Acetic acid

“ Acetic acid largely diluted with water, vegetable gluten, mucilage, sugar, extractive matter, and frequently malic and tartaric acids, together with small proportions of sulphate of lime, sulphate of potass, and alcohol. Its composition however varies according to the fermented liquor from which it is obtained: [325] e. g. wine yields a paler, purer, and stronger acid than fermented malt liquors or solutions of sugar, hence the superiority of that prepared in France and Italy. ”

“ Acetic acid, familiar to us in a diluted and flavored form as vinegar, is when concentrated of great value in industry, especially as a solvent. I have already referred to its use in combination with cellulose as a "dope" for varnishing airplane canvas or making non-inflammable film for motion pictures. Its combination [Pg 243] with lime, calcium acetate, when heated gives acetone, which, as may be seen from its formula (C3H6O) is closely related to the other compounds we have been considering, but it is neither an alcohol nor an acid. It is extensively employed as a solvent. ”

“ An Acetic acid sufficiently strong and pure for many ordinary purposes may be obtained without distillation, by pouring strong sulphuric acid, 60 parts, diluted with water, 5 parts, on well-dried acetate of lime, 100 parts; digesting, with occasional agitation in a close vessel, decanting the clear liquid, and straining the remainder. ”

“ Acetic acid is added to the pyrogallic acid to prevent its too rapid decomposition, and to facilitate the more easy flowing of the fluid over the plate. But the more acetic acid is used, the more slow will be the development. ”

“ It is a monobasic acid, forming one normal and two acid potassium salts, and basic salts with iron, aluminium, lead and copper. Ferrous and ferric acetates are used as mordants; normal lead acetate is known in commerce as sugar of lead (q.v.) ; basic copper acetates are known as verdigris (q.v.) .
Pharmacology and Therapeutics.—-Glacial acetic acid is occasionally used as a caustic for corns. The dilute acid, or vinegar, may be used to bathe the skin in fever, acting as a pleasant refrigerant. Acetic acid has no valuable properties for internal administration. ”

“ Pure acetic acid is colorless, possesses strong acid properties and taste, and no empy­reu­matic flavor. It should have, according to the new London Phar­ma­copœia, a specific gravity of 1.048, and one hundred grains should saturate eighty-seven grains of crystal­lized car­bonate of soda; consequently the phar­ma­copœial acid consists of thirty-one per cent. of the anhydrous acid, and sixty-nine per cent. of water. It should leave no residuum by evaporation. Sul­phu­ret­ted hydrogen, nitrate of barytes, ferro­cya­nu­ret of po­tash, and nitrate of silver, should produce no precipitate in it. ”

“ When the colours are alike the amount of pure acid present in the sample is equal to the amount of pure acid added. All mineral acids should be absent, even acetic acid affects the reaction. To detect the presence of salicylic acid added to beer or milk, four ounces of these liquids are dialysed for twelve hours in a pint of distilled water ”

“ Lunge's Process.—In this process acetic acid is used in place of hydrochloric or sulphuric acids, etc., to set free the chlorine or hypochlorous acid, in the ordinary method of bleaching with hypochlorite of lime, or bleaching powder, which, the inventor says, "combines all the advantages of the materials formerly employed, without any of their drawbacks.... The price is no impediment, for a minimal quantity is sufficient, the same being regenerated over and over again. At first acetic acid and chloride of lime decompose into calcium acetate and free hypochlorous acid. ”

“ When water, acidulated with acetic acid, is employed in the preparation of extracts, the vegetable substances are usually macerated in it, in the cold, or the dilute acid is sprinkled over the bruised plant in the fresh or recent state, and the whole is then submitted to strong pressure, to expel the juice, which is strained and evaporated in the usual way, but preferably in a well-tinned or plated-copper pan. ”

“ Taken internally, it acts by dissolving the animal tissues, and by thus destroying the organisation causes death, like the other acids. In the dilute form it acts as a stimulant, rubefacient, alterative, refrigerant, and escharotic.
Uses. Acetic acid is much employed by the chemist and pharmaceutist, in the manufacture of various preparations, and in analysis; by the perfumer, in the composition of several of his most refreshing and agreeable scents; and in medicine, as an antiseptic, stimulant, rubefacient, alterative, refrigerant, and escharotic. ”

“ In the case of hard water, or of impure bleaching liquors, a good deal of the acetic acid would be consumed in neutralising the lime; in this case, some hydrochloric or sulphuric acid may be added, but only sufficient for the purpose, so that no acid but hypochlorous or acetic acid exists in the free state. The process is applicable to the bleaching of vegetable fibres, whether spun or in the unspun state, and for bleaching paper pulp made from rags, wood, straw, esparto, etc. Besides acetic acid, any other weak organic acid of an analogous nature may be used. ”

“ The optically inactive form of tartaric acid, known as racemic acid, has been obtained by M. Gensesse as an eventual product of the action on glyoxalic acid—an acid found in gooseberries, grapes, and other fruits—with nascent hydrogen liberated from a mixture of zinc-dust and acetic acid. ”

“ In Massachusetts, also, the acidity must be equivalent to 41⁄2 per cent. of acetic acid, and cider vinegar must contain, at least, 2 per cent. of solid matter. The English standard of strength is 3 per cent. of acetic acid.
Analysis.—For the requirements of the United States Customs Service, the only estimations ordinarily made are the specific gravity, and a determination of the acidity. The former is accomplished by means of the specific gravity bottle; the latter, by placing 10 c.c. of the sample in a beaker, adding about 30 c.c. ”

“ Acetic or other similar organic acid may be used instead of the lactic acid, but sulphuric or mineral acids must not be used. The acid liquid is afterwards neutralized by ammonia, which is added when the bate is to be used, and there are then formed certain chemical compounds similar to those found in a dung bate.
The addition of the acid to the nutrient medium will immediately stop the growth of bacteria, but the acid is not added for that particular reason, but for the particular purpose set forth. ”

“ There is a deal to be said in favour of the use of another organic acid, formic acid. It is equally as safe as acetic acid, and quite efficacious; the only drawback is that, taking all things into consideration, it is very slightly more expensive. ”

“ Advantage is taken, in analysis, of such differences. Acetic acid, for instance, is used when only a slight degree of acidity is desired—as in recognizing barium-ion by its chromate, or oxalic acid by means of its calcium salt. Hydrochloric or nitric acid is used when decided acidity is required—as in the separation of groups by hydrogen sulphide (Chap. XI) .
The Ionization of Bases.—The same relations hold for bases as for acids: the weaker bases give ionization constants as [p106] do the weaker acids; the strong bases, again, as was mentioned above, do not give constants. ”

“ One eighth of the acetic acid passes over by the heat developed by the reaction of the ingredients. The heat of a sand bath is next applied and continued until the contents of the retort become quite liquid. The distillate, carefully rectified, yields two parts of pure acid, containing only 20 per cent. of water. On exposing the latter portion which comes over in16 a closed vessel to a temperature below 40° Fahr., crystals of hydrated acetic acid are deposited. The weaker, or liquid portion, being poured off, the crystals are again melted and re-crystallised by cooling. ”

“ In addition to our annual supply of 4,000,000 tons of paper stock, we depend upon the forests for our supply of acetic acid, methyl alcohol and acetone. In countries where there is not the exorbitant tax upon fermented mash that exists in the United States there would seem to be an opening for a process for the production of acetic acid from alcohol in a more concentrated form than can be produced through the aid of mycoderma aceti. ”

“ In other cases, dilute acetic acid or acidulated water is employed as the menstruum, when the products (ACETIC EXTRACTS; EXTRACTA ACETICA, L.) possess much greater activity than when prepared with water; and would in many cases prove fatal, if exhibited in doses as large as those of the aqueous extracts. Still more active extracts are obtained by a combination of the last two menstrua. According to Ferrari, plants treated with rectified spirit of wine, mixed with 1⁄36th part of acetic acid, yields extracts of remarkable activity. ”

“ In the body, these same carbo-hydrates, in continued contact with nitrogenous matter, are transformed into carbonic acid and water: substances which are also more highly oxidized and more stable than those from which they result. And since acetic acid is itself resolved by further oxidation into carbonic acid and water ”

“ Although originally described as acetylketen, it has proved to be a cyclic compound (Ber., 1909, 42, p. 4908) . It is soluble in water, the solution showing an acid reaction, owing to the formation of aceto-acetic acid, and with alkalis it yields acetates. ”

“ Acetic acid increases its powers, although it relieves the effects of an overdose, if administered after the stomach has been emptied. This apparent anomaly is easily explained when we consider, that in the first case its operation is purely chemical, increasing the solubility of the active principle of the plant, while in the latter case it operates as a vital agent, restoring to the nervous system that energy which has been suspended by the narcotic influence of the vegetable. ”

“ The product is 38 to 381⁄2 parts of crystallised sugar of lead. It is found to be advantageous to preserve a very slight excess of acid during the boiling and crystallisation, to prevent the formation of any basic acetate the presence of which impedes the formation of regular crystals.
From litharge, 112 lbs.; acetic acid (sp. gr. 1·057) , 128 lbs. Prop. 180 to 184 lbs. ”

“ Again, if in wood spirit we substitute an atom of oxygen for 2 of the remaining atoms of hydrogen we obtain formic acid, CHO.OH, the first of a long series of acids, of which the second, corresponding to ordinary alcohol, is acetic acid, and the highest members, such as stearic acid, C18H35O.OH, are solid fats. ”

“ In all cases it is usual to represent substances by formulae which to the best of our knowledge express their molecular composition in the state of gas, and not merely the relative number of atoms which they contain; thus, acetic acid consists of carbon, hydrogen and oxygen in the proportion of one atom of carbon, two of hydrogen, and one of oxygen, but its molecular weight corresponds to the formula C2H4O2, which therefore is always employed to represent acetic acid. ”

“ The developing agent with the pyrogallic and formic acids will keep good a very long time, longer, I think, than that in which acetic acid is used, but cannot be used as a dipping bath.
6. I find the formic acid which I obtain from different chemists rather variable in its strength. What I use is rather below the average strength, so that in general about six drachms of the commercial acid will suffice where I use one ounce; but the excess seems to produce no bad result. ”

“ The A24 acid is obtained by boiling the dihydrobromide of the AM acidwith alcoholic potash or by continued boiling of the AM acid with caustic soda.
The AM acid is formed when phthalic acid is reduced in the cold by sodium amalgam or by heating the AM and AM acids with caustic soda. The trans-modification of A3'5 acid is produced when phthalic acid is reduced by sodium amalgam in the presence of acetic acid. When heated for some time with acetic an hydride it changes to the cis-form. ”

“ And the alcohols, with their allies, have no great power of resisting decomposition. These bodies, formed by the union of oxygen, hydrogen, and carbon, are also, as a class, chemically inactive. Formic and acetic are doubtless energetic acids; but the higher members of the fatty-acid series are easily separated from the bases with which they combine. Saccharic acid, too, is an acid of considerable power; and sundry of the vegetable acids possess a certain activity, though an activity far less than that of the mineral acids. ”

“ Evaporate to dryness; mix acid by tests within the with equal quantity of scope of the bacteriological arsenious oxide and heat laboratory. on platinum foil. Unpleasant smell of cacodyl = acetic acid. (d) Add a few drops of mercuric chloride solution in test-tube, and heat to 70° C. Precipitate of mercurous chloride which is slowly reduced to mercury = formic acid.
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8. If the distillation of "B" is continued as long as acid comes over (distilled water being occasionally added to the distilling flask) the distillate can be measured and 50 c.c. used for titration. ”

“ Bases, consisting of amines, skatol, and indol, and varying amounts of ammonia, according to the age of the dung.
The organic acids exist partly as salts of the alkaline earths, partly combined with amines. A distillation of “puer,” after acidifying with H2SO4, gave 2·2 grm. per litre of volatile acids reckoned as acetic. No HCl came over. On decomposing the sodium salts of the acids with H2SO4, the smell of butyric acid predominated. I have also shown the presence of lactic acid in the dung, but have been unable to determine the amount. ”