Synthesis Of Ti-MCM-41 And Its Application In Epoxidation Of Propylene By Using Cumene Hydroperoxide As The Oxidant

Ti-MCM-41 molecular sieve is prepared by hydrothermal crystallization, appending cumene hydroperoxide (CHP) to control hydrolyzation of tetrabutyl titanate (TBOT). The samples are characterized with XRD, UV-Vis and XRF. Effects of n(CHP) : n(TBOT), crystallization temperature and time on structure and titanium species distribution of Ti-MCM-41 molecular sieve have been investigated and the best synthesis conditions are obtained: crystallization temperature 100℃ , crystallization time 3⁶ d, n(CHP) : n(TBOT) = 8¹2. The characterization results show that appending CHP has important effect on distribution of titanium species and can effectively avoid produce of anatase TiO₂. Ti-MCM-41 molecular sieve prepared in different conditions are tested by epoxidation of propylene, in which cumenen hydroperoxide is used as oxidant. The reaction results show that proper crystallization temperature, reasonable n(CHP) : n(TBOT) and long crystallization time are favor of increasing activity of catalyst, the byproduct propylene glycol is found and catalytic activity lies on amount of framework titanium. effective conversion of CHP is 49.7% and selectivity of PO is 84.4% when the best catalyst is tested.Ti-SiO₂ is synthesized and characterized with XRD and UV-Vis. The prepared catalyst is used in epoxidation of propylene, in which cumenen hydroperoxide is used as oxidant. Molybdenum and vanadium are introduced in Ti-MCM-41 by steep and activity of catalysts are tested, The reaction results show vanadium is favorable for epoxidation of propylene, but is prone to casting from the catalyst.The catalyst Ti-MCM-41 is used in epoxidation of propylene, in which cumenen hydroperoxide is used as oxidant, alkalescence of solution, reaction temperature and solvent are tested. The results showed that alkalescence of solution can increase reactivity of reaction;methanol, ethanol and iso-propanol can restrain decomposability of CHP at high temperature;methanol is the best solvent that is favorable for epoxidation of propylene. effective conversion of CHP is 49.5% and selectivity of PO is 98.7% when methanol is used as solvent.