I180
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
Vol.
12,
No.
1 2
active principles and separate them in pure form as has digitalis. The list of investigators is seemingly endless; and the products resulting from their researches are equally numerous. While much of the recent work has been carried out primarily t o obtain purified preparations adapted t o certain particular purposes or modes of administration, with no specific attempt t o isolate a single pure principle or t o separate one from another if more than one are present, unquestionably the underlying thought is t o accomplish this end. This is shown by the products, such as digitalone, digipuratum, digipoten, and others, in which the resulting product is more or less purified and is probably better adapted t o prompt therapeutic response than the average pharmaceutical. The author has now succeeded in isdating from digitalis two active agents, although probably not in absolutely pure form. One of these is soluble in chloroform and the other insoluble, but solubility in this reagent is so dependent on the presence or absence of other constituents of digitalis or on a mixture of the two active agents t h a t i t is exceedingly difficult t o arrive a t a point where the complete solubility of the one or insolubility of the other can be established. If a n attempt is made t o extract digitalis leaves with chloroform, no considerable amount of active matter is obtained in the extract. If one attempts even t o use this as a solvent for Extract Digitalis, U. S. P., little of the active substance is dissolved. On the other hand, a mixture of alcohol and chloroform can be applied with greater success, and under certain conditions the whole of the active ingredients will be found in this mixture of solvents. Again after a partial purification of a digitalis extract, by which the water-soluble inert substances have been removed, chloroform will dissolve all the active material along with the chlorophyll, both of the distinctly different constituents dissolving with equal facility. It appears, therefore, t h a t certain constituents prevent solution of either active agent in chloroform, while others aid solution, even permitting t h e ordinarily insoluble principle t o dissolve. By careful manipulation, however, removing first one and then another of the inactive constituents of the leaf, i t is possible t o arrive a t a point where t h e product is sufficiently free from substances which affect its physical properties t o permit the separation from each other of one substance soluble, the other insoluble in chloroform. Both are soluble in ethyl alcohol, neither entirely soluble in acetone, but this does not seem t o indicate the presence of a mixture, the behavior toward acetone being so far unexplainable. THE CHEMISTRY OF DIGITALIS' Neither is more than slightly soluble in water alone, By Herbert C. Hamilton but the alcoholic solution of the chloroform-insoluble RESEARCH LABORATORY, PARKE,DAVIS & Co., DETROIT,MICHIGAN part is clearly soluble in water, even when only a Few, if any, plants used in medicine have been the minute amount of alcohol is present, while the chlorosubject of such exhaustive research t o discover the form-soluble part from an alcoholic solution gives a 1 Presented before the Division of Biological Chemistry at the 60th hazy solution when mixed with water. Meeting of the American Chemical Society, Chicago, Ill., September 6 to The proportion of the two present in the leaf has 10, 1920.
outlet end, and t h e scum, unimpeded by the submerged baffles, passes along with i t and is gently brushed over an inclined lip a t the end of the tank by a 3-in. roller, extending across the full width of the tank, into the scum trough. The clear liquor is syphoned off continuously a t the outlet end from a few inches below the surface, flowing through a regulating orifice made t o deliver the requisite number of gallons per hour, while the feed device maintains a constant level. I n one of the trial runs 6375 gal. of washed sugar liquor a t 63' Brix were treated in 6.75 hrs., or a t the rate of 945 gal. per hour, with the production of 352 gal. of scum (3.65 per cent of the original solids). The clarified liquor passed t o the char filters and the scum was twice washed by decantation, leaving 298 gal. t o be filter-pressed, containing 1 . 0 5 per cent of the original solids. The pressed cake occupied a volume equal t o 31 gal., and weighed 1 5 7 lbs. The purity of the press water was 93.3 as compared with 94.3 for the first dilution. There were produced 1 8 . 2 gal. of sweet water for IOO gal. of original liquor, and a considerable portion of t h a t could be utilized in preparing succeeding washed sugar liquor. The invert sugar rose from 0 . 6 9 t o 0.83 per cent in the liquor during treatment. I n another run 5,770,356 lbs. of washed sugar were ~ treated in a week, defecating with 5 1 0 lbs. P z O per million pounds of washed sugar, with lime t o neutralize. The rate of flow was 844 gal. per hour for each clarifier. 92.4 per cent of the dissolved solids passed into the liquor and 7.6 per cent into the scums, which weighed 9 . 1 1 lbs. per gal. and upon evaporation contained 6 1 . 1 4 per cent solids. Of the scum, 53.77 per cent was filter-pressed; 46.23 per cent was first diluted, heated, settled, and the muddy portion then filtered, producing sweet water of 28.83 Brix. It is shown by calculation t h a t if all the scum were defecated 97.35 per cent of the total solids entering the work would be recovered, of which 92.40 per cent would be in defecated liquor, 4.95 per cent in defecated.sweet water, and 2.65 per cent in press sweet water from residual scums. There was no inversion in the liquor. I n the sweet water the glucose rose from 1.26 t o 1 . 5 7 per cent (dry basis), and ash from 0.45 in liquor t o 0.66 in sweet water from scum, and 0.82 in sweet water from filter pressing the residual mud. The advantages of this mode of clarification are the doing away with bag filters and filter presses for t h e bulk of the liquor, and the consequent economy of labor in this arduous and mussy work. The introduction of automatic control apparatus also simplifies the labor and promises t o give more uniform work and products.
