Bromine

“ In nature it is found in sea-water combined with alkaline bases, and in the waters of many saline springs and inland seas. The salt springs of Ohio abound in the compounds of bromine, and it is found in the waters of the Dead Sea. The only use which has been made of bromine in the arts is in the practice of photography. It is also used in medicine In a chemical point of view it is very interesting, from its similarity in properties, and the parallelism of its compounds to chlorine and iodine. ”

“ With the other elements it unites to form bromides, often with explosive violence; phosphorus detonates in liquid bromine and inflames in the vapour; iron is occasionally used to absorb bromine vapour, potassium reacts energetically, but sodium requires to be heated to 200° C. The chief use of bromine in analytical chemistry is based upon the oxidizing action of bromine water. Bromine and bromine water both bleach organic colouring matters. ”

“ Chloride of Bromine.--M. Bissou, a French experimentalist, has found that bromine associated with chlorine, prepared in a similar manner to chloride of iodine, already described, a solution of bromine being substituted for the iodine, is a very sensitive solution; by means of it daguerreotype proofs are obtained in half a second, and, thus very fugitive subjects are represented, making it the very best compound for taking children. So quick is its operation, that even persons or animals may be taken in the act of walking. ”

“ Bromide of Lime.—In preparing large quantities of this, we adopt the following method: Fill a four-quart bottle about two-thirds full of hydrate of lime; pour into this about one or two ounces of bromine; then shake well, add more of the bromine, shake well and let it stand for a few hours, adding sufficient bromine to give it a fine red color. It is better when kept in the large bottles, as it forms a more perfect combination: in other words it improves by age.
Use.—Coat over the iodine to a rose red and then over this mixture to a purple or slate ”

“ A salt which is obtained from hydrobromic acid, bromide of iron, &c., by similar processes to those adopted for the iodide. The following process for the preparation of bromide of ammonium is from the formula for the new medicaments adopted by the Paris Pharmaceutical Society: “Add bromine very slowly to a solution of ammonia, with continual stirring, until the liquid remains faintly and persistently coloured by a slight excess of bromine.” It forms white prismatic crystals; and, in its general properties, resembles bromide of potassium. It is volatile, and easily decomposed. ”

“ This solution is evaporated to dryness, and the salts being collected are heated in a glass retort with sulphuric acid and a little oxide of manganese. The bromine is distilled, and is condensed in a cooled receiver, into a red liquid.
Properties.—Bromine somewhat resembles chlorine in its odor, but is more offensive. At common temperatures it is a very volatile liquid, of a deep red color, and with a specific gravity of 3, being one of the heaviest fluids known. Sulphuric acid floats on its surface, and is used to prevent its escape. At zero it freezes into a brittle solid. ”

“ It may be prepared by passing hydrogen gas and bromine vapour through a tube containing a heated platinum spiral. It cannot be prepared with any degree of purity by the action of concentrated sulphuric acid on bromides, since secondary reactions take place, leading to the liberation of free bromine and formation of sulphur dioxide. The usual method employed for the preparation of the gas consists in dropping bromine on to a mixture of amorphous phosphorus and water, when a violent reaction takes place and the gas is rapidly liberated. ”

“ Elementary Nature of Bromine.—Iodine colours a solution of starch blue, bromine renders a similar solution orange colour. M. A. de la Rive added a few drops of bromine to a solution of starch [p466] coloured blue by iodine, and obtained a compound which gave two distinct colours with starch, one brown, the other yellow; the difference of colour corresponding with the two bromides of iodine described by M. Balard. ”

“ Flückiger [213] tests for small quantities of carbolic acid in creasote, by mixing a watery solution of the sample with one-fourth of its volume of ammonia hydrate, wetting the inside of a porcelain dish with this solution, and then carefully blowing bromine fumes on to the surface. A fine blue colour appears if carbolic acid is present, but if the sample consists of creasote only, then it is dirty green or brown. Excess of bromine spoils the reaction. ”

“ Bromine proved to be an unusually interesting element, being the only non-metallic one that is liquid at ordinary temperatures, and being strikingly intermediate in its properties between chlorine and iodine. It has been obtained in large quantities from brines, and is produced extensively in the United States. ”

“ Alexander Scott (Journal of Chem. Soc., 1900, 77, p. 648) prepares pure hydrobromic acid by covering bromine, which is contained in a large flask, with a layer of water, and passing sulphur dioxide into the water above the surface of the bromine, until the whole is of a pale yellow colour; the resulting solution is then distilled in a slow current of air and finally purified by distillation over barium bromide. At ordinary temperatures hydrobromic acid is a colourless gas which fumes strongly in moist air, and has an acid taste and reaction. ”

“ H2 + Br2 = HBr + HBr,
in addition to the energy expended in decomposing the hydrogen and bromine molecules, energy is also expended in converting the liquid bromine into the gaseous condition, and probably less heat is developed by the combination of bromine and hydrogen than by the combination of chlorine and hydrogen, so that the amount of heat finally, developed is much less than is developed in the formation of hydrochloric acid. ”

“ Agent for Neutralizing Bromine, Chlorine, and Iodine Vapors.—Aqua ammonia, sprinkled about the chemical or coating room, will soon neutralize all the vapor in the atmosphere of either chlorine, bromine, or iodine. No operator should be without, at least, a six-ounce bottle filled with ammonia. A little of its vapor about the camera-box has a decided and happy effect. Burnt coffee, pulverized, has also the property of destroying the vapors of the above chemicals, as also almost any other agent employed about the Daguerreotype room. ”

“ Hydrobromic acid is formed with a series of flashes at the part heated. The resultant HBr, together with traces of bromine, passes into a Woulfe's bottle into which hydrogen is also introduced, and the mixture is then carried through another heated tube, after which it is passed through water which dissolves the hydrobromic acid. According to the method proposed by Newth (1892) a mixture of bromine and hydrogen is led through a tube containing a platinum spiral, which is heated to redness after the air has been displaced from the tube. ”

“ The liquid is allowed to cool, evaporated to smaller bulk if necessary, and exactly neutralised with dilute nitric acid. It is then diluted with water to 500 c.c., and an aliquot part titrated with N/10 silver nitrate solution, using potassium chromate as indicator; 240 parts of bromine correspond to 58 parts of acetone. The complete analysis can be performed in one and a half to two hours. It is imperative that the bromine used should be pure, as crude bromine frequently contains bromoform. ”

“ But by virtue of the fact that chlorine and bromine act, in the manner shown, on the simplest typical hydrogen compounds, their action on the more complicated ones may be assumed to be the same. This can be easily demonstrated. The hydrogen of benzene, C6H6, reacts feebly under the influence of light on liquid bromine, but Gustavson has shown that the addition of the smallest quantity of metallic aluminium causes energetic action and the evolution of large volumes of hydrogen bromide. ”

“ Bromides.—Hydrobromic acid reacts with metallic oxides, hydroxides and carbonates to form bromides, which can in many cases be obtained also by the direct union of the metals with bromine. As a class, the metallic bromides are solids at ordinary temperatures, which fuse readily and volatilize on heating. The majority are soluble in water, the chief exceptions being silver bromide, mercurous bromide, palladious bromide and lead bromide; the last is, however, soluble in hot water. They are decomposed by chlorine, with liberation of bromine and formation of metallic chlorides ”

“ The decomposition of 2HBr into H2 + Br2 only requires, if the bromine be obtained in a gaseous state, a consumption of about 24,000 units, whilst in the decomposition of 2HI into H2 + I2 as vapour about 3,000 heat units are evolved; [68] these facts, without doubt, stand in causal connection with the great stability of hydrogen chloride, the easy decomposability of hydrogen iodide, and the intermediate properties of hydrogen bromide. ”

“ Another got twenty grains in solution every two or three days for a month without injury. In some of these experiments hydrobromic acid was detected in the blood and urine.
Little is yet known of the effects of bromine on man. Butske found that a drop and a half in half an ounce of water produced a sense of heat in the mouth, gullet, and stomach, and subsequently colic pains; and that two drops and a half in an ounce of mucilage excited, in addition to the preceding symptoms, great nausea, hiccup, and increased secretion of mucus. ”

“ The residual potassium bromide is estimated by means of standard silver nitrate solution. Bromoform is specially suitable for this purpose for several reasons. It is very readily formed by the action of bromine and potash on acetone, and although very volatile in steam, it is not liable to loss due to its own evaporation. Further, its high molecular weight and large percentage of bromine conduce to accurate results, 58 grms. of acetone being responsible for the formation of 357 grms. ”

“ The discovery of bromine in 1826 by A.J. Balard completed for many years Berzelius’s group of “halogen” elements; the remaining member, fluorine, notwithstanding many attempts, remained unisolated until 1886, when Henri Moissan obtained it by the electrolysis of potassium fluoride dissolved in hydrofluoric acid. Hydrobromic and hydriodic acids were investigated by Gay Lussac and Balard, while hydrofluoric acid received considerable attention at the hands of Gay Lussac, Thénard and Berzelius. ”

“ The silver surface is first thoroughly cleaned and freed from all organic matter, then exposed to vapor of iodine, producing an iodide of silver. The plate upon which is this salt, is again exposed to the vapor of bromine, forming a bromo-iodide of silver, a salt also.
As most of the various accelerators are compounds of bromine, with either chlorine or fluorine combination, they partake somewhat of the nature of these latter, giving results which can be detected by the experienced operator. ”

“ Schweitzer a letter of appreciation, to which we have referred in connection with the Chemical Exchange, makes a very significant reference to chemical warfare. "Of still greater and more beneficial effect is the support which you have afforded to the purchase of bromine. We have a well-founded hope that, with the exclusion of perhaps small quantities, we shall be in a position to buy up the total production of the country. Bromine, together with chloral, is used in making nitric gases, which are of such great importance in trench warfare. ”

“ This should be well stirred and allowed to cool, and then bottled in order to prevent it from giving off the hydrate and recovering the carbonic acid from the atmosphere. The last is detrimental to its use with bromine, and is one cause of the complaint that “it will not take bromine.” The hydrate of lime should, not be dried over a heat, as has been supposed by many, for in that case the hydrogen is expelled and it returns to a carbonate. It is advisable to cool it in a damp place like a ground cellar. Much of the lime in our market will not, except it be quite damp, combine with the bromine. ”

“ Bromine absorption has now been almost entirely superseded by the iodine absorption, although there are several good methods. The gravimetric method of Hehner (Analyst, 1895, 49) was employed by one of us for many years with very good results, whilst the bromine-thermal test of Hehner and Mitchell (Analyst, 1895, 146) gives rapid and satisfactory results. More recently MacIlhiney (Jour. Amer. Chem. Soc., 1899, 1084-1089) drew attention to bromine absorption methods and tried to rewaken interest in them. ”

“ The instability of the solution appears, however, to be influenced to a considerable extent by the alkalinity of the glass of the containing vessel, for concentrated solutions free from dissolved alkali are found to be perfectly stable. Bromine and iodine react in a remarkable manner with free hydroxylamine.
Crystals of iodine dissolve instantly in contact with it, with evolution of a gas and considerable rise of temperature. Bromine reacts with violence, a gas again being explosively evolved and hydrobromic acid formed. The nature of the gas evolved is now undergoing investigation. ”

“ It has been found that certain acids, certain salts, and certain compounds containing only two elements—of which one is a metal—have a tendency to split up, or resolve themselves into their several constituents, when exposed to the action of light. On the other hand, chlorine, bromine, and iodine exhibit, under the same conditions, an exalted affinity for the hydrogen of organic matters. ”