Cooley's Cyclopaedia of Practical Receipts Volume I Part 142

In the more recently made decomposers we believe the nine towers were abolished, and one chamber subst.i.tuted for them, the drain-pipes being at the same time abandoned for pieces of brick and clay marbles.

A decomposer upon this latter principle is said to have been in use for several months at a factory in Berlin, and to have worked perfectly satisfactorily. After leaving the decomposer, the gaseous mixture, which now consists of chlorine, water, nitrogen, unconsumed oxygen, and undecomposed hydrochloric acid, after being cooled, is pa.s.sed through water, by which means it is deprived of its hydrochloric acid.

It is next made to ascend a tower, where, meeting with a stream of sulphuric acid running over c.o.ke, it is deprived of its water. The chlorine (diluted with nitrogen and oxygen) is now ready for the lime chamber.

One great objection urged against the adoption of the above process, viz., that in consequence of the large volume of the evolved gases enormously large chambers for the preparation of the bleaching would be necessitated, seems to have been met by pa.s.sing the gas through a series of chambers, in which the first contains nearly finished bleaching powder; the second, lime in a less saturated condition; and so on, until the last chamber contains merely slaked lime.

The following table, exhibiting the amount of chlorine contained in different batches of bleaching powder made by Deacon's process, is extracted from 'Chemistry, Theoretical, Practical, and a.n.a.lytical,'

published by Mackenzie:--

----------+-----------+----------+----------- Strength. Strength.

----------+-----------+----------+----------- July 14 360 July 22 343 " 15 348 " " 365 " " 361 " 24 368 " 17 364 " " 375 " " 360 " 25 361 " 18 372 " " 367 " " 379 " " 368 " 19 372 " 26 362 " " 370 " " 369 " 20 379 " 27 369 " " 367 " " 355 " 21 360 " 28 372 " " 353 " " 370 " " 377 " " 3675 ----------+-----------+----------+-----------

Writing on this process in his late work, 'The Alkali Trade,' Mr Kingzett says:--"The process bearing Mr Deacon's name was first brought before the public at the British a.s.sociation Meeting in 1870.

"It excited at that time much attention, and indeed for some period it was doubtful whether it would not rival or even displace the Weldon process.

Further experience, however, discovered difficulties in the practical working of this beautiful method, which exercise a deteriorating influence on its value, and lessen its applicability. Although several plants have been erected in connection with this mode of manufacturing chlorine, most of them have been since abandoned, and at the present time most of the chlorine is manufactured according to the process of Mr Weldon."

Dr Jurisch, in a communication to 'Dingler's Polytechnic Journal,' 1876, remarks that when Deacon's process was first taken up within a short time by more than twelve English and two German establishments, the view was generally entertained that the b.a.l.l.s of clay steeped in solution of copper would ensure an uninterrupted production of chlorine gas for a year or two, if not longer. Before many months had elapsed complaints were heard of the action of the b.a.l.l.s. He, therefore, undertook to determine what can be the cause of these b.a.l.l.s declining so rapidly in their efficacy. His conclusion is, that the true cause of this speedy decrease in the decomposition is due to sulphuric acid, which pa.s.ses through the interstices of the clay-b.a.l.l.s mixed with the other gases. This injurious action, according to Hasenclever and Sartori, is probably to be explained by the following reaction:--The vapour of sulphuric acid in contact with sulphate of alumina at a dull red-heat, as is found in the b.a.l.l.s, is resolved into sulphurous acid, watery vapour, and oxygen; the sulphurous acid thus formed is reoxidised at the expense of the free chlorine, is again decomposed, and thus keeps up a destructive circulation in the apparatus, which reduces or totally checks the chlorine.[244]

[Footnote 244: Extracted from the 'Chemical News.']

_Prices of Bleaching Powder_ (CLAPHAM).

In 1805 120 0 0 per ton.

" 1810 84 0 0 "

" 1815 80 0 0 "

" 1820 47 0 0 "

" 1825 27 0 0 "

" 1830 23 0 0 "

" 1832 21 0 0 "

" 1835 23 0 0 "

" 1840 21 0 0 "

" 1846 18 0 0 "

" 1850 13 15 0 "

" 1855 10 15 0 "

" 1857 13 10 0 "

" 1860 11 0 0 "

" 1868 10 12 0 "

_Prop., Uses, &c._ 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 2-1/2 heavier than atmospheric air; sp. gr. 147. 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 a.r.s.enic, and several other substances thrown into chlorine immediately inflame. Under a pressure of 4 atmospheres it is condensed into a yellow, limpid liquid. Moist chlorine gas cooled to 32 Fahr.

condenses into yellow crystals, containing 35-1/2 parts of chlorine and 90 parts of water. The most remarkable property of chlorine is its power of destroying almost all vegetable and animal colours, and the putrid odour of decomposing organic matter; hence its value as a bleaching agent, and as a disinfectant and fumigator. When first proposed as a bleaching agent by Berthollet, it was used much the same way as sulphur is now in bleaching woollen goods; afterwards a solution of the gas in water was employed, but the final improvement was Tennant's patent of combining the gas with lime to form "chloride of lime." With the bases chlorine forms an important series of compounds called chlorides.

_Tests._ Free chlorine is readily distinguished from other gases by its colour, suffocating odour, and bleaching properties. The aqueous solution dissolves gold leaf, and with nitrate of silver gives a white, curdy precipitate.

=CHLORINE STILLS.= The accompanying figure represents a section of one of the earlier forms of still used in the preparation of chlorine.

[Ill.u.s.tration: FIG. 1.]

These stills were sometimes made of strong sheet lead, the lower part of which was enclosed in a jacket of cast iron, into which steam was forced, by which means the contents of the still were heated. The steam was injected from an ordinary boiler through the pipe H, and the materials, after the decomposition had been completed, were drawn off by the pipe G.

The four openings, C, D, E, F, were secured by water lutes, capable of bearing a pressure greater than that required in the chamber where the saturation took place. In some cases the lower half of the still was made of cast iron, and fitted into a groove made in the upper part, the two sections being united by means of a strong cement. In the latter case the heating of the still was effected by a naked fire applied to the bottom.

Into the orifice C the said materials employed were introduced, whilst the acid was poured through the opening F. The gas evolved pa.s.sed off through the pipe E to the purifier and chamber, where it was absorbed by the lime, and converted into bleaching powder, and the shaft of the agitator pa.s.sed up through D.

The use of the leaden stills survived for a longer time in France than in this country. In some parts of Germany large gla.s.s globes with long necks were employed, in which the chlorine was generated from a mixture of hydrochloric acid and manganese. But these were only applicable in cases where comparatively small quant.i.ties of bleaching powder were to be manufactured. When the chlorine is obtained from a mixture of manganese, common salt, and sulphuric acid, the apparatus, being required to withstand a greater heat, is made entirely of metal.

[Ill.u.s.tration: FIG. 2.]

In fig. 2. _a a_ represents a shallow iron pan, fitted with the tube _b_, for the purpose of emptying the contents of the leaden cylinder _d d_.

This iron vessel serves as the lower part of the cylinder _d d_, the top of which is provided with an opening for a funnel syphon tube, for the introduction of the acid, and another opening, _f_, for the manganese. The entire apparatus stands on a flue leading from the furnace.

[Ill.u.s.tration: FIG. 3.]

The foregoing drawing represents a vessel for the manufacture of chlorine on a large scale, and is extensively used in Germany.

It consists of a cylindrical vessel of sandstone, the lower half of which, A, is carved out of a single block; the upper half, B, also of one piece, fits into the lower by means of a grooved joint, the two parts being united by means of a cement made of clay and boiled linseed oil. About six inches from the bottom the cylinder widens by 2 inches, and the rim thus formed carries a perforated bottom, C, upon which the manganese is deposited in large lumps. The tube D, likewise of stone, pa.s.ses beneath the perforated bottom, and is at the other end joined to the steam-tube E.

The steam must therefore, when introduced, enter the cylinder through the perforations of the false bottom. The top of the cylinder is closed by a lead cover, K, which is fastened down by means of iron clamps; this lid has an aperture, G, and the tubes E, F, H, pa.s.s through it; tube E serves, as already stated, for the introduction of the steam; tube F is for the delivery of chlorine; the bent tube, H, which ends in a funnel, for the introduction of the hydrochloric acid; and the opening G for throwing the lumps of manganese into the cylinder. The solution of manganese chloride, resulting from the action of the hydrochloric acid upon the manganese, is removed through I, which is kept closed by a wooden stopper whilst the reaction proceeds.

See also, under CHLORINE, the description of WELDON'S stills, and of DEACON'S apparatus.

=CHLORITE.= A salt in which the hydrogen of chlorous acid, HClO_{2}, is replaced by a metal or other basic radical. See CHLOROUS ACID.

=CHLOROCHROMIC ACID.= CrOCl. _Syn._ CHLOROCHROMIC ANHYDRIDE. _Prep._ Bichromate of pota.s.sium, 3 parts; common salt, 3-1/2 parts; are intimately mixed together, put into a gla.s.s retort, and oil of vitriol, 9 parts, added; heat is next applied and maintained as long as dense, red vapours are given off. The product in the receiver is a heavy, deep-red liquor, greatly resembling bromine in appearance. Water resolves it into hydrochloric and chromic anhydride.

=CHLORODYNE.= See PATENT MEDICINES.

=Chlorodyne= (Dr Browne's). Acid muriat. conc., 5 parts; ether, chloroform, tinct. cannab. Ind., tinct. capsici, of each 10 parts; morphia, prussic acid, of each 2 parts; oil of peppermint, 1 part; syrup, 50 parts; tinct. hyoscyami, tinct. aconiti, of each 3 parts.

=Chlorodyne, English.= A filtered mixture of 5 grammes tinct. aromat., 4 grammes tinct. opii simp., 1 gramme morph. mur., 10 grammes aq. amygd.

amar., 80 grammes syrup of liquorice, 1 gramme extract of liquorice, 40 grammes 90 per cent. spirit of wine, 5 drops oil of peppermint, 10 drops ether, 30 drops chloroform.

=CHLOROFORM.= CHCl_{3}. _Syn._ TERCHLORIDE OF FORMYLE, FORMYL-CHLORIDE; CHLOROFORMYL, TRICHLOROMETHANE, CHLOROFORMUM, L. A remarkable fluid discovered by Liebig in 1830, and independently by Soubeiran in 1832, and carefully examined in 1834 by Dumas. In 1842 its action upon animals was investigated by Dr M. Glover, and in 1847 it was introduced to the medical profession as an anaesthetic agent by Dr Simpson of Edinburgh.

It was first obtained by the action of caustic alkali upon chloral, but it is more easily prepared by distilling alcohol or wood spirit with chloride of lime. It may also be procured from wood spirit, acetone, oil of turpentine, and several essential oils, as well as from amylic alcohol, acetic acid, tartaric acid, and phenol; when these different bodies are severally subjected to the action of chloride of lime. When chlorine is made to act on marsh gas, or when chloral is treated with an alkali, chloroform is also produced.

_Prep._ 1. Chloride of lime (in powder), 4 lbs.; water, 12 lbs.; mix in a capacious retort or still, add of rectified spirit, 12 fl. oz., and cautiously distil as long as a dense liquid, which sinks in the water it pa.s.ses over with, is produced; separate this from the water, agitate it with a little sulphuric acid, and, lastly, rectify it from carbonate of barium.

2. Chloride of lime, 4 lbs.; water, 10 pints; rectified spirit, 1/2 pint; proceed as last, using a s.p.a.cious retort that the mixture will only 1-3rd fill, and the heat of a sand bath. When ebullition commences remove the fire as quickly as possible, lest the retort be broken by the suddenly increased heat, and let the solution distil into a receiver as long as there is nothing which subsides, the heat being restored if it be at all needed. Add to the distilled liquid four times as much water, and shake the whole well together; next cautiously separate the heavier part as soon as it has subsided, and to this add chloride of calcium, broken into fragments, 1 dr.; and shake occasionally during an hour; finally, let the fluid again distil from a gla.s.s retort into a gla.s.s receiver.

3. Hydrate of lime, 1 part, is suspended in cold water, 24 parts, and chlorine pa.s.sed through the mixture until nearly the whole of the lime is dissolved; hydrate of lime, q. s. just to restore the alkaline reaction of the liquid, is then added; and, afterwards, rectified spirit of wine or wood spirit, 1 part, is mixed in; the whole, after repose for 24 hours in a covered vessel, is cautiously distilled as before.

4. (B. P.) Take of chlorinated lime 10 _lbs._; rectified spirit, 30 fluid ounces; slaked lime, a sufficient quant.i.ty; water, 3 gallons; sulphuric acid, a sufficient quant.i.ty; chloride of calcium in small fragments 2 _oz._; distilled water, 10 fluid ounces. Place the water and the spirit in a capacious still, and raise the mixture to a temperature of 100 F. Add the chlorinated lime, and 5 _lbs._ of the slaked lime, mixing thoroughly.

Connect the still with a condensing worm, encompa.s.sed by cold water, and terminating in a narrow-necked receiver; and apply heat so as to cause distillation, taking care to withdraw the fire the moment that the process is well established. When the distilled product measures 50 fluid ounces the receiver is to be withdrawn. Pour its contents into a gallon bottle, half filled with water; mix well by shaking, and set it at rest for a few minutes, when the mixture will separate into two strata of different densities. Let the lower stratum, which contains crude chloroform, be washed by agitating it in a bottle with 3 fluid ounces of the distilled water. Allow the chloroform to subside, withdraw the water, and repeat the washing with the rest of the distilled water, in successive quant.i.ties of 3 oz. at a time. Agitate the washed chloroform for five minutes in a bottle with equal volume of sulphuric acid, allow the mixture to settle, and transfer the upper stratum of liquid to a flask, containing the chloride of calcium, mixed with 1/2 oz. of slaked lime, which should be perfectly dry. Mix well by agitation. After the lapse of an hour connect the flask with a Liebig condenser, and distil over the pure chloroform by means of a water bath. Preserve the product in a cool place in a bottle furnished with an accurately ground stopper. The lighter liquid which floats on the crude chloroform after its agitation with water, and the washings with distilled water, should be preserved and employed in a subsequent operation. Sp. gr. 1456.

_Prop., &c._ Liquid; transparent; colourless; odour fragrant, ethereal, and apple-like; taste ethereal, sweetish, but slightly acrid; soluble in 2000 parts of water; mixes in all proportions with alcohol and ether; dissolves (readily) bromine, camphor, caoutchouc, gutta percha, iodine, oils, resins, wax, and several other like substances; boils at 1418 Fahr.; kindles with difficulty; burns, when strongly heated, with a greenish flame; and communicates a dull, smoky-yellow colour to the flame of alcohol. Sp. gr. 148 (1497, Miller); density of vapour 42. The vapour has the remarkable property of rendering a person breathing it temporarily insensible to pain.

Chloroform is frequently adulterated with alcohol and ether; and owing to careless manipulation, is also sometimes contaminated with other substances, as chloral, hydrochloric acid, free chlorine, aldehyde and certain chlorinated oils. These latter compounds are not only the most objectionable and prejudicial of the impurities found in chloroform, but if present in it to any appreciable extent, they render its anaesthetic administration not only inefficient, but frequently absolutely dangerous.

These deleterious chlorinated oily compounds may be removed by agitation with strong sulphuric acid, or by distillation from it. Chloroform made from wood spirit is said to be more impure than that from alcohol. When pure it is free from colour, and of a pleasant odour. It is not perfectly soluble in water; and does not turn the colour of litmus red. Rubbed on the skin it quickly evaporates, scarcely leaving any odour. Dropped into water, it falls to the bottom and remains bright and limpid; but if it contain alcohol the surface of the drop becomes opaline. If the same experiment be made with diluted sulphuric acid, sp. gr. 144, the drop of pure chloroform will fall to the bottom; but that which contains spirit, if not shaken, will float or remain suspended in the acid solution. When contaminated with heavy hydrocarbon oils, a drop evaporated from the palm of the hand leaves behind a strong smell. Hydrochloric acid and free chlorine are detected by the ordinary tests.