Ultrasound-assisted intensification of bio-catalyzed synthesis of mono-N-alkyl aromatic amines

Bio-catalyzed process for mono-N-alkylation of primary aromatic amines was considerably improved by the use of sonochemical energy. The optimized method exhibited good tolerance toward various aromatic primary amines as well alkylating agents. A comparative study was done by carrying out the bio-catalyzed reaction in the presence of ultrasound and non-ultrasound conditions both at room temperature and elevated temperature. The results showed that ultrasonication gave enhanced yields in shorter reaction times. The optimization studies also included variation in organic solvents, amount of catalyst and reaction temperature. These studies conclusively suggest that ultrasound technique improved the activity of catalyst thereby saving time and energy, improving the selectivity and yield of the product. In addition, the bio-degradable and non-toxic bio-catalyst was easily recycled till five consecutive runs.

Figure optionsDownload as PowerPoint slideHighlights
► Significant improvement of bio-catalyzed process for selective N-alkylation of aromatic amines.
► Mild, efficient and environmentally benign process.
► Recyclability of lipase shows good stability of bio-catalyst in ultrasound.
► Optimization and comparative studies reveal faster reaction in comparison to thermal method.
► Ultrasound emerges as an efficient alternative to conventional procedure in lipase-catalyzed reaction.