温和条件下 Cu-Zn/Al2O3 催化剂上酯加氢制醇

 制备了新型无铬非晶态 Al2O3 负载的 Cu-Zn 催化剂, 并采用 X 射线衍射、透射电镜、程序升温还原和红外光谱进行了表征, 考察了其液相酯加氢制高碳醇的催化性能, 并优化了反应条件. 结果表明, 在 240 °C 和 10 MPa 氢压相对温和的反应条件下, 髙碳醇收率达 86.3%, 远远高于相同条件下传统的 Cu-Cr 基催化剂. 对前体、焙烧后及还原后催化剂的物相进行了研究, 探讨了催化剂组分及表面羟基的作用.     

Hydrogenation of Epoxides to Anti-Markovnikov Alcohols over a Nickel Heterogenous Catalyst Prepared from Biomass (Rice) Waste

The synthesis of primary alcohols (from olefins) is an important and challenging transformation, as most of the current methods suffer from regioselectivity issues. This work describes the utilization of rice husk (RH) from agricultural waste as support for the preparation of a catalyst for the conversion of olefin oxides to primary alcohols. The catalyst was synthesized by pyrolysis of RH impregnated with nickel, and characterized by IR, AAS, XRD, BET, XPS, TEM, and TPD technics. The catalyst shows excellent activity and selectivity towards anti-Markovnikov alcohols, acting simultaneously as Brønsted acid, solid Lewis acid, and as hydrogenation catalyst. A substrate screening was done, the catalyst's recycling stability was assessed, and a plausibly reaction mechanism was proposed.     

[（n-C4H9）3SnO2C（CH2）2CO2Sn（C4H9-n）3]：A Novel Three-dimensional Framework Structure of Organotin Complex

The bis(tributyltin) ester of succinic acid was synthesized by the reaction of disodium salt of succinic acid with tributyltin chloride in a molar ratio of 1:2. The crystal structure was determined by X-ray single-crystal diffraction. It belongs to orthorhombic with space group Pccn, a = 20.949(3), b = 17.470(3), c = 20.345(3)A, V= 7446(2)A^3, Z= 8, Dc = 1.242 g/cm^3, μ=1.365 mm^-1, F(000) = 2864, R = 0.0544 and wR = 0.1417. The tin atom is of five-coordination in a trigonal bipyramidal structure by bridging two carboxylate groups in different directions and the resulting structure which contains straight twist large ring channels along the axes of a, b and c is a three-dimensional framework polymer containing two different tin atoms.     

Effect of Lanthanum on Catalytic Performance of Ru/Al2O3 Catalyst for Hydrogenation of Esters to Corresponding Alcohols

Ru-La/γ-Al₂O₃ catalyst was prepared by impregnation method and characterized by temperature programmed reduction(TPR), transmission electron microscopy(TEM), X-ray photoelectron spectra(XPS), Brunauer- Emmett-Teller(BET), X-ray diffraction(XRD), and NH₃-temperature programmed desorption(NH₃-TPD). NH₃-TPD revealed that the strong acidic centers in γ-Al₂O₃ are not the major factor to cause the hydrolysis of esters to acids in the hydrogenation of esters. The results of TPR and TEM indicate that the appropriately added lanthanum results in the good dispersion of ruthenium and the easy reduction of ruthenium oxide on Ru-La/γ-Al₂O₃, which could promote the catalytic activity of Ru-La/γ-Al₂O₃ for the hydrogenation of methyl propionate to propanol. When the amount of lanthanum added in the catalyst was up to 9%(mass fraction), 4%Ru-9%La/γ-Al₂O₃ catalyst gave a conversion of methyl propionate of 98.1% and a selectivity of 94.8% to propanol at a reaction temperature of 180 ℃ and a hydrogen pressure of 5.0 MPa.     

Thiourea-halide lattices. Part 1. Crystal structures of (n-C4H9)4N+F−·3(NH2)2CS, (n-C4H9)3(CH3) N+X−·2(NH2)2CS (X = Cl,Br), and (n-C3H7)4N+I−·(NH2)2CS

The title complexes (1, X = F;2, X = C 1; 3, X = Br and isomorphous with2; 4, X = I) have been prepared and characterized by X-ray crystallography. Crystal data, MoKα radiation:1, space groupCc,Z =4,a = 12.017(3),b = 14.263(5),c = 17.210(7) Å,β = 103.06(2)°, andR _F =0.053 for 2044 observed data;2, space groupCc,Z = 4,a = 12.817(3),b = 11.072(2),c = 16.781(5) Å,β =90.74(2)°,R _F = 0.044 for 2249 data;3,a = 12.873(4),b = 11. 119(2),c = 16.957(2) Å,β = 89.11(2)°,R _F = 0.049 for 2059 data;4, space groupP2₁/n,Z = 4,a = 8.858(2),b = 14.358(3),c = 15.379(3) Å,β = 93.88(1)°,R _F = 0.068 for 3119 data. In all four structures each thiourea molecule interacts with adjacent thiourea molecules via N-H ... S hydrogen bonds to give a ribbon-like arrangement, and also forms a pair of ‘chelating’ N-H ... X hydrogen bonds with a halide ion, resulting in an anionic framework (in1–3) or composite ribbon (in4) as a component in the crystal packing. The measured ranges of N... X distances are: 2.819(5)-2.994(7) Å for1, 3.252(3)-3.291(3)Å for 2, 3.353(6)-3.459(6)Å for3, and 3.564(5)-3.680(5) Å for 4.     

Alcohols,Ethers, and Esters with Peroxy Groups Prepared from 2-tert-Butylperoxy-2-methylpentan-4-one

2-tert-Butylperoxy-2-methylpentan-4-one reacts with butyllithium providing saturated tertiary peroxyalcohol, with 1-lithioalkynes, among them lithiooxy- and peroxy-containing, gives rise to the corresponding tertiary acetylene mono- and diperoxyalcohols and diols. The thermal stability of peroxides obtained was evaluated by derivatography.     

Raman study of phase transitions in (n-C4H9NH3)2BiCl5

The Raman spectra of (n-C₄H₉NH₃)₂BiCl₅ were recorded and analysed from 4 K to 390 K. The phase transition (α → β) at 370 K to the metastable form is manifested by changes in the low-frequency Raman spectra, indicating the changes in the anionic structure of the crystal. The phase transition at 215 K is clearly manifested by the temperature evolution of the internal modes of the butylammonium cation. The phase transition is likely to be due to a reorientational motion of the cation.     

Water‐Enhanced Synthesis of Higher Alcohols from CO2 Hydrogenation over a Pt/Co3O4 Catalyst under Milder Conditions

The effect of water on CO₂ hydrogenation to produce higher alcohols (C₂–C₄) was studied. Pt/Co₃O₄, which had not been used previously for this reaction, was applied as the heterogeneous catalyst. It was found that water and the catalyst had an excellent synergistic effect for promoting the reaction. High selectivity of C₂–C₄ alcohols could be achieved at 140 °C (especially with DMI (1,3‐dimethyl‐2‐imidazolidinone) as co‐solvent), which is a much lower temperature than reported previously. The catalyst could be reused at least five times without reducing the activity and selectivity. D₂O and ¹³CH₃OH labeling experiments indicated that water involved in the reaction and promoted the reaction kinetically, and ethanol was formed via CH₃OH as an intermediate.     

Sn4+离子修饰的Pd/γ-Al2O3催化卤代芳香硝基化合物选择性加氢

用乙醇．水混合溶液还原方法制备了以聚乙烯吡咯烷酮（PVP）稳定的Pd／γ-Al2O3负载型单金属催化剂，用于二氯代硝基苯中硝基的选择性加氢．实验结果表明，在催化反应体系中直接加入Sn^4＋作为修饰剂，虽在一定程度上降低了Pd／γ-Al2O3的催化活性，却大大提高了二氯苯胺的选择性．在其它反应条件相同的情况下，当不添加和添加Sn^4＋时，二氯代硝基苯的转化率分别在80℃和110℃达100%，而2，5-、2，4-、2，3-二氯苯胺的选择性分别由不加修饰剂的84．5％、76．1％、86．8％上升到Sn^4＋修饰后的98．7％、100％、100％．Sn^4＋的添加方式影响对催化剂的修饰效果．     

Kristallstruktur von (NMe4)2[Re3Br11(H2O)] [Re3Br9(H2O)3](H2O)2

Crystal Structure of (NMe₄)₂[Re₃Br₁₁(H₂O)] [Re₃Br₉(H₂O)₃](H₂O)₂ . (NMe₄)₂[Re₃Br₁₁(H₂O)] [Re₃Br₉(H₂O)₃](H₂O)₂ crystallizes from hydrobromic acid solution of Re₃Br₉ · 2 H₂O and NMe₄Br at 0 – 5°C. The crystal structure (monoclinic; P2₁/m (Nr. 11); a = 967.9(3); b = 1 529.7(4); c = 1 710.9(4) pm; β = 91.66(2)°; Z = 2; R = 0.113; R_w = 0.068) has been determined from four-circle diffractometer data. The structure contains two different cluster units of trivalent rhenium, isolated anionic [Re₃Br₁₁(H₂O)]^2? units and neutral cluster units that are connected through crystal water molecules to chains{[Re₃Br₉(H₂O)₃](H₂O)₂}.     

Characteristics of antiaromatic ring pi multi-hydrogen bonds in (H2O)n-C4H4 (n = 1, 2) complexes

By counterpoise-corrected optimization method, the six antiaromatic ring pi multi-hydrogen bond structures with diversiform shapes for (H2O)n-C4H4 (n = 1,2) have been obtained at the MP2/aug-cc-pVDZ level. At the CCSD(T)/aug-cc-pVDZ level, the interaction energy obtained mainly depends on the numbers of H2O and fold numbers of the pi multi-hydrogen bond. The interaction energy order is -2.342 (1a with pi mono-hydrogen) < -2.777 (1b with pi bi-hydrogen) < -4.683 (2a with pi bi-hydrogen) < -4.734 (2b with pi tri-hydrogen) < -4.782 (2c with pi tri-hydrogen) < -5.009 kcal/mol (2d with pi tetra-hydrogen bond). Strangely, why is the interaction energy of the pi bi-hydrogen bond in 1b close to that of the pi mono-hydrogen bond in 1a (their difference is only 15.7%)? The reason is that a pi-type H-bond (as an accompanying interaction) between two lone pairs of the O-atom and a near pair of H-atoms of C4H4 exists shoulder by shoulder in structures 1a, 2a, 2b, and 2c and contributes to the interaction energy. Another accompanying interaction, a repulsive interaction between the pi H-bond (using the H-atom(s) of H2O) and the near pair of H-atoms of C4H4, is also found. For the structures and interaction energies, the pi-type H-bond produces four effects: bending the strong pi H-bond, attracting the pair of H-atoms of C4H4 so that they deviate from the C4 ring plane, showing the interaction energy contribution, and bringing the larger electron correlation contribution. The repulsive interaction also produces four effects: pushing the pair of H-atoms of C4H4 so that they deviate from its ring plane, elongating the distance of the pi H-bond, promoting the formation of pi-type H-bond, and slightly influencing the interaction energy. In the present paper, one C=C bond with two H2O (over and below the ring plane) forms a pi H-bond link in two ways: a strong-weak pi H-bond link and a strong-strong pi H-bond link. The stability contribution of the former is more favorable than the latter. One H2O forms a pi H-bond with C4H4 in two ways. One strong pi H-bond part (over or below the ring plane) always is accompanied by another H-bond part. The accompanying part is either a weak pi H-bond or pi-type H-bond.     

Polyoxoanions functionalized by diorganotin groups: the tetrameric, chiral tungstoarsenate(III), [{Sn(CH3)2(H2O)}2{Sn(CH3)2}As3(alpha-AsW9O33)4]21-

The tetrameric, hybrid organic-inorganic tungstoarsenate(III) [{Sn(CH3)2(H2O)}2{Sn(CH3)2}As3(alpha-AsW9O33)4]21- is composed of four (B-alpha-AsW9O33) fragments that are linked by three dimethyltin groups and three As(III) atoms resulting in an unprecedented, chiral polyoxoanion assembly with C1 symmetry.     

用射频等离子体技术制备乙炔选择加氢催化剂及其性能研究

 采用射频等离子体技术制备了α－Al2O3（MgO修饰）负载钯催化剂，以乙炔选择加氢为模型反应考察了制备方法、钯含量、助剂种类及反应温度对催化剂性能的影响．结果表明，采用等离子体技术制备的催化剂具有催化活性及乙烯选择性高、操作简便和工艺流程短等优点，在50℃下反应时乙炔转化率可达100％，乙烯选择性可达71．3％，而且在反应20h后催化剂样品仍保持有高活性．CeO2助剂的加入能改善催化剂的催化性能．     

Cr2O3-Co3O4／SiO2对十八醇氧化生成十八酸反应的催化性能

 制备了一系列不同Cr／Co比例的Cr2O3－Co3O4／SiO2催化剂，并用XRD，FT－IR和BET等手段对催化剂进行了表征；考察了催化剂对十八醇氧化生成十八酸反应的催化性能，及反应条件（反应温度和反应时间）对催化性能的影响，确定了最佳反应条件．结果表明，金属硝酸盐在773K焙烧后转变成相应的氧化物并负载于二氧化硅上．Cr2O3－Co3O4／SiO2催化剂对十八醇氧化反应有很高的催化活性，十八酸选择性最高可达99．93％，收率可达52．44％．Cr2O3－Co3O4／SiO2催化剂的活性明显高于单一的Cr2O3／SiO2或Co3O4／SiO2催化剂