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CO2的资源化利用引起了广泛的关注,将其作为碳氧资源转化成能源、材料和化工产品等是当今各国政府及科学界的重大战略课题。目前,CO2的大规模利用主 要集中在替代光气合成脲类化合物和碳酸酯[1]。N-取代氨基甲酸酯在有机合成、医药、农药等领域具有广泛用途,特别是非光气合成异氰酸酯的重要原料。脲 类化合物与碳酸二烷基酯合成N-取代氨基甲酸酯是典型的原子经济反应,有必要开发一种成本较低、活性较高的多相催化剂体系。这里,在无催化剂的情况下,我 们利用脂肪二胺与CO2成功合成了聚脲化合物。然后,在MgO-ZnO复合氧化物催化剂作用下,聚脲与碳酸二烷基酯反应,高效地合成了N-取代的二氨基甲 酸酯,Scheme 1。催化剂可以重复使用多次而活性基本不变,而且对合成不同的N-取代氨基甲酸酯也表现出很好的催化活性。

MgO-ZnO 复合氧化物.jpg

尚建鹏,王利国,邓友全. Mgo-zno 复合氧化物催化聚脲与碳酸二烷基酯原子经济反应合成 N-取代的氨基甲酸酯[C]. 第二十八届中国化学会年会第1分会场摘要集.2012,17.

This paper reports an effective route for the syntheses of N-substituted dicarbamates from dialkyl carbonates and polyurea derivatives, in which polyurea derivatives could be successfully synthesized from aliphatic diamines and CO2 in the absence of any catalyst. Under the optimized reaction conditions, various N-substituted carbamates were successfully synthesized with 93–98% isolated yields over a MgO–ZnO catalyst. The catalyst could be reused for several runs without deactivation. The catalysts were characterized with X-ray photoelectron spectroscopy, X-ray diffraction and temperature-programmed desorption.

★★★★☆ Green Chem., 2012, 14, 2899–2906

Magnetic binary Mg\Fe oxides were prepared by co-precipitation method, characterized and tested in the synthesis of 2-oxazolidinones from epoxides and carbamates. The catalytic results showed that the catalyst with Mg/Fe molar ratio of 1 and calcined at 400 °C exhibited superior catalytic activity. The catalyst could be magnetically separated, recycled and reused for five runs without noticeable deactivation. Under the optimized conditions, various 2-oxazolidinones derivatives were successfully synthesized with good to excellent isolated yields.

Keywords: 2-oxazolidinone; Epoxide; Carbamate; Solid base; Magnetic oxides

★★★☆☆ J. Shang et al. / Catalysis Communications 28 (2012) 13–17

A series of catalysts of magnetic iron oxide containing Ni with different nickel content were prepared with co-precipitation method and tested in the syntheses of N-substituted carbamates from various amines and alkyl carbamates. Under the optimized reaction conditions, various N-substituted carbamates were successfully synthesized with 90–98% isolated yield. The catalyst could be recovered based on the magnetic property of the catalyst and reused for five runs without deactivation. The catalysts were characterized with X-ray photoelectron spectroscopy, X-ray diffraction, temperature-programmed reduction, temperature-programmed desorption, and Mössbauer spectroscopy analyses. The results showed that the catalytic activity may be derived from the delicate synergy between Ni and Fe species resulted in specific basic sites. Quasi in situ FT-IR and isotopic tracer revealed that the formation of substituted urea was the key step and the N-substituted carbamate was formed via further alcoholysis of the substituted urea.

Keywords: Non-phosgene; Carbamate; Carbonylation; Magnetic iron oxide

★★★☆☆ J. Shang et al. / Journal of Catalysis 279 (2011) 328–336