Catalytic activity of ZIF-8 in the synthesis of styrene carbonate from CO2 and styrene oxide
Catalytic activity of ZIF-8 in the synthesis of styrene carbonate from CO2 and styrene oxide
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DOI：
10.1016/j.catcom.2012.12.003
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发表时间：
2013-02
影响因子：
3.7
通讯作者：
Minqi Zhu;D. Srinivas;S. Bhogeswararao;P. Ratnasamy;Moises A. Carreon
中科院分区：
文献类型：
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作者：
Minqi Zhu;D. Srinivas;S. Bhogeswararao;P. Ratnasamy;Moises A. Carreon
研究了ZIF-8分子筛在二氧化碳和环氧苯乙烷合成碳酸苯酯反应中的催化活性。ZIF-8晶体即使在低至50°C的温度下也表现出催化活性，在100°C时，碳酸苯酯的产率高达~54%。与许多现有的催化剂相比，不需要溶剂或助催化剂。以吡啶和氨为探针分子，估算了新鲜和重复使用的ZIF-8催化剂的酸中心类型和密度。吸附吡啶的漂移光谱表明，同时存在Brnsted(B)和Lewis(L)酸中心。在回收的ZIF-8催化剂中，B位几乎消失了。在ZIF-8分子筛中同时存在咪唑连接基的酸位和氮碱性基团，促进了CO2在固体表面的吸附，并进一步转化为环状碳酸酯。ZIF-8催化剂可回收再利用，催化活性不会有明显损失。
The catalytic activity of ZIF-8 in the synthesis of styrene carbonate from carbon dioxide and styrene oxide is presented. ZIF-8 crystals displayed catalytic activity even at temperatures as low as 50°C, with styrene carbonate yields as high as ~54% at 100°C. In contrast to many prior-art catalysts, solvents or co-catalysts were not required. Pyridine and ammonia were used as probe molecules to estimate the type and density of acid sites in fresh and reused ZIF-8 catalysts. DRIFT spectroscopy of adsorbed pyridine revealed the presence of both Brönsted (B) and Lewis (L) acid sites. The B-sites have nearly vanished in the case of recycled ZIF-8 catalysts. The simultaneous presence of both the acid sites and the nitrogen basic moieties from the imidazole linker in ZIF-8 promoted the adsorption of the CO2on the solid surface and its further conversion to the cyclic carbonate. The ZIF-8 catalysts could be recycled and reused without significant loss in catalytic activity.