Improved Ti species distribution and hierarchical pores in TS-1: Towards regeneration of deactivated TS-1 caused by the corrosion of alkali
An effective strategy to regenerate deactivated titanium silicalite-1 zeolite (TS-1) from industrial cyclohexanone ammoximation process has been explored by using tetrapropylammonium bromide (TPABr) and ethanolamine solution under hydrothermal condition. For deactivated TS-1, the yield of cyclohexanone oxime was only 19.2% in cyclohexanone ammoximation reaction. After the second regeneration, the regenerated TS-1 showed higher catalytic performance than fresh TS-1 and the yield of cyclohexanone oxime was up to 99.4%. Characterization results showed that the relative crystallinity, micropore surface, micropore volume, and surface framework Ti species significantly restored and huge hierarchical pores were introduced after regeneration. Moreover, the regenerated TS-1 exhibited excellent performance than fresh TS-1 in resisting the corrosion of alkali. The exploration of effective regeneration strategy for deactivated TS-1 can bring about the benefits of economic and environment in commercial ammoximation process, and provide new perspectives for developing more robust TS-1.