ABSTRACT
There are some severe limitations of the stopped-flow technique of gas chromatography (GC) described in the previous chapter. These are: 1. When used for catalytic studies, the reactant must have a relatively long retention time on the column containing the catalyst. 2. It does not seem to apply to reactions other than those with one reactant and first-order steps. For example, it is difficult to apply the stopped-flow method 88in hydrogenation reactions with complicated kinetics, like methanation of carbon monoxide. From the point of view of physical principles, there is also a small drawback of this technique: It continuously switches the system under study from a flow dynamic one to a static system and vice versa, by repeatedly closing and opening the carrier gas flow. Longitudinal diffusion and other related phenomena, which are usually negligible during the gas flow, may become important when the flow is stopped.
