Ring conversion of γ-butyrolactone into N-methyl-2-pyrrolidone over modified zeolites

Catalytic activities of metal ion exchanged zeolites for the ring conversion of gamma-butyrolactone (GBL) with methylamine (MA) into N-methyl-2-pyrrolidone (NMP) were investigated using a continuous fixed bed reactor system. Among the zeolites tested, cation exchanged Na-BEA zeolite was more active than cation exchanged Na-X or Na-Y. Copper or calcium ion exchanged catalysts showed the highest yield among the cation exchanged Na-BEA zeolites. Furthermore, the activity was maintained for more than 300 h over these catalysts, It is assumed that the catalytic activities of the metal ion exchanged zeolites for the reaction are more or less related to the Lewis acidic properties of catalysts. A simple reaction mechanism is proposed based on the reaction and characterization studies. (C) 2002 Published by Elsevier Science B.V.