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

• 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

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.

氩气、氮气等化学惰性气体，当接近极化位点时会出现极化状态，它们之间存在静电相互作用。固体酸上极化程度最高的位点预计是酸位点。极化酸位点与氩或氮的诱导偶极子之间的这种相互作用是类似酸碱的相互作用。可以容易地预期相互作用的强度将取决于酸强度。结果表明，应用亨利型吸附等温线获得的氩气吸附热是质子型丝光沸石、β、ZSM-5、硫酸化氧化锆和二氧化硅-氧化铝固体酸的相对酸强度的指标。吸附等温线不是亨利型 特别是，得到的氩的吸附热为近似值。详细研究的结果表明，应用Lngmuir型吸附等温线获得的氩气吸附热表示相对酸强度，计算出的吸附量饱和度等于酸性位点的数量。此外，吸附量的温度依赖性与固体酸的孔径有关。为了确定酸位的酸强度分布，将Clausius-Clapeyron方程应用于不同温度下测量的氩和氮吸附等温线。获得的氩气吸附数据表明了热力强度的分布。在几种具有路易斯型酸位的固体酸上测量到了更大的氮吸附热。该结果表明，通过比较氮气和氩气的吸附热可以区分酸位的类型。

项目成果

Hiromi Matsuhashi, Keiko Yamagata, Kazushi Arata: "Distinction of Acid-type on Solid Acid Surface by Comparison of Adsorption Heats of Nitrogen and Argon"Chemistry Letters. 554-555 (2004)

Hiromi Matsuhashi、Keiko Yamagata、Kazushi Arata：“通过比较氮和氩的吸附热来区分固体酸表面的酸类型”化学快报。

Hiromi Matsuhashi, Kazusi Arata: "Measurement of the Relative Acid Strength and Acid Amount of Solid Acids by Argon Adsorption"Physical Chemistry Chemical Physics. 6. 2529-2533 (2004)

Hiromi Matsuhashi、Kazusi Arata：“通过氩吸附测量固体酸的相对酸强度和酸量”物理化学化学物理。

松橋博美, 荒田一志: "Measurement of the Relative Acid Strength and Acid Amount of Solid Acids by Argon Adsorption"Physical Chemistry Chemical Physics. 6. 2529-2533 (2004)

Hiromi Matsuhashi、Kazushi Arata：“通过氩吸附测量固体酸的相对酸强度和酸量”物理化学化学物理。 6. 2529-2533 (2004)

松橋博美, 山縣桂子, 荒田一志: "Distinction of Acid-type on Solid Acid Surface by Comparison of Adsorption Heats of Nitrogen and Argon"Chemistry Letters. 33. 554-555 (2004)

Hiromi Matsuhashi、Keiko Yamagata、Kazushi Arata：“通过比较氮和氩的吸附热来区分固体酸表面的酸类型”化学快报 33. 554-555 (2004)。

松橋博美, 田中孝枝, 荒田一志: "Study on Measurement of Relative Acid Strength and Acid Amount on Solid Acid by Argon Adsorption"Physical Chemistry and Chemical Physics. (発表予定).

Hiromi Matsuhashi、Takae Tanaka、Kazushi Arata：“通过氩吸附测量固体酸的相对酸强度和酸量的研究”物理化学和化学物理（待提交）。