담지 금속 촉매를 이용하여 메탄을 2단계 반응에 의해 C2 이상의 탄화수소로 전화시키는 방법을 연구하였다. 1단계로 메탄을 금속 촉매와 접촉시켜 금속-탄소화합물 및 수소를 만들고, 2단계로 금속-탄소화합물을 수소와 반응시켜 C2 이상의 탄화수소를 얻었다. 반응은 알루미나 루세늄 혹은 백금을 담지시킨 촉매층을 채운 석영반응기에서 진행되었고 질량분석기 및 GC를 이용하여 반응물을 분석하였다. 수소화분해 반응 활성이 너무 큰 촉매는 수소화반응 단계에서 메탄을 주로 생산하여 C2 이상의 탄화수소 수율이 낮고, 수소화분해 반응 활성이 너무 작은 촉매는 탄소화합물의 생성이 어려울 뿐 아니라 생성 속도도 낮았다. 따라서 적당한 수소화분해 반응 활성이 2단계 반응에 의한 메탄전화 반응 촉매의 필수 조건임을 추정할 수 있었다. 담지 금속은 루세늄에 비해 백금이, 백금 담지시 담지량은 0.5%보다는 5%가 적당한 수소화분해 반응 활성을 소유함을 알 수 있었다. 메탄흡착의 최적온도는 250 ℃부근이었다. 본 연구에서는 사용된 귀금속 촉매들은 메탄으로부터 수소를 직접 제조하는 촉매 분해기술에도 사용 가능성이 있음을 확인하였다.

Methane could be converted to higher hydrocarbons by the two-step reaction using supported metal catalysts. At the first stage methane contacted with metal surface to produce carbonaceous species and hydrogen. Carbonaceous species then reacted with hydrogen to produce higher hydrocarbons at the second stage. Experiments were carried out with aluminasupported ruthenium or platinum catalysts using a quartz tubular reactor. The reaction mixtures were analyzed with a mass spectrometer and a gas chromatograph. The catalyst with too high hydrogenolysis activity produced mostly methane in the second-stage hydrogenation reaction, resulting in the low selectivity toward higher hydrocarbons. When the catalytic activity for the hydrogenolysis reaction was too low, both the selectivity of higher hydrocarbons and the reaction rate were low. Thus, it was concluded that the metal catalyst should have the moderate catalytic activity toward the hydrogenolysis reaction for the maximum conversion of methane to higher hydrocarbons. Supported platinum catalysts exhibited the lower hydrogenolysis activity than the supported ruthenium catalyst, producing larger amounts of higher hydrocarbons. Among supported platinum catalysts, the 5% platinum supported on alumina catalyst, having the moderate hydrogenolysis activity, was superior to the 0.5% Pt supported catalyst. The optimum temperature for the adsorption of methane on metal surface was about 250 ℃. The noble metal catalysts tested in this work can also be applied to the process of producing hydrogen by_x000D_ direct decomposion of methane.

Methane Conversion Higher Hydrocarbon Supported Metal Catalyst

Keller GE, Bhasin MM, J. Catal., 73, 9 (1982) 
Ito T, Wang JX, Lin CH, Lunsford JH, J. Am. Chem. Soc., 107, 5062 (1985) 
Korf SJ, Roos JA, Diphoorn JM, Veehof RHJ, van Ommen JG, Ross JRH, Catal. Today, 4, 279 (1989) 
Lee JS, Oyama ST, Catal. Rev.-Sci. Eng., 30, 249 (1988)
Lunsford JH, Catal. Today, 6, 235 (1990) 
Koerts T, van Santen RA, J. Chem. Soc.-Chem. Commun., 1281 (1991)
Koerts T, Deelen MJA, Pareja P, Amariglio H, J. Catal., 138, 101 (1992) 
Koerts T, van Santen RA, J. Mol. Catal., 74, 185 (1992) 
Solymosi F, Erdohelyi A, Cserenyi J, Felvegi A, J. Catal., 147(1), 272 (1994) 
Marceau E, Tatibouet JM, Che M, Saint-Just J, J. Catal., 183(2), 384 (1999) 
Bellgued M, Pareja P, Amariglio A, Amariglio H, Nature, 352(29), 689 (1991)
Belgued M, Amariglio A, Pareja P, Amariglio H, J. Catal., 159(2), 441 (1996) 
Belgued M, Amariglio A, Pareja P, Amariglio H, J. Catal., 159(2), 449 (1996) 
Amariglio A, Pareja P, Bellgued M, Amariglio H, J. Chem. Soc.-Chem. Commun., 561 (1994)
Satterfield SN, "Heterogeneous Catalysis in Practice," McGraw-Hill, New York, NY, 131 (1980)
Amariglio H, Saintjust J, Amariglio A, Fuel Process. Technol., 42(2), 291 (1995)