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 IsST R Y
January 15, 1932
51
TABLEV. NUMBERS FOR DIFFERENT VARIETIESOF SHELLAC CALCULATED ON BASISOF RESIN SAMPLE
T. N. orange Heart orange hperfine orange A. S. 0. orange (special) Seedlac Seedlac Bleached shellac Refined bleached shellac
HOTALCOHOL INSOLUBLE WAX
ACIDNo.
MOISTURE RESIN
%
%
%
%
2.32 2.29 2.20 0.66 6.20 5.34 0.01 0.01
5.07 4.88 5.00 5.00 5.00 5.08 4.91 0.20
0.94 1.01 1.11 0.94 1.33 1.26 0.90 2.33
91.67 91.82 91.69 95.40 87.47 88.32 94.18 97.46
probably been oxidized to carboxyl groups, but that on the whole the molecules, as indicated by the ester number, remain unchanged. Table V gives values for the corrected acid, saponification, and ester numbers on the basis of resin content as calculated from the percentages of insoluble matter, wax, and moisture. The analyses were made in accordance with the methods given in the Booklet of Official Methods of Analysis of the United States Shellac Importers’ Association, Inc., and the American Bleached Shellac Manufacturers’ Association, Inc. (1930). The values for corrected ester numbers are surprisingly uniform for a substance of this type, especially when one considers the variety of conditions t o which different samples have been subjected in their manufacture. It is an index of the remarkable stability of this commodity. These numbers can be used for identifying a resin as shellac. Although contrary to general practice, a calculation of these chemical constants on the basis of resin content, rather than on total weight of sample, is recommended for identification purposes.
LITERATURE CITED (1) Carothers, W. H., J. Am. Chem. SOC.,51, 2548 (1929). (2) Carothers, W. H., Ibid., 52, 314, 3292, 3470, 5289, 5307 (1930).
72.9 75.0 70.1 73.9 70.6 69.6 93.6 107.5
ESTER No.
SAPONIFICATION
No.
225.3 234.1 230.1 230.0 225.9 220.9 259.0 276.0
152.4 159.1 160.0 156.1 155.3 151.3 166.4 168.5
-RESIN Acid no.
BASISSaponification no.
79.5 81.6 76.4 77.4 80.7 78.9 99.4 110.6
245.7 254.8 250.9 241.0 258.2 250.1 275.6 283.7
Ester
no.
166.2 173.2 174.5 163.6 177.5 171.2 176.6 173.1
(3) Dieterich, K., “Analysis of Resins, Balsams, and Gum-Resins,” Scott, Greenwood, 1920. (4) Gardner, W. H., and Whitmore, W. F., IND.E m . CHEM., 21, 226 (1929); Anal. Ed., 1, 205 (1929). (5) G u p t a , D. N., J. Indian Inst. Sei., 7, 142 (1924). (6) Harries, C., and Nagel, IT.,Ber., 55B, 3822 (1922). (7) Harries, C.9 and Nagel, W., Chem. Umschau Fette, Ole, Wachse Harze, 31, 173 (1924) ; Wiss. Ver6fentlich. Siemens-Konrern, 3, 12 (1924). (8) Harries, C., and Nagel, W., Ber., 60, 605 (1927). (9) Kerschbaum, M., Ibid., 60, 902 (1927).
..
ii;;
~
~
w.,
~~ ~ ~ $ ~ ~~ f ) * siemens-
and KGrchen, M,, Wiss, Ver6fentlieh, Konzern, 6, 235 (1927). (13) Rusicka, L.,et al., H e h . Chim. Acta., 9, 230, 249, 339, 399,499, 715, 1008 (1926); 10, 696 (1927); 11, 496, 670, 686, 1174, 1159 (1928). (14) Sin&, p., J. ,yoc. Chem. Ifid., 29, 1435 (1910). (15) Williams, R., Pharm. Zentralhalle, 30, 152 (1889).
(I2) Nagel,
REOBIVEDSeptember IO, 1931. Presented before the Division of Paint and Varnish Chemistry at the 82nd Meeting of the American Chemical Sooiety, Buffalo, N. Y., August 31 to September 4, 1931. Based upon part of the thesis submitted by Mr. Vi‘einberger in partial fulfilment of the requirements for the degree of bachelor of science a t the Polytechnic Institute of Brooklyn, June, 1931. Contribution 4 from the Shellac Research Bureau of the Umted States Shellac Importers’ Association.
Silver in Lead Bullion Determination by Volumetric Method W. R. WAGSTAFF,430 Welby Ave., Salt Luke City, Utah
T
0 DETERMINE silver in lead bullion by the volumetric method, weigh three sets of two lead gum drops, flattened to hasten dissolving. Place in a 400-cc. beaker and add 10 grams of tartaric acid to keep antimony in solution, then add enough nitric acid so that there is 1 cc. of acid for each gram of lead present, and then add three times as much water
