338 BENZOLE 



among thorn that of Mr. Mansfield, to whom wo aro indebted for an excellent in- 

 vestigation on coal-naphtha. Benzole is greatly used in commerce, owing to its 

 valuable solvent properties. It dissolves caoutchouc and gutta-percha readily, and, 

 on evaporation, leaves them in a state well adapted for waterproofing and many other 

 purposes. Its power of dissolving fatty, oily, and other greasy matters, has caused 

 it to become an article of commerce under the name of bcmoline. It readily extracts 

 grease even from the most delicate fabrics, and, as it soon, on exposure to the air, 

 evaporates totally away, no odour remains to betray the fact of its having been used. 

 It dissolves readily in very strong nitric acid, and, on the addition of water, it is 

 precipitated as a heavy oil, having the composition C 12 H J N0 4 (C H 5 wro 2 ). The latter 

 compound is nitrotxtncole ; it is regarded as benzole in which one atom of hydrogen is 

 replaced by hyponitric acid. Nitrobenzole, in a state of tolerable purity, is a pale- 

 yellow oil, having a sweetish taste, and an odour greatly resembling bitter almonds. 

 Owing to its compirative cheapness, it is employed in perfumery. Nitrobcnzolo can 

 be prepared with nitric acid of moderate strength, such as is ordinarily obtained in 

 commerce ; but it then becomes necessary to distil the acid and the hydrocarbon 

 together several times. The product so obtained is darker in colour, and in other 

 respects inferior to that obtained with highly concentrated acid. By treatment with 

 acetate of protoxide of iron, nitrobonzole becomes transformed into aniline. This 

 change may be effected, but far less conveniently, by means of sulphide of ammonium. 

 Benzole is extremely valuable in many operations of manufacturing chemistry. It 

 dissolves several alkaloids, and, on evaporation, leaves them in a state of purity. It 

 dissolves quinine, but not cinchonine, and may therefore be employed as a means of 

 separation. Morphia and strychnine are also dissolved by it, but not in great quan- 

 tity. To obtain many natural alkaloids existing in plants, it is merely necessary to 

 digest the dry extract with caustic potash and then with benzole. The latter is to bo 

 decanted, and then distilled off on a water-bath. The alkaloid will be left behind in 

 a state well adapted for crystallisation or other means of purification. Benzole is 

 becoming much used as a solvent in researches in organic chemistry. Many sub- 

 stances, such as chrysene and bichloride of naphthaline, crystallise better from benzole 

 than from any other solvent. 



Benzole may be employed in many ways for illuminating purposes. It is so easily 

 inflamed that great care is necessary in using it. It does not require a wick to enable 

 it to burn. If poured, even on an uninflammable surface and a light be applied, it takes 

 fire like a train of gunpowder, and burns with a brilliant flame, emitting dense clouds 

 of smoke, which, soon condensing into soot, presently fall in a shower of blacks. Even 

 on the surface of water it burns as freely as anywhoro else. If a drachm or two bo 

 poured on water contained in a pan, and a pellet of potassium be thrown in, the ben- 

 zole inflames, and rises in a column of flame of considerable height. A method of 

 destroying enemies' shipping has been founded on this principle. In consequence of 

 the smoky nature of the flame of benzole (caused by the comparatively larger per- 

 centage of carbon), it is often convenient to burn a mixture of one volume of 

 benzole and two volumes of alcohol. A stream of air driven through benzole 

 becomes so inflammable as to serve for the purposes of illumination. For this mode 

 of using the hydrocarbon, it should be kept slightly warm to assist its vaporisation. 

 A machine on this principle, of American invention, has been employed to illuminate 

 houses. The air is driven through the benzole by a very simple contrivance, the 

 motive power being a descending weight. See GAS, AIR. 



When quite pure, benzole freezes at 32 to a beautiful snow-white substance, resem- 

 bling camphor. The mass retains the solid form until a temperature of 40 or 41 is 

 reached. This property of solidifying under the influence of cold may be made 

 use of to produce pure benzole from the more volatile portion of coal-naphtha. To 

 obtain it perfectly pure, it should bo frozen at least three times, the portion not 

 solidifying being removed by filtration through calico. The unfrozen portion con- 

 tains hydrocarbons, homologous witli olefiant gas. 



Benzole dissolves free iodine and bromine, and has oven been used in analysis to 

 separate them from kelp and other substances containing them. They must of course 

 bo set free before acting with the hydrocarbon. The presence of benzole in mixtures 

 may easily be demonstrated, even when present in very small quantity, by converting 

 it into aniline, and obtaining the characteristic reaction with chloride of lime. For 

 this purpose the mixture is to be dissolved in concentrated nitric acid and the nitro- 

 benzolo precipitated by water. The fluid is then agitated with ether, which dissolves 

 the nitro-compound. The ethereal solution is mixed with an equal bulk of alcohol and 

 hydrochloric acid : a little granulated zinc being added, hydrogen is evolved, and, by 

 acting in a nascent state on the nitro-compound, reduces it to the state of aniline. The 

 base is then to be separated by an excess of potash, and the alkaline fluid is shaken 

 with ether to dissolve the base. The ethereal fluid being evaporated, leaves the aniline. 



