서지주요정보
니켈 - 텅스텐 담지촉매에서 에틸벤젠의 수소화 알킬기 제거반응 = Hydrodealkylation reaction of ethylbenzene over supported nickel - tungsten catalyst
서명 / 저자 니켈 - 텅스텐 담지촉매에서 에틸벤젠의 수소화 알킬기 제거반응 = Hydrodealkylation reaction of ethylbenzene over supported nickel - tungsten catalyst / 송요순.
저자명 송요순 ; Song, Yo-Soon
발행사항 [대전 : 한국과학기술원, 1992].
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등록번호

8002469

소장위치/청구기호

학술문화관(문화관) 보존서고

DCE 92012

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초록정보

Hydrodealkylation reaction of ethylbenzene was studied over nickel and nickel-tungsten catalysts supported on silica-alumina. The effect of varying composition of supported metals and reduction conditions on the activity and selectivity of the catalysts was investigated. Special emphasis is place upon capability of the catalysts to suppress the methanation of the decomposed benzene. Thermal hydrodeakylation reaction was also studied for comparison with the catalytic reaction. The reduction state of metal was examined using X-ray diffraction, Xray photoelectron spectroscopy and oxygen titration. While supported nickel oxide was almost completely reduced to the metal around 500℃, supported tungsten oxide tended to defy reduction: only 24% was reduced at 600℃ and 90% at 700℃ on the basis of $W^{+6} → W^{+4}$. Depending on the reduction treatment condition, tungsten reduced rather nonuniformly to a mixed state of valences. It was observed, however, that the reduction of tungsten was promoted by the cosupported nickel. The interaction between the supported nickel and tungsten was investigated by Auger electron spectroscopy, and their reaction activity by heat of reversible adsorption of aromatic compounds and by temperature programmed decomposition of dioxane. Tungsten showed weak interaction with benzene ring at each reduction state. Supported nickel catalyst showed high activity for the decomposition of dioxane, but activity was reduced when coimpregnated with tungsten. Thermal hydrodealkylation of ethylbenzene did not proceed to an appreciable extent below 600℃. At higher temperatures, benzene and diethylbenene were produced mainly by disproportionation. although benzene might be produced directly at highly elevated temperatures. Methanation of benzene ring was not observed under the investigated experimental condition. Hydrodealkylation reaction of ethylbenzene over nickel, tungsten and nickel-tungsten catalyst was studied. Over supported nickel catalyst the reaction proceeded even below 400℃ with high selectivity to toluene. The selectivity to benzene gradually increases with rising temperature, but the benzene was greatly susceptible to methanation above 450℃. The supported tungsten catalysts showed good activity and selectivity to benzene when reduced above 600℃. Over cosupported nickel-tungsten catalysts, high selectivity to benzene was obtained as a result of suppression of the methanation of the benzene ring. Although the level of activity and selectivity varies depending on composition of metals and the reduction condition. Mechanism of thermal and catalytic hydrodealkylation were proposed which account for the observed product distribution behavior. The catalytic characteristics of tungsten was discussed in relevance to its reduction state. The two metals, nickel and tungsten, were compared with respect to their catalytic function and interaction.

서지기타정보

서지기타정보
청구기호 {DCE 92012
형태사항 xi, 105 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Yo-Soon Song
지도교수의 한글표기 : 임선기
지도교수의 영문표기 : Son-Ki Ihm
학위논문 학위논문(박사) - 한국과학기술원 : 화학공학과,
서지주기 참고문헌 : p. 98-103
주제 Reduction (Chemistry)
Ethylbenzene.
촉매 반응. --과학기술용어시소러스
환원. --과학기술용어시소러스
Catalysts.
에틸벤젠
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