STUDIES ON IR FRAMEWORK VIBRATION SPECTRA OF MEW TYPE PILLARED CLAYS
Hao Yu-zhi, Zhang Ying-zhen, Tao Long-xiang and Zheng Lu-bin (Dalian Institute of Chemical Physics, Academia Sinica, Dalian 116011)
The pillared clays including silica pillared montmorillomte (Si-CLM), silica pillared rectorite (Si-CLR) and alumina pillared rectorite(Al-CLR)were prepared by our new metho-gel dispersion method. The IRframework vibration spectra of 1000-1200 and 400-500cm-1 stem from tetrahedral antisymmetric stretching and Si-O bending vibration modes respectively. Compared with one vibration spectrum of montmorillonite, there are two vibration spectra of rectorite at the corresponding position. After calcination at 450--500℃ for 2 h, some spectra of pillared ciays shift to the higher frequency (CLR: A-47 cm-1; CLM. A = 14 cm-1), but under the same treatment conditions,the tetrahedral antisymmetric stre- tching vibration spectra of clays and pillaring agents remain unchanged, and the spectra of uncalcined pillared clays are similar to those of clays. This shows that after calcination there is a kind of chemical action between pillaring agent and clay. A pillaring mechanism is suggested that after calcination some tetrahedral silicon or aluminium reverse to gallery and react with pillaring agents whether or not there exists tetrahedral aluminium substitution in clays.
【Fund】： 国家自然科学基金;; 中国石油化工总公司科研基金