MARCH, 1951
A VERSATILE GAS-ABSORPTION APPARATUS ROBERT R. RUSSELL Missouri School of Mines and Metallurgy, Rda, Missouri
THEauthor wishes t o call attention to the not necessarily original apparatus illustrated in the accompaning diagram. The arrangement has been succesifuliy employed in our laboratory for the adsorption of noxious gases which can be readily absorbed in liquid media. Its utility is apparent from its simple construction from materials usually available in all laboratories. As diagramed, the container A is an absorption tower and B a conventional drying tower. The absorbing liquid is filled to some convenient height in A while the liquid level in B is only high enough to cover the lower end of the tube C by a em. or so as usually operated. The function of the liquid in B is to act as a seal. When the aspirator is pulling a vacuum so that bubbles rise in A. the pressure will be reduced in B. When the pressure i s reduced below atmospheric pressure by an amount equal to the liquid head in B air will enter through the tube C. If the evolution of gas in the system is more rapid than its evacuation through A, the liquid in B will rise in the tube C, thus increasing the pressure. The pressure increase will cause more rapid gas passage through A until equilibrium can be established. If the pressure builds up too rapidly, C acts as a safety valve by allowing the liquid in B to be expelled through it until the difficulty can be remedied. This apparatus has been found very satisfactory in .our laboratory for the absorption of hydrogen chloride generated in Friedel-Crafts reaction, sulfur dioxidehydrogen chloride mixtures from reactions with thionyl chloride, and excess ketene from acetylations using the
To ASPIRATOR
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FROMSYSTEM
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gaseous reagent. I n all of these applications aqueous caustic solution worked very, nicely as the absorbing liquid. If very large quantities of gas were absorbed so that heat became an item, the tower A was replaced by a larger container, placed in a trough, and water run over the exterior a t a rate sufficient to remove the excess heat.
