In Situ IR Studies on the Mechanism of Dimethyl Carbonate Synthesis from Methanol and Carbon Dioxide

Catalysts

YousefS. Al-Zeghayer¹  SulaimanI. Al-Mayman²  Aghaddin Mamedov³  KhalidA. Almusaiteer⁴ 

[1] Department of Chemical Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia;Energy and Water Research Institute, King Abdulaziz City for Science and Technology, P.O. Box 6086, Riyadh 11442, Saudi Arabia;SABIC Corporate T&I, 1600 Industrial Blvd, Sugar Land, TX 77478, USA;SABIC Corporate T&I, Thuwal 23955-6900, Saudi Arabia;

关键词: DMC;    CO₂;    DRIFTS;    methanol;    catalyst;    DME;   

DOI  :  10.3390/catal11040517

来源: DOAJ

【 摘 要 】

The synthesis of dimethyl carbonate (DMC) from methanol and Carbon dioxide (CO₂) has been investigated over 5% Rh/Al₂O₃ catalyst. Diffuse Reflectance Infrared Fourier Transfer Spectroscopy (DRIFTS) was used to probe the reaction adsorbates which showed that activation of methanol and CO₂ involves generation of intermediate methoxy species and formate ingredients, participating in elementary steps of DMC formation. Formation of DMC involves parallel routes comprising interaction of the OH group of Al₂O₃ through an acid/base mechanism and formate pathway with participation of metal sites. DMC in acid/base pathway is formed via methoxy species to form methoxy carbonate (CH₃O)CO₂ (active adsorbate), which then reacts with the methyl species to form DMC. The pathway involving metal Rh sites generates an additional elementary step for the involvement of CO₂ in the reaction through active formate species. The synergy of parallel pathways determines the performance of the 5% Rh/Al₂O₃ catalyst. Further improvement of catalyst performance should be based on such a feature of the reaction mechanism.

【 授权许可】

Unknown