Ethene／norbornene copolymerization by[Me2Si（3—^tertBuCp）（N^tertBu）]TiCl2／MAO—catalyst

?Ethene/norbornene copolymerization by the catalyst system [Me_2Si( 3- tertBuCp)(N tertBu)]TiCl_2/MAO was investigated in detail at 30 ℃, 60℃, and 90℃. A mass flow controller was used in this work to obtain kine tic data and investigate tempera ture's effects on activity, norbornene incorporation, copolymerization parameter , microstructure, glass transition temperature, and molar masses were described. H igh copolymerization values r_E and high alternation are determined. The n umber of isotactic alternating sequences is much higher than that of the syndiot actic alter nating sequences.

Insight into the topology effect on the diffusion of ethene and propene in zeolites: A molecular dynamics simulation study

Selectivity control is a difficult scientific and industrial challenge in methanol-to-olefins(MTO)conversion.It has been experimentally established that the topology of zeolite catalysts influenced the distribution of products.Besides the topology effect on reaction kinetics,the topology influences the diffusion of reactants and products in catalysts as well.In this work,by using COMPASS force-field molecular dynamics method,we investigated the intracrystalline diffusion of ethene and propene in four different zeolites,CHA,MFI,BEA and FAU,at different temperatures.The self-diffusion coefficients and diffusion activation barriers were calculated.A strong restriction on the diffusion of propene in CHA was observed because the self-diffusion coefficient ratio of ethene to propene is larger than 18 and the diffusion activation barrier of propene is more than 20 kJ/mol in CHA.This ratio decreases with the increase of temperature in the four investigated zeolites.The shape selectivity on products from diffusion perspective can provide some implications on the understanding of the selectivity difference between HSAPO-34 and HZSM-5 catalysts for the MTO conversion.

Synthesis, Structure and Norbornene Polymerization Catalyzed by Bis{1-[[(3- ethyl-6-methyl-2-pyridinyl)imino]methyl- enyl]-2-naphthalenolato-N,O}nickel( Ⅱ)

The title complex bis{1-[[（3-ethyl-6-methyl-2-pyridinyl）imino]methylenyl]- 2-na- phthalenola-to-N,O}nickel has been synthesized by the reaction of 1-[[（3-ethyl-6-methyl-2- pyridinyl） imino] methylenyl]-2-naphthalenol with Ni（CH3 COO）2 ·4H2 O, and characterized by IR spectrum and single-crystal X-ray diffraction analysis. The crystal belongs to the orthorhombic system, space group Pbca with a = 11.100（2）, b = 15.900（3）, c = 18.000（4）, V = 3176.8（11）3, C38 H34 N4 NiO2, Mr = 637.40, Z = 4, Dc = 1.333 g/cm3, μ = 0.651 mm-1, F（000） = 1336, the final R = 0.0783 and wR = 0.2119. This title compound was investigated for the catalytic behavior towards norbornene（NB） vinyl addition polymerization. And the complex exhibited good catalytic activity to catalyze norbornene polymerization using MAO as a cocatalyst.

Effect of Reaction Temperature and Pressure on the Metathesis Reaction between Ethene and 2-Butene to Propene on the WO_3/Al_2O_3-HY Catalyst

Effect of reaction temperature and pressure on the metathesis reaction between ethene and 2-butene to propene was studied on the WO3/γ-Al2O3-HY catalyst. The activity is found to increase with elevated temperature and reaches a plateau at 150-240 ℃. After that, the activity undergoes a remarkable decrement at too high temperature. The effect of temperature is elucidated by the oxidation state of tungsten species. The evaluation results also indicate that the stability is dependent on this reaction parameter. Medium pressure （0.5-0.8 MPa） is favorable for stability, while atmospheric pressure or too high pressure （〉1.0 MPa） deteriorates the stability. For explanation, UV Vis, FT-IR, O2-TPO, and TG techniques are used to characterize the spent catalysts.

Cross metathesis of butene-2 and ethene to propene overMo/MCM-22-Al_2O_3 catalysts with different Al_2O_3 contents

A series of 3.0Mo/MCM-22-Al2O3 catalysts with γ-Al2O3 contents in the range of 0-100 wt% were prepared and applied in the metathesis reaction of ethene and butene-2. Addition of γ-Al2O3did not affect the structure of MCM-22 zeolite as evidenced by XRD and N2 adsorption measurements. It was deduced from TPR experiments that γ-Al2O3 phase favored the formation of polymolybdate or multilayered Mo oxide, while more Al2（MoO4）3 species were generated over MCM-22 zeolites. Alumina content in the support was directly related to the metathesis activity of ethene and butene-2 to propene. Mo species with higher valence （Mo6＋or Mo5＋） contributed more to the excellent performance of catalyst than metallic Mo. The best catalyst activity and stability was obtained over 3.0Mo/（MCM-22-30%Al2O3） under the reaction condition of 1.0 MPa and 125℃ using N2 as the pretreatment gas.

Synthesis, Structure and Norbornene Polymerization Catalyzed by o-Benzene Diimine Di-nuclear Palladium(Ⅱ) Complex

The title complex, C20H17N4Pd2Cl3·0.5CH3OH, crystallizes in the triclinic system, space group Pī with α = 9.927（6）, b = 11.079（6）, c = 11.233（6） ？, a = 73.970（12）, β = 85.738（16）, γ = 83.300（12）o, V = 1178.1（11） ？3, Mr = 648.55, Z = 2, Dc = 1.520 g/cm3, μ = 1.884 mm-1, F（000） = 634, the final R = 0.0460 and wR = 0.1280. This title compound was investigated for the catalytic behavior towards norbornene （NB） vinyl addition polymerization. And the complex exhibits good catalytic activity to catalyze norbornene polymerization using MAO as a cocatalyst.

Synthesis, Structure and Norbornene Polymerization Catalyzed by Palladium Complex Bearing the 1,3-Diphenyl-2-((quinolin-8-ylamino)-methylene)-propane-1,3-dione Ligand

The title complex 1,3-diphenyl-2-（（quinolin-8-ylamino）methylene）propane-l,3- dione-palladium was synthesized by the reaction of 1,3-diphenyl-2-（（quinolin-8-ylamino）-methylene）propane-1,3-dione with PdCl2, and characterized by IR spectrum and single-crystal X-ray diffraction analysis. The crystal belongs to the orthorhombic system, space group P21212 with a = 21.838（4）, b = 8.3952（17）, c = 11.497（2） A, V= 2107.9（7） A3, C25H17C1N2O2Pd, Mr = 519.26, Z= 4, Dc= 1.636 g/cm3, H = 1.032 mm-1, F （000） = 1040, the final R = 0.0307 and wR = 0.0778. This compound was investigated for the catalytic behavior towards norbornene （NB） vinyl addition polymerization. And the complex exhibits excellent catalytic activities up to 2.18×10^8g of PNB （tool of Pd）-1 h-1 with high monomer conversion using methylaluminoxane （MAO） as the cocatalyst.

Polymerization of Norbornene via an Iron-Based Complex/MAO Catalytic System

Polynorbornenes were synthesized in the presence of an iron based catalyst, 2,6-bis[1-(2,6-diisopropyl-phenylimino)ethyl]pyridine iron(Ⅱ) dichloride. The FTIR, 1H NMR and 13C NMR analysis results revealed that the structure of the obtained polynorbornenes consisted of vinyl addition polymer substructures without any ring-opening structures. The polymers were amorphous with a short-range order, displayed in the WAXD(wide angle X-ray diffraction) diagrams. The glass transition temperatures ranged from 200 to 400 ℃. The effects of the polymerization reaction conditions, such as Al/Fe molar ratio and toluene/CH_2Cl_2 volume ratio, on the activity, intrinsic viscosity and T_g were also studied.

Synthesis,Structure and Norbornene Polymerization Catalyzed by Bis{(2-benzhydryl-4,6-dimethyl-phenyl)-(3,5-di-tert-butyl-2-methyl-benzylidene)-amine-N,O}nickel(Ⅱ)

The title complex bis{（2-benzhydryl-4,6-dimethyl-phenyl）-（3,5-di-tert-butyl-2-methyl-benzylidene）-amine-N,O}nickel has been synthesized by the reaction of（2-benzhydryl-4,6-dimethyl-phenyl）-（3,5-di-tert-butyl-2-methyl-benzylidene）-amine with Ni（CH3COO）2·4H2O, and characterized by IR spectrum and single-crystal X-ray diffraction analysis. The crystal belongs to the monoclinic system, space group P21/c with a = 12.373（4）, b = 18.434（7）, c = 27.814（10） A, β = 92.291（6）o, V = 6339（4） A^3, C7 2H8 0N2 Ni O2, Mr = 1064.09, Z = 4, Dc = 1.115 g/cm^3, μ = 0.350 mm^-1, F（000） = 2280, the final R = 0.0846 and wR = 0.2926（I 〉 2s（I））. This title compound was used as homogeneous catalysis of polymerization of norbornene, and the complex exhibited good catalytic activity to catalyze norbornene polymerization using MAO as a cocatalyst.

Synthesis,Crystal Structure and Characterization of a Nickel Complex Based on Phenoxyimine Ligand and Catalysis of the Vinyl Polymerization of Norbornene

The title complex N,O-bis{2-[[（2-benzhydryl-4,6-dimethylphenyl）imino]-methyl]-phenol}-nickel（II）（C56H48N2NiO2） has been synthesized by the reaction of 2-[[（2-benzhydryl-4,6-dimethylphenyl）mino]-methyl]-phenol with Ni（CH3COO）2·4 H2O, and characterized by elemental analysis and IR spectrum. The spatial structure of the complex has been confirmed by single-crystal X-ray diffraction analysis. The compound belongs to the monoclinic system, space group C2/c with a = 39.035（8）, b = 13.276（3）, c = 17.679（4） A°, β = 98.06（3）°, V = 9071（3） A°^3, C56H48N2NiO2, Mr = 839.67, Z = 8, Dc = 1.230 Mg/m^3, μ = 0.472 mm^-1, F（000） = 3536, T = 293（2） K, the final R = 0.0675 and w R = 0.1345（I 〉 2s（I））. The compound showed excellent catalytic activity up to 1.268 × 10^7 g of PNB（mol of Ni）^-1h^-1 for the addition polymerization of norbornene by using methylaluminoxane（MAO） as a cocatalyst.

Self-metathesis of 1-butene to ethene and hexene over molybdenum-based heterogeneous catalysts

A novel route involving self‐metathesis of1‐butene under mild conditions that gave high yields ofethene and hexene was proposed.The results of thermodynamic analysis revealed that the Gibbsenergy of the target Metathesis I reaction(1‐butene?ethene+3‐hexene)was much higher thanthat of the main side Metathesis II(1‐butene+2‐butene?propene+2‐pentene).Suppression of1‐butene double‐bond isomerization was the key step to increase the selectivity for the target olefinin the reaction network.The relationship between the catalytic performance and support nature was investigated in detail.On basis of H2‐TPR,UV‐Vis spectra and HRTEM results,an alumina(Al2O3)support with large surface area was beneficial for the dispersion of molybdenum(Mo)species.Both suitable acidity and sufficient Mo dispersion were important to selectively promote the self‐metathesis reaction of1‐butene.On the optimal6Mo/Al2O3catalyst,1‐butene conversion reached47%and ethene selectivity was as high as42%on the premise of good catalytic stability(80°C,1.0MPa,3h?1).?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.

Synthesis, Structure and Norbornene Polymerization Catalyzed by Nickel(Ⅱ) Complex Bearing N,O-bis(1-(6-ethylpyridin-2-ylimino)-methylenyl)naphthalen-2-ol Ligand

The title complex bis{1-{[（6-ethyl-2-pyridinyl）imino]methylenyl}-2-naphthale- nolato-N,O}-nickel（lI） （C36H32NnO2Ni） has been synthesized by the reaction of l-{[（6-ethyl-2- pyridinyl）imino]methylenyl}-2-naphthalenol with Ni（CH3COO）2·4H2O, and characterized by IR spectrum, elemental analysis and TG. The complicated space structure has been confirmed by single-crystal X-ray diffraction analysis. The crystal belongs to the monoclinic system, space group P21/c with a = 11.410（4）, b = 14.382（4）, c = 18.121（6） ,A, β = 97.147（6）% V= 2950.5（16）A3, C36H32N4O2Ni, Mr = 611.37, Z = 4, Dc = 1.376 g/cm3, μ = 0.698 mm-1 F（000） = 1280, the final R = 0.0519 and wR = 0.1493 （1 〉2σ（I））. This title compound was used as precatalysts for the polymerisation of norbornene. When activated with MAO, the complex exhibited excellent catalytic activity up to 1.98 × 107 g ofPNB （mol of Ni）-1 h-1 with high monomer conversion.

Stereo-Selective Synthesis of 5-Norbornene-2-<i>exo</i>-carboxylic Acid—Rapid Isomerization and Kinetically Selective Hydrolysis

Simple and efficient stereo-selective synthesis of exo-5-norbornene-2-carboxylic acid (NBCA) is reported. Preliminary studies on base promoted isomerization of methyl 5-norbornene-2-carboxylate (MNBC) revealed that rapid isomerization was accomplished with sodium tert-butoxide (tBuONa), and the exo-content at the equilibrium was ca. 60%. The hydrolyses of endo-rich MNBC (endo/exo = 80/20) under various conditions were carried out. The exo selectivity for resulting NBCA was improved when the hydrolysis was conducted with equimolar water at room temperature in the presence of the stronger base (tBuONa) (endo/exo: 18/82). Whereas the use of excess amount of water led to rapid and non-selective hydrolysis affording high endo content of the product. The plausible reaction mechanism involving rapid equilibrium of thermodynamic isomerization and kinetically preferred hydrolysis of exo ester is proposed.

A Novel Phenoxyimine-based Schiff Base Ligand and Its Mononuclear Nickel(Ⅱ) Complex：Synthesis,Crystal Structure,Norbornene Polymerization and Catalytic Activity

A novel phenoxyimine-based Schiff base ligand and its mononuclear complex [C（58）H（52）N2NiO2]（L = 2-benzhydryl-4-dimethoxy-3,5-dimethyl-salicylaldehyde） has been synthesized and characterized by IR spectrum, elemental analysis, TG, WAXD spectra, ^1H NMR and ^（13）C NMR. In addition, the molecular structure has been measured by single-crystal X-ray diffraction analysis. The crystal belongs to the monoclinic system, space group P21/c with a = 14.510（6）, b = 18.573（7）, c = 20.961（6） A, β = 123.453（19）°, V = 4713（3）A^3, Mr = 867.73, Z = 4, Dc = 1.223 g/cm^3, μ = 0.456 mm^-1, F（000） = 1832, the final R = 0.0685 and wR = 0.1758（I 〉 2σ（I））. The complex was used as homogeneous catalysis of polymerization of norbornene, and the MAO as cocatalyst. The nickel complex exhibited good catalytic activity up to 1.913 × 10^7 g of PNB（mol of Ni）^-1h^-1,and the yields of these reactions depend on the nature of the substituent in the aromatic ring.

Molecular Dynamics Simulations of Ethene Diffusion in Orthorhombic and Monoclinic MFI

运用分子动力学（ＭＤ）模拟研究了３００Ｋ下乙烯在正交晶系和单斜晶系ＭＦＩ中的吸附、极化和扩散行为，获得了温度、能量、分子扩散速度、分子与沸石骨架间的相互作用、分子在沸石孔道中的吸附能以及分子的偶极矩等计算结果；同时发现，分子在直孔道和Ｚ型孔道的交叉部位的边界处极化最大，且在交叉部位的中心区域处出现的几率最大．

Oxidative dehydrogenation of ethane to ethene over a superbase supported LiCl system

LiCl-promoted superbase catalysts were found to be stable and highly selective to ethene for oxidative dehydrogenation of ethane,giving 84%ethane conversion and 74%ethene yield at 923 K.Results indicated that the stronger the basicity of LiC1-based catalysts,the better the catalytic performance.

ON NONEQUILIBRIUM OF PYROLYSIS PROCESS IN THE MANUFACTURE OF ETHENE

Nonequilibrium process for cracking ethane and n-buthane in the manufacture of ethene has been analytically and numerically investigated in a Heaviside function temperature field and through a normal shock wave. The results demonstrate that, while the reaction temperature increases, the maximum value of ethene yield is increased, and the optimal reaction duration is sharply shortened. For the identical initial reaction temperature, the maximum value of ethene yield through a stationary normal shock wave is less than that in a Heaviside function temperature field. However, the ethene consumption after the maximum value in the former case is less than that in the latter. Higher ethene yield will be obtained by using the gasdynamic heating method than by using the current methods. (Edited author abstract) 5 Refs.

SYNTHESIS AND CHARACTERIZATION OF BIS-[2-[[(2-ALKOXYPHENYL)IMINO]METHYL]-PHENOLATO-O,N,O]NICKEL(II)COMPLEXES AND THEIR NORBORNENE POLYMERIZATION

A series of salicylaldimines, synthesized in high yield via microwave-assisted condensation of salicylaldehyde and 2-alkoxyaniline were allowed to react with nickel chloride to form six-coordinated nickel complexes. These nickel complexes were carefully characterized, and the solid structure of la was elucidated by X-Ray diffraction. Activated with MAO, the nickel complexes showed good activity for homopolymerization of norbornene. Reaction parameters, such as the ratio of nickel precursor to MAO, monomer concentration, reaction time and the reaction temperature, as well as the nature of the ligands were found to have significant effects on the catalytic activity and some properties of the resulting polynorbornene.

NMR SPECTROSCOPIC STUDY ON COPOLYMER OF ETHYLENE-NORBORNENE

A series of ethylene-norbornene copolymers were synthesized using VO (Oft) Cl-2/Al2Et3Cl3 catalytic system and their structure was characterized by H-1-NMR, H-1-H-1 COSY NMR and C-13-NMR. Assignments of NMR spectra were given and discussed in detail.