Shang Shu, Shao Wei, Luo Xiao, Zuo Ming, Wang Hui, Zhang Xiaodong, Xie Yi
Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.
Institute of Energy, Hefei Comprehensive National Science Center, Hefei 230031, China.
Research (Wash D C). 2022 Oct 14;2022:9878054. doi: 10.34133/2022/9878054. eCollection 2022.
Cycloaddition of epoxides with CO to synthesis cyclic carbonates is an atom-economic pathway for CO utilization with promising industry application value, while its efficiency was greatly inhibited for the lack of highly active catalytic sites. Herein, by taking BiOX (X = Cl, Br) with layered structure for example, we proposed a facet engineering strategy to construct Lewis acid-base pairs for CO cycloaddition, where the typical BiOBr with (010) facets expose surface Lewis acid Bi sites and Lewis base Br sites simultaneously. By the combination of diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and theoretical calculations, the oxygen atom of the epoxide is interacted with the Lewis acid Bi site to activate the ternary ring, then facilitates the attack of the carbon atom by the Lewis base Br site for the ring-opening of the epoxide, which is the rate-determining step in the cycloaddition reaction. As a result, the BiOBr-(010) with rich surface Lewis acid-base pairs showed a high conversion of 85% with 100% atomic economy in the synthesis of cyclic-carbonates without any cocatalyst. This study provides a model structure for CO cycloaddition to high value-added long chain chemicals.
环氧化物与一氧化碳环加成合成环状碳酸酯是一条具有原子经济性的一氧化碳利用途径，具有广阔的工业应用价值，然而，由于缺乏高活性催化位点，其效率受到极大抑制。在此，以具有层状结构的BiOX（X = Cl，Br）为例，我们提出了一种晶面工程策略来构建用于一氧化碳环加成的路易斯酸碱对，其中典型的具有（010）晶面的BiOBr同时暴露表面路易斯酸铋位点和路易斯碱溴位点。通过漫反射红外傅里叶变换光谱（DRIFTS）和理论计算相结合的方法，环氧化物的氧原子与路易斯酸铋位点相互作用以活化三元环，然后促进路易斯碱溴位点对碳原子的进攻以实现环氧化物的开环，这是环加成反应中的速率决定步骤。结果，具有丰富表面路易斯酸碱对的BiOBr-（010）在无任何助催化剂的情况下合成环状碳酸酯时显示出85%的高转化率和100%的原子经济性。本研究为一氧化碳环加成制备高附加值长链化学品提供了一种模型结构。
