On oxidation with potassium permanganate it is converted into acetyl urea, together with other products.
Notwithstanding these errors, the value of the " ethyl theory " was perceived; other radicals - formyl, methyl, amyl, acetyl, &c. - were characterized; Dumas, in 1837, admitted the failure of the etherin theory; and, in company with Liebig, he defined organic chemistry as the " chemistry of compound radicals."
Thus the radical of acetic acid, acetyl,' was C 2 H 3 C 2.
The second series can be further divided 1 This must not be confused with the modern acetyl, CH3 CO, which at that time was known as acetoxyl.
Considering derivatives primarily concerned with transformations of the hydroxyl group, we may regard our typical acid as a fusion of a radical R CO - (named acetyl, propionyl, butyl, &c., generally according to the name of the hydrocarbon containing the same number of carbon atoms) and a hydroxyl group. By replacing the hydroxyl group by a halogen, acid-haloids result; by the elimination of the elements of water between two molecules, acid-anhydrides, which may be oxidized to acid-peroxides; by replacing the hydroxyl group by the group. SH, thio-acids; by replacing it by the amino group, acid-amides (q.v.); by replacing it by the group - NH NH2, acid-hydrazides.