AUGUST 15, 1939
ANALYTICAL EDITION
419
materials would probably be more informative in the absence 3 0 c of a vehicle. The effect of preliminary reduction in the absence of coal increases the efficiency of ammonium molybdate. It is advisable, therefore, to make comparative tests on both reduced and nonreduced materials. The preliminary reduction, when carried out quantitatively, also serves to indicate the state of combination in which the catalyst exists under the conditions of the test. Literature Cited (1) Askey, P. J., Holroyd, R., Cockram, C., and Imperial Chemical
FIGURE 5. INCREASE IN YIELDDUE TO AMMONIUM MOLYBDATE AND REDUCED AMMONIUM MOLYBDATE (DATAFROM TABLES V I AND VII)
Industries, British Patent 363,445 (1931). (2) Fuel Research Board (British), Annual Reports, London, H. M. Stationery Office, 1932 t o 1938. (3) Gordon, K., J. Inst. Fuel, 9, 69 (1935). (4) Horton, L., King, J. G., and Williams, F. A., Ibid., 7, 85 (1933). (5) Warren, T. E., and Gilmore, R. E., IND.ENO.CEEM.,29, 353 (1937). PRESENTED before the Division of Gas and Fuel Chemistry a t the 97th Meeting of the American Chemical Society, Baltimore, Md. Published by permission of the Director, Mines and Geology Branch, Department of Mines and Resouroes, Canada.
TABLEVI. RESULTSOF TESTSWITH AMMONIUM MOLYBDATE Ammonium Molybdate, Per Cent of Charge 0.0146 0.121 0.817 4.91 9 06
Yield of Volatile Products, Per Cent of Ash- and Moisture-Free Coal With ...-Vehir-le -. Without Vehicle Increase Increase due to due t o catalyst Total catalyst Total v ehio1e 75.1 14.6 57.6 0.6 78.1 17.8 55.7 -1.5 80.9 20.8 58.2 0.9 79.3 19.5 56.2 -1.2 1.0 84.2 24.8 58.4 58.2 * 0.8 83.6 24.6 5.8 85.7 27.2 63.2 63.1 5.8 83.0 26.8 84.7 66.0 8.8 66.8 9.7 83.6
.. ..
AMMONIUM TABLE VII. RESULTSOF TESTSWITH REDUCED MOLYBDATE Reduced Molybdate, Per Cent of Charge 0.0070 0.0825 0.889 3.59 5.86
Laboratory Fractionating Column
+
Yield of Volatile Products, Per Cent of Ash- and Moisture-Free Coal, without Vehiole Total Increase due to oatalyst 57.5 -0.4 58.0 0.3 59.0 1.4 2.1 59.6 71.9 14.5 72.0 14.8 81.1 23.9 79.3 22.1 81.6 24.4 82.1 24.9
date required to produce the corresponding concentration of residue shown in curve 2.
Discussion The effectof catalysts in small concentrations is pronounced. For instance, 0.01 per cent of stannous oxide brings about the production of nine hundred times its own weight of volatile material. However, in high concentrations the catalysts are much less efficient,and there is practically no increase in yield when the catalyst concentration is increased beyond 5 per cent. Suitable concentrations for test purposes, therefore, would be 1 per cent in the absence and 0.1 per cent in the presence of a vehicle. The vehicle renders the catalysts more effective in small concentrations, but slightly decreases their efficiency at high concentrations. It tends to eliminate differences in their efficiency, and for this reason comparative tests of catalytic
GEORGE F. REYLING Foster D. Snell, Inc., Brooklyn, N. Y.
S
MALL packed laboratory fractionating columns with constricted bases often tend to become filled with condensed liquid which cannot return to the flask because of pressure of the rising vapors. Consequently the column becomes filled with liquid and fails to operate properly when near its maximum capacity. This condition may be alleviated by placing a glass tube, bent as shown in the diagram, in the bottom of the column. This arrangement permits return of the condensed liquid to the flask, and a t the same time allows the vapors to pass unhindered to the top of the column.
SMALL GLASS
I TO 31NCHES DEPENDING ON COLUMN DIAMETER
