GB897275A - Production of acrylonitrile cyclic dimer - Google Patents

Abstract

Acrylonitrile cyclic dimers are prepared by heating acrylonitrile in the vapour phase at a pressure of at least 1000 p.s.i. out of contact with stainless steel, copper, or any other non-noble metal and/or in the presence of water at a pH of less than 8. The process may be carried out in a platinum-, glass- or silver-lined pressure-resistant vessel, in the presence or absence of water at a pH of less than 8; or in any suitable vessel in the presence of water at a pH of less than 8. The acidity may be provided by the presence of water-soluble amine acceptors, such as CO2, sulphuric, phosphoric and sulphurous acids, potassium hydrogen phosphates, oxalic, hydroxyacetic, trimethylacetic, propionic, butyric, succinic, acrylic and acetic acids, and water-soluble phenols. The preferred quantity of water is 0.3%-10% based on the acrylonitrile charged. Adiponitrile may be prepared by hydrogenation of acrylonitrile cyclic dimers at atmospheric pressure at 175 DEG C.-400 DEG C. in the presence of a reduced cobalt oxide catalyst.