February, 1924
INDUSTRIAL AND ENGINEERING CHEMISTRY
too high a temperature, (2) use of too dilute testing solution, (3) the solution and char were not heated together for sufficient time, and (4)the chars were tested in some cases on
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the volume basis and in other cases on the weight basis, using a t the same time widely varying ratios of char to total solids.
. The True Dry Substance Content of Beet Molasses1 By R. G . Gustavson and J. A. Pierce UNIVERSITY OF
DENV&R,D E N V E R , COLO.
temperature of from 100” TANDARD methods Surfur dioxide, carbon dioxide, ammonia, iodoform-producing to 105” C. might be mainof determining the true substances, and an unidentified oil distil from the molasses when tained, was employed. A dry substance content dried under conditions approximately similar to those employed in large Liebig condenser, of beet sugar juices, and determining dry substance under the method recommended by the mounted vertically, premore particularly of molasAssociation of Oficial Agricultural Chemists. The fotal percenfage served a constant boiling ses, presuppose that, when of these compounds, othe) than water and oil, passing o$ is 1.965. point by preventing the subjected to a uniform heat A t a temperature approximating 104” C. an amido constituent of evaporation of the water in of from 100” to 105” C., the molasses decomposes with liberation of ammonia. the solution. nothing passes off but water. I t is suggested that these results will explain in part the variation Instead of the aluminium Since an accurate knowlexisting between dry substance content as found by the refractometer dish used in the standard edge of the Percentage of and byoven drying. method, a flask of about 75dry substance is necessary ml. capacity was employed. in formulating the degree of “true purity” in the original substance, any doubt that This modification was suggested by Paul M. Grissinger, rethe standard method is accurate leads to the corollary doubt search chemist with the Great Western Sugar Company, with the statement that experiments have indicated that glass that the figures obtained by the formula and aluminium vessels give identical results. 100s p =Three small holes were bored through the door of the oven P to permit the insertion of a plain glass tube, a thermometer, are correct. The method recommended by the Association and a soda-lime bulb. All three had entrance to the disof Official Agricultural Chemists, usually known as the tilling flask through a tightly fitting rubber stopper. The “Standard Method,” is so generally accepted by sugar chem- thermometer bulb was inserted into the mass of sand and ists tha,t it is considered by most of them to be exact. Very molasses, since preliminary experiments showed that the little literature on the subject can be found in any published interior of the mixture did not reach the temperature of the treatises on sugar analysis. &ken2 states that “the use of empty part of the flask for a t least 20 minutes when the latter the vacuum oven to determine whether there might he some registered 105’ C. A small soda-lime bulb was used to predecomposition of the less stable constituents of beet mo- vent the ingress of carbon dioxide from the air. The other lasses at 105” C . did not indicate that any such decomposi- end of the plain tube was attached to a small Liebig condenser. tion took place.” To the authors this is not a satisfying The receiving vessels consisted, a t various times, of a conclusion. 200-ml. flask containing 50 ml. of distilled water, a similar Lack of data on dry substance determinations, the reali- flask containing 50 ml. of 0.1 N sulfuric acid, a similar flask zation that factory processes of manufacture indicate the pos- containing 50 ml. of 0.1 N sodium hydroxide, one containing sible volatilization of carbon dioxide and sulfur dioxide, 50 ml. of saturated bromine water, and a potash bulb of the and tho fact that the analyses of Wiley and Browne3 show usual type. Protection by means of calcium chloride tubes the presence in molasses of comparatively unstable amido was employed a t necessary points. A bent tube attached compounds were the reasons for the series of experiments to the discharge end of the Liebig condenser was kept a t all described herein. times below the surface of the solution in the flasks as in the Kjeldahl method. A suction apparatus of sufficient strength DESCRIPTION OF APPARATUS AND MATERIAL to neutralize the pressure in the train of apparatus was used Stroiig efforts were made to parallel as closely as possible continuously, and regulated to maintain as closely as possible the conditions existing when molasses is dried by the standard a pressure of one atmosphere. method. The fact, however, that the volatile fraction and The material investigated was a molasses known as “standnot the residue was the object under investigation made it ard molasses,” from a factory whose ltme rock and water necessary to employ a still and a series of flasks and bulbs to were of sufficient purity to result in a product considered to be collect the distillate. This train of apparatus resulted in the typical. It had a Brix of 93.2” and a slight negative alkaformation of atmospheric conditions different from those linity. Dry substance by the refractometer was 79.2 per cent. found in the standard method, and it was necessary to counThe sand employed was prepared by the standard method teract this effect. The authors believe that in all essentials of sifting, treating with hydrochloric acid to remove soluble the conditions of drying the substance were exactly as they iron, washing, and drying on a hot plate. Sand between 40 would have been under the official method. and 60 mesh was used exclusively. A small, double-walled drying oven, containing in the jacket tt glycerol solution of such a strength that a constant EXPERIMENTAL
S
1
Received July 11, 1923.
* THISJOURNAL, 1 Sherman,
18, 979 (1920). “Food Products,” 1914, yp. 421, 427,431.
Sand and a known quantity of molasses were mixed in proportions of about 25 to 1. Great care was taken to make
INDUSTRIAL A N D ENGINEERING CHEMISTRY
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the resulting mass uniform in texture. The conclusions of Aiken were followed as far as possible in this regard. The completely mixed mass was very porous, and had a tendency to "crawl" when held in an inclined position. The amount of molasses used in each trial was approximately 4 grams. The maximum temperature reached in any one run was 105" C.; the average maximum was 104" C. The oven was heated until the thermometer in the glycerol-water solution registered a steady temperature of 105" C., and then the distilling flask was inserted and the apparatus connected. It was found that if the flask was placed in the oven when the latter was cold and the mass allowed to heat gradually, it had a tendency to impact on the surface and form a more or less impermeable layer. It was also found that in a sample of the'size used it took 1 hour and 20 minutes for the interior of the mass to register the same degree of heat indicated by the glycerol-water solution. The distillate, which came over very slowly and at a uniform rate, was colorless, with an acid, empyreumatic taste. The odor was very distinct, somewhat alcoholic, but reminding one of the odor of the original material. Even before the liquid passed through the condenser tube into the receiving flask, the contents of that flask acquired the odor of the distillate. At the end of several hours the liquid, when dip tilled into water or 0.1 N sulfuric acid, lost its transparency and became turbid. This turbidity could be removed by repeated filtration through kieselguhr, but could not be determined quantitatively. The aqueous solution of distillate precipitated heavily with basic lead acetate and with barium chloride. It tested strongly for ammonia with Nessler's solution. It was distinctly acid even to litmus paper. The dried substance left in the flask was neutral to litmus.
Vol. 16, No. 2
Thus, the total percentage of the original material, exclusive of water and oil, which passed over at 104" C., was 1.965. Sulfur, estimated as sulfur trioxide, was obtained by three methods: (1) By distilling into 50 mI. of neutral water in a 200-ml. flask, adding copper sulfate and phosphoric acid solutions to this distillate, redistilling into saturated bromine water in an atmosphere of carbon dioxide, boiling off the excess of bromine, adding 2 ml. of dilute hydrochloric acid, precipitating with barium chloride solution, filtering through asbestos, igniting, and weighThis method was used in Trial 2. (2) By distilling into neutral water as above and titrating with 0.1 N sodium hydroxide for total acidity of the solution. (Trials 1 and 3) (3) By distilling into 0.1 N sodium hydroxide and titrating with 0.1 N sulfuric acid. (Trial 4)
Carbon dioxide was determined (approximately) by the gravimetric (potash bulb) method. No claim is made for exactness. Iodoform-producing substances were determined quantitatively by a slightly modified form of the Messinger method. The only deviation was the use of 0.05N iodine andsodium thiosulfate solutions, instead of 0.2 N as recommended. In addition to the foregoing qualitative and quantitative determinations, it was found that if the temperature is approximately 104" C. a t the beginning of the distillation, a mixture of splfur dioxide, carbon dioxide, ammonia, iodoformproducing compounds, and oil is given off. However, if a temperature of 90" C. is maintained for several hours, an acid fraction containing sulfur dioxide, carbon dioxide, iodoform-producing compounds, and oil passes over. Then, if the temperature is raised to 104" or 105" C. a strongly alkaline distillate appears which tests for ammonia by Ness-
TABLE I Trial
1 2 3 4 Av.
Weight of Sample 2.4839 3.4762 4.4162 4.9000 3.8189
Per cent
Loss 17.71 17.44 17.69 17.56 17.60
Time Hours 10 18 17 19 16
Temperature O
c.
Per cent Sulfur as
104 104 104 105 104
As a check on the results obtained by distillation of the molasses-sand mixture, a 4-gram sample of molasses was diluted with 100 ml. of neutral water and distilled from an ordinary retort. Conditions of pressure and temperature were maintained as closely as possible to those mentioned above. At 90" C, an acid distillate was evolved which gave a positive iodoform test. When this fraction had passed over and the temperature was raised to 105" C., the distillate was found to be alkaline, and tested strongly for ammonia by the Nessler reaction. The undistilled residue in the flask, as in the case of the molasses-sand mixture, was neutral. The distillate from the molasses-sand mixture was tested qualitatively for iodoform-producing substances, carbon dioxide, ammonia, and sulfur dioxide, with positive results. Qualitative tests for cyanogen and furfural were made, with negative results. An attempt was made to determine the presence of the fatty acids by means of the Duclaux constants, but the presence of sulfur dioxide, and the small amount of the distillate interfered. The turbidity found after the distillate had stood for several hours was determined by saponification with sodium hydroxide, and by absorption with ether, to be some unidentified oil. The foregoing qualitative determinations were made by standard, recognized tests. When a substance was found by one test, confirming tests were made with other reagents. The results are give in Table I.
so3
Per cent NHa
0.937 0.918 0.924 0.920 0.925
o:ii4 0.927 0.920
...
Per cent COP
... 0.06 0.09 ...
0,075
Oil Trace Trace Trace Trace Trace
Per cent Iodoform Producers Calculated as Acetone
o:i.i1 0:iio 0.045
ler's reagent. This indicates that at 104" or 105" C. an amido component of the molasses decomposes. It is suggested that this compound might be aminosuccinamic acid. This is indicated chiefly by the well-recognized analyses of Browne and Wiley, mentioned above, of sugar beet juice, discard molasses, and schlempe. Thorpe6 also states that, in the presence of certain mineral acids, asparagine (aminosuccinamic acid) splits into ammonia and aspartic acid. 4
a
Great Western Su'gar Company, "Methods of Analysis," 1920,p. 120. Dictionary of Applied Chemistry. Vol. I, p. 310.
25th Anniversary of the Discovery of Radium The anniversary of the epoch-making discovery of radium by Becquerel and M. and Mme. Curie was celebrated by appropriate exercises in the Grand Ampitheater of the Sorbonne on Wednesday, December 26. President Millerand was in the chair and gave a brief address at the close of the meeting. The most important addresses were by Perrin on "Radioactivity and Its-Importance in the Universe," and by Beclere on "Radium in Medicine." One interesting feature of the meeting was the reading of two of the first published communications on the subject of radium. Several experiments were shown t o illustrate the fundamental phenomena o€ radioactivity. Of especial interest were the discharge of an electroscope by the proximity of radium, the effect of single alpha particles emitted from polonium under such conditions that a sound, amplified to be audible to the large audience, was produced, and the fluorescence produced by radium emanation with a tube a meter in length. Madame Curie was present and made a brief address.-W. A. NOYES
