Cooley's Cyclopaedia of Practical Receipts Volume I Part 86

=BELLADONNINE.= _Syn._ ATROPIA, which see.

=BELL'Y= (-e). The abdomen (which _see_).

=BELTS.= In their connection with health and disease, _see_ BANDAGE, DRESS, STAYS, &c.

=BENEDICTINE'S HEALING-PLASTER= (Hauber). 35 grammes of a dark brown plaster, prepared by digesting together 1 part litharge with 2 parts olive oil until they become blackish-brown, then adding 4 parts yellow wax, containing the heat for a short time, and then pouring out. (Wittstein.)

=BENGAL'= (-gawl'). A thin fabric of silk and hair interwoven, originally from Bengal.

=Ben'gal Light.= A firework used as signals. See FIRES (coloured).

=Ben'gal Stripes.= Cotton cloth, woven with coloured stripes, orig. from Bengal; gingham.

=BEN'JAMIN*.= Benzoin.

=BEN'ZENE.= See BENZOL.

=BEN'ZINE= (-zin). Benzol.

=BEN'ZOATE= (-zo-ate). [Eng., Fr.] _Syn._ BEN'ZOaS, L. A salt in which one atom of benzoic acid is replaced by a metal or other basic radical. The benzoates may, in general, be easily prepared by either neutralising the acid with the base, or by double decomposition. Most of them are more or less soluble in water, and crystallisable. Those of the alkalies and ammonia are very soluble, and rather difficult to crystallise. See BENZOIC ACID and the respective bases.

=BEN'ZOENE*.= See TULUOLE.

=BENZO'IC ACID= (-zo'-ik). HC_{7}H_{5}O_{2} _Syn._ FLOWERS OF BENZOIN'; HY'DRATED BEN'ZOYL; ACIDUM BENZO'Ic.u.m (B. P.); ACIDE BENZOQUE, FLEURS DE BENJOIN, &c., Fr.; BENZOESaURE, &c., Ger. A substance which is commonly stated to be the characteristic const.i.tuent of the two balsams. Pure oil of bitter almonds suffers gradual conversion into this acid by exposure to the air.

_Prep._ The acid of commerce is princ.i.p.ally obtained from gum-benzoin, either by sublimation (dry way), or by dissolving it out by means of an alkali, or an alkaline earth in the form of a salt (moist way); but chiefly by the first method.

1. By SUBLIMATION:--

_a._ Good benzoin, crushed small or in the state of coa.r.s.e powder, is placed in a cylindrical iron pot with a flat bottom, and from 8 to 9 inches in diameter, so as to form a layer of from 1 to 2 inches deep. The open end of the pot is next covered with a sheet of soft and loose blotting-paper,[146] which is attached to the rim with paste. A cone, cap, or cylinder formed of strong thick paper (cartridge paper), open at its lower end, is then placed over the top of the pot, including the blotting-paper; and this is also attached with paste and string. The apparatus, thus prepared, is then placed on a sand bath,[147] and exposed for 4 to 6 hours to a gentle and uniform heat. It is next removed from the sand bath, and, when it has sufficiently cooled, inverted, and the string detached, when crystals of benzoic acid are found in the paper cone. If, owing to want of care in manipulating, the product is either coloured or empyreumatic, it must be enveloped in several folds of bibulous paper, then submitted to powerful pressure, and afterwards resublimed. The simple form of apparatus figured in the engraving answers well on the small scale, and is that recommended by Dr Mohr.

[Footnote 146: Felt--Liebig.]

[Footnote 147: On an iron plate on which sand has been spread--Ph. Bor.]

[Ill.u.s.tration]

_b._ (Ph. D. 1850.) The subliming pot is ordered to be of sheet-iron. It is to be fitted into a circular hole in a sheet of pasteboard, and a collar of tow interposed between it and the f.l.a.n.g.e, so as to produce a nearly air-tight junction. The paper receiver or cap is to be cylindrical, open at one end and about 18 inches high, with a diameter at least twice that of the pot; and it is to be secured in an inverted position on the pasteboard, and fastened to it by slips of paper and flour-paste. A couple of inches of the pot is to be pa.s.sed through a corresponding hole in a plate of sheet-tin, which is to be kept from contact with the pasteboard by the interposition of a few corks; and a heat[148] only just sufficient to melt the benzoin is to be applied for at least six hours.

[Footnote 148: That of a gas-flame is recommended. A ring of very small gas-jets answers better.]

_c._ (Process adopted at Apothecaries' Hall, London.) The best gum-benzoin is put into an iron pot, set in brickwork over a suitable small fire-place (or flue),[149] and communicating by a conical metal neck, with a wooden box (technically termed a 'house') lined with white blotting-paper, as a receiver for the flowers. A piece of fine muslin, or of bibulous paper, is interposed between the top of the subliming-pot and the receiver, to prevent the sublimate falling back into the former. The sublimation is conducted rather rapidly, and the acid condenses in beautiful white, soft, flexible crystals, which are at once ready for the market. When the process is conducted more slowly, the product is proportionately scaly.

[Footnote 149: A pan with a steam-jacket answers well, and is very manageable.]

_Obs._ Good samples of benzoin yield from 10 to 12%, or even 12-1/2%, of 'flowers' or 'acid of the first sublimation.' This, after being pressed in blotting-paper and again sublimed, gives 8-1/2 to 10% of nearly pure benzoic acid. The loss arising from a second sublimation is thus so great that the utmost care should be taken to avoid its necessity.

2. In the MOIST WAY:--

_a._ (Ph. D. 1826; Scheele's Process.) Equal parts of benzoin and hydrate of lime, in fine powder, are intimately mixed together and boiled for about an hour, with 40 parts of water; the liquor, after filtration, is evaporated to 1/5th, and the lime saturated with hydrochloric acid; the benzoic acid crystallised out as the liquor cools, and is then either washed with very cold water, and dried by a gentle heat, or it is dried and sublimed in the manner already explained. The product of the sublimation is extremely white and pure.

_Obs._ An economical and productive process; but, to ensure success, a perfect mixture of the dry ingredients must be first made; as otherwise the benzoin runs into a solid ma.s.s in the boiling water, and the operation fails. _Prod._ "1 lb. of (gum) benjamin yields 1 oz. 6 dr. 2 scr. of flowers." (Gray.)[150]

[Footnote 150: A quant.i.ty which, in our own experiments, we were never able to obtain.]

_b._ (Process of Stoltze.) The benzoin is dissolved in 3 times its weight of alcohol, the solution introduced into a retort, and a solution of carbonate of soda in weak spirit-and-water, is gradually added, until all the free acid present is neutralised; water, equal to about twice the weight of the benzoin employed, is next poured in, and the alcohol removed by distillation. The floating resin is now skimmed off the residual liquid and washed with a little water, and the was.h.i.+ngs added to the contents of the retort, which will deposit crystals of benzoate of soda on cooling, and more by subsequent evaporation. From this salt the benzoic acid is obtained by saturating the alkali with an acid (as the hydrochloric), and by subsequent sublimation of the crude precipitated crystals.

3. Other Methods:--

_a._ Ordinary hippuric acid is very gently boiled, for about 15 minutes, in nitric acid[151] (sp. gr. 142); water is then added, and the solution allowed to cool and crystallise. The crystals are collected on a filter, washed with a little very cold water, dried by pressure in bibulous paper, and lastly, purified by sublimation, as before.

[Footnote 151: Hydrochloric acid as well as sulphuric acid also convert hippuric acid into benzoic acid; as does likewise a sufficient degree of heat. See HIPPURIC ACID.]

_b._ From the urine of horses, cows, and other graminivorous animals, in a similar way to that by which hippuric acid is obtained, only allowing the urine to acquire a slight degree of putridity before evaporation, which last should be effected by a heat slightly under that of ebullition. The crude acid thus obtained is purified as previously directed.

_Obs._ Large quant.i.ties of benzoic acid are said to be obtained in this way on the Continent; but, owing to the process being clumsily conducted, it is generally of inferior quality, and hence unsaleable. It may, however, by skilful purification, be rendered quite equal to that obtained from gum benzoin.[152]

[Footnote 152: "A manufactory of sal-ammoniac, near Magdeburgh, which uses urine, is able to supply flowers of benjamin by the cwt." (Gray.)]

_Prop._ When obtained by sublimation benzoic acid forms soft, light, feathery, white, flexible crystals, which are transparent or semi-transparent, with more or less of a mother-of-pearl l.u.s.tre; when by slowly cooling its aqueous solution, or by precipitation from a solution of a benzoate, it forms either thin plates or scales, or a dazzling white crystalline powder. It is inodorous when cold,[153] but acquires a faint balsamic odour when gently warmed; fuses at about 212 Fahr., and begins to sublime freely at a temperature a little above it, but does not boil until heated to about 460; burns with a bright yellow flame; is very soluble in alcohol, dissolves in about 200 parts of cold water, and about 25 parts of boiling water; resists the action of ordinary nitric acid even when boiling; and forms salts (BEN'ZOATES) with the bases. Sp. gr. 0667.

Its vapour, which is very suffocating and irritating, has a density of 427. Added to fat and fatty substances it either prevents, or greatly r.e.t.a.r.ds, the accession of rancidity.

[Footnote 153: That of the shops usually smells slightly of benzoin, owing to the presence of a trace of volatile oil.]

_Test, &c._ It may be recognised--1. By its physical properties (appearance, fusibility, volatility, odour, &c.) already enumerated:--2.

By its ready solubility in solutions of the alkalies; and by being precipitated from these solutions, on the addition of one of the stronger acids, under the form of a dazzling white powder, which is only sparingly soluble in cold water:--3. By its neutral salts with the alkalies, or its neutral solution in an alkali, giving a bulky, flesh-coloured precipitate with perchloride of iron, which is insoluble in water:--4. By its solution not being precipitated by acetate of lead until after neutralisation with a fixed alkali, when the acetate produces a white, flocculent precipitate:--5. By a mixture of alcohol, ammonia, and solution of chloride of barium, neither disturbing a solution of the free acid, nor that of one of its salts with the alkalies.

It is chemically distinguished from cinnamic acid by not yielding essential oil of almonds when it is distilled with oxidising agents, as chromic acid or a mixture of b.i.+.c.hromate of pota.s.sium and sulphuric acid; and from succinic acid, by its different deportment with sesquichloride of iron (_Test 3, ante_), and with a mixture of alcohol, ammonia, and solution of chloride of barium (_T. 5, ante_).

_Estim._--1. By weighing it as benzoic acid, obtained either by precipitation, or by very careful sublimation in a gla.s.s apparatus:--2. By neutralising its alcoholic or aqueous solution, by the usual method of acidimetry:--3. By precipitating its neutral solution with acetate of lead, or with sesquichloride of iron, and weighing the carefully washed and dried precipitate either as benzoate of lead, or as ferric benzoate.

_Pur., &c._ White crystalline silky plates and needles, have an aromatic odour. Solubility in cold water, 1 in 300; in boiling water, 1 in 12; in spirit, 1 in 4. Also soluble in caustic alkalies and lime. Borax considerably increases its solubility in water; 1 of benzoic acid and 1 of borax are soluble in 100 of water. It sublimes without residue when heated. It is sometimes met with adulterated with hippuric acid, which may be easily detected by its altered form, by its diminis.h.i.+ng solubility in cold water, and by its exhaling an odour of tonquin-beans, and afterwards of hydrocyanic acid, when sublimed. The presence of succinic acid may be readily detected by its greatly increased solubility in cold water; that of sugar, not only by its increased solubility, and partial volatility, but also by the odour of caramel being evolved on the application of sufficient heat, and the residuum being black and carbonaceous; that of camphor, by its peculiar odour when gently heated. Spermaceti, specially prepared for the purpose, is also an occasional adulterant, easily detected by its insolubility and other well-known properties. All these substances either destroy or lack the proper crystalline form of benzoic acid, which is one of the best proofs of its purity. They also greatly increase its sp. gr.

_Uses, &c._ Its chief use in _medicine_ is as a stimulant and expectorant.

It is an ingredient in the compound tincture of camphor (paregoric elixir) of the pharmacopia.--_Dose_, 10 to 30 gr., dissolved in water by the aid of a little ammonia or pota.s.sa; in old coughs, &c.

=BENZOIC AL'COHOL.= A peculiar oily fluid, discovered by M. Cannizzaro, and obtained by the action of an alcoholic solution of pota.s.sa on pure oil of bitter almonds.

=BENZOIN'=, B. P. (-zoyn'; zo'-in). _Syn._ GUM-BENZOIN*, BEN'JAMIN*, GUM-B.*; BENZoI'NUM, L., B. P.; BENJOIN, Fr.; BENZoE, Ger. The balsamic resin exuded from incisions made in the stem of the _styrax benzoin_, a native of Sumatra, Java, Borneo, Laos, and Siam. Several varieties of benzoin are in the market; two only, however, are chiefly used in medicine, one in agglutinated ma.s.ses, the other (from Siam), in tears, being the purer and having the stronger odour.

_Prop., &c._ Odour agreeable, and somewhat like that of vanilla, but more balsamic; fracture conchoidal; l.u.s.tre greasy; sp. gr. 1063 to 1092. It fuses at a gentle heat and exhales white fumes, which, on condensation, are found to be benzoic acid contaminated with a little volatile oil.

Alcohol dissolves the larger portion of it, ether much less, and the volatile and fixed oils only a little. It contains from 9% to 18, or (occasionally) nearly 20%, of benzoic acid, according to the quality. It burns with an agreeable odour. The resin and its alcoholic solution strike a bright red colour with oil of vitriol, and a green colour with chloride of iron.

Benzoin has occasionally been sold by fraudulent dealers after its benzoic acid has been removed by the wet method. When the gum has been thus treated it will not show the agglutinated tears, upon fracture, which commonly distinguishes it when intact.

_Uses, &c._ It is chiefly employed in perfumery, and as an ingredient in incense, fumigating pastilles, &c.; also in court-plaster, in certain cosmetics, and to scent the varnish used for snuff-boxes, walking-sticks, &c. As a medicine, its general effects resemble those of the other true balsams, and of benzoic acid.--_Dose_, 5 or 6 to 20, or even 30 gr., in powder, and usually in combination with some other remedy; chiefly in chronic pulmonary and bronchial affections, when occurring in torpid habits, and unaccompanied by inflammatory symptoms or gastric irritation.

Also as a fumigation in the same diseases, hooping-cough, &c. Like benzoic acid, it is used to prevent rancidity in ointments, pomades, and other fatty preparations.

=BENZOINUM.= See BENZOIN.