<p>In a separator (11), designed to separate mixtures composed of liquids of various densities, the inflow (12) of the liquid mixture is so arranged and so designed that the inflowing liquid mixture hits an inner wall(16), located opposite the separator outflows, at an angle alpha of 0 DEG - 45 DEG relative to the normal to the container wall. Such a separator can be used in the manufacturing process for acrylic acid through catalytic vapour-phase oxidation of propene.</p>