Preparation of beta-methylthiopropionaldehyde

摘要

Beta-methylthiopropionaldehyde is prepared by (I) condensing a gaseous feedstream comprising both acrolein and water, advantageously the off-gas resulting from the air oxidation of propylene (and after the acrylic acid content has been absorbed therefrom), to obtain an aqueous condensate containing a fraction of said acrolein and a gaseous acrolein effluent, (II) partially vaporizing said aqueous condensate whereby to obtain a gaseous phase comprising essentially all of said acrolein fraction and a liquid phase comprising essentially no acrolein, (III) recycling said gaseous phase into said gaseous feedstream to be condensed, and (IV) directly reacting said gaseous acrolein effluent with methylmercaptan.