Part 12 (1/2)

C_{6}H_{5}NO_{2} + HNO_{3} = C_{6}H_{4}(NO_{2})_{2} + H_{2}O

Di-nitro-benzene

These nitro bodies are not acids, nor are they ethereal salts of nitrous acid, as nitro-glycerine is of glycerine They are regarded as formed from nitric acid by the replacement of hydroxyl by benzene radicals

~Mono-nitro Benzene~ isbenzene with concentrated nitric acid, or a mixture of nitric and sulphuric acids The latter, as in the case of the nitration of glycerine, takes no part in the reaction, but only prevents the dilution of the nitric acid by the water formed in the reaction Small quantities may be made thus:--Take 150 cc of H_{2}SO_{4} and 75 cc HNO_{3}, or 1 part nitric to 2 parts sulphuric acid, and put in a beaker standing in cold water; then add 15 to 20 cc of benzene, drop by drop, waiting between each addition for the co the operation When finished, pour contents of beaker into about a litre of cold water; the nitro-benzol will sink to the bottom Decant the water, and wash the nitro-benzol two or three ti funnel ater Finally, dry the product by adding a little granulated calciu to stand for some little time, it may then be distilled Nitro-benzene is a heavy oily liquid which boils at 205 C, has a specific gravity of 12, 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 899 C It can be made thus:--The acid mixture used consists of equal parts of nitric and sulphuric acids, say 50 cc of each, and without cooling add very slowly 10 cc of benzene from a pipette After the action is over, boil the mixture for a short time, then pour into about half a litre of water, filter off the crystals thus produced, press between layers of filter paper, and crystallise from alcohol Di-nitro-benzene, or meta-di-nitro-benzene, as it is sometimes called, enters into the composition of several explosives, such as tonite No 3, roburite, securite, bellite

Nitro-benzene isa bench a row of glass flasks, containing 1 gallon each (1 to 2 lbs

benzene), are placed, and the acids added in s with the first, and adding a small quantity to each in turn, until the nitration was coerous one, and is now obsolete The first nitro-benzene land, by Messrs Siton, in 1856, was by this process Noever, vertical iron cylinders,operation They are about 4 feet in diaed in a row, at a convenient height fro Each cylinder is covered with a cast-iron lid having a raised rie to a vertical shaft, and two or s allow the benzene and the s is surrounded with a deep rim, so that the whole top of the cylinder can be flooded ater so into the interior of the nitrator The lid overhangs the cylinder somewhat, and in the outer rim a number of shot- holes or tubes allow the water to flon all over the outside of the cylinder into a shallow cast-iron dish, in which it stands By ood supply of cold water, the top, sides, and bottom of the whole apparatus is thus cooled and continually flooded The agitator consists of cast-iron arms keyed to a vertical shaft, with fixed arms or dash-plates secured to the sides of the cylinder The shaft has awheel on the horizontal shafting running along the top of the converters This latter is secured to a clutch; and there is a feather on the shaft, so that any one of the converters can if necessary be put either in or out of gear This arrangeers or belts of leather, cotton, or indiarubber will not stand the atmosphere of the nitro-benzole house

Above and close to each nitrator stands its acid store tank, of iron or stoneware

The building in which the nitration is carried out should consist of one story, have a light roof, walls of hard brick, and a concrete floor of 9 to 12 inches thick, and covered with pitch, to protect its surface from the action of the acids The floor should be inclined to a drain, to save any nitro-benzol spilt Fire hydrants should be placed at convenient places, and it should be possible to at once fill the building with stea, is advisable The building should also be as far as possible isolated

The acids are mixed beforehand, and allowed to cool before use The nitric acid used has a specific gravity of 1388, and should be as free as possible froen The sulphuric acid has a specific gravity of 1845, and contains froood mixture is 100 parts of nitric to 140 parts of sulphuric acid, and 78 parts of benzene; or 128 parts HNO_{3}, 179 of H_{2}SO_{4}, and 100 of benzene (C_{6}H_{6}) The benzene having been introduced into the cylinder, the water is turned on and the apparatus cooled, the agitators are set running, and the acid cock turned on so as to allow it to flow in a very thin stream into the nitrator

Should it be necessary to check the machinery even for a itation continued for soour that if the benzene being nitrated co occurs, and the mixture may inflame Accidents from this cause have been not infrequent

The operation requires between eight to ten hours, agitation and cooling being kept up all the time When all the acid is added the water is shut off, and the temperature allowed to rise a little, to about 100 C When it ceases to rise the agitators are thrown out of gear, and the mixture allowed some hours to cool and settle The acid is then drawn off, and the nitro-benzene is ashed ater, and sometimes distilled et steam, to recover a little unconverted benzene and a trace of paraffin (about 5 per cent together) At allons, or 800 to 1,760 lbs, are nitrated at a time, and toluene is often used instead of benzene, especially if the nitro-benzene is for use as essence of ravity 16 to 17, contain a little nitro-benzene in solution and some oxalic acid They are concentrated in cast-iron pots and used over again

~Di-nitro Benzene~ is obtained by treating a charge of the hydrocarbon benzene with double the quantity of es, the second lot of acid being run in directly after the first The cooling water is then shut off, and the temperature allowed to rise rapidly, or nitro-benzene already e quantity of acid fumes come off, and some of the nitro- and di-nitro-benzol produced coood condensing apparatus of stoneware must be used to prevent loss The product is separated from the acids, washed with cold water and then with hot It is slightly soluble in water, so that the washi+ng waters ain Finally it is allowed to settle, and run while still warm into iron trays, in which it solidifies in masses 2 or 4 inches thick It should not contain any nitro-benzol, nor soil a piece of paper when laid on it, should be well crystallised, fairly hard, and almost odourless The chief product ispoint 898, but ortho-di-nitro-benzene,point 172, are also produced Thepoint of the commercial product is between 85 to 87 C

Di-nitro-toluene is made in a si a very large excess of the mixed acids Nitro- benzene, when reduced with iron, zinc, or tin, and hydrochloric acids, forms aniline

~Roburite~--This explosive is the invention of a Gerlish patent 267A, 1887), and is now an It consists of two coel'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 aes claimed for the introduction of chlorine into the nitro co effect upon the NO_{2} groups, and enables the coroups alone are present

The formula of chloro-di-nitro-benzol is C_{6}H_{3}Cl(NO_{2})_{2} The theoretical percentage of nitrogen, therefore, is 1382, and of chlorine 1753 Dr Roth states that, from experiments he has made, the dynamic effect is considerably increased by the introduction of chlorine into the nitro compound Roburite burns quickly, and is not sensitive to shock; it must be used dry; it cannot be made to explode by concussion, pressure, friction, fire, or lightning; it does not freeze; it does not give off deleterious fumes, and it is to all intents and purposes flameless; and when properly tamped and fired by electricity, can be safely used in fiery nited by it The action is rending and not pulverising Co fro to the substance acted upon It is largely used in blasting, pit sinking, quarrying, &c, but especially in coalis the equation of its decomposition:--

C_{6}H_{3}Cl(NO_{2})_{2} + 9HN_{4}NO_{3} = 6CO_{2} + 20N + HCl

In appearance roburite is a brownish yelloder, with the characteristic sravity is 140 The Company's state been questioned by the miners of the Garswood Coal and Iron Works Colliery, a scientific coe the question The members of this committee were Dr N Hannah, Dr DJ Mouncey, and Professor HB Dixon, FRS, of Owens College After a protracted investigation, a long and technical report was issued, co the innocuousness of roburite when properly used In the words of _The Iron and Coal Trades' Review_ (May 24, 1889), ”The verdict, though not on every point in favour of the use in all circumstances of roburite in coal mines, is yet of so pronounced a character in its favour as an explosive that it is impossible to resist the conclusion that the clairounds”

Roburite was also one of the explosives investigated by the committee appointed in September 1889 by the Durham Coalowners' and Miners'

associations, for the purpose of deter whether the fumes produced by certain explosives are injurious to health Both owners and workmen were represented on the committee, which elected Mr T Bell, HM Inspector of Mines, as its chairman, with Professor PP Bedson and Drs Drummond and Hume as professional advisers The problem considered hether the fumes produced by the combustion of certain explosives, one of which was roburite, were injurious to health The trial comprised the chemical analysis of the air at the ”intake,” and of the vitiated air during the firing of the shots at the ”return,” and also of the smoky air in the vicinity of the shot-holes Five pounds and a half of roburite were used in twenty-three shots It had been asserted that the fumes from this explosive contained carbon-as could be discovered after the explosion On another occasion, however, when 47 lbs of roburite were exploded in twenty-three shots, the air at the ”return” showed traces of CO gas to the extent of 042 to 019 per cent

The medical report which Drs Hume and Druated every case of suspected illness produced by exposure to fu caused They say, ”No case of acute illness has, throughout the inquiry, been brought to our knowledge, and we are led to the conclusion that such cases have not occurred”

~Manufacture~--As now made, roburite is a mixture of ammonium nitrate and chlorinated di-nitro-benzol The nitrate of around, and then heated in a closed steam-jacketed vessel to a teanic compound is added, and the whole stirred until an inti, the yelloder is ready for use, and is stored in straight canisters orto the deliquescent nature of the nitrate of ammonia, the finished explosive must be kept out of contact with the air, and for this reason the cartridges are waterproofed by dipping them in melted wax

Roburite is lish Coan, which have been at work now for so started in 1888 These works are of considerable extent, covering 30 acres of ground, and are equal to an output of 10 tons a day A canal runs through the centre, separating the chemical from the explosive portions of the works, and the Lancashi+re and Yorkshi+re Railway runs up to the doors Besides sending large quantities of roburite itself abroad, the Company also export to the various colonies the two components, as manufactured in the chemical works, and which separately are quite non-explosive, and which, having arrived at their destination, can be easilythe special advantages claimed for roburite are:--First, that it is ie by percussion, fire, or electric sparks

If a cartridge or layer be struck with a heavy hae a explosive is not in the least affected, and no detonation whatever takes place If roburite be unpowder fired, the explosion si it in the least In fact, the only way to explode roburite is to detonate it by rareat safety for use in coalby detonation at a very low te is required when fired in the as possible, and not at all in a mixture of air and coal dust--a condition in which the use of gunpowder is highly dangerous

Mr WJ Orse, Nottinghaives the temperature of detonation of roburite as below 2,100 C, and of aelatine is as ard to the composition of the fumes formed by the explosion of roburite, Mr Orsman says: ”With certain safety explosives--roburite, for instance--an excess of the oxidising material is added, naen here causes a di decoen effectually prevents the foren”

The following table (A), also froives the composition of five proases for 10 gr an internal diameter of 5 inches

With respect to the influence of a the temperature of explosion of the various substances to which it is added, it was found by a French Commission that, when dry and finely powdered, a the heat of deco the power of the explosive below a useful li table (B) shows the composition of the explosives examined, and the temperatures which accompanied their explosion

A ______________________________________________________________________ | | | | | | | Composition of Gases | | |Volume |__________________________| | Explosive |of Gas | | | | | | |formed|CO_{2}| CO |CH_{4}| N | | | | | | &H | | |___________________________________|_______|_______|_____|______|_____| | | | | | | | | | | Per | Per | Per | Per | | | cc | cent |cent|cent |cent| |Gunpowder-- | | | | | | | Nitre 75 parts | | | | | | | Sulphur 10 '' | 2,214 | 513 | 35| 35 | 417| | Charcoal 15 '' | | | | | | |Gelignite-- | | | | | | | Nitro-glycerine 565 parts | | | | | | | Nitro-cotton 35 '' | 4,980 | 25 | 7 || 67 | | Wood-meal 80 '' | | | | | | | KNO_{3} 320 '' | | | | | | |Tonite-- | | | | | | | Nitro-Cotton | 3,750 | 30 | 8 || 62 | | Barium nitrate | | | | | | |Roburite-- | | | | | | | Ammonium nitrate, 86 parts | | | | | | | Di-nitro-chloro-benzol 14 '' | 4,780 | 32 ||| 68 | |Carbonite | | | | | | | Nitro-glycerine 25 parts | | | | | | | Wood-meal 40 '' | 2,100 | 19 | 15 | 26 || | Potas nitrate 34 '' | | | | | | |___________________________________|_______|_______|_____|______|_____|