Continuous synthesis of 2,2,6,6-tetramethyl-4-piperidinol over CuCrSr/Al2O3: effect of Sr promoter

A continuous process was developed for catalytic hydrogenation of triacetoneamine (TAA) to 2,2,6,6-tetramethyl-4-piperidinol (TMP), both of which are indispensable raw materials of hindered amine light stabilizers. A series of promoter-modified CuCr/Al2O3 catalysts were prepared by co-precipitation method and evaluated by the above reaction. The effect of promoter on the catalytic performance was explored by characterization tools, in which, CuCrSr/Al2O3 exhibited excellent catalytic performance with nearly complete conversion of TAA and over 97% selectivity of TMP at 120 degrees C. The characterization results indicated that the doped Sr could decrease the size of Cu nanoparticles to provide more active sites, improve the ratio of Cu+/Cu-0 to promote the adsorption of substrates, and reduce the surface acidity to depress side reactions, thus remarkably enhancing catalytic performance. This work provides a low-cost, reliable and efficient strategy for the continuous industrial production of TMP.