxidation (reagent and conditions) 2-amino-3-methoxycarbonylpyrazine 1-oxide (m-chloroperoxybenzoic acid in chloroform at reflux) (880, 1222) 2-amino-5-chloro-3-methoxycarbonyl(and methylcarbamoyl)pyrazine 1-oxide (m-chloroperoxybenzoic acid in chloroform at reflux) (1222) 2-amino-5-bromo-3-methoxycarbonylpyrazine 1-oxide (wperoxyacetic acid) (906) 2-amino-3-bromo-5,6-dimethylpyrazine 1-oxide (peroxyacetic acid) (907) and 2,3-bis(pyridin-2 -yl)pyrazine 1,4-dioxide (hydrogen peroxide in sulfuric acid at room temperature) (754). 

Bis(diphenylphosphino)methane was converted in two steps to a tetra-dentate phosphine-iminophosphorane ligand that gave the disulfide and the dioxide by reaction with sulfur and hydrogen peroxide, respectively (Scheme 15). ... 

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... 

Inorganic Methods. Before the development of electrolytic processes, hydrogen peroxide was manufactured solely from metal peroxides. Eady methods based on barium peroxide, obtained by air-roasting barium oxide, used dilute sulfuric or phosphoric acid to form hydrogen peroxide in 3—8% concentration and the corresponding insoluble barium salt. Mote recent patents propose acidification with carbon dioxide and calcination of the by-product barium carbonate to the oxide for recycle. 

Toxic or malodorous pollutants can be removed from industrial gas streams by reaction with hydrogen peroxide (174,175). Many Hquid-phase methods have been patented for the removal of NO gases (138,142,174,176—178), sulfur dioxide, reduced sulfur compounds, amines (154,171,172), and phenols (169). Other effluent treatments include the reduction of biological oxygen demand (BOD) and COD, color, odor (142,179,180), and chlorine concentration. 

Analytical Methods. The official NIOSH recommended method for determining sulfur dioxide in air consists of drawing a known prefiltered volume of air through a bubbler containing hydrogen peroxide, thus oxidising the sulfur dioxide to sulfuric acid. Isopropyl alcohol is then added to the contents in the bubbler and the pH of the sample is adjusted with dilute perchloric acid. The resultant solution is then titrated for sulfate with 0.005 M. barium perchlorate, and Thorin is used as the indicator. 

The Reich test is used to estimate sulfur dioxide content of a gas by measuring the volume of gas required to decolorize a standard iodine solution (274). Equipment has been developed commercially for continuous monitoring of stack gas by measuring the near-ultraviolet absorption bands of sulfur dioxide (275—277). The deterrnination of sulfur dioxide in food is conducted by distilling the sulfur dioxide from the acidulated sample into a solution of hydrogen peroxide, foUowed by acidimetric titration of the sulfuric acid thus produced (278). Analytical methods for sulfur dioxide have been reviewed (279). 

A smaller but important use for sulfur dioxide is for stabilization of pulp (qv) brightness after hydrogen peroxide bleaching of mechanical pulps. Sulfur dioxide neutralizes the alkalinity and destroys any excess hydrogen peroxide, which if left in the pulp would cause it to lose brightness. 

Hydroxyl radicals, generated from hydrogen peroxide and titanium trichloride, add to the sulfur atom of 2-methylthiirane 1-oxide leading to the formation of propene and the radical anion of sulfur dioxide (Scheme 102) (75JCS(P2)308). 

Sulfur Dioxide EPA Method 6 is the reference method for determining emissions of sulfur dioxide (SO9) from stationary sources. As the gas goes through the sampling apparatus (see Fig. 25-33), the sulfuric acid mist and sulfur trioxide are removed, the SO9 is removed by a chemical reaction with a hydrogen peroxide solution, and, finally, the sample gas volume is measured. Upon completion of the rim, the sulfuric acid mist and sulfur trioxide are discarded, and the collected material containing the SO9 is recovered for analysis at the laboratory. The concentration of SO9 in the sample is determined by a titration method. 

When lcad(II) sulfide is treated with hydrogen peroxide, the possible products are either lead(II) sulfate or lead(IV) oxide and sulfur dioxide, (a) Write balanced equations for the two reactions, (b) Using data available in Appendix 2A, determine which possibility is more likely. 

C03-0008. Write chemical formulas for the following compounds chlorine monofluoride, xenon trioxide, hydrogen bromide, silicon tetrachloride, sulfur dioxide, and hydrogen peroxide. 

This is one source of acid rain, a serious environmental problem. The sulfur dioxide content of an air sample can be determined. A sample of air is bubbled through an aqueous solution of hydrogen peroxide to convert all of the SO2 to H2 SO4. H2 O2 + SO2 H2 SO4 Titration of the resulting solution completes the analysis (both H atoms of H2 SO4 are titrated). In one such case, the analysis of 1.55 X 10 Lof Los Angeles air gave a solution that required 5.70 mL of 5.96 X 10 M NaOH to complete the titration. Determine the number of grams of SO2 present in the air sample. 

Combinations of hydrogen peroxide, sulfuric acid, and urea have been proposed [1]. The temperature influences the urea decomposition into ammonia and carbon dioxide that provokes pressure buildup in a formation model and a 19% increase of oil-displacement efficiency in comparison with water. 

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