Cleaning Porcelain Crucibles
1
July 15, 1942 ANALYTICAL EDITION 533 16. 12- a B- 4- 0 2 4 6 a 10 12 wt. % Ot Benzene FIGURE 4. ACID HEAT TEST DATA FOR BENZENE-CYCLO- EEXANE Initial temperature, 20°, 25', and 30' C. same direction. Presumably this anomalous relationship of AT to initial temperature is attributable to the relative speeds of demulsification at the different temperatures. PURITY OF HYDROCARBONS. The benzene was of reagent quality; the cyclohexane was made from it by catalytic hydrogenation under pressure at about 135" C. The cyclo- hexane was shaken with nitrating acid, washed with water, and distilled. Its freezing point of 5.9" C. indicated a purity of 99.7 per cent. TABLE I. ACID HEAT TEST DATA FOR BENZENE-CYCLOHEXANE (FIGURE 4) Weight Percentage of Benzene 0.00 0.56 1.08 1.56 3.29 6.38 10.15 12.01 AT from Initial Temperatures of 200 c. 25' C. 30' C. 0.10 1.10 2.07 2.87 5.59 10.82 17.13 20.13 0.10 1.10 2.04 2.79 5.40 10.44 16.55 19.44 0.10 1.09 2.00 2.70 5.22 10.07 16.00 18.75 TABLE 11. ACID HEAT TEST DATA FOR TOLUENE-METHYL- CYCLOHEXANE (FIGURE 5) Weight Percentage of of Toluene 0.00 1.34 3.50 5.49 AT from Initial Temperaturea of 200 c. 25" C. 30' C. 0.32 3.96 9.71 15.00 0.32 3.95 9.64 14.89 0.32 3.95 9.58 14.80 De termination of Benzene in Cyclohexane One hundred cubic centimeters of nitrating acid (1 volume of sulfuric acid, d. 1.84, plus 2 volumes of nitric acid, d. 1.42), measured in a 100-cc. volumetric flask, are poured into a thermos bottle, the flask being allowed to drain 15 seronds. The ther- mometer is placed in the thermos, the bulb resting on the bot- tom of the latter, and the temperature is read after 2 to 3 min- utes (with a ma nifying lens). Fifty cubic centimeters of hydro- carbon sample (neasured in a 50-cc. volumetric flask and a t the same temperature as the acid) are added to the acid in the ther- mos. An interval timer is started and the flask is allowed to drain 15 seconds. The stirrer is placed in the thermos, with the bottom of the stirring blade about 1.25 cm. (0.5 inch) from the bottom of the thermos, and when the timer reaches 30 seconds the motor is started. The stirrer is run 9.5 minutes and then removed from I 2 3 4 5 6 WI. % of Toluene FIQURE 5. ACID HEAT TEST DATA FOR TOLUENE-HEXA- EYDROTOLUENE Initial temperature, 20°,25", and 30' C. the mixture. The thermometer is placed in the thermos (bulb resting on bottom of thermos) and the temperature is read 10 minutes after stopping the stirrer-i. e., 20 minutes after the addi- tion of the hydrocarbon. The mixture is not shaken nor stirred during the la& 10 minutes. For precise work, not only should the acid and hydrocarbon be thermostated to the same temperature, but the thermos bottle should also be at that temperature (although its heat capacity is small). The benzene content is read from the family of curves cor- responding to the data in Table I, and it is to be noted that AT is essentially independent of the initial temperature (20"to 30' C.) up to 1.5 per cent of benzene. Table I1 presents acid heat data for toluene-methylcyclo- hexane mixtures. Literature Cited (1) Seyer, Wright, and Bell, IND. ENQ. Cmm., 31,759-60 (1939). CONTRIBUTION from the Koppers Multiple Fellowship on Tar Synthetics. Mellon Institute, Pittsburgh, Penna. Cleaning Porcelain Crucibles JOHN E. D. CARWARDINE 55 Donald St., Winnipeg, Manitoba, Canada method described here can save considerable time THE and confusion by cleaning "burner grime" and marking inks such as ferric chloride from porcelain crucibles. It does not injure the glaze in any manner, but leaves the crucible with a perfectly clean surface. Place the crucible in a dish of fused potassium bisulfate for about 5 minutes. Remove, allow to cool, and wash with hot water. Reprint Orders Because articles printed in both the Industrial and Analytical Editions of INDUSTRIAL AND ENGINEERING CHEMISTRY are now copyrighted by the AMERICAN CHEMICAL SOCIETY, permission must be secured before reprints can be supplied to others than authors of the papers in question. Requests should be addressed to the Editor, INDUSTRIAL AND ENGINEERING CHEMISTRY, 1155 Sixteenth St., N. W., Washington, D. C.
Transcript of Cleaning Porcelain Crucibles
July 15, 1942 A N A L Y T I C A L E D I T I O N 533
16.
12- a
B -
4 -
0 2 4 6 a 10 12 wt. % Ot Benzene
FIGURE 4. ACID HEAT TEST DATA FOR BENZENE-CYCLO- EEXANE
Initial temperature, 20°, 25', and 30' C.
same direction. Presumably this anomalous relationship of AT to initial temperature is attributable to the relative speeds of demulsification at the different temperatures. PURITY OF HYDROCARBONS. The benzene was of reagent
quality; the cyclohexane was made from i t by catalytic hydrogenation under pressure a t about 135" C. The cyclo- hexane was shaken with nitrating acid, washed with water, and distilled. I t s freezing point of 5.9" C. indicated a purity of 99.7 per cent.
TABLE I. ACID HEAT TEST DATA FOR BENZENE-CYCLOHEXANE (FIGURE 4)
Weight Percentage of Benzene
0.00 0.56 1.08 1.56 3.29 6.38 10.15 12.01
AT from Initial Temperatures of 200 c. 25' C. 30' C. 0.10 1.10 2.07 2.87 5.59 10.82 17.13 20.13
0.10 1.10 2.04 2.79 5.40 10.44 16.55 19.44
0.10 1.09 2.00 2.70 5.22 10.07 16.00 18.75
TABLE 11. ACID HEAT TEST DATA FOR TOLUENE-METHYL- CYCLOHEXANE (FIGURE 5 )
Weight Percentage of of Toluene
0.00 1.34 3.50 5.49
AT from Initial Temperaturea of 200 c. 25" C. 30' C. 0.32 3.96 9.71 15.00
0.32 3.95 9.64 14.89
0.32 3.95 9.58 14.80
De termination of Benzene in Cyclohexane One hundred cubic centimeters of nitrating acid (1 volume of
sulfuric acid, d. 1.84, plus 2 volumes of nitric acid, d. 1.42), measured in a 100-cc. volumetric flask, are poured into a thermos bottle, the flask being allowed to drain 15 seronds. The ther- mometer is placed in the thermos, the bulb resting on the bot- tom of the latter, and the temperature is read after 2 to 3 min- utes (with a ma nifying lens). Fifty cubic centimeters of hydro- carbon sample (neasured in a 50-cc. volumetric flask and a t the same temperature as the acid) are added to the acid in the ther- mos. An interval timer is started and the flask is allowed to drain 15 seconds.
The stirrer is placed in the thermos, with the bottom of the stirring blade about 1.25 cm. (0.5 inch) from the bottom of the thermos, and when the timer reaches 30 seconds the motor is started. The stirrer is run 9.5 minutes and then removed from
I 2 3 4 5 6 WI. % o f Toluene
FIQURE 5. ACID HEAT TEST DATA FOR TOLUENE-HEXA- EYDROTOLUENE
Initial temperature, 20°, 25", and 30' C.
the mixture. The thermometer is placed in the thermos (bulb resting on bottom of thermos) and the temperature is read 10 minutes after stopping the stirrer-i. e., 20 minutes after the addi- tion of the hydrocarbon. The mixture is not shaken nor stirred during the la& 10 minutes.
For precise work, not only should the acid and hydrocarbon be thermostated to the same temperature, but the thermos bottle should also be at that temperature (although its heat capacity is small).
The benzene content is read from the family of curves cor- responding to the data in Table I, and i t is to be noted that AT is essentially independent of the initial temperature (20"to 30' C.) up to 1.5 per cent of benzene.
Table I1 presents acid heat data for toluene-methylcyclo- hexane mixtures.
Literature Cited (1) Seyer, Wright, and Bell, IND. ENQ. Cmm., 31, 759-60 (1939).
CONTRIBUTION from the Koppers Multiple Fellowship on Tar Synthetics. Mellon Institute, Pittsburgh, Penna.
Cleaning Porcelain Crucibles JOHN E. D. CARWARDINE
55 Donald St., Winnipeg, Manitoba, Canada
method described here can save considerable time THE and confusion by cleaning "burner grime" and marking inks such as ferric chloride from porcelain crucibles. It does not injure the glaze in any manner, but leaves the crucible with a perfectly clean surface.
Place the crucible in a dish of fused potassium bisulfate for about 5 minutes. Remove, allow to cool, and wash with hot water.
Reprint Orders Because articles printed in both the Industrial and Analytical
Editions of INDUSTRIAL AND ENGINEERING CHEMISTRY are now copyrighted by the AMERICAN CHEMICAL SOCIETY, permission must be secured before reprints can be supplied to others than authors of the papers in question. Requests should be addressed to the Editor, INDUSTRIAL AND ENGINEERING CHEMISTRY, 1155 Sixteenth St., N. W., Washington, D. C.
