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          Ionic Liquids 離子液體

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          王利國 / 鄧友全
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          CO2作為碳氧資源的轉化利用對于經濟社會的可持續發展具有重要意義。環狀碳酸酯在有機合成、溶劑、紡織、印染等領域具有廣泛用途。CO2與環氧化合物合 成環狀碳酸酯是典型的原子經濟性反應[1],現已報道的催化體系不同程度存在一些問題,如催化劑成本高、活性不高、催化劑不易分離、易流失等問題。我們合 成了一系列不同類型硅膠接枝的雙季銨鹽離子液體,路線如Fig.1所示。其中MCM-41接枝的TMEDA+I-在環氧丙烷與CO2的反應中表現出較優的 催化性能,TOF可達>60h-1。催化劑重復使用多次而活性沒有明顯下降,且對于合成其它環狀碳酸脂也表現出很好的催化活性。

          介孔MCM-41.jpg

          王利國,王培學,楊本群,等. 介孔 Mcm-41 接枝雙季胺化離子液體高效催化環氧化合物與 Co2環化反應合成環狀碳酸酯[C]. 第二十八屆中國化學會年會第1分會場摘要集.2012,18.

          王利國 / 鄧友全
          2.81 MB

          Catalytic syntheses of cyclohexyl carbamates via alcoholysis of dicyclohexyl urea (DCU), which can be synthesized from CO2 and amines, were first investigated with low-molecular-weight alcohols, i.e., methanol, ethanol, butan-1-ol. TiO2/SiO2 catalyst was prepared by wet impregnation method using tetrabutyl titanate as titanium source. The catalyst was characterized by inductively coupled plasma/atomic emission spectroscopy (ICP/AES), N-2 adsorption, X-ray diffraction (XRD), field emission/scanning electron microscopy (FE/SEM), transmission electron microscopy TEM), and NH3/temperature-programmed desorption (TPD) in detail. TiO2/SiO2 with 5 wt % loadings and calcination at 600 degrees C exhibited better catalytic activity, and excellent yields of > 95 % with 98 % selectivities for desired carbamates were achieved. Accordingly, the strong acidity was considered to be responsible for its superior activity. Moreover, the catalytic activity can essentially be preserved during the recycling tests. The scope was also expanded to synthesize other alkyl or aryl carbamates via alcoholysis of the corresponding disubstituted ureas, and 94 % yields with 96 % selectivities can be achieved. It provided a good candidate for the organic carbamates syntheses via a phosgene/halogen-free and effective route.

          Keywords: alcoholysis;  disubstituted ureas;  N-substituted carbamates;  TiO2/SiO2;  phosgenefree

          ★★★☆☆ Wang LG,Shang JP,Liu SM,et al. Environmentally Benign And Effective Syntheses Of N-substituted Carbamates Via Alcoholysis Of Disubstituted Ureas Over Tio2/sio2 Catalyst[J]. Pure And Applied Chemistry,2012,84:461-471.

          王利國 / 鄧友全
          736.37 KB

          The binary zinc–yttrium oxides were prepared by co-precipitation method, characterized and tested in the synthesis of DMC via transesterification of ethylene carbonate with methanol. The catalytic results showed that the catalyst with Zn/Y molar ratio of 3 and calcined at 400 °C exhibited superior catalytic activity, corresponding to TOF of 236 mmol/gcat h. Appropriate content of yttrium in the catalyst enhanced the catalytic activity remarkably. Moreover, the abundance of medium basic sites (7.2bH_b9.8, as determined by Hammett indicator method) was considered to be responsible for the superior catalytic activity.

          Keywords: Dimethyl carbonate; Ethylene carbonate; Transesterification; Binary zinc–yttrium oxide

          ★★★☆☆ L. Wang et al. / Catalysis Communications 16 (2011) 45–49

          王利國 / 鄧友全
          705.41 KB

          Lanthanum oxide catalyst prepared by precipitation method and calcined at 600 °C exhibited better catalytic activity in the catalytic synthesis of glycerol carbonate from glycerol and urea with TOF up to 1506 mmol/g·h. It was proposed that the lanthanum oxide catalyst with more strong basic sites (TdN400 °C) exhibited higher catalytic activity. Accordingly, the catalyst containing appropriate amount of La2O2CO3 phase exhibited higher catalytic activity. Moreover, the recycling experiments demonstrated that the catalytic activity can be essentially preserved during the recycling tests investigated.

          Keywords: Glycerol carbonate; Urea; Glycerol; Lanthanum oxide; Solid base

          ★★★☆☆ L. Wang et al. / Catalysis Communications 12 (2011) 1458–1462

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