I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
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reaction of both methane and ethylene with oxygen andis, a t the same time, being burned to carbon dioxide. For the moment, assume that carbon monoxide and hydrogen react simultaneously with oxygen according to the following equations: I
2co + 0 2 = 2COn 2Hz
+
0 2
2H20
Assume, also, that the formation of these gases from methane and ethylene can be neglected. It follows that:
The result of application of this relation to the data is shown in PcRcwE6 Figure 4 (neglecting the Figure 4 factor l/(Hz) and l/(CO) for initial conditions). This indicates that such an expression holds very well throughout the entire range of the experiments. The value of the slope is
Vol. 17, No. 12 = 4.86
kco If one assumes a similar expression to hold for the simultaneous combustion of hydrogen and methane, a curve of the t y p e shown in Figure 5 results. This curve is flat and can be approximated .by a straight line the slope of which is ‘CH~ 3.0 km E
It follows that the rate of combustion of carbon monoxide relative to methane is ‘
4 -
Figure 5
‘ s4 = (4.86)(3.0) = kco
14.5
It must be remembered, however, that these expressions can only be considered as empirical, for the case under consideration.
A Thermoregulator’ By H. J. Wing with T. J. Thompson T H E UNIVERSITY OF NBBRASKA, LINCOLN. NEBR.
HE usual form2 of glass thermoregulator carrying toluene and mercury is fragile because the weight of the large tube is carried by a bend in a small tube. As has been pointed out by Davis and Pratt,3 it has the additional disadvantage that toluene tends to creep past the mercury and contaminate the contact surface. In this type of regulator the toluene is first filled in through the tube which later carries the mercury. For this reason it is almost impossible to obtain a clean mercury surface even at the beginning of the use of the regulator. The regulator shown in the accompanying illustration overcomes these difficulties and offers some advantages over that devised by Davis and Pratt, such as a temperature range of any desired amount, greater mechanical strength, freedom from contact contamination by oxidation or from the toluene, ease of adjustment, and comparative simplicity of construction. The inner tube, C, is sealed inside the expansion bulb, thus placing the weight directly below the point of support. The stopcock and overflow cup are sealed on and the tubes A and B attached. Since for a given volume of liquid the sensitivity is increased as the diameter becomes smaller, a 25-mm. tube with a wall 1.5 mm. thick is suitable for the bulb. The bulb is filled with mercury well above the end of the tube C , and then for a 100’ C. range of the regulator 10 cc. of mercury are added for each 100 cc. volume of the bulb. The bulb is then filled with toluene through the tube B. The bulb should then be placed in a boiling water bath to
T
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Received October 22, 1925.
* Findlay, “Practical Physical Chemistry.” p. 82. * J . Am. Chem. SOL, 97, 1198 (1915).
drive off the air dissolved in the toluene. After cooling to room temperature the bulb is completely filled with toluene and sealed off a t B. Any air left in the:tube will be quickly dissolved in the air-free toluene and will give no trouble. The side tube A carries the electrodes. After this tube is filled with mercury dry hydrogen is drawn in and the tube is sealed off above the upper electrode, D , leaving some hydrogen here for expansion in making the temperature adjustments. This leaves the contact points in an atmosphere of dry hydrogen which prevents the oxidation of the mercury ~urface.~t5If the contact point, D , is of iron, the instrument will give better regulation because the mercury does not crwetl’the iron.6 The regulator is set by drawing the mercury surface below the level of the contact point D. By use of the s t o p cock the temperature of the bath may be carefully adjusted. This form of regulator could be used as well for saturated vapors, which are said to be more ~ensitive.~ Clark, J . A m . Chem. SOC.,96, 1889 (1913). Ramberg, Svenk. Kem. Tids., 96,101 (1924); C. A . , 18, 3297 (1924). 6 Beaver and Beaver, THISJOURNAL, 16,359 (1923). 1 Feild, J . Am. Chcm. SOC.,86, 72 (1914). 4
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