Synthesis of Propylene Carbonate from Carbon Dioxide and Propylene Oxide Using Zn-Mg-Al Composite Oxide as High-efficiency Catalyst

• Published in: Catalysis letters Vol. 136; no. 1-2; pp. 35 - 44
• Main Authors: Dai, Wei-Li, Yin, Shuang-Feng, Guo, Rui, Luo, Sheng-Lian, Du, Xin, Au, Chak-Tong
• Format: Journal Article
• Language: English
• Published: Boston Boston : Springer US 01.05.2010; Springer US; Springer; Springer Nature B.V
• Subjects: Alkaline earth metals; Aluminum; Ammonia; Barium; Basicity; Calcium; Carbon dioxide; Carbonates; Catalysis; Catalysts; Chemical industry; Chemical synthesis; Chemistry; Chemistry and Materials Science; Cycloaddition; Exact sciences and technology; General and physical chemistry; Heterogeneous catalysis; Hydrothermal treatment; Industrial Chemistry/Chemical Engineering; Magnesium; Organometallic Chemistry; Physical Chemistry; Precursors; Propylene; Propylene oxide; Reaction mechanisms; Recyclability; Roasting; Selectivity; Strontium; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Zinc; Zinc compounds; Propylene oxide; Heterogeneous catalysis; Zn; Al-O composite oxide; Propylene carbonate; Carbon dioxide; Oxides; Selectivity; Alkaline earth metal; Precursor; Base; Composite material; Ammonia; Hydrotalcite; Propene; Synthesis; Hydrothermal treatment; Zn-Mg-Al-O composite oxide; Acids; Efficiency; Oxirane(methyl); Reaction mechanism; pH; Alkalinity; Carbonates; Catalyst
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1007/s10562-009-0198-2

A series of Zn-Al composite oxides that were modified with alkaline earth metals, Zn-M-Al-O (M = Mg, Ca, Sr, and Ba) were fabricated via calcination of the corresponding hydrotalcite precursors, and evaluated as catalysts for the synthesis of propylene carbonate (PC) from CO₂ and propylene oxide. Among the Zn-M-Al-O catalysts, Zn-Mg-Al-O (Zn/Mg = 4.0, pH = 10, without hydrothermal treatment) is the best in performance, showing PC selectivity of 99.2% and yield of 88.8% (140 °C, 12 h). Furthermore, the Zn-Mg-Al-O catalyst can be readily reused and recycled without any loss of activity in a test of five cycles. Through detailed studies of the basic nature of the Zn-M-Al-O catalysts, it was found that a moderate basicity (6.1 ≤ H ₀ < 8.9) is beneficial to the cycloaddition reaction. The NH₃- and CO₂-TPD results also indicate that the Zn-Mg-Al-O catalyst has acid-base bifunctional properties, and a reaction mechanism is proposed. Graphic Abstract Zn-Mg-Al composite oxides were prepared via calcination of the corresponding hydrotalcite precursors, and used as catalysts for the synthesis of propylene carbonate from CO₂ and propylene oxide. We achieved high catalytic efficiency under mild conditions, easy separation of catalyst from the product, and good recyclability of the catalyst. A plausible reaction mechanism has been proposed for the catalytic action. [graphic removed]