What Is an Example of a Solid-Liquid Reaction? Industrial Cases and Reactor Types A clear example of a solid-liquid reaction is the catalytic hydrogenation of a liquid oil using a solid metal catalyst: the oil (liquid) and hydrogen (gas) contact a suspended solid catalyst (such as nickel or palladium), and the double bonds are saturated. In this three-phase reaction, the solid is a catalyst, the liquid is the reactant, and mass transfer between phases controls the rate. Other