Ozone-sulfur reaction

Bell, K. A., W. S. Linn, and J. D. Hackney. Effects on pulmonary function of humans exposed to mixtures of ozone, sulfur dioxide, and their reaction products. Fed. Proc. 34 428, 1975. (abstract)... 

The principal cause of acid rain is the combustion of fossil fuels that produce sulfur and nitrogen emissions. The primary sources are electrical power plants, automobiles, and smelters. Power plants produce most of the sulfur emissions and automobiles most of the nitrogen emissions. Other sources of acid rain include nitrogen fertilizers, jet aircraft, and industrial emissions. Just as in our discussion of ozone, numerous reactions are involved in the formation of acid rain. The process can be understood by considering the transformation of sulfur and nitrogen oxides into their respective acidic forms sulfuric acid and nitric acid. Sulfur, present up to a few percent in fuels such as coal, is converted to sulfur dioxide when the fuel is burned. The sulfur dioxide reacts with water to produce sulfurous acid, H,SO ,, that is then oxidized to sulfuric... 

A reaction at the P atom preserving the double bond and culminating in an oxidative increase of the coordination can be realized with special phosphaalkenes using ozone, sulfur, selenium [Eq. (9a-c)] (42-46), or some carbenes [Eq. (9d)] (47-49). 

Spectra from the chemiluminescent gas phase reactions at 0,5 torr, of ozone with ethylene, tetramethylethylene, trans-2-hutene, and methyl mercaptan at room temperature are presented, and a summary of the general features of the emissions obtained from reaction in the gas phase of ozone with fourteen different olefins is given. The emitting species in the ozone-olefin reactions have been tentatively identified as electronically excited aldehydes, ketones, and a-dicarbonyl compounds. The reaction of ozone with hydrogen sulfide, methyl mercaptan, and dimethylsulfide produces sulfur dioxide in its singlet excited state. 

Kummer et al. 8) have reported that at pressures of about 0.5 torr, the relative emission intensities of the higher olefins and of the organic sulfides were substantially greater than that of ethylene Table II summarizes the reported relative emission intensities. Since a recently developed commercial ozone monitor is based on the chemiluminescent reaction between ozone and ethylene, this suggests the possibility of using the sulfide-ozone chemiluminescent reaction to monitor the low concentration of sulfur compounds in ambient air. This possibility is being further investigated now. 

The P-oxides, -sulfides and -selenides are also produced from the P(III) compounds by action of H2O2 or ozone, sulfur and selenium <80IZV1626, 86IZV640, 86ZOB2256>. Imines (phenylimines, for instance) are readily obtained by Staudinger reactions using azides <83izv2550>. 

The reaction between oxygen atoms and nitric oxide produces a continuum between 400 and 1400 nm from excited nitrogen dioxide. These are significantly lower wavelengths than those of the previously discussed reaction between nitric oxide and ozone. This reaction has been used to determine oxygen atoms in kinetic experiments. As with the oxidation of sulfur monoxide with ozone, oxidation with oxygen atoms produces sulfur dioxide in electronically excited states. In this case, the emission is distributed from 240 to 400 nm with a maximum at 270 nm. 

Hatakeyama, S., Kobayashi, H., Akimoto, H. Gas-phase oxidation of sulfur dioxide in the ozone-olefin reactions. J. Phys. Chem. 88, 4736-4739 (1984)... 

Production of hydrogen fluoride from reaction of Cap2 with sulfuric acid is the largest user of fluorspar and accounts for approximately 60—65% of total U.S. consumption. The principal uses of hydrogen fluoride are ia the manufacture of aluminum fluoride and synthetic cryoHte for the Hall aluminum process and fluoropolymers and chlorofluorocarbons that are used as refrigerants, solvents, aerosols (qv), and ia plastics. Because of the concern that chlorofluorocarbons cause upper atmosphere ozone depletion, these compounds are being replaced by hydrochlorofluorocarbons and hydrofluorocarbons. 

Similar heterogeneous reactions also can occur, but somewhat less efticientiy, in the lower stratosphere on global sulfate clouds (ie, aerosols of sulfuric acid), which are formed by oxidation of SO2 and COS from volcanic and biological activity, respectively (80). The effect is most pronounced in the colder regions of the stratosphere at high latitudes. Indeed, the sulfate aerosols resulting from emptions of El Chicon in 1982 and Mt. Pinatubo in 1991 have been impHcated in subsequent reduced ozone concentrations (85). 

It was not their reactivity but their chemical inertness that was the true surprise when diazirines were discovered in 1960. Thus they are in marked contrast to the known linear diazo compounds which are characterized by the multiplicity of their reactions. For example, cycloadditions were never observed with the diazirines. Especially surprising is the inertness of diazirines towards electrophiles. Strong oxidants used in their synthesis like dichromate, bromine, chlorine or hypochlorite are without action on diazirines. Diazirine formation may even proceed by oxidative dealkylation of a diaziridine nitrogen in (186) without destruction of the diazirine ring (75ZOR2221). The diazirine ring is inert towards ozone simple diazirines are decomposed only by more than 80% sulfuric acid (B-67MI50800). 

Although it does not physically explain the nature of the removal process, deposition velocity has been used to account for removal due to impaction with vegetation near the surface or for chemical reactions with the surface. McMahon and Denison (12) gave many deposition velocities in their review paper. Examples (in cm s ) are sulfur dioxide, 0.5-1.2 ozone, 0.1-2.0 iodine, 0.7-2.8 and carbon dioxide, negligible. 

Figure 4-13 shows an example from a three-dimensional model simulation of the global atmospheric sulfur balance (Feichter et al, 1996). The model had a grid resolution of about 500 km in the horizontal and on average 1 km in the vertical. The chemical scheme of the model included emissions of dimethyl sulfide (DMS) from the oceans and SO2 from industrial processes and volcanoes. Atmospheric DMS is oxidized by the hydroxyl radical to form SO2, which, in turn, is further oxidized to sulfuric acid and sulfates by reaction with either hydroxyl radical in the gas phase or with hydrogen peroxide or ozone in cloud droplets. Both SO2 and aerosol sulfate are removed from the atmosphere by dry and wet deposition processes. The reasonable agreement between the simulated and observed wet deposition of sulfate indicates that the most important processes affecting the atmospheric sulfur balance have been adequately treated in the model. 

Although the cracking of mbbers is related to the reaction of ozone on the double bond, it must be mentioned that ozone reacts also with sulfur cross-links. These reactions, however, are much slower. The reaction of ozone with di- and polysulfides is at least 50 times slower than the corresponding reaction with olefins [49]. 

Because process mixtures are complex, specialized detectors may substitute for separation efficiency. One specialized detector is the array amperometric detector, which allows selective detection of electrochemically active compounds.23 Electrochemical array detectors are discussed in greater detail in Chapter 5. Many pharmaceutical compounds are chiral, so a detector capable of determining optical purity would be extremely useful in monitoring synthetic reactions. A double-beam circular dichroism detector using a laser as the source was used for the selective detection of chiral cobalt compounds.24 The double-beam, single-source construction reduces the limitations of flicker noise. Chemiluminescence of an ozonized mixture was used as the principle for a sulfur-selective detector used to analyze pesticides, proteins, and blood thiols from rat plasma.25 Chemiluminescence using bis (2,4, 6-trichlorophenyl) oxalate was used for the selective detection of catalytically reduced nitrated polycyclic aromatic hydrocarbons from diesel exhaust.26... 

Two other compounds containing carbon and sulfur should be mentioned. The first of these is carbon monosulfide, CS. This compound has been reported to be produced by the reaction of CS2 with ozone. The second compound is COS or, more correctly, OCS (m.p. -138.2 °C and b.p. -50.2 °C). It is prepared by the reaction... 

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