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ANALYTICAL EDITION
Vol. 5 , NO. 5
DISCUSSION SUMMARY Total gossypol determined in a modification of the method Experiments showed that little if any gossypol could be of Carruth (3) of meal 1578 was 1.102 per cent, of which free extracted from moisture-free meal by anhydrous ether, gossypol on the air-dry sample constituted 4.82 per cent; and this also held for air-dry meal. Heat, used in drying the with the meal conditioned, the free gossypol constituted meal, was eliminated as a cause of this difficulty, Little 11.87 per cent of the total, or an increase of 7.05 per cent due gossypol could be extracted from meals containing 5 to 7 to the change in moisture content of the meal and to extrac- per cent of moisture. tion with ether saturated with water. It was found that water is the important factor in the exGossypol is considered to exist in cottonseed meal in two traction of gossypol. The addition of moisture to the forms, free and bound, being distinguished by their difference meal in amounts varying from 17.6 to 27.3 per cent and to the in solubility in ether. By the process of condensing steam or ether in the extraction flask aided the extraction, yielding merely by the addition of moisture uniformly distributed in increases of gossypol from twice to many times that obthe meal, there is a loosening of the gossypol in some manner tained from air-dry meal with ordinary ether. Increased so that it can be extracted in greater quantity by moist ether amounts of gossypol were obtained when water was also added in the presence of water in the receiving flask. t o the ether in the receiving flask. The author's results indicate that there is no fixed limit The extraction of appreciably more gossypol, with ether between free and bound gossypol. saturated with water from meals suitably moistened, sugIn the determination of free gossypol, it is essential that gests that there is no definite limit between bound and etherthe moisture content of the meal immediately preceding the extractable gossypol. Soxhlet extraction be controlled and that the extraction be LITERATURE CITED done by ordinary ether in the presence of about 5 cc. of water Anal. Ed., per 350 cc. of ether in the receiving flask. The presence of (1) Halverson, J. O., and Smith, F. H., IND.ENG.CHXIM., 5 , 29-33 (1933). 20 to 25 per cent of moisture in the meal will yield appreciably (2) Sohwartee, E. W., and Alsberg, C. L., J.Agr. Research, 25, 285-95 more gossypol than is obtained from an air-dry meal. (1923). The data show that the amount of gossypol obtained by (3) Sherwood, F. W., Ibid., 32,793-800 (1926). extraction with ether will depend largely upon the amount of Racmvnn May 15, 1933. Presented before the Division of Biological gossypol present in the meal and its moisture content at the Chemistry at the 85th Meeting of the American Chemical Society, Washtime of extraction with ether in the presence of water in the ington, D. C., March 26 to 31, 1933. Published with the approval of the Director of the North Carolina Agricultural Experiment Station as Paper 69 receiving flask. of the Journal Series.
Preparation of Permeable Extraction Thimbles for Laboratory Filtration F. J. WILLIAMS,Mineral Industries Experiment Station, The Pennsylvania State College, State College, Pa.
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HE problem has arisen in this laboratory of preparing a permeable thimble to be used in a pressure Soxhlet for the hydrogenation of coal. The commercially obtainable thimbles were not the desired size nor were they of sufficient permeability. The thimbles described below were made in this laboratory with the equipment on hand. The body used was as follows: Monmouth stoneware clay' 50 Anthracite coal (-28, $35 mesh) 50 The clay is blunged with water and lawned through a 28-mesh sieve. The coal is then added and the slip blunged until a thorough mixing is achieved. The resultant slip should have a specific gravity of approximately 1.8. The slip is drain-cast in a 2-piece plaster of Paris mold2 until the walls are about 0.19 inch (0.47 em.) thick. The pieces are dried and then slowly heated in a small electric furnace with free access of air until the coal is burned out, 600" to 700" C. sufficing. The densely packed layer of clay which has settled on the outside surface during casting is then removed with sandpaper until the open structure is disclosed, after which the pieces are fired to 1050" C. The Stoneware clays can be 1 Any stoneware or good casting clay will do. procured from The Western Stoneware Co., Monmouth, Ill.; H. C. Perrine and Sons, South Amboy, N. J., and others. 2 For details on mold-making and casting see any elementary book on oeramica-e. g., The Potter's Craft, by Charles F. Binns. D. Van Nostrand co.,1922, pp. 43-67 and 129-32.
total shrinkage is about 17 per cent on the wet basis (20 per cent on the fired basis) and should be allowed for in the mold construction. The resultant thimbles are ideal for the desired use. When 100 cc. of cold tetralin, the solvent used, were poured into a thimble of 200 cc. capacity, 2 inches (5 em.) in diameter, 50 cc. were delivered in 1 minute. Some finely ground coal was placed in a thimble and washed several times, using alcohol to insure wetting of the coal and at the same time to prevent solution of the coal substance. The coal particles that were washed through were caught on a filter paper and their diameters measured under a microscope, using a micrometer, ocular previously calibrated against a micrometer slide. The diameter of the largest particles was approximately 0.04 mm. The openings in a 325-mesh standard Tyler sieve are 0.044 mm., so the thimbles correspond favorably t o 325 mesh per inch. The permeability of the thimbles will vary approximately as the particle size of the coal used in the construction. Coal of larger particle size than that used (-28, +35 mesh) invokes difficulty in casting, while finer sizes give lower * permeability. The author's thanks are due to the staff of the Ceramics Department of The Pennsylvania State College for use of supplies and equipment in making these thimbles. RECEIVED July 10, 1933,
