Paraffins Nitration

Gas-phase oxidations, photocatalytic, 19 85 Gas-phase paraffin nitration, 17 165 Gas phase polymerization, 20 540 of linear low density polyethylene, 20 194-195... 

Processes for Paraffin Nitrations. Propane is thought to be the only paraffin that is commercially nitrated by vapor-phase processes. Temperature control is a primary factor in designing the reactor, and several approaches have been investigated. A spray mtrator in which liquid nunc acid is spiayed into hoi propane is used industiially. Relatively small-diameter tubular reactors, fluidized-bed reactors, and molten salt reactors have all been successfully used in laboratory units. 

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. 

Unlike spark-induced combustion engines requiring fuel that resists autoignition, diesel engines require motor fuels, for vhich the reference compound is cetane, that are capable of auto-igniting easily. Additives improving the cetane number will promote the oxidation of paraffins. The only compound used is ethyl-2-hexyl nitrate. 

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. 

Strike couldn t find any decent nitroethane synths except for a couple of Chemical Abstract articles. One suggestion is to treat 1.5 moles of Na2C02 with 1 mole of sodium ethylsulfite and 0.0645 moles of K2CO3 at 125-130°C. Another route would be to use silver nitrate and ethyl iodide [8 p119]. This type of reaction has been used to nitrate other paraffins and would probably work. 

Silver fluorocomplexes are also used ia the separation of olefin—paraffin mixtures (33), nitration (qv) of aromatic compounds (34), ia the synthesis of (9-bridged bicycHcs (35), pyrroles (36), cyclo-addition of vinylbromides to olefins (37), and ia the generation of thioben2oyl cations (38). 

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. 

Both vapor-phase and Hquid-phase processes are employed to nitrate paraffins, using either HNO or NO2. The nitrations occur by means of free-radical steps, and sufftciendy high temperatures are required to produce free radicals to initiate the reaction steps. For Hquid-phase nitrations, temperatures of about 150—200°C are usually required, whereas gas-phase nitrations fall in the 200—440°C range. Sufficient pressures are needed for the Hquid-phase processes to maintain the reactants and products as Hquids. Residence times of several minutes are commonly required to obtain acceptable conversions. Gas-phase nitrations occur at atmospheric pressure, but pressures of 0.8—1.2 MPa (8—12 atm) are frequentiy employed in industrial units. The higher pressures expedite the condensation and recovery of the nitroparaffin products when cooling water is employed to cool the product gas stream leaving the reactor (see Nitroparaffins). 

Reactions 8 and 9 are important steps for the Hquid-phase nitration of paraffins. The nitric oxide which is produced is oxidized with nitric acid to reform nitrogen dioxide, which continues the reaction. The process is compHcated by the presence of two Hquid phases consequentiy, the nitrogen oxides must transfer from one phase to another. A large interfacial area is needed between the two phases. 

Only 20—40% of the HNO is converted ia the reactor to nitroparaffins. The remaining HNO produces mainly nitrogen oxides (and mainly NO) and acts primarily as an oxidising agent. Conversions of HNO to nitroparaffins are up to about 20% when methane is nitrated. Conversions are, however, often ia the 36—40% range for nitrations of propane and / -butane. These differences ia HNO conversions are explained by the types of C—H bonds ia the paraffins. Only primary C—H bonds exist ia methane and ethane. In propane and / -butane, both primary and secondary C—H bonds exist. Secondary C—H bonds are considerably weaker than primary C—H bonds. The kinetics of reaction 6 (a desired reaction for production of nitroparaffins) are hence considerably higher for both propane and / -butane as compared to methane and ethane. Experimental results also iadicate for propane nitration that more 2-nitropropane [79-46-9] is produced than 1-nitropropane [108-03-2]. Obviously the hydroxyl radical attacks the secondary bonds preferentially even though there are more primary bonds than secondary bonds. 

The danger of an explosion of a nitrated product generally increases as the degree of nitration increases, eg, trinitroaromatics are more hazardous as compared to dinitroaromatics or especially mononitroaromatics. Nitroaromatics and some polynitrated paraffins are highly toxic when inhaled or when contacted with the skin. AH nitrated compounds tend to be highly flammable. 

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%). 

An important advance in dynamite was the substitution of ammonium nitrate for part of the nitroglycerin to produce a safer and less expensive explosive. Nobel made this new dynamite successful by devising gelatins that contained from 20 to 60 percent ammonium nitrate. Ammonium nitrate was too hygroscopic, hence, work began to develop a nongelatinous form., The solution, found in 1885, was coating ammonium nitrate with a little paraffin to produce a series of ammonia dynamites,... 

Note Rhodamine B is a universal reagent that can be used on silica gel, talc, starch [5] and cellulose layers, just as on urea [1] or silver nitrate-impregnated [7] phases. Liquid paraffin-impregnated silica gel and RP layers are less suitable, since the background to the chromatographic zones is also intensely colored. It is often possible to increase the detection sensitivity by placing the plate in an atmosphere of ammonia after it has been sprayed or dipped, alternatively it can be oversprayed with sodium or potassium hydroxide solution. 

Uses of Nitric Acid. The primary use of nitric acid is for the production of ammonium nitrate for fertilizers. A second major use of nitric acid is in the field of explosives. It is also a nitrating agent for aromatic and paraffinic compounds, which are useful intermediates in the dye and explosive industries. It is also used in steel refining and in uranium extraction. 

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. 

Maxim Explosive. Patented in 1885 in Engl.-Prepd by mixing lp of compn (K nitrate 74.18, sulfur 14.40 paraffin 11.42%) with 3ps of regular BlkPdr Ref Daniel (1902), 420... 

The older technique for this purpose (Ref 8), variously referred to as the paraffin test, the paraffin-glove test, the dermal nitrate test, and the diphenylamine test, had been abundantly shown to be unreliable, was no longer accepted in most US courts, and was now seldom used by good crime investigation laboratories... 

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. 

The use of paraffin in the expl industry is extensive, not only as a moisture protecting agent, but as a desensitizer. Paraffin can be incorporated either directly with ingredients of expl compns (at a temp above its mp), or one or more ingredients can be coated separately with molten paraffin and then mixed. When hygroscopic substances, such as AN, Na nitrate, etc, are coated in such a manner, they are rendered less hygroscopic, and, when the same procedure is applied to sensitive compds or expls (K chlorate, RDX, PETN, etc) their sensitivity can be markedly reduced... 

Pittius Explosives. C. vanPittius of Holland obtd a BritP in 1910 on expls consisting of combustible mats and oxidizers. The combustible constituent is prepd by mixing resin (lOp) and stearin (5p) together at 150°, and incorporating paraffin (lOp) and a blend consisting of TNT (25p) and NG (5p) or NC (3p). Molten TNT (50p) is then added and blended while maint the mixt at 85°. The reddish-brnmixt is termed TNT paste . To use this expl the TNT paste is mixed with oxidizers, viz, a) TNT paste 20, K nitrate 30, amm perchlorate 30 and K perchlorate 20% b) TNT paste 8 and amm nitrate 92%... 

Pollard Explosive. A mixt of S, paraffin, and either a nitrate or chlorate Ref Daniel (1902), 635... 

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