Abstract: A method is disclosed for the concentration of an aqueous acrylamide solution prepared by hydration of acrylonitrile or an aqueous acrylamide solution substantially free of acrylonitrile. The method makes use of a concentration apparatus at least a part of whose solution-contacting section is made of a copper-containing material. The concentration is conducted while introducing an oxygen-containing gas into the apparatus. Use of this method can prevent formation, adhering, accumulation and the like of popcorn polymers inside the concentration apparatus upon concentration of the aqueous acrylamide solution, and can also produce high-quality acrylamide.

Abstract: A process for preparing alkanolamines which comprises steps of reacting ammonia with an alkylene oxide in the presence of a carbonate of ammonia to obtain a crude alkanolamine solution, distilling off ammonia, carbon dioxide and water to regulate the content of carbon dioxide in the crude alkanolamine solution to 1% by weight or less, and distilling the crude alkanolamine solution to separate and collect the alkanolamines, whereby the production ratio of a monoalkanolamine can be increased and impurities can be decreased.

Abstract: An improved process is disclosed for the purification of an aqueous solution of acrylamide. It comprises bringing a crude aqueous solution of acrylamide into contact with oxygen or an oxygen-containing gas and thereafter subjecting the solution to a dual treatment with a strongly acidic cation exchange resin followed by a weakly basic anion exchange resin. If necessary, the aqueous solution of acrylamide is treated, while maintaining its oxygen content at least at 4ppm and then subjected to the treatment with the ion exchange resins.