Synthesis of MCM–41 mesoporous molecular sieves containing heteroatoms and their catalytic activity

MCM-41 mesoporous molecular sieves containing heteroatoms(Zn,Ni,Fe,Al,Cu,Ce) (T-MCM-41) were synthesized by direct hydrothermal process and were applied in the synthesis of dioctyl phthalate(DOP) in this paper.The effects of different heteroatoms incorporation on structure,specific surface area and pore volume,aciditity and catalytic activity of T-MCM-41 were investigated.The results show that T-MCM-41 which still remains the well-ordered hexagonal mesostructure of MCM-41 has high surface area(550-900 m~2/g),large pore diameter(～3 nm).Meanwhile,it has high catalytic activity and selectivity in DOP synthesis because heteroatoms incorporation can produce acid centers.When T-MCM-41 (T=Zn,Fe,Al,Cu) is used as the catalyst,the conversion of phthalic anhydride(PA) reaches above 95.5%and DOP selectivity reaches above 96.5%in 5 h.Moreover,T-MCM-41 has good stability and Al-MCM-41 holds good catalytic activity after being reused five times.