METHOD OF SEPARATION OF THE RESINS.
After the removal of the crystalline methysticin from the extract, the following method of separation of the resinous products was used.
The free acids were removed by shaking the total resins successively with solutions of one percent ammonium carbonate, one percent sodium carbonate and one percent sodium hydroxide. The acids thus removed were recovered by treating the alkaline solution with dilute hydrochloric acid and shaking out with ether. The three acids were not markedly different in their physical properties. They possessed the characteristic odor of the crude drug, were viscous, brown in color and did not solidify at minus ten degrees Centigrade. These free acids constitute about five percent of the total resins.
The remainder of the extract was treated with alcoholic potassium hydroxide and saponified by heating the solution to about eighty degrees for fifteen minutes. After the alcohol was removed by distillation a small quantity of water was added. This resulting solution was then extracted with ether to remove the alcohol radical or radicals and the unsaponifiable material from the saponified product. The ether extract was saved to be used in the work on the alcohol radicals. The aqueous portion was evaporated to a semi-solid mass. Carbon dioxide was passed over this mass for about fifteen minutes to change any excess of potassium hydroxide to potassium carbonate. Alcohol (95%) was then added to precipitate the carbonate. The carbonate was then filtered off and water added to the filtrate.
To the clear filtrate a solution of barium chloride was added. Immediately a dense thick cream yellow precipitate formed. Barium chloride was added in excess. The barium salt was filtered off by means of a suction pump and the precipitate washed with water. The filtrate was treated with a few drops more of barium chloride so as to be sure that an excess had been added, which was proven if no further precipitate formed. To this clear filtrate an excess of a solution of ferric chloride was added. Immediately a thick heavy precipitate of the iron salt came down, which was filtered off by means of a suction pump and the precipitate washed with water.
The barium precipitate was treated with dilute hydrochloric acid and heated to boiling to decompose the barium resinate, and to liberate the free resin acid. The liberated acid was a brown resin of a thin consistency and had a characteristic odor. This acid was removed by shaking out with ether. The ethereal solution was dried with anhydrous sodium sulphate, filtered, and the ether removed by distillation. The last traces of ether were removed by heating the resin acids in a vacuum oven at sixty five degrees Centigrade. This resinous acid is the acid spoken hereafter in this paper as the BARIUM ACID.
The iron precipitate was treated with dilute sulphuric acid (ferric chloride is soluble in ether and ferric sulphate is not) and heated to boiling to decompose the iron resinate. The acid when liberated had a strong characteristic aromatic odor. It was extracted with ether in the same manner as the barium acid. This resinous acid is the acid spoken of in this paper as the IRON ACID.
The resinous extract left after the removal of the crystalline methysticin is spoken of as the TOTAL RESINS.
The resin acids removed by the preliminary shaking out with the various aqueous alkalies are spoken of as the TOTAL FREE ACIDS.