Nitration laboratory scale

Fig. 7. A bead filter, one of many types of biological filters, shown in association with a laboratory-scale recirculating water system. Small plastic beads inside the fiber glass chamber provide surface area for colonisation by bacteria that convert ammonia to nitrate.

Heat, and sometimes gas, transfer from the core of a bulk material, also influences auto-ignition and explosion. The concept of critical mass is not limited to nuclear explosives (though shape is also important). Some entries in this text, such as sodium chlorate, ammonium nitrate and ammonium perchlorate, have proved extremely destructive dining industrial storage by the tens of tonnes, but are incapable of explosion at the ten gramme scale. Many other entries are for hazards significant only beyond laboratory scale [1]. 

Nitroalkanes can be formed from the direct nitration of aliphatic and alicyclic hydrocarbons with either nitric acid ° or nitrogen dioxide in the vapour phase at elevated temperature. These reactions have achieved industrial importance but are of no value for the synthesis of nitroalkanes on a laboratory scale, although experiments have been conducted on a small scale in sealed tubes. 

A range of primary and secondary nitroalkanes and their derivatives have been converted to the corresponding gem-dinitroalkanes via oxidative nitration, including the conversion of nitroethane, 1-nitropropane, 2-nitropropane and 2-nitro-1,3-propanediol to 1,1-dinitroethane (78 %), 1,1-dinitropropane (86 %), 2,2-dinitropropane (93 %) and 2,2-dinitro-1,3-propanediol (77 %) respectively. The silver nitrate used in these reactions can be recovered quantitatively on a laboratory scale and this has led to a study where oxidative nitration has been considered for the large-scale production of 2,2-dinitropropanol (25) from the nitroethane (22). ... 

Energetic materials with strained or caged structures are often much more difficult to synthesize compared to their open chain counterparts. This presents a further challenge to researchers of new energetic materials - while new compounds can be synthesized on a laboratory scale, and their properties and performance tested, the complexity of the synthetic routes may render their use as explosives nonfeasible. This particularly applies to polynitropolycyclic hydrocarbons because the direct nitration of these hydrocarbons is not a feasible route of introducing nitro groups without considerable decomposition. 

The direct action of nitric acid and its mixtures on the parent alcohol is by far the most important method for the production of nitrate esters on both an industrial and laboratory scale." While such reactions are essentially esterifications they are commonly referred to as 6>-nitrations because the reaction mechanism, involving substitution of hydrogen for a nitro group, is not dissimilar to other nitrations and frequently involves the same nitrating species. 

The reaction of alkyl halides with silver nitrate constitutes an extremely useful method for the synthesis of high purity nitrate esters on a laboratory scale. ° The driving force for these reactions is the formation of the insoluble silver halide. Reactions have been conducted under homogenous and heterogeneous conditions. For the latter a solution of the alkyl halide in an inert solvent like benzene or ether is stirred with finely powdered silver nitrate. However, this method has been outdated and reactions are now commonly conducted under homogeneous conditions using acetonitrile as solvent. 

An extremely mild method for the synthesis of nitrate esters from easily oxidized or acid-sensitive alcohols involves the decomposition of a nitratocarbonate (29). The nitratocar-bonate is prepared in situ from metathesis between a chloroformate (reaction between phosgene and an alcohol) and silver nitrate in acetonitrile in the presence of pyridine at room temperature. Under these conditions the nitratocarbonate readily decomposes to yield the corresponding nitrate ester and carbon dioxide. Few examples of these reactions are available in the literature and they are limited to a laboratory scale. 

The direct nitration of aromatic substrates is usually the method of choice for the synthesis of aromatic nitro compounds on both industrial and laboratory scales. Other routes are usually only considered when the required product has an unusual substitution pattern or is so deactivated that nitration is exceptionally difficult. Many of these alternative methods are limited to a laboratory scale. 

Hodgson and Turner [5] examined the action of various concentrations of nitric acid alone on dimethylaniline, by nitrating 5 g test specimens of the latter on a laboratory-scale. 

In this way, from 100 parts of diethylene glycol, these authors obtained 158 parts of the product. This is 85.4% of the theoretical yield. Laboratory scale nitration can give 93% yield [42]. 

The commercial preparation of mercury fulminate is carried out by a process which is essentially the same as that which Howmrd originally recommended. Five hundred or 600 grams of mercury is used for each batch, the operation is practically on the laboratory scale, and several batches are run at the same time. Since the reaction produces considerable frothing, capacious glass balloons are used. The fumes, which are poisonous and inflammable, are passed through condensers, and the condensate, which contains alcohol, acetaldehyde, ethyl nitrate, and ethyl nitrite, is utilized by mixing it with the alcohol for the next batch. 

For nitrating on the laboratory scale, mixtures of nitric acid esters or acyl nitrates, e.g. acetyl nitrate CH3C0N03, and sulphuric acid may also be used. 

Several lesser known nitrating agents, which can find practical use on a laboratory scale are metal nitrates in the presence of acetic acid or acetic anhydride, described by Menke [2], tetranitromethane and hexanitroethane in an alkaline medium, used by Schmidt [3], Mid nitroguanidine in solution in sulphuric acid, used for the nitration of aromatic amines Mid phenols. 

Since analytical results do not give a clear idea as to the usefulness of xylene for nitration, nitration tests on a laboratory scale are recommended. 

Just as phenol can he nitrated or sulfonated, it if also possible to introduce the arsonic acid residue intc the molecule by treatment of phenol with arsenic acid The following conditions have been found very satis factory on a laboratory scale 1... 

Nitroalkanes. Acyl nitrates can be prepared by several methods, the most convenient of which on a laboratory scale is treatment (a) of an acid anhydride (tenfold excess) with 90% nitric acid (20°). The by-product acid can be reconverted into the... 

These two concepts have been proved on a laboratory scale, mainly for hydrogenation reactions but can be transposed to many gas-liquid catalyzed reactions. Interesting potential applications have been mentioned, such as asphaltene hydrocracking or nitrate and nitrites removal from drinking water by catalytic nitrate reduction. However, the characteristics of ceramic... 

The influence of the concentration of sodium hydroxide used as regenerant on the concentration of sodium chromate recovered from a weak base resin has been investigated on the laboratory scale [32, 33]. Also, the influence of the concentration of nitric or sulfuric acid on the concentration of ammonium nitrate or sulfate recovered from a strong acid resin has been investigated on the pilot-plant scale [ 1, Sl. These studies have confirmed the above observation... 

The method of manufacture of nitroform from acetylene found as early as 1900 by Baschieri (Voi. I, p. 587) was described by Orton and McKie [141]. It became possible to convert one of the carbons of acetylene to nitroform through a mercury catalysed oxidation-nitration process with nitric acid. Nitroform is an intermediate product of nitration and yields tetranitromethane under the action of excess nitric acid (Vol. I, p. S94). The method was developed during World War II by Schultheiss I42] and Schimmelschmidt 143 on a large laboratory scale with the atm of producing tetranitromethane. l ater the industrial scale method for the manufacture of nitroform was created by Wctter-holm [I44 (and is described below). 

Among nitrating agents the most important still remain nitric acid-sulphuric acid mixtures, but some other very efficient nitrating agents related to nitric acid have been found and are in use, mainly on a laboratory scale. 

Nitration. As pointed out in Vol. II (p. 321) the only industrial method ol nitrating cellulose consists in using a nitric acid -sulphuric acid nitrating mixture. The other nitrating mixtures, such as nitric acid/phosphoric anhydride, nitric acid/acctic anhydride, nitric acid/chlorinated hydrocarbons were in use occasionally on a laboratory scale to solve some problems connected with the nitration of cellulose. Thus Bennett and Timell (10 confirmed the work of Bouchonnet, Trombe and Petitpas (Vol. II, p. 344) that the nitration of cotton dust with a mixture of nitric acid-acetic acid acelic anhydride (in proportion 43 32 25) at 0 C can yield fully nitrated cellulose, that is, cellulose trinitrate of 14.14% N... 

The off-gas from melting of mixtures of salt cake with either basalt and B2O3 or sand and lime consists mainly of NO and CO2 from decomposition of nitrate, nitrite, and carbonate salts. The off-gas will also contain water vapor and, possibly, traces of SO2. Not unexpectedly, some radio-cesium also volatilizes when salt cake is converted to glass at 1100°-1200°C. Our laboratory-scale tests suggest, however, that of the order of 5%, or less, of the radio-cesium will volatilize when salt cake is converted to glass in a conventional continuous glass melter. 

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