MoO<sub>3</sub>/bismuth molybdate 혼합 2상 촉매의 구조에 따른 프로필렌 선택산화반응 특성

차태병; 최명재; 박대원; 정종식

Journal of the Korean Industrial and Engineering Chemistry, Vol.3, No.1, 53-63, March, 1992

Export Citation

MoO₃/bismuth molybdate 혼합 2상 촉매의 구조에 따른 프로필렌 선택산화반응 특성

Effect of the Structure of MoO₃/bismuth molybdate Binary Phase Catalysts on the Selective Oxidation of Propylene

차태병, 최명재, 박대원, 정종식

초록

프로필렌을 선택산화시켜 아크로레인을 제조하는 반응을 Bi-molybdate 촉매상에서 고정층 반응기를 사용하여 연구하였다. α-Bi₂Mo₃O₁₂ 위에 MoO₃를 담지시킨 M/BM-series 촉매는 함침법으초 제조되었고, 역으로 BM/M-series 촉매는 MoO₃ 위에 α-Bi₂Mo₃ O ₁₂ 을 침전시켜 제조하였다. 또한 촉매의 특성분석을 위하여 질소흡착과 XRD, SEM을 이용하였다. M/BM-series 촉매에서는 MoO₃가 작은 입자로 분산되고 α-Bi₂Mo₃O₁₂의 결정구조는 MoO₃상이 추가되어도 그 형상이 변하지 않는 채로 유지되었으나, BM/M-series 촉매의 표면형상 및 전체 구조는 촉매제조 중에 생기는 침전물인 Bi(OH)₃가 소성 도중 MoO₃와 반응하여 α-Bi₂Mo₃O₁₂을 형성하는 관계로 그 조성에 따라 매우 불규칙적으로 변화하였다. 반응실험 결과, 두 종류의 촉매 모두에서 excess MoO₃가 포함되었을 때 활성이 크게 증가하였는데, 이는 선별산화반응이 주로 α-Bi₂Mo₃O₁₂에서 일어나고 MoO₃는 α-Bi₂Mo₃O ₁₂에 산소 공급을 원활히 하여 활성을 증가시키기 때문으로 판명되었다. 또한 이러한 활성 증가는 α-Bi₂Mo₃O₁₂와 기계적 혼합물 (mechanical mixture)에서도 관찰되었다.

M/BM -series catalysts, MoO₃ supported on α-Bi₂Mo₃O₁₂were also prepared by impregnation method. BM/M-series catalysts, α-Bi₂Mo₃O₁₂ supported on MoO ₃ were also prepared by coprecipitation. Structure and catalytic properties of the two phase catalysts were studied by means of using nitrogen adsorption, X-ray diffraction, and scanning electron microscopy. The reaction test for the selective oxidation of propylene to acrolein over Bi -molybdate catalysts was studied using a fixed-bed reactor system. In M/BM-series catalysts, MoO₃ was dispersed on α-Bi₂Mo₃O₁₂, and the crystal structure of α-Bi₂Mo₃O₁₂ remains unchanged by the pres- ence of excess MoO₃. However the surface morphology and bulk structure of BM/M-series catalysts were altered probably because the precipitated Bi(OH)₃ reacted with MoO₃ during the calcination to form α-Bi₂Mo₃O₁₂ phase. The results of propylene oxidation on both series catalysts showed that the reaction took place over the surface of α-Bi₂Mo₃O₁₂ particle and the role of excess MoO₃ was to supply oxygen to α-Bi₂Mo₃O ₁₂. These increasing effects on activity were also observed in the mechanical mixtures of α-Bi₂Mo₃O₁₂ and MoO₃.

[References]

Hucknall DJ, "Selective Oxidation of Hydrocarbons," Academic Press, New York, p. 23 (1974)
Weng LT, Ruiz P, Delmon B, J. Mol. Catal., 52, 349 (1989)
Weng LT, Ruiz P, Delmon B, J. Mol. Catal., 61, 99 (1990)
Ozcan U, Schrader GL, J. Catal., 95, 120 (1985)
Ozcan U, Schrader GL, J. Catal., 95, 137 (1985)
Carson D, Coudurier G, Forissier M, Verdine JC, J. Chem. Soc.-Faraday Trans., 79, 1921 (1983)
Grzybowska B, Mazakiewicz A, Bull. Acad. Pol. Sci. Ser. Sci. Chem., 27, 149 (1979)
Trifiro F, Hoser H, Scarle RD, J. Catal., 25, 12 (1972)
Haber J, Sochacka M, Grzybowska B, Golzbiewski A, J. Mol. Catal., 1, 35 (1975)
El-Jamal M, Forisser M, Coudurier G, React. Kinet. Catal. Lett., 37, 349 (1985)
Gasselli RK, Appl. Catal., 15, 127 (1985)
Haber J, Witko M, Pure Appl. Chem., 50, 923 (1978)

[Referenced By]

[1] Hucknall DJ, "Selective Oxidation of Hydrocarbons," Academic Press, New York, p. 23 (1974)

[2] Weng LT, Ruiz P, Delmon B, J. Mol. Catal., 52, 349 (1989)

[3] Weng LT, Ruiz P, Delmon B, J. Mol. Catal., 61, 99 (1990)

[4] Ozcan U, Schrader GL, J. Catal., 95, 120 (1985)

[5] Ozcan U, Schrader GL, J. Catal., 95, 137 (1985)

[6] Carson D, Coudurier G, Forissier M, Verdine JC, J. Chem. Soc.-Faraday Trans., 79, 1921 (1983)

[7] Grzybowska B, Mazakiewicz A, Bull. Acad. Pol. Sci. Ser. Sci. Chem., 27, 149 (1979)

[8] Trifiro F, Hoser H, Scarle RD, J. Catal., 25, 12 (1972)

[9] Haber J, Sochacka M, Grzybowska B, Golzbiewski A, J. Mol. Catal., 1, 35 (1975)

[10] El-Jamal M, Forisser M, Coudurier G, React. Kinet. Catal. Lett., 37, 349 (1985)

[11] Gasselli RK, Appl. Catal., 15, 127 (1985)

[12] Haber J, Witko M, Pure Appl. Chem., 50, 923 (1978)