Nitrobenzene

“ SOME DERIVATIVES OF BENZENE
Attention has been called to the complex nature of coal tar. Among the compounds present are the hydrocarbons, benzene, toluene, naphthalene, and anthracene. These compounds are not only useful in themselves but serve for the preparation of many other important compounds known under the general name of coal-tar products.
Nitrobenzene (oil of myrbane) (C6H5NO2) . When benzene is treated with nitric acid a reaction takes place which is expressed by the following equation:
C6H6 + HNO3 = C6H5NO2 + H2O.
The product C6H5NO2 is called nitrobenzene. ”

“ Sulfuric acid-treated glass fiber filters were used to collect aniline and o-toluidine, while nitrobenzene was collected on the silica gel sorbent [1] . Nitrobenzene collection on silica gel tubes was significantly reduced under conditions of high relative humidity [1] . Dermal badge samplers (cotton pouch with 1 g silica gel) and gauze wipes were developed to estimate exposures via splashes, spills, and passive collection of aerosol vapors. ”

“ With nitro compounds Sach and Hilbert concluded that those containing a ⋅CH⋅ side group in the ortho position to the ⋅NO2 group were decomposed by light. For example, ortho-nitrobenzaldehyde in alcoholic solution gives nitrosobenzoic ester and 22′ azoxybenzoic acid, with the intermediate formation of nitrobenzaldehydediethylacetal, NO2⋅C6H4⋅CH (OC2H5) 2 (E. Bamberger and F. Elgar, Ann. 1910, 371, p. 319) . Bamberger also investigated nitrosobenzene, obtaining azoxybenzene as chief product, together with various azo compounds, nitrobenzene, aniline, hydro quin one and a resin. ”

“ Avoid inhalation. Nitrobenzene and m-nitrotoluene are absorbed through contact with skin and can cause methemoglobinemia [5,6] . 4-Chloronitrobenzene is a carcinogen. Methanol is highly flammable.
SAMPLING: 1. Calibrate each personal sampling pump with a representative sampler in line. 2. Break the ends of the sampler immediately before sampling. Attach sampler to personal sampling pump with flexible tubing. 3. Sample at an accurately known flow rate between 0.01 and 0.2 L/min for nitrotoluene isomers. Use a flow rate of 1 L/min or less for nitrobenzene and 4-chloronitrobenzene. ”

“ Instances of its application are found in the separation of ortho- and para-nitrophenol, the o-compound distilling and the p- remaining behind; in the separation of aniline from the mixture obtained by reducing nitrobenzene; of the naphthols from the melts produced by fusing the naphthalene monosulphonic acids with potash; and of quinoline from the reaction between aniline, nitrobenzene, glycerin, and sulphuric acid (the product being first steam distilled to remove any aniline, nitrobenzene, or glycerin, then treated with alkali, and again steam distilled when quinoline comes over) . ”

“ Here again we find scientific research reacting on technology. A few words of chemical explanation will make this manufacture intelligible. By the action of reducing agents on nitro and nitroso-compounds, the nitro and nitroso-group become converted into the amido-group. Thus when nitrobenzene is reduced by iron and an acid we get aniline; similarly when nitrosodimethylaniline is reduced by zinc and an acid we get amidodimethylaniline, and this is the base used in the preparation of methylene blue. By oxidizing this base in the presence of sulphuretted hydrogen, the colouring-matter is formed. ”

“ Many of the popular synthetic remedies belong to the benzene series. Benzene is obtained from coal-tar, but, as shown by Berthelot, it is possible to prepare it by heating the gaseous hydrocarbon, acetylene, C2H2, in a closed vessel. By this means three molecules of acetylene are condensed into one, C6H6, which is benzene. Benzene acted upon by nitric acid yields nitrobenzene, and this by the action of nascent hydrogen is changed into aniline. ”

“ Phenylglycin is obtained by the action of monochloracetic acid on aniline, which in its turn is164 obtained through nitrobenzene from benzene. Since benzene can be synthetically prepared by the condensation of acetylene, which can be obtained by the direct union of carbon and hydrogen at a high temperature, it is theoretically possible to build up indigo blue from inorganic materials. ”

“ Aniline is toxic, poisonous and a potential human carcinogen. o-Toluidine is toxic and a potential human carcinogen. Nitrobenzene is toxic and poisonous. Nitrobenzene has a synergistic effect on the toxicity of aniline and o-toluidine [5] . Ethanol is flammable and a dangerous fire risk. ”

“ It also appears as an intermediate product in the electrolytic reduction of nitrobenzene in sulphuric acid solution. By gentle oxidation it yields nitrosobenzene. Derivatives of the type R2N·OH result in the action of the Grignard reagent on amyl nitrite. Dihydroxy-ammonia or nitroxyl, NH (OH) 2, a very unstable and highly reactive substance, has been especially studied by A. Angeli (see A. W. Stewart, Recent Advances in Physical and Inorganic Chemistry, 1909) .
HYDROZOA, one of the most widely spread and prolific groups of aquatic animals. ”

“ APPENDIX: STANDARDIZATION OF CALIBRATION STOCK SOLUTION. Pipet 10-mL aliquots of the stock solution into two separate 250-mL Erlenmeyer flasks. Add 10 mL 2.5% hydrazine sulfate to one of the flasks and allow to stand 10 minutes with occasional swirling. The other flask serves as a blank and determines any free halide ion already present. Add 10 mL 0.100 N silver nitrate solution, 5 mL nitric acid solution, and 2 mL ferric ammonium sulfate solution to each flask. Swirl and add 2 mL nitrobenzene. ”

“ Applied loosely to compounds having nitrogen variously combined, as in cyanides, nitrates, etc. (b) Now especially applied to compounds containing a two atom nitrogen group uniting two hydrocarbon radicals, as in azobenzene, azobenzoic, etc. These compounds furnish many artificial dyes. See DiazoÏ. Az·oÏben¶zene (?) , n. [AzoÏ + benzene.] (Chem.) A substance (C6H5.H2.C6H5) derived from nitrobenzene, forming orange red crystals which are easily fusible. AÏzo¶ic (?) , a. [Gr. ? priv. + ? life, from ? to live.] Destitute of any vestige of organic life, or at least of animal life ”

“ The nitro-substitution explosives are made from nitrobenzenes, nitrotoluenes, nitronaphthalenes, nitrophenols, and bodies of a similar character, and one of them, called joveite, has given excellent results in this country. After having demonstrated that the destructive effect of joveite was greater than that of gunpowder, smokeless powder, or gun cotton, Shooting an Oil Well with Nitroglycerin. ”

“ Nitro-benzene is a heavy oily liquid which boils at 205° C., has a specific gravity of 1.2, and an odour like that of oil of bitter almonds. In the arts it is chiefly used in the preparation of aniline.
~Di-nitro Benzene~ is a product of the further action of nitric acid on benzene or nitro-benzene. It crystallises in long fine needles or thin rhombic plates, and melts at 89.9° C. It can be made thus:—The acid mixture used consists of equal parts of nitric and sulphuric acids, say 50 c.c. of each, and without cooling add very slowly 10 c.c. of benzene from a pipette. ”

“ If the graphic formula of benzene be represented thus (No. 1) , then the positions 1 and 2 represent the ortho, 1 and 3 the meta, and 1 and 4 the para compounds. When the body phenol, C_{6}H_{5}.OH, is nitrated, a compound is formed known as tri-nitro-phenol, or picric acid, C_{6}H_{2} (NO_{2}) {3}OH, which is used very extensively as an explosive, both as picric acid and in the form of picrates. Another nitro body that is used as an explosive is nitro-naphthalene, C{10}H_{6} (NO_{2}) {2}, in roburite, securite, and other explosives of this class. ”

“ The lesson this table teaches is, that it is almost impossible to nitrate cellulose in small quantities, and get uniform results, when the nitration is carried on at high temperatures. As regards the solubility of pyroxyline, Parks found that nitro-benzene, aniline, glacial acetic acid, and camphor, dissolved in the more volatile solvents methyl-alcohol and alcohol-ether, were much the best solvents for producing a plastic, as they are less volatile, and develop greater solvent action under the influence of heat. Nitro-benzene gives a solution that is granular ”

“ For this purpose a little of it is dissolved in concentrated nitric acid, and the nitrobenzol thus formed is precipitated by the addition of water. The fluid is then agitated with ether, to dissolve out the nitrobenzol, and the resulting ethereal solution is mixed with an equal bulk of alcohol and hydrochloric acid and a little granulated zinc at once added. Hydrogen is evolved, and by its action the nitro-compound is converted into aniline. The liquid is next alkalised with potassa in excess, and the alkaline fluid agitated with ether. ”

“ Nitro- benzene, when reduced with iron, zinc, or tin, and hydrochloric acids, forms aniline.
~Roburite.~—This explosive is the invention of a German chemist, Dr Carl Roth (English patent 267A, 1887) , and is now manufactured in England, at Gathurst, near Wigan. It consists of two component parts, non-explosive in themselves (Sprengel's principle) , but which, when mixed, form a powerful explosive. The two substances are ammonium nitrate and chlorinated di-nitro-benzol. Nitro-naphthalene is also used. Nitrate of soda and sulphate of ammonium are allowed to be mixed with it. ”

“ On prolonged boiling nitro-benzene produces at the edge of the liquid a crimson ring, which on the addition of a solution of bleaching powder turns emerald- green. And nitro-glycerine in ether solution, by placing a few drops of the suspected solution, together with a drop or two of aniline, upon a watch-glass, evaporating off the ether, and then adding a drop of concentrated sulphuric acid to the residue, when, if nitro-glycerine is present, the H_{2}SO_{4} will strike a crimson colour, due to the action of the aniline sulphate upon the nitric acid liberated from the nitro- glycerine. ”

“ Dinitro-benzol is formed, which is dissolved in alcohol, and the resulting solution subjected to the reducing action of ammonia and sulphuretted hydrogen, as described under aniline. Nitraniline forms yellow, acicular crystals, little soluble in cold water, but freely soluble in alcohol and ether. Its salts are crystallisable.
NI′TRATE. Syn. Nitras, L. A salt of nitric acid (e.g. AgNO3, nitrate of silver) . The nitrates are very easily prepared by the direct solution of the metal, or its oxide, or carbonate, in nitric acid, which, in most cases, should be previously diluted with water. ”

“ On nitration it yields chiefly meta-nitro-benzaldehyde, crystallizing in needles which melt at 58° C. The ortho-compound may be obtained by oxidizing ortho-nitrocinnamic acid with alkaline potassium permanganate in the presence of benzene; or from ortho-nitrobenzyl chloride by condensing it with aniline, oxidizing the product so obtained to ortho-nitrobenzylidine aniline, and then hydrolysing this compound with an acid (Farben fabrik d. Meister, Lucius und Brüning) . ”

“ The increase in weight resulting from the fixation of the {23} nitric acid residue is approximately equal to that of cotton “nitrated” under the same conditions.
They are freely soluble in acetone. On examination they prove to be homogeneous. If the fibre be warmed with the mixture after the first reaction is completed, it dissolves. The solution is found to contain oxalic, succinic, and suberic acids, but no aromatic nitro-derivatives, whereas if ligno-cellulose contain a benzene nucleus, as has been supposed, such derivatives could not fail to be formed under these conditions. ”

“ The amount of the former substances plus the moisture and sulphur, deducted from the total loss on extraction with chloroform, gives the quantity of nitro-glycerine. Nitro-benzene may be detected, according to J. Marpurgo, in the following manner:—In a porcelain basin are placed two drops of liquid phenol, three drops of water, and a fragment of potash as large as a pea. The mixture is boiled, and the aqueous solution to be tested then added. ”

“ A solution of nitro-aniline in hydrochloric acid gives a colorless solution showing no trace of absorption band to indicate isorropesis. The structure of the hydrochlorate, therefore, is purely benzoïd in type and enters not into the quinoïd form by reason of the saturation of both nitrogen atoms. In the case of the nitrophenols similar reasoning may be followed. The absorption band of para-nitrophenol, O2N—C6H4—OH, in neutral alcoholic solution, is identical with that of para-nitroanisol, O2N—C6H4—OCH3, the methyl ether of this phenol. ”

“ The composition is now 50 per cent. of soluble nitro-cotton and 50 per cent. of nitro-glycerine. As nitro-glycerine will not dissolve its own weight of nitro-cotton (even the soluble variety) , benzol is used as a solvent, but is afterwards removed from the finished product, just as the acetone is removed from cordite. About 1 per cent. of diphenylamine is added for the purpose of increasing its stability.
The colour of ballistite is a darkish brown. It burns in layers when ignited, and emits sparks. The size of the cubes into which it is cut is a 0.2-inch cube. ”

“ Substitution of the Benzene Ring.—As a general rule, homologues and mono-derivatives of benzene react more readily with substituting agents than the parent hydrocarbon; for example, phenol is converted into tribromphenol by the action of bromine water, and into the nitrophenols by dilute nitric acid; similar activity characterizes aniline. Not only does the substituent group modify the readiness with which the derivative is attacked, but also the nature of the product. ”

“ For example: nitric acid and sulphuric acid readily react with benzene and its homologues with the production of nitro derivatives and sulphonic acids, while in the aliphatic series these acids exert no substituting action (in the case of the olefines, the latter acid forms an addition product) ; another distinction is that the benzene complex is more stable towards oxidizing agents. This and other facts connected with the stability of benzenoid compounds are clearly shown when we consider mixed aliphatic-aromatic hydrocarbons, i.e. ”