An iron oxide immobilized palladium catalyst was prepared for the N-alkylation of amines with alcohols under base and organic ligand free conditions. Applying the optimized reaction conditions, the coupling reactions of amines and alcohols with various structures could be realized with up to 99% isolated yields. The catalysts were studied by XRD, BET, and XPS and the mechanism was studied by DFT calculations.

Keywords: Palladium; Alkylation; Alcohol; Amine

★★★★☆ Zhang Y,Qi XJ,Cui XJ,et al. Palladium Catalyzed N-alkylation Of Amines With Alcohols[J]. Tetrahedron Letters,2011,52:1334-1338.

Complicated and expensive organic ligands are normally essential in fine chemical synthesis at preparative or industrial levels. The synthesis of fine chemicals by using heterogeneous catalyst systems without additive organic ligand is highly desirable but severely limited due to their poor generality and rigorous reaction conditions. Here, we show the results of carbon–nitrogen or carbon–carbonbond formation catalyzed by an Ag/Mo hybrid material with specific Ag6Mo10O33 crystal structure. 48 nitrogen-or oxygen-containing compounds, that is, amines, carboxamides, sulfonamides, and ketones, were successfully synthesized through a borrowing-hydrogen mechanism. Up to 99% isolated yields were obtained under relatively mild conditions without additive organic ligand. The catalytic process shows promise for the efficient and economic synthesis of amine, carboxamide, sulfonamide, and ketone derivatives because of the simplicity of the system and ease of operation.

Keywords: Ag/Mo · amines · carboxamides · ketones · sulfonamides

★★★★☆ Cui XJ,Zhang Y,Shi F,et al. Organic Ligand-free Alkylation Of Amines, Carboxamides, Sulfonamides,and Ketones By Using Alcohols Catalyzed By Heterogeneous Ag/mo Oxides[J]. Chem. Eur. J.,2011,17:1021-1028.

★★★★☆ Cui XJ,Zhang Y,Shi F,et al. Ruthenium-catalyzed Nitro And Nitrile Compounds Coupling With Alcohols: Alternative Route For N-substituted Amine Synthesis[J]. Chem. Eur. J.,2011,17:2587-2591.

Six ionic liquid (IL)-modified dyes were synthesized and characterized. Compared to the methyl red and methyl orange, these IL-modified [MR]
- or [MO]
-based dyes exhibit lower melting points and enhanced solubility, and can be used as sensitive indicators towards free proton in both aqueous and non-aqueous solutions. This work also supplies a new concept of developing novel modified materials with the ILs.

★★★☆☆ Analyst, 2011, 136, 1302–1304

A practical method for the synthesis of carbamates from ureas and organic carbonates was developed with 100% atom economy using La2O3/SiO2 as catalyst without any additional solvent. The scope of the protocol is demonstrated in the synthesis of 14 carbamates with various functional groups in excellent yields (76–95%).

Keywords Atom economy; carbamates; carbonates; clean synthesis; lanthana; urea derivatives

Guo XG,Shang JP,Li J,et al. Green And Practical Synthesis Of Carbamates From Ureas And Organic Carbonates[J]. Synthetic Communications,2011,41:1102-1111.

Nine 1-allyl-3-alkylimidazolium ([ACnIm]) or 1-vinyl-3-alkylimidazolium ([VCnIm]) dicyanamides (DCA) were prepared and characterized, and their physicochemical properties were studied in detail. Except for [AVIm]DCA and [AC4Im]DCA, the other dicyanamides with hexyl or longer alkyl chains on the cation exhibited the characteristic of hydrophobicity. Among them, [AC8Im]DCA and [AC10Im] DCA were found to possess similar densities to water, i.e. 1.007 g cm
3 and 0.988 g cm
3 at 25 C, respectively. Interestingly, a reversible phase reversion of a [AC8Im]DCA/H2O mixture was observed as the temperature varied. These environmentally-friendly liquid materials have potential applications as precursors for syntheses of conducting polymeric materials.

★★★☆☆ J. Mater. Chem., 2011, 21, 6864–6868

A novel Au&Pd/Fe(OH)x catalyst with separate Au and Pd active sites was designed and synthesized. It was found for the first time that total conversion of CO + H2 could be achieved at room temperature over this catalyst. The separate Au and Pd sites in Au&Pd/Fe(OH)x catalyst were confirmed by the XPS, XRD, 197Au MÖssbauer characterizations and the activity measurements, although a small amount of Au–Pd alloy formed after the catalyst was calcined at 500 ℃.

Keywords: Gold; Palladium; Bimetal; Separate active sites; Co-oxidation

★★★☆☆ Qiao BT,Wang AQ,Masashi Takahashi,et al. A Novel Au&pd/fe(oh)x Catalyst For Co + H2 Co-oxidations At Low Temperatures[J]. Journal Of Catalysis,2011,279:361-365.

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

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.