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A Convenient Apparatus for Reactions Involving Gases Under Moderate Pressure I t is frequently desirable to conduct reactions involving gaseous reagents under a moderate pressure for a variety of reasons. These reasons may include a need to increase a reaction rate or to shift an equilibrium. Pressures up to 10 atm mav safelv be accommodated in sealed elass tubes if the eas ~ , intsre5t f is cmdcniahle, bul in the easr d nonrondrnsnhle gases aume ~ t h e apparatus r rcquirrd. The apporntus d r scnhed helux and ahown m the f ~ g ~ ha8 r e found cxtrnswe use in both research and instructional laboratories for a number of applications involving gases such as HI, D2.SO*, CHz=CH2, CO, and PF3 and pressures to 60 psig. The design is adapted from the standard Parr HydroFeneratar and uses either the 250- or 500-ml Parr Bottle. This apparatus is easily constructed, largely from eommercia1 components. The compact size of the pressure bottle allows it to be carried into inert atmosphere enclosures for charging with air sensitive reactants. Other arrangements of values and Swagelok feed line connectors may he desirable depending upon the application. This design permits evacuation and flushing of the bottle and gas feed 1ines.l Stirring is accomplished using a magnetic stirrer. If a series of runs are required involving air stable materials, the valve and gauge assembly may be mounted on a rack and the lower plate made the moveable one. The bottle is attached from the bottom and the lower plate snugged up to provide the seal. Elevated temperatures are easily obtained through heat transfer bv the lower aluminum d a t e from a hot late. Calibratwn r u n . e i should he made if the temperature rs critrcal Alternatiwly the entire apparatus may bc placed in a n 011 bath of appropriate size.
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Apparatus for low pressure gas reactions involving gases. The frame is constructed of aluminum with steel studs. The adapter tar the rubber stopper plug which also serves as the gas inlet is of brass. All joints in this piece are silver soldered.
1 Adcquatz safety prerautions should always be taken. If presrurr regulation i:. not available for the gas rource and if potrntially exothermic reactions are undertaken, a loll psi rupture disc should be invludrd in the vacant arm of the rce The pres3urc bottler; should be wrapped well with tape or a metal sureen placed nrnund them when they arr under pressure t o reduce flying glass in the event of a n explosion. Of course a safety shield should always be used
University of Illinois Urbana, 61801
E. Kent Barefield
Volume 50, Number 10, October 1973
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697
