Green and efficient cycloaddition of CO2 toward epoxides over thiamine derivatives/GO aerogels under mild and solvent-free conditions

• 来源期刊: 中国科学:化学（英文版）
• 年，卷（期）: 2017,（7）
• 页码范围: 990-996
• 页数: 7页
• 语种: 英文
• DOI: 10.1007/s11426-016-0376-3

摘要

Thiamine derivatives that are cheap,readily available,non-toxic and green are used as heterogeneous catalyst for the generation of cyclic carbonates through cycloaddition of CO2 to epoxides without the need of co-catalyst and solvent.The interaction between thiamine hydrochloride (VB1-C1) and substrates (CO2 and propylene oxide) was proven by ultraviolet-visible spectroscopy and 1H nuclear magnetic resonance analysis,and it is deduced that the synergistic action among multi-functional groups (hydroxyl,halide anion and amine) is a favorable factor for cycloaddition reaction.A series ofVB1/GO aerogels were facilely prepared through the addition of aqueous VB1 derivatives to a suspension of GO in ethanol at room temperature.It was found that the aerogel generated through the interaction of VB1-Cl with GO shows catalytic activity and stability higher than those of VB1-Cl.It is because the electrostatic interaction between GO and VB1-Cl enhances the nucleophilicity and leaving ability of anion.The effects of reaction temperature,catalyst loading,CO2 pressure and reaction time on CO2 cycloaddition to propylene oxide were thoroughly studied.