화학공학소재연구정보센터
홈 로그인 로그아웃 연락처 사이트맵
HWAHAK KONGHAK, Vol.30, No.1, 1-8, February, 1992
Export Citation
Ge(OCH3)4의 화학증착에 의한 HZSM-5 촉매의 형상선택성에 관한 연구
On the Shape Selectivity of HZSM-5 Catalyst by Ge(OCH3)4-CVD Method
문세기, 김형진, 김문혁, 손영순
초록
300℃, 2×10-3 torr 진공하에서 germanium methoxide[Ge(OCH3)4]를 증착한 후, 400℃ 대기 중에서 소성하여 germanium oxide가 증착된 제올라이트(GeHZSM-5)를 제조하였다. 제조된 촉매는 암모니아 승온탈착법과 water, p-xylene, o-xylene 등의 흡착실험 침 IR 분석을 수행하여 특성을 분석하였다. 증착된 germanium oxide는 촉매의 내부 산점 및 구조에 변화를 일으키지 않고, 외부표면상에서만 증착되어, HZSM-5 촉매의 pore-opening size를 미세하게 조절하는 역할을 하는 것으로 추측된다. 이러한 pore-opening size의 조절효과를 톨루엔(toluene)의 메탄올(methanol)에 의한 알킬화 반응을 행하여 확인하였다. 반응시의 주 생성물인 xylene isomer 중에서 가장 작은 kinetic diameter를 갖는 p-xylene의 수율은 증가하는 반면, m-, o-xylene의 수율은 감소하였다. 결론적으로, 증착된 germanium oxide의 역할은 HZSM-5 촉매의 pore-opening size를 미세하게 조절하여 HZSM-5 촉매의 형상선택성을 증가시키는 것으로 생각된다.
Germanium methoxide was deposited irreversively by CVD(chemical vapor deposition) on the zeolite(HZSM-5) under 2 TIMES 10-3 torr and at 300℃, and the deposited materials were calcined at 400℃ in air, finally forming germanium oxide-deposited zeolites(GeHZSM-5). These were characterized by tempera-ture-programmed desorptiion of ammonia, FT-IR analysis and adsorption experiments using water, p-xylene and o-xylene as adsorbates. It was suggested that the germanium oxide was deposited only on the external surface of the catalysts and narrowed the pore-opening size effectively without changing the internal structure and the acidity of the catalysts. The fine control of pore-opening size was tested by alkylation of toluene with methanol. Hydrocarbon product distribution shifted to smaller molecules over GeHZSM-5 than HZSM-5 catalyst;that is, the yields of m-, o-xylenes were decreased, but the yield of p-xylene was increased. Enhance-ment of the para-shape selectivity in xylene isomers indicated the fine control of the pore-opening size accord-ing to the deposition extent.
  1. Frillete VJ, Weisz PB, Golder RL, J. Catal., 1, 301 (1962) 
  2. Weise PB, Proc. Int. Congr. Catal., 7th, 57 (1981)
  3. Ransley DL, "Kirk-Othmer Encyclopedia of Chemical Technology," 3rd ed., Vol. 24, 709 (1984)
  4. Niwa M, Murakami Y, J. Phys. Solids, 50(5), 487 (1989) 
  5. Niwa M, Kato S, Hattori T, Murakami Y, J. Phys. Chem., 90, 6222 (1986)
  6. Sato S, Hasebe S, Sakurai H, Urae K, Izumi Y, Appl. Catal., 29, 107 (1987) 
  7. Niwa M, Kato S, Hattori T, Murakami Y, J. Chem. Soc.-Faraday Trans., 80, 3135 (1984) 
  8. Breck DW, "Zeolite Molecular Sieve," John Wiley Sons, Inc., New York, London (1974)
  9. Rabo JA, "Zeolite Chemistry and Catalyst," ACS Washington D.C. (1976)
  10. Kiselev AV, Lygin VI, "Infrared Spectra of Surface Compounds," John Wiley Sons, Inc., New York (1974)
  11. Flanigen EM, Khatami H, Szymanski HA, "Molecular Sieve Zeolite," Adv. Chem. Ser., 101, ACS, Washington D.C. (1971)
  12. Anderson JR, Foger K, Kole T, Rajadhyasha RA, Sanders JV, J. Catal., 58, 114 (1979) 
  13. Hidalgo CV, Itho H, Hattori T, Niwa M, Murakami Y, J. Catal., 85, 362 (1984) 
  14. Chen NY, Garwood WE, J. Catal., 52, 453 (1978) 
  15. Barrer RM, Brook DW, J. Chem. Soc.-Faraday Trans., 49, 1049 (1953) 
  16. Kaeding WW, Chu C, Weinstern B, Young LB, Butter SA, J. Catal., 67, 159 (1981) 
  17. Haag WO, Olson DH, U.S. Patent, 3,856,871 (1974)
  18. Morrison RA, U.S. Patent, 3,856,872 (1974)
  19. Derouane EG, Cabelica Z, J. Catal., 65, 486 (1980) 
  20. Chu YF, Keweshan CF, Vansant EF, "Zeolite as Catalyst. Sorbent and Detergent Builders," 749 (1989)