The N-alkylation of morpholine with alcohols in gas–solid phase was investigated in a fixed-bed reactor over CuO–NiO/γ–Al2O3 catalyst prepared by the impregnation method. The N-methylation of morpholine with methanol gave a 95.3% conversion with a 93.8% selectivity of N-methylmorpholine under the optimum reaction condition, and the corresponding apparent activation energy is 46.20 kJ mol−1. The present catalytic system is also applicable to other low-carbon primary alcohols. However, secondary alcohols enjoy relatively low product selectivity for the resulting ketone is a poorer electrophile than an aldehyde. For cyclohexanol, the low conversion and selectivity are mainly due to steric effects. The catalyst shows a high catalytic activity without obvious fluctuation during a long period of 120 h.
Solcova, O, Jiratova, K (1994) J Mol Catal88:193–204.