THE IRON ACIDS.
Reading edition
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.
Wt. of boat 2.6950 2.6950
Wt. of boat and substance 2.8470 2.8495
Wt. of substance .1520 .1545
KOH bulb 50.9620 51.0805
Bulb and CO2 51.3370 51.4610
Wt. of CO2 .3750 .3805
Carbon equivalent .1023 .10376
Sulphuric acid tube 76.2448 76.3450
Tube and water 76.3400 76.4453
Wt. of water .0952 .1003
Hydrogen equiv. .0106 .01114
Percent Carbon 67.3% 67.2%
Percent hydrogen 7.0% 7.2%
Percent Oxygen 25.7% 25.6%
An analysis of the iron salt obtained by precipitation from the potassium soap gave the following data.
Wt. of substance used .2955 .3387
Wt. of FeSO4 .0445 .0509
Ferric equiv. .03208 .03676
Percent Iron 10.85% 10.85%
The following method was used in making the above analysis. The weighed material was ignited in a platinum crucible by gently heating until the combustible gases formed were given off. The crucible was then strongly heated until the carbonaceous material was completely burned off. The residue was weighed and the percentage of iron determined.
Expressed as the ACID NUMBER, or the number of milligrams of KOH required to neutralize the free acids in one gram of the substance, the following data was obtained.
Ferric equivalent .03208 .03676
Fe expressed as KOH equiv. .0965 .1107
Wt. of material used .2955 .3387
Mg. of KOH per gram 326.6 326.7
Acid number 326.6 326.7
The following gives the ACID NUMBER obtained by direct titration of the Iron acid. The method is the same as that used in getting the titration value of the Barium acid.
Wt. of substance .2450 .2472
Cc of alkalie 2.2 2.3
KOH equiv. .01232 .01288
KOH equiv. per gram 53.87 52.
An attempt was made to saponify some of the iron acid, but it was impossible. The alcohol was partially distilled off, and the acid freed by making the mass acid with sulphuric acid, and shaking out with ether. The ether was distilled off, but the remaining acid had different physical properties from the acid with which the experiment was started. It was lighter in color, and solidified at zero degrees. At room temperature it was almost solid. On ignition it left no ash. This probably is a polymerization product of the original acid.
Since many organic acids whose salts cannot be prepared by the ordinary methods can be prepared by passing dry ammonia gas through a solution of the acid in anhydrous ether, this method was tried with the iron acid. The iron acid was dissolved in anhydrous ether, and the dry ammonia gas was bubbled through this ether solution. At first no change was noted, but after several minutes there was a flocculent thready precipitate formed which was light brown in color. The experiment was repeated. At first the precipitate was a very light brown, but after forming it quickly darkened. After standing a few hours the flocculent precipitate changed to a sticky brown mass. This same change was produced immediately if the precipitate was exposed to the air. The resulting mass had no odor of ammonia.
The flocculent precipitate formed at first was probably the ammonium salt of the iron acid, which like most ammonium salts, it was precipitated due to its insolubility in ether. Due to the ease of hydrolysis this salt immediately decomposed to the acid and ammonia when traces of moisture were present.