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as follou7s: 0.5, 0.5, 1.5, and 2.5 cc. (This procedure prevents the production of a fine precipitate which is difficult to transfer, filter, and wash.) Digest gently 15 to 20 minutes and let stand overnight. Filter through the weighed Go.och crucible, wash with alcohol (50 per cent), then with a small amount of petroleum ether, followed by 5 cc. of alcohol (95 per cent), then four times with water. Dry a t 100' C. to constant weight. The factor 0.775 times the weight of dinniline gossypol gives the weight of gossypol. The results of eight determinations on meal 1578 (Table I) average 1.102 per cent total gossypol with a maximum variation of 4.99 per cent. The recovery from 20 mg. of purified gossypol by this method is given in the last column. The average recovery is 19.2 mg., or 95.9 per cent with a variation of 4.2. By the Carruth method, meal 1578 yielded 0.881 per cent gossypol and 0.958 per cent by the modified Carruth method, whereas the method proposed gave 1.102 per cent gossypol. The difference in results between the proposed method and the Carruth method is 0.221 per cent. Part of this difference is probably due to the gossypol remaining in the meal as it still retains a faint yellow color, and small
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additional amounts can be extracted from the residue from Carruth's method. After the treatment with aniline and 90 per cent alcohol on the Pickel apparatus by the proposed method, all residues are devoid of any yellow color. SUMMARY A method for total and bound gossypol in cottonseed meal has been outlined which gives results of an accuracy of 95.9 per cent on known ambunts of gossypol. The method is readily performed and is economical, yielding somewhat higher results than the Carruth method. LITERATURE CITED (1) C a r r u t h , F. E., J . Am. Chem. Soc., 40, 647-63 (1918). (2) Clark, E. P., J . Bid. Chem., 76, 229-35 (1928). E N G . CHEM.,Anal. E d . , (3) Halverson, J. O., and Smith, F. H., IND. 5, 29-33 (1933). (4)Sherwood, F. W., J . Agr. Research, 32, 793-800 (1926). RBCEWEDMay 15, 1933. Published with the approval of the Director of the North Carolina Agricultural Experiment Station &a Paper 71 of the Journal Series.
Relation of Moisture to Extraction of Gossypol from Cottonseed Meal with Ether J. 0. HALVERSON AND F. H. SMITH, Agricultural Experiment Station, Raleigh, N. C.
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HAT swine do not thrive Isolated gossypol is readily soluble in anhyEFFECT OF METHODS OF DRYING drous or ordinary ethyl ether. However, anhywhen f e d relatively Cottonseed meal, dried over large amounts Of certain drous ether extraots little or no gossypol from dried phosphorus pentoxide at 2,-inch c o t t o n s e e d meals over a long period is ascribed to the small Or air-dry whether the be vacuum for 2 and 6 hours a t 50' amounts of gossypol present in dried with or without heat. Moisture is the C.,wasextractedwith anhydrous important factor in extracting gossypol from and with ordinary ether. Little t h e s e m e a l s . Therefore the if a n y gossypol could be exfactors affecting the estimation cottonseed meal with ether, the highest yields tracted by the anhydrous ether Of gossypol are Of importance' occurring when the charge of meal contains about (an average of o.oo50 per cent), In the usual method of estima2o per cent Of water and when water is added while the ordinary grade gave tion (8) gossypol is extracted to the ether in the receiving flask. Meals SO s o m e w h a t higher results (an from air-dry cottonseed meal treated have yielded from twice to ten times more average of 0.0127 per cent). with ordinary ethyl ether. Algossypol than the Same samples of aipdry meal. TOascertain whether the heat t h o u g h gossypol, purified, or e m p l o y e d in drying the meal isolated from the seed, is readily had rendered the gossypol unsoluble in anhydrous ethyl ether, it was found that anhydrous ether extracts materially less extractable, charges were dried in a desiccator over calcium chloride without any heat except that of room temperature. gossypol from moisture-free cottonseed meal. In the quantitative estimation of gossypol, a recently The results were no different from those obtained by drypublished modified method (1) was used in which a portion ing with heat and vacuum. The average amount of gossypol extracted with anhydrous of the oil was removed from charges of 75 grams of meal by washing with petroleum ether and the meal allowed t o dry ether from meals dried as above and also dried for 48 hours overnight in trays by exposure to the air. During this ex- a t room temperature in a desiccator over calcium chloride is posure, the meal readily absorbed or lost moisture, being 0.0069 per cent, compared to 0.0130 per cent with ordinary ether. responsive t o the humidity of the air. The Soxhlet apparatus was employed for the extraction of EFFECT OF MOISTURE IN ETHER gossypol by ether. The extraction was usually continued for Since ordinary ether extracted slightly more gossypol, 48 hours, but later was extended to 72 hours because of a slightly increased yield. Both ordinary ethyl ether (not for other charges of meal dried in a vacuum oven but a t 30" C. anesthesia or medicinal use) and anhydrous ether, which were extracted with anhydrous ether and with ether saturated with water. The results of determinations with anhydrous was distilled over sodium, were employed.
September 15, 1933
I N D U ST 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
ether averaged 0.0070 per cent. Results were higher (0.0414 per cent) where ether saturated with water was used, especially where more of the saturated ether was used to replace that lost during extraction (0.0471 per cent). Anhydrous ether and ether saturated with water were also used with air-dry charges of meal 1421, with the result that the anhydrous ether gave an average yield of 0.0266 per cent, being appreciably higher than the results on the dried meals above. Air-dry meal with ether saturated with water yielded an average of 0.0468 per cent. It was observed a t this time that the charges of air-dry meal, which became damp during a rainy spell when the petroleum ether was allowed to evaporate, gave a higher yield of gossypol, an average of 0.0770 per cent.
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extracted was investigated. The charges of meal were all moistened to contain 17.6 to 20.0 per cent of water. The amounts of gossypol extracted, when water was added to the receiving flask containing the ether and to the meal, compared with those obtained without the addition of water, showed that the addition of 5 cc. of water to 350 cc. of ether in the receiving flask gave a better extraction of gossypol, averaging 0.0424 per cent compared with 0.0193 per cent with ordinary ether.
EFFECT OF MOISTURE IN MEALAND ETHER
Moisture appears to be the important factor which enables more gossypol to be extracted when water is present both in the meal and in the solvent, as well as when added to the receiving flask. Therefore, the results obtained on charges TABLEI. FACTORS AFFECTINQESTIMATION OF GOSSYPOL IN COTTOXSEED MEAL of meal conditioned or moistened with water were compared to those obtained on air-dry charges of the same meal. A. EFFECTOF METHODSOF DRYINQUPON AMOUNT OF GOSSYPOL EXTRACTED, MEAL 1421 In the extraction of the meal conditioned with moisture, ANHYDROUS ORDINARY ETHER ETHER 5 cc. of water were added to each 350 cc. of ether in the reGossypol Gossypol DRIED ceiving flask. I n the set of air-dry meals, ordinary ether was % % used without the addition of water. 6 hours a t 50' C. over phosphorus 0.0000 0.0121 pentoxide in vacuum oven at 27 in. 0.0075 0.0133 Moisture was determined in the charges of meal im0.0076 .... 2 hours as above 48 hourn at room temperature in 0.0082 0.0137 mediately preceding the extraction with ether. The charges, deaiccator over calcium chloride 0.0112 .... of air-dry meal were taken from samples kept in quart fruit Av. 0.0069 0.0130 B . EFFECTOD' MOI0TURE I N ETHERUPON AUOUNT O F GOSSYPOL EXTRACTED jars, sealed with a rubber ring and cover. The meal stored FROM OVEN-DRIED A N D AIR-DRYMEAL1421 in the chemical laboratory usually contained approximately ETHER SATURATED WITH 5 to 7 per cent of moisture. ANHYDROUB ETHER WATER B Y WASHING Detn. Gossypol Detn. Gossypol The meal was conditioned for moisture by passing con% % densing steam slowly (5 hours) over thin layers of meal 0.0397 15 0.0075 4a 0.0373 5a 0.0075 20 spread out in trays on shelves in an inclosed box until the 0.0471 0.0061 3a 6a meal contained approximately 20 per cent or more of moisture. Av. 0.0070 Av. 0.0414 The shelves were so arranged that the condensing steam cir7b 0.0277 9s 0.0450 8a 0.0254 10b 0.0460 culated over each tray successively from the top to the llb 0.0493 bottom. Av. 0.0266 Av. 0.0468 The data (Table I, D) show that with the addition of water C. EFFECTOF ADDITION OF WATERIN RECEIVINQ FLASK ON AMOUNT OF GOSBYPOL EXTRACTED (RESIDUESOF M ~ A 1578 L AFTBR PARTIAL EXTRAC- to the ether in the receiving flask and also with a considerable' TION OF GOSSYPOL) increase in the moisture content of the meals, larger amounts r ORDINARY ETHERETHER WITH 6 CC. WATER ADDED Water in Water in of gossypol can be extracted. For meals 1414 and 1412, Detn. meal Gossypol Detn. meal Goesypol both containing over 25 per cent of moisture, 0.0810 and % % % % 1 20.0 4 lS16 0.0408 0.0228 0.0294 per cent of gossypol, respectively, were obtained. This 2 17.6 5 19.3 0.0463 0.0168 is appreciably more than the 0.0070 and 0.0123 per cent 0.0400 3 17.6 0.0182 6 19.3 Av. 0.0193 Av. 0.0424 obtained from these air-dry meals without the addition of D. E F F ~ C OPTMOISTURE I N MEALAND ETHERUPON AMOUNT OF GOSSYPOL water to the receiving flask. Thus the gossypol extracted BXTRACTED from the conditioned meals with ether was respectively 11.6 Y A I R - D R Y MEAL-? -MOISTINED MIALand 2.4 times greater than for the charges of the same air-dry MEAL Detn. Water Gossypol Detn. Water Gossypol % % % meals. 1414 1 , ,. 0.0059 6 26.8 O.Oi76 The influence of moisture, both in the meal and with water 2 ... 0.0065 6 26.8 0.0843 3 ... 0.0083 added to the receiving flask in contact with the ether, was 4 ... 0.0071 shown in three ofiher samples. Air-dry meals 1578, 1742, Av. 0.0070 Av. 0.0810 and 1743, containing moisture varying from 4.9 to 6.1 per 1412 1 ... 0.0117 4 27.3 0.0285 2 ... 0.0133 5 27.3 0.0302 cent, yielded 0.0531,0.0043, and 0.0005 per cent of gossypol, 3 ... 0.0120 respectively. When these meals were conditioned with moisAv. 0.0123 Av. 0.0294 1578 1 4.9 0.0409 4 19.7 0.1237c ture varying from 19.3 to 21.4 per cent, the gossypol ob2 5.0 0.0485 6 19.7 0.0947 tained was respectively 0.1309, 0.0739, and 0.0687 per cent. 3 5.0 0.0610 6 21.4 0.1378 7 21.4 0.1312 Some air-dry meals yielding little gossypol contained Av. 0.0531 Av. 0.1309 from 4.9 to 6.1 per cent of moisture. This is quite low. 1742 1 6.1 0.0020 4 19.3 0.0674 Meal held in storage during long dry spells will contain less 2 6.1 0.0049 5 20.8 0.0785 3 5.6 0.0061 6 20.8 0.0757 moisture, probably comparable to those given above. For Av. 0.0043 Av. 0.0739 several years the authors have been unable to extract weigh1 6.8 0.0002 3 21.4 0 0688 1743 able amounts of gossypol from such meals. 2 5.8 0.0007 4 21.4 0 0686 Av. 0.0005 Av. 0.0687 The results show that a considerably larger amount of a 6 hours a t 30" C. over phosphorus pentoxide in vacuum oven at 28 in. gossypol can be extracted when the meal is moistened with b Air-dry as sampled. Omitted in average. water varying from 19.3 to 27.3 per cent, and that an increased amount of gossypol can likewise be obtained from a EFFECTOF WATERIN RECEIVING FLASK meal containing as much as 33 per cent moisture. It is not As more gossypol was extracted with an ether saturated possible to state the amount of moisture in a meal that is with water, the effect of addition of water to the receiving necessary for the best extraction of gossypol, but from 20 to flask in the Soxhlet apparatus upon the amount of gossypol 25 per cent appears to be favorable. ~~
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ANALYTICAL EDITION
DISCUSSION Total gossypol determined in a modification of the method of Carruth (3) of meal 1578 was 1.102 per cent, of which free gossypol on the air-dry sample constituted 4.82 per cent; with the meal conditioned, the free gossypol constituted 11.87 per cent of the total, or an increase of 7.05 per cent due to the change in moisture content of the meal and to extraction with ether saturated with water. Gossypol is considered to exist in cottonseed meal in two forms, free and bound, being distinguished by their difference in solubility in ether. By the process of condensing steam or merely by the addition of moisture uniformly distributed in the meal, there is a loosening of the gossypol in some manner so that it can be extracted in greater quantity by moist ether in the presence of water in the receiving flask. The author's results indicate that there is no fixed limit between free and bound gossypol. In the determination of free gossypol, it is essential that the moisture content of the meal immediately preceding the Soxhlet extraction be controlled and that the extraction be done by ordinary ether in the presence of about 5 cc. of water per 350 cc. of ether in the receiving flask. The presence of 20 to 25 per cent of moisture in the meal will yield appreciably more gossypol than is obtained from an air-dry meal. The data show that the amount of gossypol obtained by extraction with ether will depend largely upon the amount of gossypol present in the meal and its moisture content at the time of extraction with ether in the presence of water in the receiving flask.
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SUMMARY Experiments showed that little if any gossypol could be extracted from moisture-free meal by anhydrous ether, and this also held for air-dry meal. Heat, used in drying the meal, was eliminated as a cause of this difficulty, Little gossypol could be extracted from meals containing 5 to 7 per cent of moisture. It was found that water is the important factor in the extraction of gossypol. The addition of moisture to the meal in amounts varying from 17.6 to 27.3 per cent and to the ether in the extraction flask aided the extraction, yielding increases of gossypol from twice to many times that obtained from air-dry meal with ordinary ether. Increased amounts of gossypol were obtained when water was also added t o the ether in the receiving flask. The extraction of appreciably more gossypol, with ether saturated with water from meals suitably moistened, suggests that there is no definite limit between bound and etherextractable gossypol. LITERATURE CITED (1) Halverson, J. O., and Smith, F. H., IND. ENG.CHXIM., Anal. Ed., 5 , 29-33 (1933). (2) Sohwartee, E. W., and Alsberg, C. L., J.Agr. Research, 25, 285-95 (1923). (3) Sherwood, F. W., Ibid., 32,793-800 (1926). Racmvnn May 15, 1933. Presented before the Division of Biological Chemistry at the 85th Meeting of the American Chemical Society, Washington, D. C., March 26 to 31, 1933. Published with the approval of the Director of the North Carolina Agricultural Experiment Station as Paper 69 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,
