高等学校化学学报

高等学校化学学报 ›› 1992, Vol. 13 ›› Issue (5): 651.

• 论文 • 上一篇    下一篇

H(Mg,Co)AlPO4-5杂原子分子筛的酸性质测定

肖丰收1, 徐如人1, 辛勤2   

  1. 1. 吉林大学化学系, 长春, 130023;
    2. 中国科学院大连化学物理研究所国家催化基础实验室
  • 收稿日期:1991-05-15 出版日期:1992-05-24 发布日期:1992-05-24
  • 通讯作者: 肖丰收

Determination of the Acidity of H(Mg)AlPO4-5 and H(Co)AlPO4-5 Molecular Sieves

XIAO Feng-shou1, XU Ru-ren1, XIN Qin2   

  1. 1. Department of Chemistry, Jilin University, Changchun, 130023;
    2. National Lab. for Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian
  • Received:1991-05-15 Online:1992-05-24 Published:1992-05-24

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摘要： 以红外光谱和程序升温脱附法研究了H(Mg,Co)AlPO4-5分子筛的酸性,样品红外谱图中的3820和3680cm-1谱峰分别归属于vAl—OH和vp—OH,而3660～3568cm-1谱峰则分别归属于HMgAlPO4-5和HCoAlPO4-5分子筛的M(OH)P(M=Mg,Co)基团的振动,酸强度顺序为:Co(OH)P>Mg(OH)P>P(OH)>Al(OH),吡啶吸附的红外光谱揭示,H(Mg,Co)AlPO4-5分子筛具有较高酸强度的B酸和L酸中心。NH3-TPD表明分子筛的酸强度顺序为H(Co)AlPO4-5>H(Mg)AlPO4-5>>AlPO4-5。

关键词: AlPO4-5, 酸性质, 表面OH基, 化学吸附, H(Mg, CO)AlPO4-5分子筛

Abstract: The acidic sites of aluminophosphate molecular sieves, AlPO4-5, containing various heteroatoms such as Mg2+ and Co2+ were investigated by using IRspectroscopy of adsorbed pyridine and temperature-programmed desorption(TPD) of NH3. The band at 3680 cm-1 is assigned to P—OH, and the band at 3820 cm-1 can be attributed to the terminal Al—OH.The bands appearing in the region from 3660 to 3568 cm-1 is possibly assigned to the bridging hy-droxyl groups M (OH) P (M=Mg,Co).The decreasing acidity sequence of acidic sites is: Co(OH)P>Mg(OH)P>P(OH)>Al(OH).The IRspectra of pyridine adsorbing these samples reveal that there are strong Band Lacidic sites in H(Mg)AlPO4-5 and H(Co)AlPO4-5, in contrast to AlPO4-5.Additionally, the TPD-NH3 experiments show the order of the acidic strength of these samples: H(Co)AlPO4-5>H(Mg)AlPO4-5>>AlPO4-5.

Key words: AlPO4-5, Acidity, Surface OH, Chemical adsorption, H(Mg,Co)AlPO4-5 molecu-lar sieves

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