Paraffin hydrocarbons, nitration

Higher paraffinic hydrocarbons than methane are not generally used for producing chemicals by direct reaction with chemical reagents due to their lower reactivities relative to olefins and aromatics. Nevertheless, a few derivatives can be obtained from these hydrocarbons through oxidation, nitration, and chlorination reactions. These are noted in Chapter 6. 

Vapor-phase nitration of paraffin hydrocarbons, particularly propane, can be brought about by uncatalyzed contact between a large excess of hydrocarbon and nitric acid vapor at around 400°C, followed by quenching. A multiplicity of nitrated and oxidized products results from nitrating propane nitromethane, nitroethane, nitropropanes, and carbon dioxide all appear, but yields of useful products are fair. Materials of construction must be very oxidation-resistant and are usually of ceramic-lined steel. The nitroparaffins have found limited use as fuels for race cars, submarines, and model airplanes. Their reduction products, the amines, and other hydroxyl compounds resulting from aldol condensations have made a great many new aliphatic syntheses possible because of their ready reactivity. 

RELATION BETWEEN THE CHAIN LENGTH OF PARAFFIN HYDROCARBONS AND THE YIELD OF NITRATION PRODUCT... 

If the toluene contains a higher proportion of paraffinic hydrocarbons it can still be nitrated, provided the mononitration product is subjected to distillation (preferably with steam) to remove saturated hydrocarbons. According to Desseigne, Gladel, Guillemin and Sousselier [3], toluene containing 30-40% of saturated hydrocarbons can be treated in this way to obtain nitrotoluene suitable for further nitration. 

Nitromethane, CH3N02, is a volatile liquid. It may be obtained by direct vapour phase nitration of paraffinic hydrocarbons either with nitric acid vapours (Hass et al. [1-8]) or with nitrogen dioxide (T. Urbanski and Slebodzinski [9]). It may also be prepared by the action of sodium- or potassium nitrite on chloroacetic acid... 

A modification of the sulphuric acid process has been patented (1) when applied to a mixture of mono-nitrotoluenes and paraffin hydrocarbons. The nitration of the toluene is carried on carefuUy so as to take it only as far as the mononitrotoluene. The mono-nitrotoluene is dissolved in sulphuric acid, but any paraflShs that may be present will not dissolve, and will form a separate layer. A separation of these two layers and the subsequent nitration of the sulphuric acid solution of mononitrotoluene yields a very high grade TNT. Thus a toluene containing a comparatively large percentage of paraffins may be utilized in the manufacture of TNT. 

Nitration with nitrogen dioxide alone Aromatic compounds Paraffin hydrocarbons Unsaturated hydrocarbons... 

Derivation Nitration of propane and other paraffin hydrocarbons under pressure. 

The main index headings for search other than the names of specific compounds are Paraffins nitration of Paraffins, nitro Paraffins, from nitration of— Paraffins, dinitro Hydrocaibons, nitration of Nitration of hydrocarbons Nitration of paraffins Petroleum, nitrogen compounds from Olefins, nitro derivatives and Acetylenes, nitro derivatives. These items are not mutually inclusive, e.g., references under Paraffins, nitration of are not necessarily to be found under Nitration of paraffins. In Chemical Abstracts collective index for 1937 to 1946, there are 19 entries under the first heading and 12 entries under the second only 10 are common to both lists. 

It should be noted that aliphatic compounds (except the paraffins) are usually oxidised by concentrated nitric acid, whereas aromatic compounds (including the hydrocarbons) are usually nitrated by the concentrated acid (in the presence of sulphuric acid) and oxidised by the dilute acid. As an example of the latter, benzaldehyde, CjHsCHO, when treated with concentrated nitric acid gives ffi-nitrobenzaldehyde, N02CgH4CH0, but with dilute nitric acid gives benzoic acid, CgHgCOOH. 

Nitrations are highly exothermic, ie, ca 126 kj/mol (30 kcal/mol). However, the heat of reaction varies with the hydrocarbon that is nitrated. The mechanism of a nitration depends on the reactants and the operating conditions. The reactions usually are either ionic or free-radical. Ionic nitrations are commonly used for aromatics many heterocycHcs hydroxyl compounds, eg, simple alcohols, glycols, glycerol, and cellulose and amines. Nitration of paraffins, cycloparaffins, and olefins frequentiy involves a free-radical reaction. Aromatic compounds and other hydrocarbons sometimes can be nitrated by free-radical reactions, but generally such reactions are less successful. 

Alkylphenols, ammonia, asbestos, chlorinated paraffins, 4-chloroaniline, cyanide, detergents, di- -butyl phthalate, polyaromatic hydrocarbons (PAHs e.g. anthracene, benzopyrene, methylcholanthrene, /i-naphthoflavone), nitrate, nitrite, petroleum oil, phenol, pentachlorophenol, 4-nitrophenol, dinitro-o-cresol, polychlorinated biphenyls (PCBs especially coplanar), polychlorinated dioxins, polybrominated naphthalenes, /i-sitosterol, sulfide, thiourea, urea, acid water, coal dust... 

Impurities can sometimes be removed by conversion to derivatives under conditions where the major component does not react or reacts much more slowly. For example, normal (straight-chain) paraffins can be freed from unsaturated and branched-chain components by taking advantage of the greater reactivity of the latter with chlorosulfonic acid or bromine. Similarly, the preferential nitration of aromatic hydrocarbons can be used to remove e.g. benzene or toluene from cyclohexane by shaking for several hours with a mixture of concentrated nitric acid (25%), sulfuric acid (58%), and water (17%). 

A series of nitrated and unsaturated hydrocarbons. The base molecule for nomenclature purposes is usually called the "ethylene series1 because the first member is ethylene, C2H4 hence a molecular type CnH(2n-x)Nx02x s derived. Other compds in the series are named after corresponding paraffins by adding to the stem ene or ylene such as 1-nitro propylene, C3H5NO2. Olefms with two conjugeted double bonds are called dienes , such as butadiene. 

Some work [5] has been performed on the photochemical reaction between sulfur dioxide and hydrocarbons, both paraffins and olefins. In all cases, mists were found, and these mists settled out in the reaction vessels as oils with the characteristics of sulfuric acids. Because of the small amounts of materials formed, great problems arise in elucidating particular steps. When NO and 02 are added to this system, the situation is most complex. Bulfalini [3] sums up the status in this way The aerosol formed from mixtures of the lower hydrocarbons with NO and S02 is predominantly sulfuric acid, whereas the higher olefin hydrocarbons appear to produce carbonaceous aerosols also, possibly organic acids, sulfonic or sulfuric acids, nitrate-esters, etc. ... 

Konig Explosives. J.B. Konig patented in 1890 a method of prepn of expls by nitration of high bp hydrocarbons derived from the distn of coal, bituminous shales or residues of petroleum refineries, paraffins and ozokerite Ref Daniel (1902), 395... 

Frdflke patented in France in 1888 St in 1899 powders consisting of K(Na, NH4 or Pb) nitrate impregnated with a molten hydrocarbon (such as a mixt of naphthalene with paraffin). Such mixtures were activated by addn of powdered K chlorate just before use Refs 1) Cun dill (1889) in MP 5, 338(1892)... 

The usual way to achieve heterosubstitution of saturated hydrocarbons is by free-radical reactions. Halogenation, sulfochlorination, and nitration are among the most important transformations. Superacid-catalyzed electrophilic substitutions have also been developed. This clearly indicates that alkanes, once considered to be highly unreactive compounds (paraffins), can be readily functionalized not only in free-radical from but also via electrophilic activation. Electrophilic substitution, in turn, is the major transformation of aromatic hydrocarbons. 

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