Abstract: A predominantly liquid filled, vapor-liquid chemical reactor having an improved distributor plate assembly is disclosed. At least one of the plates in the assembly is formed with an active area having a plurality of apertures formed through the plate, an opening, and a downwardly depending lip proximate the opening. As vapor ascends through the reactor, the plate and the lip cooperate to trap the vapor upwardly against the bottom of the plate, forming a vapor region. This vapor region facilitates vapor liquid interaction and the flow pattern of liquid through the reactor.