The Preparation of Theine
By CHAS. FREDICKE.
In the Medical Times and Gazette Mr. Lewis Thompson publishes an article entitled, "Use of Theine as a Therapeutical Agent," reported in the Druggists' Circular for June, page 96, in which he described a convenient method for the preparation of this agent; but the writer found the hollow and movable axis of the rotary coffee-roaster rather awkward, besides its length of three feet much too short to insure the deposition of all the crystallizable particles of the vapor given out by two pounds of coffee. The complete utilization of that amount of vapor would require a tube (being one inch in diameter) nine to twelve feet in length, and even longer. To obviate these disadvantages, recourse was had to a little stationary arrangement. It consists in a Linden's patent coffee-roaster, a thin cast iron pot, whose contents may be turned over by a perforated and toothed shovel. To the cover a tube of two inches in diameter was fitted, the whole length of which is three feet, made in three sections, for convenient removal and cleaning. Put on a stove and heat the pot to between 300° and 400°, then turn in the coffee, fit on the cover and pipe, passing the free end of the latter through a card board into a gallon bottle, then raise and continue the heat for 15 or 20 minutes, during which time the crank must be turned, and the cover now and then raised to examine the color of the beans, though this is not necessary after two or three repetitions of the process, when the cover may be luted on by a cement made with a little water out of two parts of linseed meal and one part plaster of Paris; besides, with a brisk fire the operation of roasting requires but ten minutes, when the coffee will have assumed the right shade of color. During the process the tube and the bottle grow rather hot, and it is advantageous to cool them by wet rags, but it is not absolutely necessary. The aqueous portion of the vapor condenses in the bottle to the amount of two ounces, and upon removal of the cover and tube, they will be found coated with a thin film, which is washed off by eight ounces distilled water, with which the bottle is also well rinsed; then the liquid is filtered and evaporated over a water bath to two ounces; to these, two ounces of dried carbonate of potassa is added (very easily made by exsiccating 2 1/4 ounces of salt of tartar in an iron ladle [fitted with a cover], one of three inches diameter by one inch depth is large enough, or a Hessian crucible will answer very well), the mixture set aside over night to allow the precipitate of theine to form. If the alkaline solution is very concentrated the precipitate will collect on the surface, but on adding a little water it will subside, the supernatant liquid is then decanted, the deposit redissolved in distilled water, evaporated over a water bath to dryness, and finally crystallized from a boiling solution in alcohol, which is distilled off and allowed to evaporate.
Theine obtained in this way is sufficiently pure for medicinal use. Two pounds of Rio coffee yielded 104 grains. It seems strange that the decided therapeutic value of this agent has thus far failed to bring it into more general use by the profession.
The above arrangement is not expensive, costing two dollars and a half, and is also useful for some similar purposes, such as the preparation of baccae juniperi tostae, glandes quercus tostae, etc., in fact for the torrefaction or incineration of many organic substances. A domestic process such as this, of almost weekly occurrence in every family, is thus turned into an interesting and profitable pharmacal operation.
To avoid repetition, the reader is referred for some further points of information on the subject, to the article above mentioned.—The Pharmacist, August, 1871.
CHICAGO, July, 1871.