Nitrates, organic, reactions

Particles are the major cause of the ha2e and the brown color that is often associated with smog. The three most important types of particles produced in smog are composed of organics, sulfates, and nitrates. Organic particles are formed when large VOC molecules, especially aromatics and cycHc alkenes, react with each other and form condensable products. Sulfate particles are formed by a series of reactions initiated by the attack of OH on SO2 in the gas phase or by Hquid-phase reactions. Nitrate particles are formed by... 

Organic Reactions. Nitric acid is used extensively ia iadustry to nitrate aHphatic and aromatic compounds (21). In many iastances nitration requires the use of sulfuric acid as a dehydrating agent or catalyst the extent of nitration achieved depends on the concentration of nitric and sulfuric acids used. This is of iadustrial importance ia the manufacture of nitrobenzene and dinitrotoluene, which are iatermediates ia the manufacture of polyurethanes. Trinitrotoluene (TNT) is an explosive. Various isomers of mononitrotoluene are used to make optical brighteners, herbicides (qv), and iasecticides. Such nitrations are generally attributed to the presence of the nitronium ion, NO2, the concentration of which iacreases with acid strength (see Nitration). 

According to Kirk Othmer (Ref 34), the reactions of nitric acid may be classified conveniently into three groups (l) reactions as an acid (formation of inorganic nitrates) (2) reactions as an oxidizing agent and (3) organic reactions... 

Nitric acid also undergoes reactions with organic compounds wherein the acid serves neither as an oxidizing agent nor as a source of hydrogen ions. The formation of organic nitrates by esterification (O-nitration) involves reaction with the hydroxyl group ... 

Ethylammonium nitrate, CH CH,NH NO , was the first ionic liquid to be discovered. Its melting point of 12°C was reported in 1914 and it has since been used as a nonpolluting solvent for organic reactions and for facilitating the folding of proteins. 

OS 31] [R 16a] [P 23] On increasing the temperature, the reaction rate for nitration of benzene increases (Figure 4.53), as usually to be expected for most organic reactions [31]. For a capillary-flow micro reactor, more than doubling of the reaction rate was determined on increasing the temperature from 60 to 90 °C. 

Thallium(I) acetate, 24 630-632 Thallium compounds, in organic reactions, 24 635 Thallium formate, 24 630 Thallium halides, 24 632 Thallium ion, 24 629 Thallium nitrate, uses for, 24 636 Thallium salts, 24 630, 632 Thallium sulfate, uses for, 24 636 Thallium (III) compounds, in organic reactions, 24 635-636 Thallium(III) fluoride, 24 632 Thallium(III) ion, 24 630 Thallium(III) salts, 24 632 Thallium(III) trifluoroacetate, 24 635 Thallium (Tl), 24 627-641... 

The reactivity of organic nitrites toward hydrolysis differs markedly from that of organic nitrates. The reaction mechanisms are summarized in Fig. 9.2. The base-catalyzed hydrolysis of organic nitrites (Fig. 9.2,a) is quite slow, in... 

Chemical radicals—such as hydroxyl, peroxyhydroxyl, and various alkyl and aryl species—have either been observed in laboratory studies or have been postulated as photochemical reaction intermediates. Atmospheric photochemical reactions also result in the formation of finely divided suspended particles (secondary aerosols), which create atmospheric haze. Their chemical content is enriched with sulfates (from sulfur dioxide), nitrates (from nitrogen dioxide, nitric oxide, and peroxyacylnitrates), ammonium (from ammonia), chloride (from sea salt), water, and oxygenated, sulfiirated, and nitrated organic compounds (from chemical combination of ozone and oxygen with hydrocarbon, sulfur oxide, and nitrogen oxide fragments). ... 

A. Crowson, R.W. Hiley, T. Ingham, T. Mccreedy, A.J. Pilgrim, A. Townshend, Investigation into the detection of nitrated organic compounds and explosives by direct chemiluminescent emission during thermally induced gas phase decomposition reactions , Anal. Commun. 34 (1997) 213-216. 

There are many different types of surfaces available for reactions in the atmosphere. In the stratosphere, these include ice crystals, some containing nitric acid, liquid sulfuric acid-water mixtures, and ternary solutions of nitric and sulfuric acids and water. In the troposphere, liquid particles containing sulfate, nitrate, organics, trace metals, and carbon are common. Sea... 

The kinetics and mechanisms of nitrate radical reactions with alkanes and a variety of other organics relevant to the atmosphere are discussed in detail in two excellent reviews by Wayne et al. (1991) and Atkinson (1991). The kinetics of the N03-alkane reactions are summarized in Table 6.3, where it can be seen that, with the exception of methane, they are in the range 10 lX-10 lf cm3 molecule-1 s-1. 

Field studies suggest that the nitrate radical reaction can also be a major contributor to isoprene decay at night, as well as contributing to the formation of organic nitrates in air. For example, Starn et al. (1998b) found that when the product of N02 and 03 (which form N03) was high in a forested region in the southeastern United States, isoprene often decayed rapidly at dusk. This reaction of N03 with isoprene was estimated to be the major sink for N03 under some conditions in this area. 

In addition to the analysis of the thermal stability of the perchloric acid organic reaction media mixtures, a procedure was worked out to determine the fate of the perchloric acid by chlorine analysis of the batch, effluent streams, etc. Preliminary analyses on selected process samples showed no tendency for perchloric acid to concentrate in recycle material and therefore build up in the reactor. A total of less than 1% of the initial charge of perchloric acid (total chlorides calculated as perchloric acid) was found in the combined recovered acid-ester and olefin fractions. Less than 1 % of the initial charge of perchloric acid was found in the finished ester. The analytical method used was an oxygen bomb decomposition, followed by titration of chlorides with 0.0liV silver nitrate, using a recording automatic titrator. The eventual fate of the perchloric acid catalyst was... 

Sodium Nitrite.—The commercial product contains 97—98% NaN02, and is suitable for most organic reactions. For estimation, see p. 490. Usual impurity sodium nitrate. 

Nitronium Ion (N02+). Nitration is one of the most studied and best understood organic reactions.510-512 The species responsible for electrophilic aromatic nitration was shown to be the nitronium ion (N02+) 219. Since the early 1900s, extensive efforts have been directed toward the identification of this ion, whose existence was first shown by Hantzsch and later firmly established by Ingold and Hughes.510... 

Nitrations of aromatic compounds represent one of the most important classes or organic reactions. However, although a lot of data has been collected in relation to simple substituted benzenes, and the reactions have been subjected to quantitative and theoretical studies, the nitration of phenyl heterocycles has been much less studied in a systematic way. This chapter has attempted to bring together as much information as possible on the topic through a manual search of Chemical Abstracts and recent literature. 

Nafion-H whose acid strength is —12 is active lor diversified organic reactions such as alkylation isomerization, disproportionation, transalkylation acyla lion, nitration, hydration, rearrangement etc [1 5] Since Nafion-H can be used m aqueous solution it is a useful catalyst... 

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