By fractional sublimation it was possible to obtain fractions with different melting points. The first sublimate melted sharply at 109 degrees. From the last fraction it was possible to separate some crystals that melt at 200 degrees Centigrade. These might possibly be p-acetyl-benzoic acid, as its properties of solubility, crystalline form, its melting point and power of sublimation agree with those of p-acetyl-benzoic acid.
Those crystals that appeared identical with benzoic acid were placed in a melting point tube, and some known benzoic acid (from toluol) was placed in another tube. These two tubes were placed in the same sulphuric acid container and their melting points taken at the same time. They melted at the same temperature.
The sublimate had a very pleasant aromatic odor resembling benzoin. It gave no coloration with ferric chloride, thus eliminating a large group of aromatic compounds. Some of the crystals were found to be identical with benzoic acid when examined under the microscope. The characteristic odor of methyl benzoate was produced when a small quantity of the crystals were heated with methyl alcohol and concentrated sulphuric acid. On treating some of the carefully neutralized product with ferric chloride solution, a flesh colored precipitate was formed. It agreed closely in its analysis with the precipitate formed with known benzoic acid.
The filtrate left after the removal of the iron precipitate was acidified and extracted with ether, and the ether removed by evaporation. The resulting substance decolorized alkaline permanganate solution, but did not decolorize bromine water. When the leaflet needles that melt at 200 degrees were mechanically removed from the original sublimate, the substance left after precipitating with ferric chloride melted at 109 degrees. When these crystals were not removed, the melting point of this material was not definite, but was over a range of five degrees, from 110 to 115 degrees Centigrade.
The oxidation product contains at least three distinct substances, benzoic acid, a substance melting at 200 degrees and—which is probably p-acetyl benzoic acid and a third substance melting at 110 degrees.
THE IRON ACIDS.
The resinous material used and spoken of as the IRON ACIDS is the material prepared and so named under the “Method of Separation”.
PHYSICAL PROPERTIES:—Transparent and reddish brown in color, oily in consistency and has a characteristic tea like odor, heavier than water, freely soluble in benzol, ether, alcohol and acetone, but insoluble in petroleum ether and water.
This resin constitutes about eighteen percent of the total ester resins.
By qualitative tests it was shown that the acids contained only carbon, hydrogen and oxygen. Combustions made on the iron acids gave the following results.