Acta Chimica Sinica ›› 1996, Vol. 54 ›› Issue (6): 545-553. Previous Articles     Next Articles

Original Articles

用TG/DTG/DTA研究硅沸石与有机分子的主体/客体相互作用

龙英才;姜慧文;曾虹   

  1. 复旦大学化学系
  • 出版日期:1996-06-15 发布日期:1996-06-15

The host/guest interaction of organic molecules on silicalite-1 studied by TG/DTA/DTA

LONG YINGCAI;JIANG HUIWEN;ZENG HONG   

  • Online:1996-06-15 Published:1996-06-15

The thermal desorption behaviour of hydrocarbons, alcohols and alkyl-amines from zeolite silicalite-1, which possesses perfect framework without cations and Si-OH defect, was studied by TG/DTG/DTA. The temperatures of desorption of these organics from silicalite-1 are lower than 300℃. AT a new concept on affinity of silicalite framework to the guest molecule has been defined as difference between Td and Tb, where Td is the temperature of weight loss peak at DTG curve and Tb the boiling temperature at standard pressure. The AT values for saturated hydrocarbons are 60~90, while 6~13 for benzene, toluene, ethyl-benzene and p-xylene. The AT value evidently decreases for alkyl -alcohol since stronger electronegativety of its hydroxy group. The AT values are negative for alcohols with muti-hydroxy groups. For methylamine and ethylamine, the AT values are 160 and 127 respectively, much higher than that for other alkylamines. The endothermal effect of desorption from silicalite-1 in DTA curves is obvious for p-xylene, alkyl-alcohols and alkylamines. The difference in AT value as well as thermal effect of desorption is from the different interaction between the framework micropore surface constructed by O^2^- and C-H groups and other polar groups of organics, and from the different situation of associate for the molecules adsorbed, which is limited by the void space in framework of silicalite-1. These facts reflect a different type of supermolecular interaction for host/guest system.

Key words: SILICON, CATALYST, ZEOLITE, CARRIERS, THERMOGRAVIMETRY, DIFFERENTIAL THERMAL ANALYSIS, INTERACTIONS

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