Two important series of acids are derived, by oxidation, from dihydric alcohols, or *gly cols,' of the paraffin series. The general for mula for these glycols being Co112. (OH),, the lactic acid series of acids is obtained from them by an oxidation which consists in the replace ment of two atoms of hydrogen by one atom of oxygen. The general formula of the lactic acid series therefore is Its most im portant members are as follows: Carbonic Acid CH2O, Glycollic Acid CaH402 Lactic Acid Hydroxybutyric Acid . C.H.O.
HydroxYvaleric Acid Ca-Ws Leucic Acid C4I-1”02 Carbonic acid is included in this list on the hypothesis that it exists in aqueous solutions of the gas in the form CO, + H2O. Except for carbonic acid, all the acids of the foregoing list are monobasic. For the reason why carbonic acid is not also monobasic, reference must be made to the Fiore extended treatises on organic chemistry.
The oxalic acid series is derived from the glycol series, given above, by an oxidation which consists in the substitution of two atoms of oxygen for four of hydrogen. The general formula for this series of acids therefore is Callao-204. The most important representatives are: Oxalic Acid GH,04 Malonic Acid C.H.O.
Succinic Acid CH.04 Pyrotartaric Acid C.H.O.
Adipic Acid GH..04 Azaleic Acid Sebacic Acid Cyan°.
The foregoing acids are all dibasic.
The carbohydrates constitute a large and im portant class of open-chain (or fatty) com pounds. They all contain carbon, hydrogen and oxygen and are called °carbohydrates' because, like water, they contain precisely twice as many atoms of hydrogen as of oxygen and can there fore be regarded as consisting merely of water and carbon. (See CARBOHYDRATES.) The carbo
hydrates are more commonly divided simply into (1) glucoses (or hexoses); (2) sac charoses; and (3) amyloses. The glucoses com prise glucose (or dextrose), fructose (or levu lose), galactose and sorbose (or sorbinose); and they all have the empiric formula The saccharoses include cane-sugar, lactose, melezitose and maltose; they all have the empiric formula G.H.:01. and are all derived by the union of two molecules of a glucose, with the elimination of one molecule of water. Their general formula may therefore be written (C.H..0.),O, and they may be regarded as re lated to the glucoses in the same way that ether is related to alcohol. The amyloses include starch, glycogen, dextrin, cellulose, inulin and the gums. They have the general empiric formula (C.H.00.)a. (See also, in this ency clopedia, ALCOHOL; CARBON COMPOUNDS; HY DROCARBONS; ISOMERISM; SUGARS; and many other titles). Consult Cohen, J. B., 'Organic Chemistry for Advanced Students) (New York 1909-13) ; Pope, F. G., 'Modern Researches in Organic Chemistry' (London 1912) ; Remsen, I., 'An Introduction to the .Study of the Com pounds of Carbon' (Boston 1908) ' • Richter, V. von, 'Organic Chemistry, Vol I, Chemistry of the Aliphatic (Spielmann trans, Philadelphia 1916) ; Stewart, A. W., 'Recent Advances in Organic Chemistry) (New York 1908).