Selective vapor phase synthesis of 1,2,3,4,5,6,7,8-octahydro acridin 9-ylamine over Al–MCM-41 molecular sieves

Cyclization of cyclohexanone, formamide and ammonia in vapor phase gives 1,2,3,4,5,6,7,8-octahydro acridin 9-ylamine (AOHA) over zeolites HY, HZSM-5, Hβ and mesoporous Al–MCM-41 molecular sieves. The screening of catalysts clearly shows that Al–MCM-41 is more suitable for the vapor phase synthesis of AOHA. Correlation of activity and selectivity of metal ion-modified Al–MCM-41 with the NH3-TPD profiles shows that though the conversions are high, the formation of AOHA is governed by the acid site strength formed by the metal ion used. Interestingly Co2+ ion modification of Al–MCM-41 resulted into two sets of acid sites with Tmax around 218 °C (weak–medium) and 673 °C (strong). The typical acidity available on Co–Al–MCM-41 around 300–350 °C is showing 100% cyclization activity facilitating the maximum synthesis of AOHA. Based on the product distribution a plausible reaction mechanism is proposed.

Cyclization of cyclohexanone, formamide and ammonia in vapor phase gives 1,2,3,4,5,6,7,8-octahydro acridin 9-ylamine (AOHA) over zeolites HY, HZSM-5, Hβ and mesoporous Al–MCM-41 molecular sieves. Co2+ ion modification of Al–MCM-41 resulted into two sets of acid sites, which resulted in 100% cyclization activity facilitating the maximum synthesis of AOHA.Figure optionsDownload as PowerPoint slide