物理化学学报 >> 1987, Vol. 3 >> Issue (04): 375-379.doi: 10.3866/PKU.WHXB19870408

研究论文 上一篇    下一篇

吡啶在几种Y型沸石上的吸附量热研究

刘献友; 周立幸; 尹安学; 郑禄彬   

  1. 中国科学院大连化学物理研究所
  • 收稿日期:1986-02-22 修回日期:1986-07-25 发布日期:1987-08-15
  • 通讯作者: 周立幸

DIFFERENTIAL HEATS OF ADSORPTION FOR PYRIDINE ON SEVERAL Y-ZEOLIES

Liu Xianyou; Zhou Lixing; Yin Anxue; Zheng Lubin   

  1. Dalian Institute of Chemical Physics; Academia Sinica
  • Received:1986-02-22 Revised:1986-07-25 Published:1987-08-15
  • Contact: Zhou Lixing

摘要: 用微量量热计测定了在室温至600 K范围内吡啶在NaY、CaY、R_EY和HY这几种Y型沸石上的吸附热。实验结果表明, 在这四种沸石上, 存在两种不同类型的酸中心, 一种是B酸中心; 另一种是非活化的L酸中心。B酸中心的酸强度随温度的升高而增加, 而非活化的L酸中心则随温度的升高而减小。在NaY沸石表面上, 只有Na~+一种非活化的L酸中心; 在HY沸石表面上则只有一种B酸中心。在R_EY和CaY表面上, 同时存在着B酸中心和非活化的L酸中心。高温时, 吡啶先吸附在强酸中心H~+上。室温时吡啶在所有试样上的吸附量均在3.0~3.2 mmolg~(-1)之间, 该值正好对应于超笼和β笼中的吸附中心数。

Abstract: Differential heats of adsorption for pyridine on NaY, CaY, R_EY and HY zeoli- tes in the temperature range from ambient temperature to 620 K have been measu- red by a micro-calorimeter. Experimental results show that there are two types of different acidic site in these four Y-zeolites. One type is B-acid site and the other one is non-active L-acid site. Acid strength of B-acid site would increase and non-active L-acid site would decrease as the temperature is raising. Only Na~+ ions act as the non-active L-acid sites on NaY surface and H~+ as the B-acid sites on HY surface for pyridine adsorption, but both B-sites and L-sites present on the surface of R_EY and CaY simultaneously. At higher temperatures the adsorption of pyridine prefers to occur on the strong B-acid sites.
At room temperature the amounts of adsorption for pyridine on these all samples are around 3.0—3.2 mmol g~(-1) which are in accordance with the numbers of the total adsorption sites in super-cages and β-cages.