Evaluation of Surface Properties of Solid Acids by the Adsorption of Inert Gases

通过惰性气体吸附评价固体酸的表面性质

基本信息

批准号：
14540524
负责人：
MATSUHASHI Hiromi
金额：
$ 1.28万
依托单位：
Hokkaido University of Education
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14540524/
关键词：
Solid acid Argon nitrogen Heat of adsorption Acid strength Bronsted acid Lewis acid Solid superacid アルゴン吸着酸量ゼオライト

项目摘要

Chemically inert gases like argon and nitrogen are to be polarized state when they are approached to a polarized sites, and there is an electrostatic interaction between them. The most polarized sited on a solid acid is expected to be acid sites. This interaction between the polarized acid sites and induced dipole of argon or nitrogen is acid-base like interaction. It can be easily expected that the strength of the interaction will depend on the acid strength.It was shown that the heat of adsorption of argon obtained by applying the Henry-type adsorption isotherms was an indicator of the relative acid strength of solid acids of proton-type mordenite, beta, ZSM-5, sulfated zirconia, and silica-alumina.The adsorption isotherm was not Henry-type in particular, and the obtained heat of adsorption of argon was approximate value. As the result of detailed research, it was clarified that the heat of argon adsorption obtained by applying Lngmuir-type adsorption isotherms indicated the relative acid strength and the calculated adsorption amount saturation was equal to the number of acid sites. Additionally, temperature dependence of adsorption amount related to the pore size of solid acids.For the purpose to determine the distribution of acid strength of the acid sites, the Clausius-Clapeyron equation was applied to the isothermos of argon and nitrogen adsorption measured at various temperatures. The obtained data of argon adsorption indicated the distribution of avid strength. The much larger heat of nitrogen adsorption was measured on several solid acid which has Lewis-type acid sites. This result indicates that the type of acid sites is possible to distinguish by comparison of the adsorption heat of nitrogen with that of argon.

当将氩气和氮之类的化学惰性气体接近极化位点时，它们将是极化状态，并且它们之间存在静电相互作用。固体酸上最偏振的位置预计将是酸位点。极化酸位点和诱导的氩或氮偶极子之间的这种相互作用是酸碱像相互作用。可以很容易地预期相互作用的强度将取决于酸的强度。这表明，通过应用亨利型吸附等温线获得的氩气吸附热是质子型蛋中型，beta，beta，zsm-5的固体酸强度的相对酸强度的指标尤其是，获得的氩气吸附的热量是近似值。详细研究的结果是，通过应用LNGMUIR型吸附等温线获得的氩吸附的热量表明相对酸强度和计算出的吸附量饱和度等于酸位点的数量。另外，吸附量与固体酸的孔径相关的温度依赖性。为了确定酸位点的酸强度的分布，将克劳西乌斯 - 克拉皮龙方程应用于在各种温度下测量的氩气和氮的糖吸附。获得的氩吸附数据表明狂热的强度分布。在具有刘易斯型酸位点的几种固体酸上测量了氮的吸附热量。该结果表明，可以通过比较氮的吸附热与氩气的吸附热来区分的酸位点的类型。