A series of silica gel immobilized lanthanum catalysts were prepared for the atom-economy synthesis of N-substituted carbamates from urea derivatives and dimethyl carbonate. The La/SiO2 catalysts with lanthanum loadings varied from 1.3 wt% to 8.5 wt% were characterized by AES, BET, XRD, TEM, FT-IR, XPS and TPD. According to the characterization, lanthanum species with particle sizes of 5—10 nm on the surface of silica gel were formed. The catalysts were all amorphous and the surface areas were 336.5—530.2 m2/g. NH3-TPD analysis showed that all samples exhibited similar acid strength with different acid amounts. FT-IR measurement indicated that the component of lanthanum speci es on the catalyst surface were La(OH)3, LaOOH and hydrated La2O3. Also, the peak value of the absolute amount of LaOOH was obt ained with 4.3 wt% lanthanum loading. The BET surface area decreased dramatically when the lanthanum loading was above 4.3 wt%. In consideration of the results ob-tained from the catalytic reactions, it could be concluded that LaOOH was the possible active species and high sur-face area was important for the high catalytic activity.

Keywords N-substituted carbamate, urea derivative, dimethyl carbonate, lanthanum, green chemistry

★★☆☆☆ Guo XG,Shang JP,Li J,et al. Atom-economy Synthesis Of N-substituted Carbamate From Urea Derivative And Dimethyl Carbonate Catalyzed By La/sio2: Characterization And Activity[J]. Chinese Journal Of Chemistry,2010,28:164-170.

One kind of novel heterogenous bifunctional catalyst, MCM-41 grafted quaternary ammonium salts with terminal amino group, was prepared. These catalysts exhibited excellent catalytic performance and good reusability in the sequential synthesis of dimethyl carbonate from epoxides, CO2, and methanol.

★★★☆☆ Li J,Wang LG,Liu SM,et al. Mcm-41 Grafted Quaternary Ammonium Salts As Recyclable Catalysts For The Sequential Synthesis Of Dimethyl Carbonate From Epoxides, Co2, And Methanol[J]. Chem. Lett.,2010,39:1277-1278.

通过一步法合成了基于1,3-二烷基咪唑阳离子和甲烷磺酸或对甲苯磺酸阴离子的无卤素离子液体, 并对它们的物理化学性质如聚集行为、表面性质、热性质、密度、黏度、折光率和电化学性质等进行了详细研究. 结果表明在甲烷磺酸阴离子基离子液体中观察到离子液体中普遍存在的离子簇行为; 同等条件下[BEim]MS的荧光光谱强度较[BEim] TS弱; [C12Mim ]M S展现出液晶行为; [TS] - 基离子液体有着较高的折光率, 大于1.51

Keywords: Sulfonate; Ionic liquids; Halogen-free; Synthesis; Physicochemical property

★★☆☆☆ Li XL,Li ZP,Liu SM,et al. Physicochemical Properties Of Halogen-free 1,3-dialkylimidazolium Ionic Liquids Based On The Sulfonate Anions[J]. 分子催化,2010,24(6):483-491.

★★★☆☆ Zhang SG,Hu XD,Qu C,et al. Enhanced And Reversible Contact Angle Modulation Of Ionic Liquids In Oil And Under Ac Electric Field[J]. Chemphyschem,2010,11:2327-2331.

The FeCl2/K2CO3 catalyst system was developed successfully for the N-alkylation of sulfonamides with benzylic alcohols via borrowing hydrogen method. XPS analysis gested a possible catalyst cycle between Fe(II) and Fe(0). Under the optimized condition, the scope of the protocol was demonstrated in 21 different alkylation reactions. High yields, in general >90%, are achieved in most cases.

Keywords: Sulfonamide; Alkylation; Alcohol; Iron

★★★★☆ Cui XJ,Shi F,Zhang Y,et al. Fe(ii)-catalyzed N-alkylation Of Sulfonamides With Benzylic Alcohols[J]. Tetrahedron Letters,2010,51:2048-2051.

The polarity of a series of ionic liquids (ILs) based on hydroxyethyl-imidazolium moiety with various anions ([PF6], [NTf2], [ClO4], [DCA], [NO3], [AC], and [Cl]) and their corresponding nonhydroxyl ILs was investigated by solvatochromic dyes and fluorescence probe molecules. Most of the nonhydroxyl ILs exhibit anionindependent polarity with similar ET(30) in the narrow range of 50.7-52.6 kcal/mol, except [EMIm][AC] (49.7 kcal/mol). However, the polarity of the hydroxyl ILs covers a rather wide range (ET(30) ) 51.2-61.7 kcal/mol) and is strongly anion-dependent. According to their ET(30) or ET(33) values, the hydroxyl ILs can be further classified into the following three groups: (Ι) acetate-based hydroxyl ILs [HOEMIm][AC] exhibit polarity scale (ET(30) ) 51.2 kcal/mol) similar to short chain alcohol and fall in the range of the nonhydroxyl ILs; (II) Hydroxyl ILs containing anions [NO3], [DCA], and [Cl] exhibit comparable polarity (ET(30) ) 55.5-56.9 kcal/mol), moderately higher than those of their nonhydroxyl ILs; (III) Hydroxyl ILs containing anions [PF6], [NTf2], and [ClO4] possess unusual “hyperpolarity” (ET(30) ) 60.3-61.7 kcal/mol) close to protic ILs and water. Kamlet-Taft parameters and density functional theory calculations indicated that the greatly expanded range of polarity of hydroxyl ILs is correlated to an intramolecular synergistic solvent effect of the ionic hydrogen-bonded HBD/HBA complexes generated by intrasolvent HBD/HBA association between the anions and the hydroxyl group on cations, wherein hydroxyl group exhibits a significant differentiating effect on the strength of H-bonding and thus the polarity. Spiropyran-merocyanine equilibrium acted as a model polarity-sensitive reaction indeed shows obviously polarity-dependent solvatochromism, photochromism, and thermal reversion in hydroxyl ILs.

★★★☆☆ Zhang SG,Qi XJ,Ma XY,et al. Hydroxyl Ionic Liquids: The Differentiating Effect Of Hydroxyl On Polarity Due To Ionic Hydrogen Bonds Between Hydroxyl And Anions[J]. J. Phys. Chem. B,2010,114:3912-3920.

A series of FeOx- and Al2O3-supported Pt, Pd catalysts (0.23–2.1%) were prepared in this study. Pt/FeOx exhibited high CO oxidation activity with turnover frequency of 151 10 3 s 1 (1% CO balanced with air, atmospheric pressure, 27 C). A systematical study of FeOx- and Al2O3-supported Pt, Pd catalysts by means of X-ray photoelectron spectroscopy, X-ray diffraction, high-resolution transmission electron microscopy, temperature-programmed reduction, H2–O2 titration, and time-resolved CO titration is reported. From 7% to 39% of Fe3+ was reduced to Fe2+ over Fe(OH)x-supported Pd and Pt catalysts, accompanied by Pd, Pt hydrogenation and hydroxyl loss, and a large amount of oxygen vacancies were proposed to be produced. Results of H2–O2 titration and time-resolved CO titration showed that a large amount of oxygen adsorbed onto FeOx support in the presence of Pt, Pd. This made CO oxidations over Pt/FeOx, Pd/FeOx proceed over two adjacent but different active sites (Pt, Pd for CO and FeOx for oxygen) with low apparent activation energies (30–34 kJ/mol), which accounted for their high activity in low-temperature CO oxidation.

Keywords: CO oxidation;  Pt catalyst;  Pd catalyst;  Kinetic measurements;  Strong metal–support interaction (SMSI);  effect;  Oxygen vacancy;  H2–O2 titration;  Time-resolved CO titration

★★★☆☆ Liu LQ,Zhou F,Wang LG,et al. Low-temperature Co Oxidation Over Supported Pt, Pd Catalysts: Particular Role Of Feox Support For Oxygen Supply During Reactions[J]. Journal Of Catalysis,2010,274:1-10.

A series of nanocomposites of ionic liquids (ILs) were prepared via a modified sol–gel method. The ILs were physically confined in mesoporous silica gels with 5–40% content. ILs from imidazolium, thiophenium and ammonium with different anions were prepared and used. Characterization using the Brunauer–Emmett–Teller (BET) method, Fourier transform infrared (FT-IR) spectroscopy, temperature-programmed desorption (TPD), differential scanning calorimetry (DSC), inverse gas chromatography (IGC), temperature-controlled Raman and fluorescence emission spectroscopies was conducted to explore any confinement effects. BET results showed that, depending on the ILs and their contents, the average pore diameter of the pure silica gel was 3–12 nm after the confined ILs were removed completely. It was suggested that ILs aggregated on the nanoscale in the mesoporous silica gel. In comparison with bulk ILs and ILs coated onto silica gels (IL/sg), IL nanocomposites (IL–sg) displayed remarkably low specific heat capacities (Cp was in the range 0.3–1.2 Jg-1K-1), disordered vibrational conformations (without phase transitions in the range 100–200 1C), greater interactions with hydrocarbon solutes (adsorption capacities of 0.3–0.4 g per 100 g for confined ILs with CO2 gas), and greatly enhanced fluorescence emission (up to 200 times stronger than bulk ILs). Furthermore, Based on the specific solubility of different compounds, the nanocomposites could also be applied to the separation of CO2 from CO2/N2 mixtures and thiophene from thiophene/octane mixtures.

★★★★☆ Zhang J,Zhang QH,Li XL,et al. Nanocomposites Of Ionic Liquids Confined In Mesoporous Silica Gels: Preparation, Characterization And Performance[J]. Physical Chemistry Chemical Physics,2010,12:1971-1981.

The integration of a free metal complex, Pd(phen)2+, and a room temperature ionic liquid (IL) solvent molecule, 1-decyl-3-methyl imidazolium bromide, into a complete catalytically active site and confined in a NaY zeolite super-cage with an appropriate spatial arrangement was investigated. This integration was achieved through a molecular self-assembly method. A preliminary test of this catalyst system for the carbonylation of aniline to methyl phenyl carbamate indicated that far higher catalytic activity could be achieved (TOF increased from 3 000 to 23 000 h–1) with far lower amounts of the IL solvent and the Pd complex in comparison with a simple mixture of Pd(phen)Cl2/IL/NaY as the catalyst. This new system can also be applied to other areas of catalysis.

Key words: active site; ionic liquid; metal complex; carbonylation; aniline; phenyl methyl carbamate; turnover frequency

★★★☆☆ Ma YB,He YD,Zhang QH,et al. Self-assembly Of Ionic Liquids And Metal Complexes In Super-cages Of Nay: Integration Of Free Catalysts And Solvent Molecules Into Confined Catalytic Sites[J]. Chinese Journal Of Catalysis,2010,31(8):933-937.

★★★★☆ Cui XJ,Zhang SG,Shi F,et al. The Influence Of The Acidity Of Ionic Liquids On Catalysis[J]. Chemsuschem,2010,3:1043-1047.