Helping San Diego, California and beyond since 1997.
Do you need
volunteer, community service, work, military or court hours?
|
|
Helping San Diego, California and beyond since 1997.
|
|
Click here and add this page to your favorites!
|
Encyclopedia Britannica - Main :: FLA-FRA |
|
|
FORMIC ACID, H2CO2 or HCOOH, the first member of the series of aliphatic monobasic acids of the general formula
series by certain characteristic properties; for example, it shows an aldehydic character in reducing silver salts to metallic silver, and it does not form an acid chloride or an acid anhydride. Its nitrile (prussic acid) has an acid character, a property not possessed by the nitriles of the other members of the series; and, by the abstraction of the elements of water from the acid, carbon monoxide is produced, a reaction which finds no parallel in the higher members of the series. Finally, formic acid is, as shown by the determination of its affinity constant, a much stronger acid than the other acids of the series. It occurs naturally in red ants (Lat. formica), in stinging nettles, in some mineral
Cal 5(OH)3+H2C20a = C3H5(OH),OCHO+CO2+H20 C8H1(OH)20CHO+H20 = C:H(OH)a+H2CO2. Many other synthetical processes for the production of the acid or its salts are known. Hydrolysis of hydrocyanic acid by means of hydrochloric acid yields formic acid. Chloroform boiled with alcoholic potash forms potassium formate (-J. Dumas, BerzeliAs Jahresberichte, vol. 15, p. 371), a somewhat similar decomposition being shown by chloral and aqueous potash (J. v. Liebig
KH+CO:=KHCO2 and KH+2 C0=KHCO2+C. A concentrated acid may be obtained from the diluted acid either by neutralization with soda, the sodium salt thus obtained being then dried and heated with the equivalent quantity of anhydrous oxalic acid (Lorin, Bull . soc. chim., 37, p. 104), or the lead or copper salt may be decomposed by dry sulphuretted hydrogen at 13o C. L. Maquenne (Bull . sec. chim., 1888, 5o, p. 662) distils the commercial acid, in vacua, with concentrated sulphuric acid below 75 C.Formic acid is a colourless, sharp
alkali metals, but the magnesium, calcium and barium salts yield carbonates only. The free acid, when heated with concentrated sulphuric acid, is decomposed into water and pure carbon monoxide; when heated with nitric acid, it is oxidized first to oxalic acid and finally to carbon dioxide. The salts of the acid are known as for-mates, and are mostly soluble in water, those of silver and lead being the least soluble. They crystallize well and are readily decomposed. Concentrated sulphuric acid converts them into sulphates, with simultaneous liberation of carbon monoxide. The calcium salt, when heated with the calcium salts of higher homologues, gives aldehydes. The silver and mercury salts, when heated, yield the metal, with liberation of carbon dioxide and formation of free formic acid; and the ammonium salt, when distilled, gives some formamide, HCONH2. The esters of the acid may be obtained by distilling a mixture of the sodium or potassium salts and the corresponding alcohol with hydrochloric or sulphuric acids. Formamide, HCONH2, is obtained by heating ethyl formate with ammonia; by heating ammonium formate with urea to 140 C., 2HCO.ONH4+CO(NH2)2 =2HCONH2+(NH4)2COs ; by heating ammonium formate in a sealed tube for some hours at 230 C., or by the action of sodium amalgam on a solution of potassium cyanate (H. Basarow, Ber., 1871, 4, p. 409). It is a liquid which boils in vacua at 15o, but at 192195 C. under ordinary atmospheric pressure, with partial decomposition into carbon monoxide and ammonia. It dissolves mercuric oxide
End of Article: FORMIC ACID, H2CO2 If you wish, you can link directly to this article.
<a href="http://jcsm.org/StudyCenter/Encyclopedia/FLA_FRA/FORMIC_ACID_H2CO2.html"> FORMIC ACID, H2CO2 </a> |
|
|
(Previous) FORMIA (anc. Formiae, called Mola di Gaeta unti... |
(Next) FORMOSA |
|
Sponsored Advertisements