氧化鋁及氧化鋁水合物對於乙醇脫水反應之研究－氧化鋁及其水合物之構造，表面狀態與活性度之關係

Studies on the Dehydration of Ethanol by Different Types of Alumina and Alumina Hydrates. (The Relation of Activity of Alumina and Alumina Hydrates to the Structures and Surface States)

趙承琛(Chen-Shen Chao)

《化學》 53年2期 (1964/06) Pp. 41-47

https://doi.org/10.6623/chem.1964009

摘要

用各種不同方法製造之氧化鋁水合物及各種不同溫度焙燒所得之氧化鋁，分別用X射線粉末繞射法檢定其結晶構造後，分別再用B. E. T. 測定融媒之全表面積並用鹼液測定測定其acid site，以檢討在乙醇脫水反應中氧化鋁構造及表面狀態與活性度之關係及其反應機構。

並列摘要

The author made many types of catalyst alumina and alumina hydrates by different methods for the dehydration of ethanol. Their crystal structures, total surface area, and acid site were determined by powder X-ray diffraction method, B. E. T. method, and alkali titration respectively. The relation of activity of alumina catalyst to its structure and surface state, and the mechanism of dehydration were discussed: (1) Crystal structure, total surface area, and number of acid site are the important factors affecting the catalytic activity for ethanol dehydration. (2) η-Alumina formed by the calcination of bayerite at 500-600°C, or amorphous alumina gel is the best catalyst for the dehydration of ethanol. r -Alumina formed by the calcination of boemite at 500° is next. (3) Many types of alumina which are prepared by calcination of the same alumina hydrate increase in the dehydration activity with the increase of number of acid site and total surface area, but not in direct proportion. The acid site as well as the total surface area, is a necessary, but not a sufficient, prerequisite. (4) The acid site of alumina catalyst may be considered to be one of two adsorption points for ethanol molecule according to Balandin's ＂multiplet hypothesis＂.