INDUSTRIAL AND ENGINEERING CHEMISTRY
56
There is a n optimum flowing quality for the production of uniform films over the normal thickness range. Coating materials with very poor flowing quality are not satisfactory for application by the dip method. The data obtained indicate the range of viscosity and rate of withdrawal necessary for surface coatings suitable for dip application to give a desired film thickness. The actual conditions of application should be determined for any specific coating and film thickness.
Acknowledgment The author takes this opportunity to express his appreciation to the American Cyanamid Company for permission to publish this work, and to the members of the Engineering Staff and Machine Shop of the Stamford Laboratories for their interest and cooperation.
Vol. 15, No. 1
Literature Cited (1)
Arlt, H. G., Bel2 Lab. Record, 14, 210 (1936).
(2) Bruins, P. F., IND.ENQ.CHEM.,ANAL.ED.,9, 376 (1937). (3) Dunn, E. J., and Baier, C., Ibid.. 13, 427 (1941). (4) Gardner, H A., “Physical and Chemical Examination of Paints”, 9th ed., p. 98, Washington, Institute of Paint and Varnish Research, 1939. ( 5 ) Haslam, G. S., IND. ENQ.CHEM.,ANAL.ED.,2, 319 (1930).
(6) N. Y . Paint and Varnish Production Club. Official Digest. Federation of Paint & Varnish Production Clubs, ConrenTion Issue, 1940. (7) Sanderson, J. McE., Proc. Am. SOC.Tesring Materials, Part I1 (1925 and 1926). (8) Scofield, F., Natl. Paint, Varnish, and Lacquer Assoc., Sci. Circ. 593 (1940). (9) Stoppel, E. A,, Proc. Am. Soc. Testing Materials, Part I, p. 285 (1923).
P R ~ S E N Tbefore B D the Division of Paint, Varnish, and Plastics Chemistry at the 104th Meeting of the ANBRICANC E ~ N I C A SOCIETY, L Buffalo, N T.
Effect of Ethanol Concentration on Purity of Potassium Chloroplatinate In Determination of Potash in Fertilizers H. L. MITCHELL AND 0. W. FORD Purdue University Agricultural Experiment Station, Lafayette, Ind.
FOR
Some time the question of the proper concentration of ethanol to be used for the determination of potash in fertilizers has been under consideration. Ford and Hughes (2) reported that higher potash values were obtained with 95 per cent ethanol than when 80 per cent ethanol wa as employed as directed by the A. 0, A. method for potash in fertilizers (1). Since this work was published, it has been suggested that perhaps the higher values \yere due to differences in the composition of the precipitate of potassium chloroplatinate rather than to decreased solubilitv of Dotassium chlorodatinate in the higher percentage of th;! ethanol. It was the-purpose of this work to investigate the possibility of changes in the composition of the potassium chloroplatinate precipitate Rhen various concentrations of ethanol are used.
c,
TABLEI. EFFECTOF ETHABOLCONCENTRATION ON POTASH VALUEOF A POTASSIUM CHLORIDE SOLUTION Ethanol Concentration
h‘lPtCl8~
TABLE11. EFFECTO F ETHANOL CONCENTRATION ON COMPOSITION OF POTASSIUM CHLOROPLATINATE PRECIPITATE Ethanol Concentration
-Platinum-
Found
Theoretical
Difference
Found
%
Gram 0.0200 0.0200 0.0199 0.0201
Gram 0.0201 0,0201 0.0201 0.0201
Gram 0.0001 0.0001 0.0002 0.0000
Gram 0.0215 0.0215 0.0216 0.0216
SO 85
90 95
-Chlorid-
Theoretical Gram 0.0219 0.0219 0.0219 0.0219
Difference Gram 0.0004
0.0004 0,0003
0,0003
Gram 0.2017
5% 80 85 90 95 a
platinum dishes. Platinum reduction was accomplished by a modification of the method pro osed by Swisher and Hummel (3) by adding 1ml. of formic acigto each dish, heating to boiling, and transferring to a steam bath for 10 minutes. The solutions were filtered through weighed Gooch crucibles without attempting to remove all the platinum black from the dishes. The crucibles had previously been padded with a small disk of Khatman No. 5 filter pa er and then with asbestos. After drying at 1100 c., both the xishes and the crucibles were reweighed. The filtrates from the platinum determination were acidified with nitric acid and chloride wa8 determined gravimetrically by precipitating with silver nitrate. The platinum and chloride values are presented in Table 11.
0.2034
0 2047 0 2052
Averages of 8 determinations.
Procedure The work of Ford and Hughes was extended to include potash determinations using 85 and 90 per cent as well as 80 and 95 per cent ethanol and acid-ethanol. These determinations were made on a solution of pure potassium chloride without evaporation and ignition. The temperature (20” C.) and the volume of ethanol (160 ml.) used were kept constant in all cases. The results obtained are presented in Table I. Sufficient quantities of potassium chloroplatinate were prepared as above, using the four concentrations of ethanol, so that approximately 1 gram of each could be dissolved in water to make 500 ml. of solution, and 25-ml. portions were placed in weighed
Discussion Table I is further confirmation of the findings of Ford and Hughes that higher percentages of ethanol give higher potash values. Table I1 indicates that, within experimental error, the composition of the potassium chloroplatinate precipitate is not changed by varying the concentration of the ethanol used.
Literature Cited (1) Assoc. 05cial Agr. Chem., Official and Tentative Methods of Analysis, 5th ed., pp. 30-1, 1940. (2) Ford, 0. W., and Hughes, C. W., IND. ENG.CHEM.,ANAL.ED., 14, 217-18 (1942). (3) Swisher, M. C., and Hummel, F. F., Ibid., 11, 162-3 (1939). JOURNAL Paper 42 of Purdue University Agricultural Experiment Station.
