插层高岭石层间醋酸钾的作用和取向

THE REACTION AND ORIENTATION OF POTASSIUM ACETATE IN THE KAOLINITE-POTASSIUM ACETATE INTERCALATE

利用X粉晶衍射和激光拉曼光谱实验分析高岭石及其醋酸钾插层物的结构。通过实验表明醋酸钾对结晶指数(HI)为0.9的高岭石进行插层,插层率为73%,使高岭石的d(001)由0.72075nm增加到1.42093nm。进入高岭石层间的醋酸根利用其羧基上的两个氧同时和高岭石的面内羟基形成氢键,在高岭石层间直立取向,而对其内羟基基本无影响。当温度升高时,与面内羟基伸缩振动有关的峰(3698cm-1,3684cm-1,3672cm-1等)发生红移,且强度增加;而与内羟基伸缩振动有关的峰(3621cm-1)则发生蓝移。温度升高到100℃以上,开始发生去插层过程;直到250℃,插层分子还不能完全从高岭石层间脱去。

Kaolinite and the kaolinite-potassium acetate intercalate were studied by X-ray diffraction and Raman spectra.X-ray diffraction shows the kaolinite with a Hinckley index of 0.9 is intercalated by potassium acetate to 73%, and expanded from d 001 spacing of 0.720 75 nm to 1.420 93 nm. Potassium acetate intercalation causes H-bonding between the two O-atoms of acetate molecular and inner-surface hydroxyl groups of kaolinite and adopts a perpendicular stance between the layers of kaolinite, and has no effect on the inner hydroxyl groups. As the temperature increases, the bands assigned to inner-surface hydroxyls stretching shift to lower wavenumbers, and their intensities increase; On the contrary, the bands assigned to the inner hydroxyls stretching shift to higher wavenumbers. Deintercalation begins at above 100℃, and acetate moleculars can not be separated from kaolinite completely even if the temperature goes up to 250℃.