Selective hydrogenation of benzene to cyclohexene over Ce-promoted Ru catalysts

Ru-Ce catalysts were prepared by a co-precipitation method.The effects of Ce precursors with different valences and Ce contents on the catalytic performance of Ru-Ce catalysts were investigated in the presence of ZnSO4.The Ce species in the catalysts prepared with different valences of the Ce precursors all exist as CeO2 on the Ru surface.The promoter CeO2alone could not improve the selectivity to cyclohexene of Ru catalysts.However,almost all the CeO2 in the catalysts could react with the reaction modifier ZnSO4 to form(Zn(OH)2)3(ZnSO4)(H2O)3 salt.The amount of the chemisorbed salt increased with the CeO2 loading,resulting in the decrease of the activity and the increase of the selectivity to cyclohexene of Ru catalyst.The Ru-Ce catalyst with the optimum Ce/Ru molar ratio of 0.19 gave a maximum cyclohexene yield of 57.4%.Moreover,this catalyst had good stability and excellent reusability.     

Synthesis Gas Production from Natural Gas on Supported Pt Catalysts

Auto-thermal reforming of methane, combining partial oxidation and reforming of methane with CO2 or steam, was carried out with Pt/Al2O3, Pt/ZrO2 and Pt/CeO2 catalysts, in a temperature range of 300-900℃. The auto-thermal reforming occurs in two simultaneous stages, namely, total combustion of methane and reforming of the unconverted methane with steam and CO2, with the O2 conversion of 100% starting from 450 ℃. For combination with CO2 reforming, the Pt/CeO2 catalyst showed the lowest initial activity at 800 ℃, and the highest stability over 40 h on-stream. This catalyst also presented the best performance for the reaction with steam at 800 ℃. The higher resistance to coke formation of the catalyst supported on ceria is due to the metal-support interactions and the higher mobility of oxygen in the oxide lattice.     

波长对Ag/TiO2催化剂上二氧化碳光催化还原的影响

Photocatalytic reduction of CO2 by water was performed in the presence of a Ag/TiO2 catalyst under illumination by lamps with different wavelengths(254,365,and 400 nm).The yields of the main products(methane and methanol)were higher with the 254 nm lamp than with the 365 lamp while no products were observed with the 400 nm lamp.This was because the electron-hole generation rate increased with increasing energy of irradiation(decreasing wavelength)and there were higher densities of electron states at higher energies in TiO2. The increased efficiency of electron-hole generation with a shorter wavelength irradiation increased the efficiency of the catalyst.The energy of the electrons excited by visible light(400 nm)was too low for CO2 photocatalytic reduction.     

Photo-promoted carbonylation of chloroalkanes with carbon monoxide by non-precious metal catalysts

The photo-promoted carbonylation of chloroalkanes with carbon monoxide was carried out under ambient conditions with copper and cadmium salts catalysts. The results indicated that the corresponding esters were produced with three salt catalysts, i.e. CuBr2, CuCl2 and CdI2. Among these catalysts, CdI2 was the most efficient in terms of ester yield and selectivity, particularly, 60% yield and 75% selectivity in the carbonylation of chlorocyclohexane were achieved. Furthermore, the yield and selectivity of the ester can be improved greatly by adding tri-n-butylamine in the CuBr2 and CuCl2 catalyst systems. On the other hand, the carbonylation did not proceed with single CdCl2, however, the catalytic activity of CdCl2 was increased greatly with NaIá2H2O as additive. As a result, we suggest that iodide ion plays an important role in the catalyst system of the cadmium salts.     

Structural analysis of [Bmim]2CuCl4 ionic liquids in the presence of water and ethanol by XAFS technique

The structure of [Bmim]2Cu Cl4 ionic liquids(Bmim: 1-butyl-3-methylimidazolium) with different ratios of H2 O and C2H5 OH was investigated using X-ray absorption fine structure(XAFS) technique. In this study, XAFS was employed to directly probe the conformational variations of copper ions in [Bmim]2Cu Cl4 with the addition of either water or ethanol. XAFS analysis confirmed that the structure of ionic liquids gradually transformed from tetrahedral to octahedral configuration with the increase in ratio of H2 O. Our results also showed that water molecules coordinated with the copper ions of [Bmim]2Cu Cl4, leading to the conformational change in ionic liquids. However, the XAFS spectra of [Bmim]2Cu Cl4/C2H5 OH indicated no coordination of anhydrous ethanol with the copper ions of [Bmim]2Cu Cl4. The structure of [Bmim]2Cu Cl4 ionic liquids is maintained as the tetrahedral configuration in presence of ethanol. Therefore, anhydrous ethanol causes little variation in the structure of ionic liquids and it is a good solvent for the dilution of ionic liquids.     

STUDIES ON CHIRAL THIOPHOSPHORIC ACIDS AND THEIR DERIVATIVES——STEREOCHEMISTRY OF ALKALINE HYDROLYSIS OF OPTICALLY ACTIVE O-ETHYL O-PHENYL PHOSPHOROTHIOIC DERIVATIVES

The reaction of optically active O-ethyl O-phenyl phosphorochloride 1 with alcohol, phenol,amine, mercaptan or thiophenol, respectively, in the presence of an alkali obtained optically activeO-ethyl O-phenyl phosphorothioic derivatives 2 with inversion of configuration. The hydrolysis of 2was carried out in 1 N NaOH-dioxane solution. The hydrolysis of 2a and 2h predominantly gaveproducts with inversion of configuration with OPh as leaving group, but also gave products withretention of configuration with OMe or SPr as leaving group. Exclusive products with inversion ofconfiguration with OPh as leaving group were only obtained from the hydrolysis of 2b, 2f and 2g.The hydrolysis of 2c gave product with inversion of configuration with OC_6H_4NO_2-p as leavinggroup. From 2d, 2e and 2i, products with retention of configuration were formed with OC (Me)-CHCO_2 Et(Z), OC(Me)-CHCO_2Et(E) and SPh as leaving group, respectively. All the above resultscan be satisfactorily interpreted in the light of trigonal bipyram     

Catalytic Performance of CeO2／ZnO Nanocatalysts on the Oxidative Coupling of Methane with Carbon Dioxide and their Fractal Features

CeO2/ZnO nanocatalysts were prepared from the coupling route of homogeneous precipitation with microemulsion and the impregnation method. The catalytic performance of these two kinds of catalysts on the oxidative coupling of methane with carbon dioxide was tested and compared; the fractal behavior of the nanocatalysts was analyzed using fractal theory. The CeO2/ZnO nanocatalysts had much higher activity than the catalysts prepared by impregnation method. There was no regular relationship between the average size of CeO2/ZnO nanocatalysts and their catalytic performance; however, the conversion of methane increased with the increase of the fractal dimension of CeO2/ZnO nanocatalysts.     

Effect of polyaniline as a surface modifier of TiO2 nanoparticles on the properties of polyvinyl chloride/TiO2 nanocomposites

Surface of TiO2 nanoparticles was modified with the in situ chemical oxidative polymerization of aniline. Polyaniline modified TiO2 nanoparticles (PANI-TiO2 ) were characterized with the FT-IR, XRD, SEM and TEM techniques. Results confirmed that PANI was grafted successfully on the surface of TiO2 nanoparticles, therefore agglomeration of nanoparticles decreased dramatically. Polyvinyl chloride nanocomposites filled with 1 wt% 5 wt% of PANI-TiO2 and TiO2 nanoparticles were prepared via the solution blending method. PVC nanocomposites were analyzed with FT-IR, XRD, SEM, TG/DTA, DSC and tensile test techniques. Effect of PANI as surface modifier of nanoparticles was discussed according to the final properties of PVC nanocomposites. Results demonstrated that deposition of PANI on the surface of TiO2 nanoparticles improved the interfacial adhesion between the constituents of nanocomposites, which resulted in better dispersion of nanoparticles in the PVC matrix. Also PVC/PANI-TiO2 nanocomposites showed higher thermal resistance, tensile strength and Young’s modulus compared to those of unfilled PVC and PVC/TiO2 nanocomposites.     

Density Functional Theory Studies on the Adsorption of CO2 on Different CaO Surfaces

Carbon dioxide adsorbed on different kinds of CaO surfaces has been investigated with the help of the first principle density functional theory plane wave calculations. Various possible configurations have been considered and the calculated results showed that CO2 was strongly adsorbed by C atom bonded with the CaO （001） and （110） surfaces with adsorption energies of 1.38 and 3.22 eV, respectively. The adsorption of CO2 molecule on defect surfaces is complicated compared with that on the pristine surfaces. The adsorption energy of CO2 absorbed on the CaO（110） surface is larger than that of CaO（001） surface when the type of defect surface is the same.     

Synthesis and Characterization of High-purity Aluminum Titanate with Water Quenching Method

High-purity aluminum titanate was synthesized via a water quenching method with waste-residue in the aluminum factory and industrial TiO2 as the main raw materials, which belongs to the comprehensive utilization of solid wastes. Compared with the conventional method, it can reduce synthesis temperature, effectively inhibit decomposition and raise the content of AT; the addition of tiny silicon powder can improve the sintering and optimize the properties of AT. The crystalline phase structure and microstructure of each sample were characterized with XRD and SEM methods; the content of each crystalline phase in each sample was confirmed with Rietveld Quantification method; the properties of each sample were also tested. The experimental results showed that No. 4 is the optimum specimen, with the corresponding mass ratio of Al2O3/TiO2 to be 1.27 and the content of AT of 97.2 wt%. The addition of optimum tiny silicon powder is confirmed to be 8wt%; its corresponding bulk density is 2.63 g/cm^3, bending strength is 46.34 MPa, and the retention of one thermal vibration bending strength is 71.5%.     

2-Substituted 5-oxo-5,6,7,8-tetrahydroquinazolines

Twenty novel 2-substituted 5-oxo-5,6,7,8-tetrahydroquinazolines in reactions of 2-formyl-1,3-cyclohexanedione and its 5,5-dimethyl- and 5-phenyl derivatives with 4-chloro- and 4-carbonylaminobenzamidines, 3- and 4-carbamidinopyridines, 2-carbamidinopyrazine, 2-carbamidino-5-trifluoromethylpyridine, 1-carbamidinopyrrolidine, 4-carbamidinomorpholine, and 1-carbamidino-3,5-dimethylpyrazole have been obtained.Riga Technical University, Riga LV-1658, Latvia; e-mail: marina@osi.lv. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 212–26, February, 2000.     

DIASTEREOSELECTIVE SYNTHESIS AND STEREOCHEMISTRY OF (Z)-1-[3-ARYL-2-(PHENYLSULFANYL)-2-OXIRANYL]-1-ETHANONES

Diastereoselective synthesis of a series of (Z)-1-[3-aryl-2-(phenylsulfanyl)-2-oxiranyl]-1-ethanones was effected from the reaction of (Z)-4-aryl-3-(phenylsulfanyl)-3-buten-2-ones with alkaline hydrogen peroxide in tetrahydrofuran. The stereochemistry of the oxiranes has been deduced from two-dimensional NOESY spectrum.     

1-(4-硝基苯基)-3-(2-吡嗪)-三氮烯的合成及与镉(Ⅱ)的显色反应

报道了显色剂1-(4-硝基苯基)-3-(2-吡嗪)-三氮烯化合物的合成及其与镉(Ⅱ)的显色反应。在非离子表面活性剂Triton X-100存在下,pH 10.5的Na2B4O7-NaOH的缓冲介质中,该试剂能与镉(Ⅱ)与发生显色反应,形成摩尔比为4∶1的黄棕色配合物,配合物在波长453 nm处有最大吸收峰,表观摩尔吸光系数ε为6.90×104L.mol-1.cm-1,镉(Ⅱ)质量浓度在0~0.56μg/mL范围内遵守比尔定律。用拟定方法测不同废水中的镉(Ⅱ)。     

Reaction of 2-(2-Azahetaryl)-4-chloro-3-oxobutyronitriles with Substituted Benzaldehyde Hydrazones. Unexpected Formation of 4-Arylideneamino-2-(1-R-benzimidazol-2-yl)-3-oxobutyronitriles

The reaction of 2-(2-azahetaryl)-3-oxo-4-chlorobutyronitriles with substituted benzaldehyde hydrazones gives 4-arylideneamino-2-(1-R-benzimidazol-2-yl)-3-oxobutyronitriles, the structures of which were proved using spectroscopic data, the results of elemental analysis, and through their chemical reactions. It was found that the reaction course depends on the basicity of the heterocyclic fragment in the starting nitrile. A likely mechanism for the process is proposed.     

Syntheses of 1-Azaazulan-2-One Analogs of Adrenergic Agents

The Friedel-Crafts reaction of 1-azaazulan-2-ones with α-haloacid chloride in the presence of aluminum trichloride gives the corresponding α-haloacyl derivatives. Treatment of these reaction products first with various secondary amines and then with sodium borohydride gives new adrenergic active amine derivatives.     

(2S)-(+)-2-溴-1-(6'-甲氧基-2'-萘基)丙-1-酮的不对称合成

以(2R,3R)-酒石酸二甲酯为手性辅助剂,6-甲氧基-2-丙酰基萘经缩酮化、溴化铜不对称溴化、水解等反应合成了(2S)-2-溴-1-(6'-甲氧基-2'-萘基)丙-1-酮。总收率94%。     

Synthesis of 4-Hydroxy- and 4-Amino-2-Methyl-3-(2-Methylindol-3-Yl)methylquinolines and Their 6- and 8-Substituted Derivatives

A method has been developed for the synthesis of substituted 4-hydroxy- and 4-amino-2-methyl-3-(2-methylindol-3-yl)methylquinolines by treating the corresponding 4-hydroxy(chloro)-2-methyl-3-(3-oxobutyl)quinolines with phenylhydrazine hydrochloride. It was found that nucleophilic substitution occurred in the case of the 4-chloroquinolines together with subsequent rearrangement to give the 4-amino derivatives. The thiosemicarbazones of the corresponding 4-hydroxy-2-methyl-3-(3-oxobutyl)quinolines were also obtained.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 554–557, April, 2005.     

2-(1,2-亚乙/1,3-亚丙二硫)亚甲基-3-羰基丁酰氯的制备及其与芳烃的酰化反应

制备了较稳定的2-(1,2-亚乙/1,3-亚丙二硫)亚甲基-3-羰基丁酰氯,并实现了其与芳烃的酰化反应,为1-芳基-2-(1,2-亚乙/1,3-亚丙二硫)亚甲基-1,3-丁二酮的合成提供了一条新途径.     

Products from condensation of 1-(3(4)-acetylphenyl)-4-carboxy-2-pyrrolidinones with <Emphasis Type="Italic">o</Emphasis>-phenylenediamine and their properties

2-Substituted benzimidazoles were synthesized by the reaction of 1-(3(4)-acetylphenyl)-4-carboxy-2-pyrrolidinones with o-phenylenediamine. Their reactions with sodium hydroxide and hydrazine and some of their chemical characteristics were investigated. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp.1625–1630, November, 2007.     

1-(2-Quinoxalyl)-, 1-[3,5-Di(trifluoromethyl)phenyl]-, 1-(2-Carboxyphenyl)-, and 1-Ethoxycarbonyl-4-oxo-4,5,6,7-tetrahydroindazoles

The corresponding 1-(2-quinoxalyl)-, 1-[3,5-di(trifluoromethyl)phenyl]-, and 1-ethoxycarbonyl-3-methyl-4-oxo-4,5,6,7-tetrahydroindazoles have been obtained from reactions of 2-acetyl-1,3-cyclohexanedione, its 5,5-dimethyl and 5-(2-furyl) derivatives, with 2-hydrazinoquinoxaline, 3,5-di(trifluoromethyl)phenylhydrazine, and ethoxycarbonylhydrazine. On interaction with ethoxycarbonylhydrazine the intermediate 2-[1-(-ethoxycarbonyl)hydrazino]ethylidene-1,3-cyclohexanediones were also isolated. From the potassium salt of 2-formyldimedone and 2-carboxyphenylhydrazine hydrochloride, 2-(2-carboxyphenyl)hydrazinomethylene-5,5-dimethyl-1,3-cyclohexanedione was obtained, the cyclization of which in ethanol in the presence of HCl led to 1-(2-carboxyphenyl)- and 1-(2-ethoxycarbonylphenyl)-6,6-dimethyl-4-oxo-4,5,6,7-tetrahydroindazole.