Sovember. 1929
11YDUSTRIAL A 9 D ESGIn'EERlNG CHEMISTRY
color readings for 90" and 100" C. It is evident that a point of inflection occurs a t about 70" C., the temperature a t which the color was found "to flow" by Cruess ( 3 ) . At 40" and 50" C. the color increases but slowly with time during the first hour of heating; a t 60" and 70" C. there is :t more rapid increase in color with time, but this increase begins to fall off after 20 and 25 minutes, respectively. The color obtained by heating a t 70" C. for 5 minutes corresponds to that obtained for 18 minutes a t 60" C., about 40 iniiiutes a t 50" C., aiid 60 minutes a t 40" C., and about 80" C. for 2 minutes. The curves shown in Figure 3 for the tannin content of thc juice are somewhat Gnilar in shape to those for intensity of color. DifTerences occur in the plot for the change in tarinin content x i t h time IJf heating a t 60" C., and for change 111 tannin content with temperature of heating. These are not directly comparable with those for color intensity. The tannin coiiteiit of the lot of Petite Sirah grape< used in these tests is conderably lower than the t a m I I content ot grape juice rqmrtecl in the literature (?, 61.
1137
Conclusions
(1) Heat,iiig to extract color from red-juice grapes affects both the concentration and the nature of color. (2) The color intensity increases slowly as the temperature is raised from 20" to 70" C., and rapidly from i o " to 90" C. (3) The color intensity increases more rapidly wit'li time at' 70" and 60" C. than a t 40" or 50" C. (4) The tannin content of the juice varies somewhat similarly with time and t,emperature of lieat,ing, as does the color intensity. Literature Cited fl) Assocti. Oficial Agr. Chem., Methods, p. 3 6 i (1925). f2) Caldwell, J . ilgr. Research, 30, 1133 (1928). (3) Cruess, University of Caliiornia Expt. Sta., Bull. 331 (1920), "Commercial Fruit and Vegetable Products," p. 321, McGra\v-Hill Book CO .
1024. (4) Hartmann and Tolman, U. S . Dept. A g . , Bull. 656. ( 5 ) Meade and Harris, J. IND.ESG. CHEM.,12, 686 (1920). (6) Soyes, King, and Martsolf, J . .tssocn. O 3 r i a Z :Igv. C h e ? 6, ~ 1 9 i (14221.
Fatty Acids of Filter-Press Cake from Spent Soap Lye' B. W. Howk and C. S. Marvel
I
N T H E purification of spent soap lye fur the recovery of
glycerol ( 2 ) some American manufacturers use the Gerber process. This method consists in neutralizing the spent lye with hydrochloric acid and treating with ferric chloride t o precipitate as the iron salts the fatt? acids who.e sodium salts have remained in solution in the lye liquors. I n the present practice these iron salts are filtered off on a filter press and discarded. The exact composition of this filter-press cahe aiid the nature of the fatty acids that are present do not beem to have been carefully investigated. I t is obvious from the source of this material that it should contain the salts of some of the lower fatty acids. Since there is some interest in the salts of these acids, an investigation of this crude filter-press cake was undertaken in order to determine whether or not it would -ewe as a source for them. Preliminary Analyses and Tests
The filter-press cake2 was analyzed for moisture by drying in a vacuum oven at, 100" C., for total ash by ignition, and total nitrogen by the Kjeldahl method. These results are as follows: moisture 55.5, ash (dry basis) 43.1, and nitrogen (dry basis) 0.19 per cent. This indicated that the filter-press cake cont'ained very little protein material. Treatment of the filter-press cake with either hydrochloric or sulfuric acids liberated water-insoluble fatty acids, which were partly volatile with steam. From 500 gmms of crude filter-press cake by treating with excess 10 per cent sulfuric acid there were obtained 35 grams of mixed water-insoluble ncids. Separation of the acids was not satisfactory, so direct esterification of the product followed by fractionation of the mixed esters was next tried. Received June 7, 1929. T h e filter cake was furnished b y the Armour Soap Works. Victor Cofman had reported that he was able t o isolate esters of the lower fatty acids from this material hut that he had not made a thorough investigation of the material.
Esterification and Fractionation of Esters
Two kg. of the undried filter-press cake and 1.5 liters of ethyl alcohol wcre placed in a 5-liter, round-bottom flask attached to a good reflux coiideiiser and fitted with an efficient mechanical stirrer. To this suspension about 300 graills of concentrated sulfuric acid were added, and the mixture was then boiled under reflux for ahout 7 hours. The material in the flask became semi-solid. About 2 liters of benzene mere added and the mixture wa3 filtered in a basket centrifuge to remove the suspended matter. This solution was distilled under ordinary pressure to remove the water, benzene, and alcohol. The r e d u a l black liquid weighed about 120 grams. This material was then carefully fractionated three times under reduced pressure, in order t o separate the various fractions. A considerable amount of black tarry residue was obtained in the first didillation. The final fractions collected are listed in Table I. Table I-Fractions
from Mixed Ethyl Esters of Filter-Press Cake Acids
FRACTION 1 2 3 4
130ILIXG P O l N T A T 4-6 M M
c.
71-73 73-93 93-98
9x-I 14
5 6
Grams 11.4 0.8
5.3
1 3 8.8
0.7
7
6.5
0.5 15.7
8 9
10 11 12
WEIGHT
2.0 28.0 Rebidue
Fractions 1, 5, 7 , 9, and 11 seemed to be reasonably pure compounds. The boiling points agree very closely with those of the ethyl esters of caprylic, capric, lauric, myristic, and palmitic acids, respectively.
1 9
Identification of Esters
The ester fractions Tvere identified by comparison of their boiling points, refractive indices, and densities with those
I N D U S T R I A L A N D ENGINEERING CHEMISTRY
1138
recorded for the pure esters. The identification was completed by saponifying the ethyl esters and converting the acid thus obtained to the solid p-bromophenacyl ester and determining the melting point of the solid derivative (1). Mixed melting points were also taken with known p-bromophenacyl esters. The results are collected in Tables I1 and 111. T a b l e 11-Comparison of Physical Properties of E t h y l Esters from F a t t y Acids of Filter-Press C a k e w i t h Known E t h y l Esters B. P. ETHYL B. P. FRACAT 4-6 ESTER AT 5 n? MM.“ d TION MM. d: OF ACID
c.
c. 1 5 7 9
71-73 114-117 134-138 156-160 178-185
11
0,83528 0.84328 0.85425 0. S4?25 0.827*5
1.4201 1.4332 1.4402 1.4441 1.4451
Caprylic Capric Lauric Myristic Palmitic
89-92 108-108 128-132 152-166 175-180
0.87817b 1 . 4 1 8 2 ~ 0.862d 1,4238~ 0.86711Qa 1.4321f 0:6ibS28c
....
T a b l e 111-Melting UXKNOWK
FRACTIOKESTER
c.
J
P o i n t s of p - B r o m o p h e n a c y l Esters ~BROMOPHENACYL ESTEROF: hfIXED
c.
The p-bromophenacyl esters of lauric and myristic acids have apparently not been previously described. They were
c.
66.0 59.0 77.0
68.0
80.0
c.g
of ethyl esters of coconut oil acids. b Cahours and Demarcay, Bull. soc. chim., [ 2 ] 34,. 482 (1850). c Determined on esters obtained from fractionation of ethyl esters of coconut oil acids. d Rowney, A n n , 79, 243 (1851). E Delffs Ibid. 92, 278 (1854). f Interdational Critical Tables, Vol. I, p. 255, McGraw-Hill Book Co., New York, 1926. o Ibid., Vol. I, p . 264.
KO.11
prepared from the corresponding acids by the method of Judefind and Reid (1) and after purification were found to melt at the temperatures recorded in Table 111. These.esters were analyzed for bromine by the Parr bomb method: p-Bromophenacyl laurate. Calcd., 20.14; found, 20.07. p-Bromophenacyl myristate. Calcd., 18.80; found, 19.05 The lauric acid ester was more granular in appearance than the other esters.
1.4347 at34.3’
a Obtained b y distilling esters that were available from fractionation
VOl. 21:
The intermediate fractions are mixtures of those esters which were not completely separated by the distillations. This was not determined definitely except in the case of Fraction 3, which was shown to be a mixture of ethyl caprylate and ethyl caprate. Literature Cited (1) Judefind and Reid, J . Am. Chem. Soc., 42, 1048 (1920). (2) Verbeek. Seifensieder-Zlg.,48, 202 (1921); C. A . , 16, 2738 (1921).
Factors Affecting Color in Sorghum Sirup’s’ J. J. Willaman3 and S . S . Easter‘ DIVISIONOF AGRICULTURAL BIOCHEMISTRY, UNIVERSITY OF hfINNESOTA, UNIVERSITY FARM, ST. PAUL, MI“.
Previous Work The main factors in quality i n sorghum sirup are color and flavor. The color m u s t be a fairly light a m sorghum sirups is Anderson ( I ) , in studying ber. The flavor m u s t be mild, b u t still characteristic s i m i l a r t o t h a t of the chemical changes caused of sorghum. Since t h e annual production of sorghum making cane sirup. It conby the clarification of sorsirup in t h e United States is about thirty million gals i s t s essentially in pressing ghum juice, noted the color lons; since a continually greater proportion of this is the juice from the stalks, of the sirup produced; but, being made o n a large industrial scale where techclarifying with heat, filtering not having any color standnical control is available, rather t h a n on the farm; or settling, and evaporating ards, he could only compare and since very little information exists about t h e conto a sirup. Refinements in, h i s s a m p l e s among themtrol of color and flavor in the manufacture of the sirup, and control of, this process selves. He concluded that t h e present work was undertaken. are possible only in the larger the amount of color in the The Pfund color grader has been found to be adf a c t o r i e s e q u i p p e d with sirup varies directly with the mirably adapted for use i n this industry. Reference laboratories. Under t h e s e amount of lime used and with tables a n d curves are presented herewith for (1) t h e conditions the control of the the time required for evapocalibration of this instrument against a spectrophoacidity and density of the ration. (2) t h e relation between color and density in tometer; sirup, the use of decolorizing Zerban and Freeland (9) sorghum sirup; (3) t h e relation between pH and dencarbons, the development of summarize the coloring matsity; and (4) t h e relation between pH and color. Frucsuperior strains of the plant, ter of sugar cane juice as tose has been found to be by far t h e most important the elimination of waste, and folloTs: is subjected to source of color when sorghum juice the utilization of by-products (1) Chlorophyll. This is of heat. Deductions are made concerning the control are possible and are being aclittle importance as it is not of color i n the manufacturing process. complished ( 5 ) . soluble and is removed with the scums. The following is a contri(2) Anthocyanins. These are present in the rhd, are soluble bution to the control of color in the sirup. It deals largely cane juice, and are precipitated by large quantities of lime but with three phases of the question: (1) the measurement of in incompletely by small quantities. color in the juice and sirup; (2) the relation of the natural (3) Saccharetin. This is present as the “incrustating” pigments of the juice to pH; and (3) the production of color coloring matter of the cane pith. It is insoluble in acid solutions, but is soluble with a yellow color in alkaline solutions. from the sugars in relation to p H and to temperature.
HE process of making
T
-
Received June 18, 1929. Presented before the Division of Sugar Chemistry a t the 78th Meeting of the American Chemical Society, Minneapolis, Minn., September 9 t o 13, 1929. 2 Published, with the approval of the Director, as Paper 866, Journal Series, Minnesota Agricultural Experiment Station. * Now at New York Agricultural Experiment Station, Geneva, N. Y. 4 Now with Waconia Sorghum Mills Co., South Fort Smith, Ark. 1
The present work was done under a fellowship grant from the company, to which grateful acknowledgment is made. 5 The U. S . Department of Agriculture restricts the term “sorghum” to the grain varieties of Andropogon sorghum, and calls the saccharin varieties “sorgos.” The sorghum sirups described in the present paper were, of course, made from the saccharin types, but the older term is retained here because i t is the only one used in the industry.
