Pu Yanfeng, Xuan Keng, Wang Feng, Li Aixue, Zhao Ning, Xiao Fukui
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences Taiyuan 030001 PR China
University of Chinese Academy of Sciences Beijing 100049 PR China.
RSC Adv. 2018 Jul 31;8(48):27216-27226. doi: 10.1039/c8ra04028a. eCollection 2018 Jul 30.
A series of Ce/SBA-15 catalysts with different degrees of hydrophobicities were prepared a post-grafting method and used for the direct synthesis of dimethyl carbonate (DMC) from CO and methanol. The Ce/SBA-15-6 catalyst exhibited the highest DMC yield of 0.2%, which was close to the equilibrium value under the reaction conditions of 130 °C, 12 h and 12 MPa. The catalysts were characterized XRD, BET, FT-IR, solid-state Si MAS NMR, CA, TEM, XPS and NH/CO-TPD; the results indicated that the hydrophobicity of the catalysts facilitated the creation of oxygen vacancies, which could act as Lewis acids to activate methanol. Higher amounts of moderate acid sites led to higher yields of DMC. In addition, the hydrophobicity of the catalysts could also reduce the adsorbed water on their surface and increase the DMC yield while shortening the reaction time.
通过后接枝法制备了一系列具有不同疏水程度的Ce/SBA-15催化剂，并将其用于由CO和甲醇直接合成碳酸二甲酯（DMC）。Ce/SBA-15-6催化剂表现出最高的DMC产率，为0.2%，这接近130℃、12小时和12MPa反应条件下的平衡值。采用XRD、BET、FT-IR、固态Si MAS NMR、CA、TEM、XPS和NH₃/CO₂-TPD对催化剂进行了表征；结果表明，催化剂的疏水性有助于产生氧空位，氧空位可作为路易斯酸活化甲醇。适量的中等强度酸性位点会导致更高的DMC产率。此外，催化剂的疏水性还可以减少其表面吸附的水，并在缩短反应时间的同时提高DMC产率。
