利用ＳＢＡ-１５介孔内纳米碳合成含介孔的ＺＳＭ-５分子筛

SBA-15介孔分子筛内填充蔗糖并炭化后, 分别在碱性和弱酸性条件下, 用含铝源及TPABr的溶液浸渍,将SBA-15分子筛孔壁的无定形结构转化成ZSM-5分子筛的晶体结构, 除碳后得到含介孔的ZSM-5分子筛. 用X射线衍射、 N_2吸附-脱附、 ~(27)Al MAS NMR、 NH_3-TPD、 TEM、 SEM等对样品进行了表征, 考察了晶化时间等参数对样品的影响. 结果表明, 碱性条件下合成的ZSM-5分子筛晶体中含有少量孔径约3.2～4.2 nm的介孔孔道, 其酸强度接近与常规ZSM-5分子筛的酸强度;弱酸性条件下合成的ZSM-5分子筛晶体中含有大量孔径约1.4～1.6 nm的孔道, 其酸强度明显低于常规ZSM-5分子筛的酸强度.

Synthesis of ZSM-5 Molecular Sieves Containing Mesopore Using Nanocarbon in SBA-15 Mesopores

The mesopores of SBA-15 molecular sieve were filled by sucrose and the fillings were carbonized. SBA-15 molecular sieves containing nanocarbon carbon were impregnated by the slution of aluminum source and TPABr under the condition of alkalinity and weak acidity repectively, the framework of SBA-15 molecular sieve was changed into the crystal construction of ZSM-5 molecular sieve and lastly the ZSM-5 molecular sieves containing me-sopore were gained after removing the carbon. The samples were characterized by XRD, N_2 adsorption-desorption, ~(27)Al MAS NMR, NH_3-TPD, TEM and SEM methods. We researched the effect of synthesis condition on structure of samples, such as crystallizing time and so on. Results showed that ZSM-5 molecular sieve synthesised under the condition of alkalinity contained a small amount mesopores with pore diameter about 3. 2nm ~4. 2nm and its acid strength was slightly lower than that of ZSM-5 molecular, the sample synthesized unde the condition of weak acidity contained more pores with pore diameter about 1.4~1. 6nm and its acid strength was obvious lower than that of ZSM-5 molecular.