Chlorine gas

“ Rolling down upon the American and French battlelines, coming out of the German trenches, where it had been generated as soon as it was noted that the wind was right, drifted a cloud of greenish yellow, choking chlorine gas.
Chlorine gas is made by the action of sulphuric acid and manganese dioxide on common salt. It has a peculiar corrosive effect on the nose, throat and lungs, and is most deadly in its effect. It is a heavy gas, and instead of rising, as does hydrogen, one of the lightest of gases, it falls to the ground, thus making it dangerously effective for the Huns. ”

“ Chlorine gas is conducted by a wide tube into a moderately strong and warm solution of hydrate or carbonate of potassium, until the absorption of the gas ceases and the alkali is completely neutralised; the liquid is then kept at the boiling temperature for a few minutes, after which it is gently evaporated (if necessary) until a pellicle forms on the surface, and is next set aside, so as to cool very slowly; the crystals, thus obtained, are drained and carefully washed on a filter, with ice-cold water, and are purified by re-solution and re-crystallisation. ”

“ The chlorine is generally combined with lime to make chloride of lime or bleaching powder. In the chemical works of Germany the amalgamation of chlorine and lime was omitted, the chlorine being liquified under pressure in tanks. This liquid chlorine was a cheap preparation used largely for bleaching linens and cloth of various kinds manufactured in the districts in which we were fighting. The bleacheries were silent and there was no longer any use in the cloth industry for the German chlorine gas, so the Germans having plenty of it on hand no doubt decided to use it against the Allies. ”

“ Water recently boiled will absorb, if cold, about twice its bulk of chlorine gas, acquiring its color and characteristic properties. The moist gas, exposed to a cold of 32 deg., yields beautiful yellow crystals, which are a definite compound of one equivalent of chlorine and ten of water. If these crystals are hermetically sealed up in a glass tube, they will, on melting, exert such a pressure as to liquefy a portion of the gas, which is distinctly seen as a yellow fluid, not miscible with the water which is present. ”

“ It is extremely unstable, decomposing with extreme violence on the slightest shock or disturbance, or on exposure to sunlight. It is readily soluble in water, with which it combines to form hypochlorous acid. Sulphur, phosphorus, carbon compounds, and the alkali metals react violently with the gas, taking fire with explosive decomposition. A. J. Balard determined the volume composition of the gas by decomposition over mercury on gentle warming, followed by the absorption of the chlorine produced with potassium hydroxide, and then measured the residual oxygen. ”

“ The possibility of injury is naturally greater from the concentrated gas prepared by the Weldon process than from the diluted gas of the Deacon process—the more so as in the latter the bleaching powder is made in the Hasenclever closed-in cylindrical apparatus in which the chlorine is completely taken up by the lime. The safest process of all is the electrolytic, as, if properly arranged, there should be no escape of chlorine gas. ”

“ At ordinary temperatures it unites directly with many other elements; thus with hydrogen, combination takes place in direct sunlight with explosive violence; arsenic, antimony, thin copper foil and phosphorus take fire in an atmosphere of chlorine, forming the corresponding chlorides. Many compounds containing hydrogen are readily decomposed by the gas; for example, a piece of paper dipped in turpentine inflames in an atmosphere of chlorine, producing hydrochloric acid and a copious deposit of soot; a lighted taper burns in chlorine with a dull smoky flame. ”

“ As a disinfectant, chlorine was first used about the year 1800 by de Morveau, in France, and by Cruikshank, in England, who prepared the gas by heating a mixture of hydrochloric acid and potassium bichromate or pyrolusite; this is essentially the same as the original mixture used by Scheele. ”

“ In air saturated with moisture micro-organisms were killed by 0.3 per cent of chlorine in three hours but when the air was dry practically no action occurred. They concluded that chlorine was not directly toxic. Warouzoff, Winogradoff, and Kolessnikoff [2] were unable to confirm the results of Fischer and Proskauer and found that a mixture of chlorine gas and air killed tetanus spores in one minute. ”

“ Dichloramine is unknown but nitrogen chloride has been prepared and is a highly explosive yellow oil that decomposes slowly when kept under water in the ice box. NCl3 can be easily prepared by passing chlorine gas into a solution of ammonium chloride and this process would suggest that a method might be found of utilising chlorine and ammonia as gases for the production of nitrogen trichloride as a germicide for water chlorination. ”

“ Ammonia, when added to solutions of chlorine gas, diminishes the property of liberating iodine from potassium iodide, the bleaching effect on dyestuffs, and the germicidal action. It is often assumed that chlorine forms hypochlorous acid on solution in water Cl2 + H2O = HClO + HCl but the results obtained on the addition of ammonia indicate that either very little hypochlorous acid is formed or that ammonia and hypochlorous acid do not form chloramine in the presence of hydrochloric acid. ”

“ Chlorine is a gas possessing a yellowish-green colour, and a pungent, suffocating odour. It is one of the heaviest substances that are gaseous at ordinary temperatures, being nearly 21⁄2 heavier than atmospheric air; sp. gr. 1·47. It is soluble to a considerable extent in water, that liquid at 60° Fahr. absorbing about twice its volume. It is non-inflammable, but its union with some of the elements is attended with the phenomena of combustion; thus, phosphorus, copper leaf, powdered antimony and arsenic, and several other substances thrown into chlorine immediately inflame. ”

“ The inhalation of air, mixed with very little chlorine gas, has also been recommended. Wells, cellars, or other underground apartments, containing carbonic acid in poisonous quantities, may be freed from this gas by pumping it out in the same way as water, observing to allow the suction hose to fully reach the floor or bottom of the place. Fresh slaked lime or milk of lime, copiously thrown in, will have a like effect, by absorbing the gas. Free ventilation, whenever it can be established, is, however, not only the cheapest, but the most efficient remedy. ”

“ Liquid chlorine practically eliminates all labour costs because of the simplicity of the apparatus and the concentrated form of the sterilising agent. The apparatus is so compact that all the cylinders and regulating apparatus required for delivering 200 pounds of gas per day can be placed in an area of about 50 square feet and it can consequently be almost invariably accommodated in locations where the trifling amount of attention required can be obtained without extra cost. ”

“ The result gives sulphate of soda and hydrochloric acid. This acid is procured in soda manufactories, and with nitric acid is called “aqua regia,” a solvent for gold. When chlorine and hydrogen are mixed in equal proportions they explode in sunlight. In the dark or by candle-light they are harmless. Dry chlorine gas can be obtained by interposing a glass filled with some chloride of calcium. The gas being heavier than air (about 21⁄2 times) , displaces it in the flask, and when it is filled another can be placed in position. This mode causes a little waste of gas, which should not be breathed. ”

“ It is tasteless, colourless and odourless gas, which is exceedingly stable and inert. It may be condensed and yields a solid which melts at -55° C. Sulphuretted hydrogen decomposes it with formation of hydrofluoric acid and liberation of sulphur. Sulphur chloride, S2Cl2, is obtained as a by-product in the manufacture of carbon tetrachloride from carbon bi sulphide and chlorine, and may also be prepared on the small scale by distilling sul hur in a chlorine gas, or by the action of sulp-hur on sulphuryl ciiloride in the presence of aluminium chloride (O. Ruff) . ”

“ Dry 98 per cent gaseous chlorine, as obtained directly from the cells of the chlorine plant, and pure carbon monoxide obtained from the producers, are mixed in approximate equal volumes and the mixture passed through catalyzers, where the two gases combine to form phosgene. The resultant gas is liquefied in the condensers, appearing in the left. ”

“ That means, that chlorine, at 18° and of atmospheric pressure, would be in equilibrium with chloride-ion of the concentration given. Since chlorine, at this temperature and pressure, has a concentration of 1 / 23.9 moles (at 18°, one mole is contained in 23.9 liters, instead of in 22.4 liters, at O°) , we have for the condition of equilibrium: [Cl−] 2 : [Cl2] = (2.88E29) 2 : (1 / 23.9) = 2E60. [Cl2] represents, thus, in the calculation of this constant, the concentration of chlorine gas (see Chapter XV concerning gas electrodes) and not the concentration of the dissolved chlorine ”

“ There is one more fact of a chemical nature in reference to chlorine which it would be unwise to throw aside, as it possesses some degree of interest. When the chemist wishes to decompose water, or in other words to liberate hydrogen from oxygen, he has no better agent to effect the purpose than this greenish-coloured gas, because it has such a strong affinity for hydrogen, which is one of the most characteristic properties of chlorine. Mix them together, and they combine with explosive violence if they are exposed to27 the beams of the sun. ”

“ When heated to a temperature of 245 deg. C. in a stream of chlorine gas it becomes incandescent, forming calcium chloride and liberating carbon, and it can also be made to burn in oxygen at a dull red heat, leaving behind a residue of calcium carbonate. Under the same conditions it becomes incandescent in the vapour of sulphur, yielding calcium sulphide and carbon disulphide; the vapour of phosphorus will also unite with it at a red heat. Acted upon by water it is at once decomposed, yielding acetylene and calcium hydrate. ”

“ For small installations only one cylinder is necessary but it is always preferable to connect more than one. When the flow of gas is rapid the temperature of the liquid chlorine falls and reduces the pressure. ”

“ The chlorine leaves the furnace mixed with much hydrochloric acid, nitrogen, and air. The gaseous mixture is drawn by a chimney draught through the coke towers, as in the making of salt-cake. By this contrivance the hydrochloric acid is recovered, yielding a solution strong enough to react upon fresh manganese in the still. The diluted chlorine may be made to ascend leaden towers, where it comes in contact with a shower of milk of lime, which absorbs the gas and forms ordinary bleaching liquid, whilst sometimes it is employed in the production of potassium chlorate. ”

“ One machine will deliver up to 200 pounds of gas per day, an amount sufficient to treat 60,000,000 U. S. A. gallons (50,000,000 Imp. gals.) at 0.40 p.p.m. of available chlorine. Unless duplicate machines are installed for the higher rates, the first cost is inversely proportional, though not directly so, to the volume of water treated. It is in all cases less than the first cost of a bleach plant of equal capacity, accuracy, and durability.
(6) Liquid chlorine installations usually tend to produce [99] less complaints as to tastes and odours. ”

“ The fresh lime is continually charged into the top cylinder, is gradually moved towards the other end, falls down into the next lower cylinder and thus gradually makes its way to the lowest cylinder. The weak chlorine gas from the Deacon apparatus travels precisely the opposite way, from the bottom upwards, the result being that finished bleaching-powder is continually discharged at the bottom and air free from chlorine leaves the apparatus at the top. ”

“ He turned both wires into the pipe leading into his fan system. He was evolving large quantities of chlorine gas from the salt in the water, and this is equally explosive when in contact with hydrogen, not only from sparks, but from strong light. ”

“ With chlorine, hydrogen forms a compound called muriatic, or hydrochloric acid gas. It cannot easily be formed by the direct union of its elements, but is procured from some compound in which it exists ready formed. Common salt (chloride of sodium) is generally employed; and when acted on by strong [41] sulphuric acid (or oil of vitriol) , the gas is disengaged in abundance. It must be collected over mercury, for water absorbs it, forming the liquid muriatic, or hydrochloric acid.
A lighted taper plunged into this gas is instantly extinguished. It is very dangerous to animal life if respired. ”

“ It is eminently noxious to animal life, and, if breathed in its undiluted state, would prove instantly fatal. It supports the combustion of many bodies, and indeed spontaneously burns several without their being previously kindled. The resulting combinations are called chlorides, and act most important parts in many manufacturing processes.
Water absorbs, at the ordinary temperature of the atmosphere, about double its volume of chlorine, and acquires the colour, smell, and taste of the gas, as well as its power of destroying or bleaching vegetable colours. ”

“ The danger of gas leakages can be eliminated by placing the apparatus in a small separate room provided with a fan and a ventilation duct. By the liberal use of glass in the construction of the room, the operation of the plant can be seen at all times without entering the chamber.
A portion of the liquid chlorine apparatus is made of glass and is consequently easily fractured. Duplicates of the glass parts should be kept in stock to prevent interrupting the supply of gas; a duplicate machine is also advisable in large installations. ”