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HWAHAK KONGHAK, Vol.26, No.6, 664-672, December, 1988
Methanol 산화반응에서 12-몰리브도 인산 동염 촉매의 특성
Catalysis of 12-Molybdophosphoric Acid Cupric Salt Catalyst on Methanol Partial Oxidation
초록
Cu2+이온으로 부분 치환된 CuxH3-2xPMo 촉매와 SiO2에 담지된 담지촉매의 특성을 반응실험, 전처리효과, TPR 및 XRD를 이용하여 조사하였다. 전처리 가스의 환원도에 따라 헤테로폴리산의 특성 구조는 부분적으로 분해되었으며, 분해된 주생성물은 C3H6인 경우는 Mo9O26, 그리고 H2인 경우는 MoO2였다. Cu2+로 부분 치환된 촉매는 치환량이 증가할수록 촉매의 환원 용이성（산화능）이 증가하였으며, formaldehyde의 선택률도 증가하였다.
담지촉매의 경우, 최적 담지량은 10 wt%일 때였으며 XRD 분석결과 담지량이 10 wt%까지는 촉매가 X-ray 무정형에 가까운 상태로 담체상에 고분산되어 있었다. Cu1.5PMo 촉매를 SiO2에 담지할 경우, Hedvall effect와 hysteresis현상이 관찰되지 않았으며, 촉매의 활성과 열적 안정성이 향상되었다.
담지촉매의 경우, 최적 담지량은 10 wt%일 때였으며 XRD 분석결과 담지량이 10 wt%까지는 촉매가 X-ray 무정형에 가까운 상태로 담체상에 고분산되어 있었다. Cu1.5PMo 촉매를 SiO2에 담지할 경우, Hedvall effect와 hysteresis현상이 관찰되지 않았으며, 촉매의 활성과 열적 안정성이 향상되었다.
CuxH3-2xPMo catalyst with various copper content（X） and Cu1.5PMo catalyst supported on SiO2 were characterized by methanol oxidation, pretreatment, TPR, and XRD. When the catalyst was pretreated with C3H6, NH3 and H2, the characteristic keggin structure was partially decomposed with the strength of the reducing power of pretreatment gases, and the decomposed main product was MoO3, Mo9O26 and MoO2, respectively.
The oxidation activity of catalyst and the selectivity of formaldehyde increased with increasing the content of Cu2+ ion in CuxH3-2xPMo catalyst. The optimum content of Cu1.5PMo supported on SiO2 was 10 wt%; and the supported catalyst was highly dispersed as a X-ray amorphous state. The supported catalyst did not show Hedvall effect and hysteresis. Its catalytic activity and the thermal stability were greatly enhanced than those of Cu1.5PMo catalyst.
The oxidation activity of catalyst and the selectivity of formaldehyde increased with increasing the content of Cu2+ ion in CuxH3-2xPMo catalyst. The optimum content of Cu1.5PMo supported on SiO2 was 10 wt%; and the supported catalyst was highly dispersed as a X-ray amorphous state. The supported catalyst did not show Hedvall effect and hysteresis. Its catalytic activity and the thermal stability were greatly enhanced than those of Cu1.5PMo catalyst.