The invention relates to an apparatus for analyzing heterogeneously catalyzed reactions comprising at least one reactor (3) through which a particulate catalyst flows and at least one reactant feed, wherein arranged downstream of each reactor (3) is a separation apparatus (17) for separating the particulate catalyst from a reaction product comprising condensable gases and arranged downstream of the separation apparatus (17) is a liquid separator (31) for separating liquid constituents from the reaction product, wherein the liquid separator (31) comprises a metallic tube (103) and a deflection body (119), wherein the metallic tube (103) is closed at its ends and the deflection body (119) is accommodated in the metallic tube (103) and the metallic tube (103) comprises a side feed (135) at a first end (105) and a gas outlet (113) at a second end (107) and the gas outlet (113) is connected to at least one sample vessel (37). The invention further relates to a process for analyzing heterogeneously catalyzed reactions in the apparatus.