~
a M. kBadgett, Jr.
and Harry A. Stansburv, Jr. Union Carbide Chemicals Company south Charleston, West Virginia
I
I
Apparatus for Handling Liquefied Gases
A simple, safe, and useful apparatus was built to facilitate the liquefaction, measurement, and one experienced in glass blowing. I t can be used conveniently to condense gases a t temperatures -8O04I0C. In a typical experiment chlorine gas from a preseurized cylinder was fed through the gas inlet tube into the graduated cylinder (see figure). A mixture of dry ice and acetone surrounding the cylinder caused the gas to liquefy. Acetone may be replaced with other lowfreezing liquids such as methanol, ethanol, or trichloroethylene. After the desired volume of liquid (in milliliters) \!-as collected a t -50°C, the gaseous feed was discontinued. The weight of liquid chlorine in grams was accurately determined by multiplication of the volume by the density of chlorine at -50°C. The frost on the outside of the cold bath sometimes made the volume difficult to read. However, removal of the frost with a cloth dampened in acetone, methanol, or ethanol permitted an accurate reading of the volume. The liquid chlorine a t -50°C was then fed dropwise through the stopcock a t the desired rate into the reaction flask. Since the solution of the other reactant was a t 20-30°C, a cold condenser (filled with dry ice-acetone mixture) was attached to the reaction flask in order to condense any chlorine that might otherwise escape to the atmosphere. The stopcock was lubricated with a silicone stopcock grease. The use of this new apparatus eliminates the old trial and error method of bubbling the gas through the reaction mixture and weighing periodically until the desired amount has been added. Moreover, gaseous by-products, such as hydrogen chloride, may be liberated during the addition of the chlorine. Since hydrogen chloride is too low-boiling to condense by practical means and is lost to the atmosphere during the reaction, it is impossible to determine the weight of chlorine
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18/7 Ball join1 Ring seal
+Vent
,24/40
5 male
Liquid level of dry ice -acetone coolant
cylinder
Ring seal Drain cock * S t o ~ cock to control
fed by 'the old trial and error method. This new procedure also avoids the use of meters which are inaccurate for the measurement of small quantities of gas. Furthermore, certain corrosive gases (such as chlorine and sulfur dioxide) cannot he transferred in the conventional meters because of serious corrosion problems.
Volume 37, Number I , b n u o r y 1960
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43
