Applied Chemistry for Engineering (공업화학)
- Volume 5 Issue 3
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- Pages.431-437
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- 1994
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- 1225-0112(pISSN)
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- 2288-4505(eISSN)
Formation and Role of Acid Sites of Heteropoly Acid Catalysts
헤테로폴리산 촉매의 산점 형성과 역할
- Song, In Kyu (Dept. Chem. Eng., Seoul Nat'l Univ.) ;
- Lee, Jong Koog (Dept. Chem. Eng., Seoul Nat'l Univ.) ;
- Song, Jae Cheon (Dept. Chem. Eng., Seoul Nat'l Univ.) ;
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Lee, Wha Young
(Dept. Chem. Eng., Seoul Nat'l Univ.)
- Received : 1994.01.19
- Accepted : 1994.03.15
- Published : 1994.06.01
Abstract
The role and the formation of surface and bulk acid sites of heteropoly acids were studied by examining ethanol conversion and MTBE (methyl t-butyl ether) decomposition reaction. In ethanol dehydration diethylether was formed on the surface acid site of 12-tungstophosphoric acid, whereas ethylene was formed in the bulk acid site of the catalyst. It was revealed that water reinforced the bulk acid site of the catalyst, while organic base decreased the bulk acid function of the catalyst. The formation of acid sites of metal salts was due to hydrolysis of crystalline water and/or partial substitution of metal, and with hydrogen treatment, the acid site was reappeared. Also catalyst design as a selective oxidation catalyst was possible by controlling acid function of heteropoly acid catalyst.
에탄을 전화반응 및 MTBE (methyl t-butyl ether)분해반응을 통하여 헤테로폴리산 촉매가 지니는 표면 및 내부 산점의 역할과 형성에 대하여 살펴 보았다. 12-텅스토인산에서 에탄올 탈수반응을 수행할 경우 디에틸에테르는 표면산점에서 생성되며 에틸렌은 촉매 내부산점에서 생성된다. 물은 산점을 강화하는 역할을 하지만 유기염기의 경우 내부 산점을 약화시킨다. 금속염의 산점 형성은 결정수의 가수분해 혹은 금속의 부분적 치환에 따른 양성자에 기인하며 수소로 처리할 경우 산점이 재생되었다. 또한 산 특성 제어를 통하여 선택적 산화반응 촉매로서의 헤테로폴리산 설계가 가능하다.
Keywords