May 1952
INDUSTRIAL A N D ENGINEERING CHEMISTRY
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ACKNOWLEDGMENT
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Figure 3.
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The authors are indebted t o W. L. Hill of the U. S. Department of Agriculture, Beltsville, Md., for kindly furnishing samples of fluorapatite, hydroxyapatite, beta-tricalcium phosphate, and hydrated tricalcium phosphate; also, t o W. H. MacIntire of the University of Tennessee, Knoxville, Tenn., for furnishing samples of hydrated tricalcium phosphate. The chemical analysis of the citrate-insoluble residue was made by Mrs. J. C. Redding of The Solvay Process Division, and the x-ray data were obtained by Ruth Grimm of Central Research Laboratory.
7, B E T & T I I I C A L C I U L I P W O S P U A I I A D D T D
Graphical Estimation of P-Tricalcium Phosphate in Citrate-Insoluble Residue
LITERATURE CITED
(1) Association of Official Agricultural Chemists, "Methods of Analysis," 7th ed., Washington, D.
sented by this sample. This, however, is not in agreement with previously published data (5, 7 ) , which state that a large proportion of the reverted material is hydroxyapatite. Considering these conclusions correct, reversion could be reduced markedly by reducing the formati6n of fluorapatite-Le., by volatilizing larger amounts of fluorine in the manufacture of superphosphate to decrease the fluoride content, and maintaining a low moisture content and temperature throughout the storage of the fertilizer materials to decreaw the mobility of the fluorides. This conclusion would appear in agreement with the data of Datin, Worthington, and Poudrier (R), which indicates that the phosphdrus pentoxide reversion of a group of ammoniated superphosphates is a linear function of the fluorine content in the range of 0.47 to 1.2%.
(2) Datin,
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R.C., Worthington, E. A., and Poudrier, G. L., IND.ENG.
CHEM.,44, 903 (1952). (3)Eisenberger, S., Lehrman, A,, and Turner, W. D., Chem. Revs., 26, 257 (1940). (4) Hendricks. S. B..Hill. W. L.. Jacob. K. D.. and Jefferson. M. E.. IND.ENG.CHEM.,23, 1413 (1931). (5) Jacob, K. D.,Hill, W. L., Ross, W. H., and Rader, L. F., Jr., Ibid.,22, 1385 (1930). (6)Jones, R. M., and Rohner, L. V., J . Assoc. Oflc. Agr. Chemists, 25, 195 (1942). (7) Keenen, F. G.,IND.ENG.CHEM.,22, 1378 (1930). ( 8 ) McCreery, G. L., J . Am. Cernm. SOC.,32, No. 4, 141 (1949). (9) MacIntire, W.H.,Palmer, G . , and Marshall, H. L., IND.ENG. CHEM.,37, 164 (1945). RECEIVED for review August 23, 1951. ACCEPTED November 28, 1951. Preaented before the Division of Fertilizer Chemistry at the 120th Meeting O f the AMZRrcAN CHEMICAL SOCIETY, NEWYork, N. Y.
Stability of Carotene Concentrates J
H. L. MITCHELL, W. G. SCHRENK, AND RALPH E. SILKER Kansas Agricultural Experiment Station, Kansas State College, Manhattan, Kan.
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ONSIDERABLE study has been devoted to the preparation of stable carotene concentrates for use in supplementing vitamin A-deficient rations. Such concentrates were made by dissolving extracted plant lipides or crystalline carotene in vegetable or mineral oils. The stability of the carotene of such concentrates has been modified by incorporation of various antioxidants into the concentrates ( I ) . A more convenient form of concentrate can be prepared by mixing the extracted plant lipides with finely ground solids, such as various feed ingredients (8, 5 ) , resulting in a free-flowing mixture. One advantage of such concentrates over the oil type is the greater ease of incorporation into the rations of animals. Furthermore, certain carriers exert some stabilizing influence on the carotene ( 2 ) . Additional studies on free-flowing concentrates have been made with three carriers to study the effect of the addition of various stabilizing substances. All three of the carriers have some inherent ability to improve carotene retention when mixed with either extracted plant lipides ( 2 )or with alfalfa meal (3). EXPERIMENTAL. The lipide fraction of dehydrated alfalfa meal was extracted and freed of chlorophyll and xanthophylls as described elsewhere ( 2 ) . The extractives were dissolved in Skellysolve B and the concentration of carotene was determined with a Beckman spectrophotometer at a wave length of 4360 A. The final solution contained 2700 micrograms of carotene per ml. The stabilizers constituted 0.2% of the final concentrate, except in the case of the rice bran extract. The latter consisted of the
Skellysolve B extract from 50 grams of unconverted rice bran (supplied by the American Rice Growers Cooperative Association, Houston, Tex.). Each stabilizer (0.15 gram) or rice bran extract was dissolved in Skellysolve B in a 600-ml. beaker. About 30 ml. of the carotene solution were added and the volume was reduced on a steam plate to 10 to 15 ml. Seventy-five grams of the desired carrier were added to the beaker and the contents mixed thoroughly. The mixture was transferred t o a sheet of paper and blended with a spatula. I t was spread out in a thin layer and kept in a dark cabinet for several hours to permit evaporation of the solvent. Each concentrate waa placed in a 4-ounce screw-cap bottle, analyzed for carotene (4), and stored a t 25" C. in a darkened constant-temperature room. The initial carotene content of each concentrate was about 1000 micrograms per gram. RESULTS
From Table I it will be seen that in the absence of added stabilizers unconverted rice bran contributed the greatest stability to the carotene. It is apparent also that the relative synergistic abilities of the stabilizers varied from one carrier to another, For example, the addition of diphenylamine or Caromax t o cottonseed meal and rice bran concentrates did not reduce carotene destruction, while some reduction did occur when these were added to soybean meal concentrates. Dimethylaniline had a
INDUSTRIAL AND ENGINEERING CHEMISTRY
1124 TABLEI.
EFFECTO F CARRIERS A N D ANTIOXIDANTS O N DESTRUCTION OF CAROTENE IN CONCENTRATES
THE
Carotene Destroyed, -1Months in Storage-1 2 4 6 8 85 47 13 26 74 Expeller cottonseed meal None 44 57 79 Caromax" 11 37 35 49 74 Dimethylaniline 16 25 22 27 37 fj6 Tenox HQb 12 Diphenylamine 50 77 43 38 l? 25 8 61 Rice bran extract 13 24 48 71 94 None 20 Expeller soybean m a l 51 27 37 Caromax 18 82 Dimethylandine 42 66 89 10 40 15 36 52 Tenox HQ 27 79 Diphenylamine 13 20 60 80 34 63 Rice bran extract 10 27 15 39 Unconverted rice bran Sone 12 16 27 40 54 Caromax 11 20 28 38 53 Dimethylaniline 12 14 24 36 46 1 9 18 36 51 Tenox HQ Diphenylamine 14 24 32 43 56 a Manufactured b y t h e B. F. Goodrich Chemical Co., Cloi.eiilnd Ohio; t h e chief active ingredient is diphenyl-p-phenylenediamine. b Manufactured by Tennessee Eastm,an Corp., Kingsport, T c n n . ; t h e chief component 18butylated hydroxyanisole. Carrier
Stabilize1
Vol. 44, No. 5
rice bran extract when it was added to the cottonseed nical and soybean meal concentrates. I-Iowever, these combinations failed to maintain their early effectiveness, as evidenced by the great increase in carotene dest'ruction between the sixth and eighth mont,h. Such behavior is charactcristic of antioxidants. Little is known of the toxicity of these substances when used at the low concentrations which will be required of an antioxidant. Before practical uye can be made of such concentrates for fortification of feeds, it will be necessary to investigate possible adverse effect.s on the animals M.hich might consume the feeds. If various carriers have different native antioxidants, addition of another antioxidant may affect each carrier in a variable manner. This technique may be used to test the ability of various combinations of chemicals and carriers to inhibit carotene oxida-. tion. It should be possible to devise systems which will perniit the preparation of reasonably stable free-flowing concentrates for supplementing deficient rations. LITERATURE CITED
(1) Bickoff, E., Williams, K. T., and Sparks, M., Oil & Soap, 22, 128
slight effect with soybeanmeal and rice bran, but nonewith cottonseed meal. Tenox HQ, on the other hand, increased carotene stability with all three carriers, although its supplemental effect with cottonseed meal was not so great during the early months of storage. Tenox I3Q was especially effective Rith rice bran for the first 4 months, after which its effect was dissipated. The greatest and most persistent synergism vas contributcd by the
(1945). Mitchell, R. L., Schienk, W. G., arid King, H. H., ISD. EXQ. CHEM.,41, 570 (1949). ( 3 ) Mitchell, H. L., and Silker, R. E., Zbzd., 42, 2325 (1950). (4) Silker, R. E., Schrenk, IF', G., and Icing, €€. H., IWD.EWG. CHEM., ANAL.ED.,16, 513 (1944). ( 5 ) lva11, hf, E., and Kelley, E. G., I N D E N 6 CHEW., 43, 1146 (1981). (2)
RIXCIVEDfor review October 8. 1951.
ACCEPTEDDecember 13, 1951. Contribution 455, Kansas 4 g i icultuial Expel inient Station, M a n h a t t a n Kan. 6
thalate
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INVESTIGATION OF THE MONOGLYCERIDE METHOD ROBERT H. RUNId Westinghouse Research Laborutories, East Pittsburgh, P a .
INCE 1936 when Ott, Bernard, and Frick (6) first disclosed the alcoholysis or monoglyceride method of preparing oilmodified alkyd resins, the protective coatings industry has shown increasing interest and activity in the reaction of fatty acid esters with polyhydric alcohols to form monoesters. The following equation shows the alcoholysis of a drying oil with glycerol: 0
CHz-0-C--R
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Drying Oil
Glycerol
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SCH,---O--C-R
hIonoglycericie
where R = C17Hs3or CllH31, etc. To the reaction mixture, after sufficient monoester is formed, phthalic anhydride or other polycarboxylic acid may be added and, by continued heating, a viscous, air-drying alkyd resin is formed. During the final reaction, esterification of the h e
hydroxyl radicals of the inonoglyceride inust compete with esterification of any unreacted or excess glycerol present. The lat8ter course leads to rapid cross linking and formation of insoluble, infusible, or gelled, glyceryl phthalate in which the oily glycerides and oil-modified glyceryl phthalate are insoluble. Thercf'ore, unless sufficient bifunctional monoglyceride is present prior t o addition of the phthalic anhydride to act m a fluxing medium for interchange, the ultimate reaction product nil1 be an insoluble gel of glyceryl phthalate suspended in oily, mixed glycerides. Such products are commercially worthless. To aid in estimating the proper degrec. of dcoholysis or conversion to nionoglyceride an cmpricial test has been evolved. A sample of reaction product is mixed Tvit,h anhydrous methanol t o observe the degree of compatibility. Marling ( 4 )has stated that when 1 volume of the glyccrol-free reaction product (upper layer) forms a char solution with a minimum of 4.5 volumes of anhydrous methanol, sufficient alcoholysis has taken place to ensure satisfactory fluxing-in of the dicarboxylic acid. This test is commonly used in the alkyl resin industry. It is the purpose of this investigation to establish a clearer knowledge of the alcoholysis reaction as applied to drying oils and alkyd resins as follows: 1. To study the rate of formation of monoglyceride and the amount present at equilibrium in alkyd resin intermediates
