Recent advances in heterogeneous catalytic hydrogenation and dehydrogenation of N-heterocycles

The selective hydrogenation of quinolines to 1,2,3,4-tetrahydroquinolines(py-THQ) and its derivatives has attracted a considerable amount of attention as they show great versatility in many pharmaceuticals, agrochemicals, and fine chemicals. Over the past few decades, great breakthroughs have been achieved in the controlled synthesis of efficient heterogeneous catalysts used for the selective hydrogenation of functionalized quinoline compounds, which allow one to correlate the structure-property relationships. In this review, we will summarize the recent significant progress achieved in this field covering the synthetic strategies, microstructural and chemical features, catalytic performance, and internal relationships. State-of-the-art noble metal-based single(Pd, Pt, Ru, Rh, Ir and Au) and bi/multi-metallic catalysts(RuCu, AuPd, and PdNi) are first introduced, followed by a summary of earth-abundant metal-based catalysts(Co, Fe, Ni, and Cu). Finally, the dehydrogenation of N-heterocycles is introduced to form a reversible hydrogenation/dehydrogenation system for H2 storage, which can be employed in a liquid organic hydrogen system. Furthermore, the reaction mechanism and future research direction in these areas are also discussed. This review will deepen our understanding of the catalytic transformation of N-heterocycles and provide guidance for researchers on the rational design of catalysts.

Calculation of Environmental Capacity of Petroleum Hydrocarbon in Jiaozhou Bay

The method has been established to calculate the environmental capacity (ECO), surplus environment capacity (SECO) of water with respect to marine petroleum hydrocarbons associated with oil (PHAOs) and the self-purification capacity (SPCO) of main self-purification process to PHAOs in the Jiaozhou Bay, China, according to the dynamic model for distribution of marine PHAOs among multiphase environments. The variation of concentration of PHAOs in the Jiaozhou Bay is well simulated by the dynamic model. Based on the model, the ECo, SECo of water with respect to PHAOs in the Jiaozhou Bay were calculated during the last 10 years under the first-class and second-class quality standard requirement, according to SPCO of main self-purification process to PHAOs. The results show that about 200 tons of PHAOs could be discharged into the Jiaozhou Bay for maintaining the first class seawater quality standard, and about 600 tons of PHAOs for the second class seawater quality standard later.

ACCESSING HIGH THERMAL EFFICIENCY POWER GENERATION USING FLUID PHASE CHEMICAL LOOPING

In order to burn a hydrocarbon fuel efficiently using conventional cycles,very high temperatures are required.Chemical looping combustion（CLC）offers an alternative cycle for large scale power production.In CLC a carrier molecule is used to transport oxygen between two redox reactions,one where the carrier is oxidised and another where it is reduced by reaction with a fuel.Separation of the oxygen carrier from fuel ash can be aided by means of phase difference and this is a key advantage of fluid phase CLC where the carrier medium proposed is sodium,potassium or zinc.The principle exploited in fluid phase CLC is the recirculation of both energy and entropy.High thermal efficiencies,circa 75% at 35 bar are theoretically achievable taking into account component efficiencies,with separation of nitrogen and carbon dioxide,in combination with the water shift gas reaction,as an inherent part of the cycle if air is used as the oxygen source.

Quantum Chemistry of PAHs Thermal Cracking with Different Hydrogenation Degree

In order to investigate the influence of hydrogenation degree and structural variety on reaction trend of polyaro- matic hydrocarbons (PAHs) in resins and asphaltenes portion of heavy oil, a series of PAHs with different hydrogenation degree were selected as model compounds to simulate their different hydrogenation stage, and the PAHs thermal cracking reaction was simulated based on free radical mechanism by the density functional theory (DFT) to search for reactions'transition state. By comparing the dynamic data obtained from reaction simulation, it is showed that processing difficulty could rise with increasing condensed aromatic ring number, and hydrogenation could promote ring cleavage reaction, but excessive hydrogenation would decrease the oil conversion rate to reduce light-end products. In conclusion, proper hydrogenation was quite critical in promoting light-end products conversion efficiency and saving the processing cost as well. Operational instructions were given based on both PAHs hydrogenation performance and conclusions were drawn up from reaction simulation results.

Performance of Ni-based, Fe-based and Co-based Oxygen Carriers in Chemical-Looping Hydrogen Generation

Ni-based, Fe-based and Co-based oxygen carriers with perovskite oxides used as the supports were prepared by citric acid complexation method, The oxygen carriers were characterized by thermal analysis, H2-temperature-programmed reduction and X-ray diffraction methods. Performance tests were evaluated through Chemical-Looping Hydrogen Genera- tion in a fixed-bed reactor operating at atmospheric pressure. The characterization results showed that all samples were composed of metal oxides and perovskite oxides. Performance results indicated that CH4 conversion over the oxygen car- riers decreased in the lbllowing order： NiO/LaNiO3〉Co203/LaCoO3〉Fe203/LaFeO3. The ability of NiO/LaNiO3 and F%O3/ LaFeO3 to decompose water was stronger than that of Co203/LaCoO3 as evidenced by our experiments. H2 amounting to 80 mL upon reacting on methane in every cycle could be completely oxidized by NiO/LaNiO3 at 900℃ in the period from the third cycle to the eighth cycle.

Recycle Demetallating Process for Hydrocarbonaceous Feedstocks

The development and research on the recycle demetallating process are introduced. It shows the recycle demetallating process is effective on removing metal elements in heavy crude oil, especially with regard to calcium, through commercial application in delayed coking unit. Finally, the ash content in petroleum coke can be decreased to less than 0.5%, which complies with the IB coke standard. At the same time, the recycle demetallating process is an environmentally friendly technique, which has little effect on production quality and equipment corrosion.

Crystal Structure of Chlorinate (N,N-1,3-Dibenzyl-benzimidazole) Hydrate

The structure of the title compound consisting of N,N-1,3-dibenzyl-benzimidazole ion, Cl- anion and hydrate was determined by X-ray diffraction method. It crystallizes in the triclinic system, space group P with a = 9.320(2), b = 9.850(2), c = 11.510(2) ? = 68.75(3), = 80.57(3), = 70.20(3)? C21H19ClN2H2O, Mr = 352.85, V = 925.6(3) 3, Z = 2, Dc = 1.266 g/cm3, F(000) = 372, = 0.217 mm-1, R = 0.0452 and wR = 0.1372. The total reflections were 3462 and 3244 (Rint = 0.0206) were independent, of which 1666 were observed with I > 2s(I). The planes of benzyl group are nearly perpendicular to each other. The water molecules with Cl-anions and C(8) atom are involved in hydrogen bonds and interactions, and - stacking interaction exists obviously between the adjacent phenyl and imidazole rings. The title complex forms a three-dimensional network throughout the structure through these hydrogen bonds and interactions.

Synthesis of TS-1 Films on Porous Supports for Epoxidation ofAllyl Chloride by Hydrogen Peroxide

Titanium silicalite-1(TS-1)films were synthesized on stainless steel plate,glass slide and monolith supports via an in-situ hydrothermal method.Characterization data showed that the formation of TS-1 films was easier on the porous flat support with rough surface such as monolith than on the smooth non-porous supports like glass slide and stainless steel plate.The film on the monolith had the highest uniformity and smallest size of crystals.The catalytic property of monolithsupported film was tested for epoxidation of allyl chloride(ACH)by H2O2in a fixed bed reactor.Under the condition of a methanol(solvent)/ACH(90% )/H2O2(30% )ratio of 12:1:1,a LHSV of 1.35 h-1and a temperature of 318 K,the conversion of allyl chloride and the selectivity to epichlorohydrin reached 79% and 51% ,respectively.

Renewable Fuels in a Four-Stroke Diesel Engine

A lack of petroleum could easily destabilize world-wide relations and lead to a major war. Also large oil reliant suppliers of such goods as plastics, heating oil and construction material would be at a loss for the necessary raw materials. Petroleum reliant power plants would be out of production and the transportation industry would have no gasoline for its vehicle. Apart from this, there is a big need for the protection of the environment. Therefore, it is important to replace the petroleum with non fossil fuels or ones that can be made to last a lot longer, such as the renewable fuels that can be used in the engines and are friendly to the environment too. This paper examines the use of diesel-soy oil mixtures and diesel-olive seed oil mixtures in a four-stroke diesel engine. For those mixtures the gas emissions of carbon monoxide （CO）, hydrocarbons （HC） and nitrogen monoxide （NO） are being measured and the fuel consumption is also examined.

Synthesis and Crystal Structure of 2-Chloromethyl-1H-benzimidazole Nitrate, [ClCH_2(C_7H_6N_2)]NO_3

The title compound [ClCH2(C7H6N2)]NO3 has been prepared and characterized by elemental analysis and X-ray studies. It crystallizes in the monoclinic system, space group P21/n with a = 7.4189(3), b =15.3064(6), c = 9.2657(3) ? b = 102.449(2)? C8H8ClN3O3, Mr = 229.62, V = 1027.44(7) 3, Z = 4, Dc = 1.484 g/cm3, F(000) = 472, = 0.363 mm-1, R = 0.0671 and wR = 0.1546. The crystal structure consists of discrete 2-chloromethyl-1H-benzimidazole cations and NO3- anions. The benzimidazole ring with the conjunction carbon atom C(1) is fairly planar, with the deviation from the least plane through the ring atoms is smaller than 0.010(3) ? The analytical results of crystal structure show that three different non-covalent interactions in the compound, NH…O intermolecular hydrogen bonds, CH…O interaction and p-p stacking interaction, play an important role in the crystal packing.

EPR and DFT Study of the Polycyclic Aromatic Radical Cations from Friedel-Crafts Alkylation Reactions

Electron paramagnetic resonance and electron-nuclear double resonance methods were used to study the polycyclic aromatic radical cations produced in a Friedel-Crafts alkylating sys- tem, with m-xylene, or p-xylene and alkyl chloride. The results indicate that the observed electron paramagnetic resonance spectra are due to polycyclic aromatic radicals formed from the parent hydrocarbons. It is suggested that benzyl halides produced in the Friedel-Crafts alkylation reactions undergo Scholl self-condensation to give polycyclic aromatic hydrocar- bons, which are converted into corresponding polycyclic aromatic radical cations in the presence of AlCl3. The identification of observed two radicals 2,6-dimethylanthracene and 1,4,5,8-tetramethylanthraeene were supported by density functional theory calculations using the B3LYP/6-31G（d,p）//B3LYP/6-31G（d） approach. The theoretical coupling constants support the experimental assignment of the observed radicals.

PuH_2分子电子结构的DVM研究

关于钚的氢化物的分子结构和分子光谱公开解密的资料与数据甚少 .基于密度泛函理论的全数值自洽场计算方法———离散变分方法 (DVM) ,数值解相对论的Dirac方程 ,在自由的钚原子和氢原子波函数的数值基及原子能级基础上计算了全电子的PuH2 分子电子结构 .得到PuH2 分子基态最佳参数为键长Pu—H =0 2 0 86 17nm ,键角θ°(H—H) =115 .0 11° ,轨道总能量为 - 19838.6 6 30a .u .,费米能级EF=- 12 .5 71eV .比较了冻芯与非冻芯全电子计算结果 .

Hierarchical CuCo_2O_4@nickel-cobalt hydroxides core/shell nanoarchitectures for high-performance hybrid supercapacitors

Ni0.5Co0.5（OH）2 nanosheets coated CuCo2O4 nanoneedles arrays were successfully designed and synthe- sized on carbon fabric. The core/shell nanoarchitectures directly served as the binder-free electrode with a superior capacity of 295.6 mAh g-1 at 1 Ag-1, which still maintained 220 mAh g-1 even at the high current density of 40 A g-l, manifesting their enormous potential in hybrid supercapacitor devices. The asassembled CuCo2O4@Ni0.5Co0.5（OH）2]]AC hybrid supercapacitor device exhibited favorable properties with the specific capacitance as high as 90 F g 1 at 1 A g-1 and the high energy density of 32 Wh kg 1 at the power density of 800 Wkg-1. Furthermore, the as-assembled device also delivered excellent cycling performance （retaining 91.9% of the initial capacitance after 12,000 cycles at 8 A g 1） and robust mechanical stability and flexibility, implying the huge potential of present hierarchical electrodes in energy storage devices.

Electrocatalytic water-splitting for the controllable and sustainable synthesis of deuterated chemicals

Tandem water electrolysis for the transformation of universal feedstock to value-added chemicals integrated with hydrogen generation and in situ utilization is a promising approach to address the economic challenges of electrochemical hydrogen evolution and storage.Herein,we present the controllable electrocatalytic deuteration of halides using inexpensive and reusable heavy water(D2 O)as a D-source for the preparation of valuable D-labelled chemicals and pharmaceuticals under mild conditions.This electrochemical deuteration method with high efficiency and selectivity furnishes a series of D-labelled chemicals and pharmaceuticals in high yields with excellent D-incorporation.The reaction efficiency and selectivity,that is,the precise substitution of deuterium atoms at different halogen positions,can be tuned by varying the applied voltages.The results show the great potential of green and economical electrocatalytic methods for producing value-added fine chemicals in addition to hydrogen evolution.