Hydrotalcite-supported nano-gold (Au/HT) was found to be a highly efficient heterogeneous catalyst for the dehydrogenative synthesis of amide from alcohol and amine. Amines and alcohols with different structures could be converted into the amides under mild reaction conditions with up to 98% isolated yields. Mechanism exploration suggested that ester might be the reaction intermediate.

Keywords: Amides; Gold; Heterogeneous catalysis; Amines; Alcohols

★★★★☆ Jiangling Zhu,Yan Zhang,Feng Shi,et al. Dehydrogenative Amide Synthesis From Alcohol And Amine Catalyzed By Hydrotalcite-supported Gold Nanoparticles[J]. Tetrahedron Letters,2012,53:3178-3180.

A Pd–Au/SiO2 catalyst was prepared for the oxidative imination of toluenes with up to 99% yields in the absence of dehydrating agents under mild conditions. Nanoparticles with a PdO layer and PdO–Au core may be the active structure for the reaction.

★★★★☆ Cui XJ,Shi F,Deng YQ. Oxidative Imination Of Toluenes Catalyzed By Pd–au/silica Gel Under Mild Reaction Conditions[J]. Chem. Commun.,2012,48:7586-7588.

★★★★★ Zhang Y,Cui XJ,Shi F,et al. Nano-gold Catalysis In Fine Chemical Synthesis[J]. Chem. Rev.,2012,112:2467-2505.

Gas-phase structure, hydrogen bonding, and cation–anion interactions of a series of 1-(2-hydroxyethyl)-3- methylimidazolium ([HOEMIm]+)-based ionic liquids (hereafter called hydroxyl ILs) with different anions (X=[NTf2]–, [PF6]–, [ClO4]–, [BF4]–, [DCA]–, [NO3]–, [AC]– and [Cl]–), as well as 1-ethyl-3-methylimizolium ([EMIm]+)-based ionic liquids (hereafter called nonhydroxyl ILs), were investigated by density functional theory calculations and experiments. Electrostatic potential surfaces and optimized structures of isolated ions, and ion pairs of all ILs have been obtained through calculations at the Becke, three-parameter, Lee–Yang–Parr/6-31+G(d,p) level and their hydrogen bonding behavior was further studied by the polarity and Kamlet–Taft Parameters, and 1H-NMR analysis. In [EMIm]+-based nonhydroxyl ILs, hydrogen bonding preferred to be formed between anions and C2–H on the imidazolium ring, while in [HOEMIm]+-based hydroxyl ILs, it was replaced by a much stronger one that preferably formed between anions and OH. The O–H___X hydrogen bonding is much more anion-dependent than the C2–H___X, and it is weakened when the anion is changed from [AC]– to [NTf2]–. The different interaction between [HOEMIm]+ and variable anion involving O–H___X hydrogen bonding resulted in significant effect on their bulk phase properties such as 1H-NMR shift, polarity and hydrogen-bond donor ability (acidity, a).

Keywords: calculation; cation–anion interaction; hydrogen bonding; hydroxyl; ionic liquids; polarity

★★★☆☆  Zhang SG,Qi XJ,Ma XY,et al. Investigation Of Cation–anion Interaction In 1-(2-hydroxyethyl)-3-methylimidazolium-based Ion Pairs By Density Functional Theory Calculations And Experiments[J]. J. Phys. Org. Chem.,2011,25(3):248-257.

A new class of azobenzene-based photoresponsive ionic liquids was prepared and showed reversible modulation of ionic conductivity in specific solvents under alternative UV/visible light irradiation.

★★★★☆ Zhang SG,Liu SM,Zhang QH,et al. Solvent-dependent Photoresponsive Conductivity Of Azobenzene-appended Ionic Liquids[J]. Chem. Commun.,2011,47:6641-6643.

Due to their unique properties, ionic liquids have offered great potential for developing clean catalytic technologies. After a short introduction of their advantages in green catalysis, recent advances in ionic liquid catalysis are reviewed with emphasis on four hot fields, viz. biomass conversion in ionic liquids, catalytic production of fine chemicals in ionic liquids, supported ionic liquid phase catalysis, as well as Friedel–Crafts reactions in ionic liquids. In particular, through selected samples, we show here the advantages and potential of ionic liquids in exploring cleaner catalytic technologies, as compared to traditional catalytic processes. Finally, further development of ILs in catalysis is briefly prospected.

★★★★☆ Green Chem., 2011, 13, 2619–2637

AC electrochemical windows (AC EWs) of ILs were first investigated on Pt, glass carbon (GC), and Au electrodes with frequency ranging from 20 to 100 Hz. The result showed that the AC EW of ILs was much wider than the DC EWs, and the AC EW increased markedly with frequency and with electrode in the order of GC > Pt > Au. Moreover, AC CVs of ILs provide not only different AC EWs but also different current density under identical voltage that are both structure-dependent.

★★★☆☆ Yang FL,Li ZP,Zhang SG,et al. Ac Electrochemical Stability Of Ionic Liquids[J]. Chem. Lett.,2011,40(12):Cl-110542(1-3).

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

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

Here, we show the one-step synthesis of N-alkylated anilines from nitrobenzenes and alcohols catalyzed by nano-gold catalyst. The yields to N-alkylated anilines were B90% under mild conditions. The mechanism of this reaction was explored. It shows promise for clean and simple synthesis of N-alkylated anilines.

★★★★☆ Peng QL,Zhang Y,Shi F,et al. Fe2o3-supported Nano-gold Catalyzed One-pot Synthesis Of N-alkylated Anilines From Nitroarenes And Alcohols[J]. Chem. Commun.,2011,47:6476-6478.