Mar., 1915
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
for pure sucrose with t h e present sugar scale, should be increased from 1 4 2 . 6 6 t o 1 4 2 . 7 8 , while if it is intended t o give t h e same figure as the direct polarieation of pure sucrose, regardless of the scale used, which is more logical, it should be further increased to 1 4 2 . 9 2 . COLLEGE OF HAWAII HONOLULU _.
THE NITROGEN AND FAT IN SHORT STAPLE COTTONSEED By C. A. WELLSAND F. H. SMITH Received December 21, 1914
The cotton plant breeders of the past have directed their efforts mainly towards increasing the yield and length of lint of cotton as well as its power of resistance, while t h e question of next importance, i. e., the relative percentage of nitrogen and f a t in different types of seed, has received little consideration. The manufacture a n d preparation of cottonseed oil and its products and of cottonseed meal constitute imgort a n t industries within themselves. Modern and intelligent management of these industries is beginning t o demand a more thorough understanding of t h e properties of the different varieties of seed. Already there is a wide-spread and growing endeavor on t h e p a r t of the manufacturer t o purchase seed containing a high percentage of f a t and nitrogen, particularly t h e latter. A study has been made in this laboratory of the commercially important chemical constituents of eighteen varieties of short staple cottonseed. These varieties were selected as typical for the upland sections of Alabama, Georgia and other states similarly situated. They were grown upon the same kind of soil (a red clay) which had been uniformly fertilized. This was deemed necessary because experience had indicated t h a t both the type of soil and nature of fertilizer may affect t h e nitrogen and oil content of the seed. The cotton was ginned in one gin under conditions as nearly uniform as possible and the remaining lint was removed by hand with a scalpel. Even though tedious, this was essential’ because, as will be shown in Table I, t h e lint not removed from t h e seed by the gin may vary from 97 t o 2 1 4 lbs. per 1 0 0 0 lbs. of seed, so t h a t it is inaccurate t o base analytical results upon t h e original weight of seed, as has often been done, without proper consideration for the unremoved lint. The.hulls were removed by hand and the kernels analyzed, using the Gunning-ArnoldDyer modification of the Kjeldahl method for nitrogen; allowing for nitrates, and the vacuum-sulfuric acid procedure for moisture. It was not found feasible to determine i h e moisture in kernels or in cottonseed meal by the usual method of drying in a n oven, because decomposition took place even a t 60”. Similarly it was found necessary t o dry the flasks containing the ether extracts by immersing them deeply into the boiling water of t h e water bath instead of drying on the water bath or in the drying oven. The analytical results are given in Table I in order of nitrogen-ascendency in two groups of nine varieties each.
TABLE1-PERCENTAGE
N ~ . VARIETY 1 Niel’s big boll. 2 Mexican big boll.. 3 Caldwell’sbigboll 4 Cook’s reimproved.. 5 Sunbeam.. 6 Cleveland big boll.. 7 Kimbrough.. 8 Poulnot.. 9 Willet’s perfection.. AVERAGE
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COMPOSITION OF UPLAND SHORT STAPLE COTTON-SEED KERNELs Seed DELINTED SEEDMoisNitrolint Hulls Kernels ture Fat gen 19.13 35.00 65.00 7.06 41.10 5 . 1 6 16.61 33.90 66.10 9.75 36.20 5.21 20.30 36.90 63.10 7 . 8 3 39.80 5.21 16.49 34.80 65.20 7 . 7 4 40.00 5 . 2 2 18.09 34.20 65.80 6.42 40.35 5 . 2 3 18.12 34.40 65.04 6 . 5 6 43.50 5 . 2 6 21.43 36.50 63.50 9 . 2 9 48.04 5 . 3 2 12.96 34.60 65.40 7.80 44.06 5.39 18.34 35.30 64.70 6 . 6 0 41.20 5 . 4 9 17.94 35.07 64.87 7 . 6 7 41.58 5 . 2 7
........... ....... ........ ..... .............. ...... ............ ............... ...... .............. Schley .................. 9 . 7 4 Pevy’s improved.. ....... 10.75 Cook’s improved.. ....... 17.45 Jarman K. sunbeam., .... 19.50
10 11 12 13 14 Willet’s ideal. 15 Cook’s No. 675 Ala. Exp. Station.. 16 Wanamaker’s ext. big boll --storm proof.. 17 King & triumph,hybrid.. 18 Hite’s early prolific.. AVERAGE.
............ 20.35 .............. 20.84
........ ...... .............
14.92 13.46 13.24 15.58
34.3 33.30 35.70 37.40 35,60
65.7 66.70 64.30 62.60 64.40
6.89 8.67 6.53 7.16 6.51
42.70 42.72 37.80 35.20 42.30
5.63 5.65 5.69 5.75 5.82
36.60 63.40
8.85 37.60 6 . 0 0
35.20 36.70 33.33 35.32
7.58 8.04 7.48 7.52
64.80 63.30 66.7 64.52
35.50 43.43 37.26 39.39
6.15 6.20 6.22 5.90
Attention has been called already * t o the difference in lint which the process of ginning may leave on t h e seed. From Table I it will be seen, also, t h a t t h e f a t in t h e kernels may vary from 3 5 . z t o 4 8 . 0 4 per cent and the nitrogen from 5 . 1 6 t o 6 . 2 2 per cent. If t h e average be taken for t h e two arbitrarily chosen groups of nine varieties each as given in t h e table, i t will be seen t h a t t h e fat varies only slightly, especially if consideration is had for the difference in lint on t h e seed, while t h e nitrogen shows a variation of approximately I O per cent. Thus a ton of mixed cottonseed from t h e second group would contain 8 . 3 Ibs. more nitrogen and 1 3 . 6 lbs. less oil t h a n a ton of seed made up similarly from Group I . This amount of nitrogen has a value of approximately $ 2 . 0 0 and t h e oil a value of about 50 cents for the expressible portion with a slight feeding value for the non-expressible portion, leaving a balance of approximately $ I 50 a ton in favor of the high nitrogen seed. This means a great saving on the total of 5,000,ooo tons of cottonseed crushed annually in t h e South. It will be interesting in the future t o ascertain if the variations noted here are constant or if they change with the seasons. ~
LABORATORY OF CHEMISTRY, GEORGIA EXPERIMENT STATION EXPERIMENT, GEORGIA
UNSAPONIFIABLE MATTER IN GREASES By E. TWITCHELL Received November 30, 1914
The following method of determining unsaponifiable matter in greases has been in use under my direction in the laboratory of the Emery Candle Co. for five or six years. Five grams of the sample (or preferably of the f a t t y acid prepared for “titer test,” as this is cleaner) are saponified with alcoholic potash in a dish and evaporated nearly t o dryness. A little alcohol is added and then water, and t h e solution obtained is washed into a separatory funnel. The ratio of alcohol t o water in this soap solution should be about I : 4, and the total volume of t h e soap solution I 50 t o zoo cc. The soap solution is shaken twice with ether, using about 50 cc. each time. The ether extracts are united, washed once with water, then shaken
218
T H E JOURiVriL O F 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
with dilute hydrochloric acid, washed again with water, transferred t o a weighed dish, evaporated, dried a t 1 1 0 ’ C. a n d weighed. This residue consists chiefly of unsaponifiable matter, b u t contains f a t t y acids as t h e ether has dissolved some soap which is afterwards decomposed by the hydrochloric acid. It is therefore taken up Kith neutral alcohol and titrated with standard alkali solution. T h e f a t t y acids thus found, calculated as oleic acid, are deducted from the weight before obtained. A third treatment with ether will extract so little more t h a t for ordinary analytical work i t may be omitted. If t h e f a t t y acids obtained from t h e grease, instead of t h e grease itself, have been used, t h e result must of course be calculated on t h e original grease. This method differs from t h a t of Allen and Thomson, given by Lemkowitschl as his preferred method, only in some details: chiefly t h e simple and accurate way of correcting for soap dissolved in t h e ether. Having this correction, i t is not necessary to be sparing in t h e use of alcohol for fear of causing t h e ether t o dissolve soap, b u t enough may be used t o cause a n almost instantaneous separation in the funnel of perfectly clear and sharply marked ethereal and aqueous layers. A determination of unsaponifiable matter can be easily completed in I I / ~hours. Ether has been found t o be t h e best general solvent fpr a variety of unsaponifiable matters found in fats and t h e objection t h a t i t dissolves some soap disappears when using this method. T h e uncertainty as t o t h e molecular weights of t h e f a t t y acids found by titration in t h e residue would lead t o error, but when t h e small percentage of these f a t t y acids calculated on t h e original sample of grease is considered i t will be seen t h a t this error is entirely negligible, and t h e f a t t y acids may be calculated as oleic acid, or, a n average molecular weight, as t h a t of tallow f a t t y acids, may be taken. The above method of determining unsaponifiable matter, when compared with other methods, has never given lower results. In some cases t h e results are higher, especially t h a n those obtained where petroleum ether is used as t h e solvent. T h a t the results are not too high has been repeatedly proven by a careful examination of t h e extract, particularly for neutral fat a n d for ethyl esters which might possibly have been formed from a little alcohol remaining in t h e ether when it is shaken with hydrochloric acid. The details of this method were worked out by Mr. C. Foerster, who has used i t in this laboratory, not only in t h e daily analysis of greases, but also with good results in extracting fats containing other t h a n t h e usual kinds of unsaponifiable matter. WYOMING, OHIO -_ _ _ ~ _ _ A NEW METHOD FOR THE DETERMINATION OF THE TOTAL FATTY ACIDS AND OTHER ETHER-SOLUBLE CONSTITUENTS OF FEEDSTUFFS By J B. RAT HER^ Received October 27, 1914
Determination of fats by direct saponification of 1 Lewkowitsch, “Chem. Technology and Anal of Oils, F a t s and Waxes.” 5 t h Ed. Vol I, p 458 Abstracted * U n d e r t h e general direction of G S. Fraps, Chemist by t h e author from Texas Exper. S t a , Bull 169.
VO\. 7 $ KO. 3
t h e sample has been proposed by Liebermann a n d Szekelyl and by Kumagawa a n d Suto.2 These methods are open t o several objections, chief among which are t h a t they make no adequate provision for t h e removal of non-fatty material from t h e extracts, a n d t h a t t h e methods, giving results comparable with ether extracts of t h e same samples, yield products not only impure b u t incompletely extracted. While i t has long been known t h a t ether does not extract all of t h e ether-soluble constituents of plant a n d animal products, t h e extraction is generally considered t o be complete enough for practical purposes. Dormeyer3 states t h a t ether extraction of meat i s far from complete a t t h e end of I O O hours. Browned states t h a t pepsin digestion of steer feces renders a larger amount soluble in ether t h a n can be obtained from untreated samples. Fraps and Rather5 show t h a t chloroform extracts considerable ether-soluble matter from hays which have previously been extracted with ether, and t h a t this extract contains f a t t y acids. We have been unable t o find any mention in t h e literature of t h e use of alcoholic soda or potash as a solvent for fats in plant or animal products. EXPERIME KTAL
A method was developed for t h e determination of total f a t t y acids and other ether-soluble constituents of feedstuffs. The experimental evidence on which t h e method is based may be found elsewhere.6 T h e following factors were considered in t h e development of t h e method (alcoholic soda method) : 1-Completeness of saponification; a-unsaponified material in t h e f a t t y acids; 3-fatty acids in t h e unsaponified material; 4-completeness of t h e extraction of t h e f a t t y acids b y petroleum ether; 5-completeness of extraction of the saponified residue; 6-saponified residue in f a t t y acids; ;-saponified residue in t h e unsaponified material; &-washing required t o remove hydrochloric acid after liberating acids in unsaponified material; 9-the checking of duplicate determinations run a t different times; 1-completeness of direct saponification; and 11-completeness of t h e extraction of t h e ether-soluble matter from t h e alcoholic soda extract. The following determinations were made on twelve samples of hays a n d excrements from them, and on twelve samples of concentrated feeding-stuffs: ether extract by t h e Official hlethod;’ constituents of t h e ether extract by t h e Precipitation a n d ethersoluble constituents by t h e Alcoholic Soda Method given below. The Precipitation Method is t h e same as t h e Alcoholic Soda Method with t h e principal exception of t h e method of extracting t h e ether-soluble matter from t h e sample. The 9lcoholic Soda Method, while very rapid, requires a knowledge of its technique for satisfactory results, so i t is given below in detail. 1
2
3 4 5
8 7
Pfiiigev’s Arch., 72 (1898), 360-366. Biochem. Zeit., 8, 212. Pfiiiger’s Arch., 61, 341-43. Proc. 20th Coss. A . 0. A . C. Texas Station, Bull. 162.
LOG.cit.
U.S. D. A,, Bureau Chem.. Bull. 107 (revised). Texas Experiment Station, Bull. 169.
