AUTOMATIC CONSTANT-PRESSURE APPARATUS FOR MEASURING ABSORPTION OR EVOLUTION OF GASES

An improved apparatus for automatic measuring and recording of the absorption or evolution of gases at constant pressure has been constructed. The instrument is applicable to kinetic studies over a wide range of operating conditions including (a) pressures up to 20 atm, (b) temperatures up to 120°C, and (c) rates of reaction as fast as 5 ml min-1. A differential-pressure transducer is used and makes the instrument sensitive to pressure changes as small as 0.020 mm Hg. The mechanical and electronic components of the system are described. The apparatus has been evaluated by measurements of the rate of oxygen uptake by Vaska's complex, IrCl(CO) (PPh 3)2. © 1968 The American Institute of Physics.