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HWAHAK KONGHAK,
Vol.30, No.1, 9-17, 1992
Vol.30, No.1, 9-17, 1992
Raney-nickel 촉매에 의한 p-Nitrotoluene의 수소화 반응에 관한 연구
A study on the Hydrogenation of p-Nitrotoluene by Raney-nickel Catalyst
Raney-nickel 촉매에 의한 p-nitrotoluene의 p-toluidine으로의 수소화 반응은 20-60℃, 20-160psig 정도의 반응조건하에서 100% 전환율을 나타내는 반응이었다. 본 연구에서는 반응속도에 대한 교반속도, 촉매 주입량, 촉매 입자 크기의 변화에 따른 물질전달의 영향을 고찰하고 반응메카니즘과 반응특성을 검토하였다. 용매는 메탄올을 사용하였으며, 교반속도 0-1,200rpm, 촉매 주입량 0.9-5.2g, 촉매 입자 크기 20-100㎛ 범위에서 실험을 실시하였다. 주어진 변수들의 적절한 범위에서 물질전달 저항이 무시되어 화학반응 단계가 율속단계인 조건을 얻을 수 있었으며, 이를 이론적인 계산에 의해 확인하였다. 이 조건하에서 얻어진 겉보기 활성화에너지는 10.2kcal/mol이었다. 본 반응은 확인된 중간체들에 의해 Haber가 제시한 반응기구를 따르는 것으로 보였으며, 반응물인 p-nitrotoluene의 감소 곡선에 의한 반응속도의 해석은 Langmuir-Hinshelwood-Hougen-Watson 반응메카니즘의 비경쟁 흡착모델에 잘 적용되었다. 이 때 얻어진 반응속도식은 다음과 같이 나타낼 수 있었다.
-ΥNT=kㆍwㆍ[(KH/H)PH2 / 1+√(KH/H)PH22]ㆍCNT
/ CNT+α(CNTo-CNT)
-ΥNT=kㆍwㆍ[(KH/H)PH2 / 1+√(KH/H)PH22]ㆍCNT
/ CNT+α(CNTo-CNT)
Hydrogenation of p-nitrotoluene to p-toluidine on Raney-nickel catalyst was such a reaction that showed 100% conversion at the reaction conditions of 20-60℃ and 20-160psig. In this work the mass transfer effect which was observed by the variation of stirring speed, catalyst loading and catalyst particle size on the reaction rate was examined, and the mechanism and characteristics of the reaction were studied. Using methanol as solvent, in some range of stirring speed 0.1,200rpm, catalyst loading 0.9-5.2g, catalyst particle size 20-100㎛. It was possible to obtain a reaction condition under which the mass transfer resistance could be neglected and the chemical reaction on the catalyst surface be regarded as the rate determining step. This was confirmed by theoretical calculation and the activation energy of apparent rate constant was about 10.2kcal/mole. The reaction mechanism was thought to follow the Haber mechanism, considering reaction intermediates detected during the experiments. Also analysis of the reaction rate based on the decreasing rate of p-nitrotoluene indicated that the present reaction could described by a non-competitive adsorption model of Langmuir-Hinshelwood-Hougen-Watson reaction mechanism as shown below;
-γNT=ksㆍw(KH/H)PH2/1+ SQRT
(KH/H)PH22ㆍCNT/CNT+α(CNTo-CNT)
-γNT=ksㆍw(KH/H)PH2/1+ SQRT
(KH/H)PH22ㆍCNT/CNT+α(CNTo-CNT)
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참고문헌정보(참고문헌, 인용문헌)는 화학공학소재연구정보센터에 의해 제공되고 있습니다.