ABSTRACT
There are two categories of apparatus which are used for measuring the uptake of gas in catalytic hydrogenations. In one the hydrogen pressure is kept constant by changing the volume the gas occupies within the reaction apparatus with the extent of hydrogen consumption determined by the volume change required to maintain a constant pressure. In the second type the volume of the system remains constant and the amount of gas consumed is determined by the corresponding pressure change. The use of a constant pressure apparatus provides for a more facile interpretation of the reaction data since there is no change in the amount of hydrogen present in the reactor as the reaction proceeds. Automation of these constant volume systems is not a factor in equipment design since only the internal pressure in the reactor changes and this can readily be recorded by means of an appropriately situated pressure transducer.
