Enhanced Product Selectivity in Continuous N-Methylation of Amino Alcohols over Solid Acid–Base Catalysts with Supercritical Methanol

The unique properties of supercritical fluids can be exploited for fine-tuning product selectivity. Under the conditions listed for the N-methylation of amino alcohols (see scheme) over solid acid—base bifunctional catalysts, the total yield and product selectivity could be improved. Enhanced product selectivity might be attributed to the milder reaction conditions possible with supercritical methanol, as well as the increased concentration of methanol on the catalyst.