Cooley's Cyclopaedia of Practical Receipts Volume Ii Part 130

_Uses._ The princ.i.p.al consumption of phosphorus is in the manufacture of lucifer matches. When swallowed, it acts as a powerful corrosive poison; but small doses of its ethereal and oily solutions are occasionally administered in cases of chronic debility, extreme prostration of the nervous powers, impotency, &c. Its action is that of a powerful diffusible stimulant and diuretic; it is also aphrodisiac. Its use requires great caution, and the effects must be narrowly watched. The treatment of poisoning by phosphorus consists of the administration of a powerful emetic and the copious use of mucilaginous drinks. The French pract.i.tioners recommend oil of turpentine as the most effective antidote.

They administer about a teaspoonful of the turpentine every four hours.

_Concluding Remarks._ From the great inflammability of phosphorus it can only be safely preserved under water. In commerce, it is always packed in tin cylinders filled with water, and soldered up air-tight. The leading points to be observed to ensure success in this manufacture are chiefly connected with the firing. The heat of the furnace should be most slowly raised at first, but afterwards equably maintained in a state of bright ignition. After 3 or 4 hours of steady firing, carbonic and sulphurous anhydride are evolved in considerable abundance, provided the materials had not been well dried in the iron pot; then sulphuretted hydrogen makes its appearance, and next phosphuretted hydrogen, which last should continue during the whole of the distillation. The firing should be regulated by the escape of this remarkable gas, which ought to be at the rate of about two bubbles per second. If the discharge comes to be intercepted, it is to be ascribed either to the temperature being too low, or to the retort getting cracked; and if, upon raising the heat sufficiently, no bubbles appear, it is a proof that the apparatus has become defective, and that it is needless to continue the operation. We may infer that the process approaches its conclusion by the increasing slowness with which the gas is disengaged under a powerful heat; and when it ceases to come over we may cease firing, taking care to prevent reflux of water into the retort (and consequent explosion), from condensation of its gaseous contents, by admitting air into it through a recurved gla.s.s tube, or through the tube of the copper adapter. The usual period of the operation, upon the great scale, is from 24 to 30 hours.

=Phosphorus, Amor'phous.= _Syn._ RED PHOSPHORUS, ALLOTROPIC PHOSPHORUS; PHOSPHORUS FUSCUS, P. RUBER. L. This is phosphorus in that peculiar condition to which Berzelius has applied the term "allotropic." The honour of its discovery is due to Dr Shrotter, of Vienna.

_Prep._ The ordinary phosphorus of commerce, rendered as dry as possible, is placed in a shallow vessel of hard and well-annealed Bohemian gla.s.s, fitted with a safety tube just dipping beneath the surface of a little hot water contained in an adjacent vessel; heat is then applied by means of a metallic bath (a mixture of lead and tin), the temperature of which is gradually raised until it ranges between 464 and 482 Fahr., and bubbles of gas escape from the end of the safety tube and catch fire as they come in contact with the air; this temperature is maintained until the amorphous condition is produced, the length of the exposure being regulated by a miniature operation with tubes conducted in the same bath; as soon as this point is reached, the apparatus is allowed to cool, and the amorphous phosphorus, which still contains some unconverted phosphorus, detached from the gla.s.s; it is then reduced to powder by careful trituration under water, drained on a calico filter, and, whilst still moist, spread thinly on shallow trays of iron or lead; in this state it is exposed, with frequent stirring, to heat in a chloride of calcium bath, at first gentle, and then gradually increased to its highest limit, and the heat continued until no more luminous vapour escapes; the residuum on the trays is then cooled, washed with water until this last ceases to affect test paper, and is, lastly, drained and dried. To render it absolutely free from unaltered phosphorus, it may be washed with bisulphide of carbon.

On the small scale, common phosphorus may be converted into amorphous phosphorus by simply exposing it for 50 or 60 hours to a temperature of about 473 Fahr., in any suitable vessel from which the air is kept excluded by a stream of carbonic acid, or any other gas which is unable to act chemically on the phosphorus.

By keeping common phosphorus fused at a high temperature, under the above conditions, for fully 8 days, compact ma.s.ses of amorphous phosphorus may be obtained.

_Prop., &c._ A reddish brown, infusible, inodorous, solid substance, which is reconverted into ordinary phosphorus by simply exposing it to a heat a little above 500 Fahr. It is unaltered by atmospheric air; is insoluble in bisulphide of carbon, alcohol, ether, or naphtha; is non-luminous in the dark below about 390 Fahr.; and does not take fire at a lower temperature than that necessary for its reconversion into the common or crystalline form. The sp. gr. ranges between 2089 to 2017, according to the method of preparing it. Its properties render it an admirable subst.i.tute for the common phosphorus in the composition for tipping matches, both as regards security from spontaneous ignition and the health of the manufacturers, who when exposed to the fumes of ordinary phosphorus, were very liable to be attacked with caries of the lower jaw.

=Phosphorus, Trichloride of.= PCl_{3}. _Syn._ PHOSPHORUS TERCHLORIDE, PHOSPHORUS CHLORIDE. By gently heating phosphorus, in excess, in dry chlorine gas; or by pa.s.sing the vapour of phosphorus through a stratum of powdered mercuric chloride, strongly heated in a gla.s.s tube. It is limpid, colourless, highly fetid, fumes in the air, and is slowly resolved by water into phosphorus acid and hydrochloric acid. Sp. gr. 145.

=Phosphorus, Pentachloride of.= PCl_{5}. _Syn._ PHOSPHORIC CHLORIDE, PERCHLORIDE OF PHOSPHORUS.

_Prep._ By the spontaneous combustion of phosphorus in an excess of dry chlorine; or by pa.s.sing a stream of dry chlorine into the liquid terchloride. By the first method it is obtained as a white crystalline sublimate; by the second, as a solid crystalline ma.s.s. It is volatile; water resolves it into phosphoric acid and hydrochloric acid.

=Phosphorus, Oxychloride of.= PCl_{3}O. _Syn._ PHOSPHORIC OXYCHLORIDE, PHOSPHORIC MONOXYCHLORIDE.

_Prep._ By heating pentachloride of phosphorus with a quant.i.ty of water insufficient to convert it into phosphoric acid. It is a colourless, fuming liquid, having the sp. gr. 17.

=Phosphorus, Hydride of.= PH_{3}. _Syn._ PHOSPh.o.r.eTTED HYDROGEN, PHOSPHURETTED HYDROGEN.

_Prep._ 1. Phosphorus acid is gently heated in a retort, and the first portion of the gas collected.

2. From phosphorus (in small lumps) boiled in a solution of hydrate of pota.s.sium or milk of lime, contained in a small retort, as before. Take a very small thin retort, capable of holding not more than 1 oz. or 1-1/2 oz. of water; place in this 3 or 4 fragments of the sticks of fused hydrate of pota.s.sium, each being about 1/2 inch in length; add as much water as will barely cover them, and then drop in a small fragment of phosphorus, about the size of a horse-bean; apply a very gentle heat with the small flame of a spirit lamp, agitating the retort continually. A pale lambent flame will first appear in the interior, and when this reaches the orifice, and burns in the open air, the retort should be placed on the stand with its beak about an inch under water. Care must be taken not to withdraw the flame of the lamp. When the bubbles of the gas rise to the surface they spontaneously inflame.

3. From phosphide of calcium and dilute hydrochloric acid, as above; or simply from the phosphide thrown into the water.

_Obs._ The gas obtained by methods 2 and 3 is contaminated with the vapour of a liquid phosphide of hydrogen, PH_{2}, which gives to it the property of spontaneous inflammability.

_Prop., &c._ Colourless; very fetid; slightly soluble in water; burns with a white flame; decomposed by light, heat, and strong acids; as commonly prepared, inflames on contact with air, at ordinary temperatures, but when pure, only at the heat of boiling water. Sp. gr. 124. It is rendered quite dry by standing over fused chloride of calcium.

=Phosphorus, Suboxide of.= P_{4}O. (Odling.) A reddish-brown powder, formed when a stream of oxygen is forced upon phosphorus, melted beneath the surface of hot water. To purify it from phosphoric acid and free phosphorus, it is washed on a filter with water, then dried by bibulous paper, and finally digested with bisulphide of carbon.

=Hypophosphorous Acid.= H_{3}PO_{2}. By cautiously decomposing a solution of hypophosphite of barium with sulphuric acid, filtering from the precipitate (sulphate of baryta), and evaporating. Dissolve hypophosphite of calcium, 480 gr. in distilled water, 6 fl. oz.; dissolve crystallised oxalic acid, 350 gr., in another portion of distilled water, 3 fl. oz.; mix the solutions and filter the mixture through white filtering paper.

Add distilled water carefully to the filtrate till it measures 10 fl. oz., and evaporate this to 8-1/2 fl. oz. The solution thus prepared contains about 10% of terhydrated hypophosphorous acid.

_Prop._ A viscid, uncrystallisable liquid having a strongly acid reaction.

It is a powerful drying agent, and forms salts called hypophosphites.

=Ammonium, Hypophosphite of.= (NH_{4})_{3}PO_{2}. _Prep._ Dissolve hypophosphite of calcium, 6 oz., in water, 4 pints; and dissolve translucent sesquicarbonate of ammonium, 723 oz. (barely 7-1/4), in water, 2 pints; mix the solutions; filter, washing out the solution retained by the carbonate of lime with water, q. s.; evaporate the filtrate to dryness with great care; dissolve it in alcohol, q. s.; filter, evaporate, and crystallise. Very soluble in both alcohol and water.

=Barium, Hyperphosphite of.= Ba_{3}(PO_{4})_{2}. _Prep._ Boil phosphorus in a solution of hydrate of barium (baryta water) till all the phosphorus disappears and the vapours have no longer a garlic odour. Filter, evaporate, and set aside to crystallise.

=Calcium, Hypophosphite of.= Ca_{3}(PO_{2})_{2}.

_Prep._ Slack recently burnt lime, 4 lbs., with water, 1 gall., and mix it with water, 4 galls., just brought to the boiling temperature in a deep open boiler, stirring until a uniform milk of lime is formed; then add phosphorus, 1 lb., and keep up the boiling constantly, adding hot water from time to time, so as to preserve the measure as nearly as may be until all the phosphorus is oxidised and combined, and the strong odour of the gas has disappeared; then filter the solution through muslin, wash out that portion retained by the calcareous residue with water, and evaporate the filtrate till reduced to 6 pints; re-filter, to remove a portion of carbonate of calcium resulting from the action of the air upon the solution; evaporate again until a pellicle forms, and set aside to crystallise--or continue the heat with constant stirring until the salt granulates.

_Obs._ As spontaneously inflammable phosphuretted hydrogen is given off during the boiling, the process must be conducted under a hood, with a strong draught or in the open air. Smaller proportions than those given may be used.

_Prop._ Hypophosphite of calcium is a white salt, with pearly l.u.s.tre, crystallising in flattened prisms; soluble in 6 parts of cold water, and slightly soluble in dilute alcohol. It is the most important of these compounds, and when introduced into the stomach it is supposed to be converted into phosphate of calcium. It has been termed 'chemical food.'

By decomposition it readily furnishes the other hypophosphites.

=Ferric, Hyperphosphite of.= FePO_{2}. _Prep._ By precipitating a solution of hypophosphite of sodium or ammonium, with solution of ferric sulphate, washing the gelatinous precipitate with care (it being somewhat soluble); and, finally, drying it into an amorphous white powder. This is freely soluble in hydrochloric and hypophosphorous acids.

=Pota.s.sium, Hypophosphite of.= K_{3}PO_{2}. _Prep._ From hypophosphite of calcium, 6 oz., dissolved in water, 4 pints; and granulated carbonate of pota.s.sium, 5-3/4 oz., dissolved in water, 1/2 pint. Mix, filter, and wash the precipitate till the filtrate measures 5 pints. Evaporate till a pellicle forms, then stir constantly, continuing the heat till the salt granulates. A white, opaque, deliquescent body, very soluble in water and alcohol.

=Quinine, Hypophosphite of.= Dissolve sulphate of quinine, 1 oz., in water, by the aid of diluted sulphuric acid; precipitate the alkaloid with ammonia; wash the precipitated quinine and digest it in hypophosphorous acid with heat (the quinine being in excess); after filtering the solution, allow it to evaporate spontaneously till the required salt crystallises. It forms elegant tufts of soft, feathery crystals, which are soluble in 60 parts of water.

=Sodium, Hypophosphite of.= Na_{3}PO_{2}. _Prep._ From hypophosphite of calcium, 6 oz., dissolved in water, 4 pints; and crystallised carbonate of sodium, 10 oz., dissolved in water, 1-1/2 pint. Proceed as in making hypophosphite of pota.s.sium, but allowing 6 pints as the measure of the filtrate. If required in crystals, the granulated salt may be dissolved in alcohol sp. gr. 835, evaporated till syrupy, and set by in a warm place.

Crystallises in rectangular tables, with a pearly l.u.s.tre; is very soluble in water and ordinary alcohol, and deliquesces when exposed to the air.

=Phosphorus, Trioxide of.= P_{2}O_{3}. _Syn._ PHOSPHOROUS ANHYDRIDE; ANHYDROUS PHOSPHORIC ACID.

_Prep._ By burning phosphorus in a limited supply of air. White flaky powder, with an odour of garlic, and rapidly absorbing water to form phosphorous acid.

=Phosphorous Acid.= H_{3}PO_{3}. _Syn._ HYDRATED PHOSPHOROUS ACID. Pure phosphorus is volatilised through a layer of powdered mercuric chloride, contained in a gla.s.s tube; terchloride of phosphorus comes over, which, on being mixed with water, is resolved into hydrochloric acid and phosphorous acid; by evaporating the mixed liquid to the consistence of a syrup, the first is expelled, and the residuum forms a crystalline ma.s.s of hydrated phosphorous acid on cooling.

_Prop., &c._ It is a powerful deoxidising agent. Heated in a closed vessel, it is resolved into hydrated phosphoric acid and pure phosphuretted hydrogen gas. With the bases it forms salts, called phosphites, which possess little practical importance.

=Phosphorous Pentoxide Acid.= P_{2}O_{5}. _Syn._ ANHYDROUS PHOSPHORIC ACID; PHOSPHORIC ANHYDRIDE; PHOSPHORIC OXIDE. By the vivid combustion of phosphorus in a stream of dry atmospheric air, or under a bell-jar, copiously supplied with dry air. The product is pure anhydrous phosphoric acid under the form of snow-like flakes. It must be immediately collected and put into a warm, dry, well-stoppered bottle. In this state it exhibits an intense attraction for water, and when thrown into it combines with explosive violence; exposed to moist air for only a few seconds, it deliquesces to a syrupy-looking liquid.

=Phosphoric Acid.= There are three distinct acids usually grouped under this head, namely, METAPHOSPHORIC ACID, HPO_{3}; PYROPHOSPHORIC ACID, H_{4}P_{4}O_{7}; and ORTHOPHOSPHORIC ACID, H_{3}PO_{4}.

=Metaphosphoric Acid.= HPO_{3}. _Syn._ MOn.o.bASIC PHOSPHORIC ACID; GLACIAL PHOSPHORIC ACID.

_Prep._ Bones (calcined to whiteness and powdered), 3 parts, are digested for several days in oil of vitriol, 2 parts, previously diluted with water, 6 parts, the mixture being frequently stirred during the time; a large quant.i.ty of water is next added, the whole thrown in a strainer, and the residual matter washed with some hot water; the mixed liquors are then precipitated with a solution of carbonate of ammonium, in slight excess, filtered from the insoluble, finally ignited in a platinum crucible.

By acting upon the anhydride with cold water.

When phosphoric acid is added to a strong solution of phosphate of zirconium, and the mixture, after concentration, is exposed to a low temperature, prismatic crystals are deposited. These, after being strongly heated to expel their basic water, are pure metaphosphate of sodium. From the solution of this salt in cold water, a solution of pure metaphosphoric acid may be obtained, as above, by means of nitrate or acetate of lead and sulphuretted hydrogen.

_Obs._ This acid precipitates the salts of silver white, and is distinguished from the other modifications of phosphoric acid by the property which its solution possesses of coagulating alb.u.men.

=Pyrophosphoric Acid.= H_{4}P_{2}O_{7}. _Syn._ DIBASIC PHOSPHORIC ACID. By strongly heating common orthophosphate of sodium. The water of crystallisation only is at first expelled, and the salt becomes anhydrous; but as the temperature reaches that of redness the salt loses water and is decomposed. By solution of the altered salt in water, crystals of pyrophosphate of sodium may be obtained. A solution of this last compound, treated with nitrate of lead, and the resulting precipitate, suspended in cold water, and decomposed by sulphuretted hydrogen, yields a solution of pure pyrophosphoric acid.

_Obs._ Heat resolves this into a solution of the ordinary acid.

Pyrophosphoric acid precipitates the salts of silver of a white colour.

The salts of this acid are called pyrophosphates.

=Orthophosphoric Acid.= H_{3}PO_{4}. _Syn._ TRIHYDRIC PHOSPHATE, TRIBASIC PHOSPHORIC ACID. Ordinary nitric acid is heated in a tubulated retort connected with a receiver, and small fragments of phosphorus are dropped into it, singly and at intervals; as soon as the oxygenation of the phosphorus is complete, the heat is increased, the undecomposed acid distilled off, and the residuum evaporated to the consistence of a syrup.

In this state it forms the phosphoric acid of the shops. Commercial phosphate of sodium is dissolved in water and the solution precipitated with another of acetate of lead; an abundant white precipitate (phosphate of lead) falls; this is collected on a filter, well washed, and, whilst still moist, is suspended in distilled water, and sulphuretted hydrogen gas pa.s.sed into it, in excess; a black insoluble precipitate forms, while pure tribasic phosphoric acid remains in solution, and is easily deprived of the residual sulphuretted hydrogen by a gentle heat. By concentration _in vacuo_ over sulphuric acid, it may be obtained in thin crystalline plates.

The solution of this acid may be boiled without change, but when concentrated and heated to about 400 Fahr. it is converted into pyrophosphoric acid, and at a red heat into metaphosphoric acid. Its salts are the ordinary phosphates, or orthophosphates, and they give a yellow precipitate with nitrate of silver.