Abstract: The disclosure is a process for recovering caprolactam monomer and oligomer from aqueous polycaprolactam extracts by removing the inorganic contaminants present therein.

Abstract: Column tray for a mass transfer column, in particular one provided with a support ring at the circumference, which tray has support elements and tray plates arranged side by side on the support elements and having passages, in particular holes, valves or bubble caps, wherein the majority, preferably the total number, of tray plates are connected liquid-tight, preferably welded, to the support elements or the support ring, in particular in discrete area elements; the majority, preferably the total number, of support elements are connected liquid-tight, preferably welded, to one another and to the column wall or the support ring, in particular in discrete area elements; and in addition the majority, preferably the total number, of adjacent tray plates and support elements are separated from one another and from the column wall or the support ring by gaps having a width of from 1 to 15 mm, preferably from 1 to 7 mm.

Abstract: A process for the separation of (meth)acrylic acid from the reaction gas mixture formed in the catalytic gas phase oxidation by countercurrent absorption using a high-boiling inert hydrophobic organic liquid, in which the reaction gas mixture is passed through an absorption column countercurrently to the descending high-boiling inert hydrophobic organic liquid and (meth)acrylic acid is subsequently fractionally separated from the liquid effluent leaving the absorption column and containing (meth)acrylic acid, wherein a rectifying process is superimposed on the absorption process occurring naturally in the absorption column by removing a quantity of energy from the absorption column which exceeds its natural energy loss resulting from contact with the ambient atmosphere.