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减肥药物盐酸西布曲明的合成研究 被引量:3
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作者 裘灵光 章爱霞 +2 位作者 杭德余 姚海波 章于川 《安徽大学学报(自然科学版)》 CAS 2001年第3期82-86,共5页
以对氯苄腈为起始原料 ,经环烃化、Grignard反应、还原、Eschweiler -Clarke甲基化反应以及成盐等合成了盐酸西布曲明 ,总收率 4 1.9% ,优化和改进了反应条件。产物经熔点、红外、元素分析、1
关键词 减肥药物 盐酸西布曲明 合成 对氯苄腈 环烃化 Grignard反应 还原反应
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Catalytic epoxidation of olefin over supramolecular compounds of molybdenum oxide clusters and a copper complex 被引量:3
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作者 高洪成 颜岩 +5 位作者 徐晓弘 于杰辉 牛会玲 高文秀 张文祥 贾明君 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2015年第11期1811-1817,共7页
The catalytic epoxidation of olefin was investigated on two copper complex-modified molybdenum oxides with a 3D supramolecular structure, [Cu(bipy)]4[Mo15O47].2H2O (1) and [Cu1(bix)][(Cu1bix) (δ-MoVl8O26)0.... The catalytic epoxidation of olefin was investigated on two copper complex-modified molybdenum oxides with a 3D supramolecular structure, [Cu(bipy)]4[Mo15O47].2H2O (1) and [Cu1(bix)][(Cu1bix) (δ-MoVl8O26)0.5] (2) (bipy = 4,4'-bipyridine, bix = 1,4-bis(imidazole-1-ylmethyl)benzene). Both compounds were catalytically active and stable for the epoxidation of cyclooctene, 1-octene, and styrene with tert-butyl hydroperoxide (t-BuOOH) as oxidant. The excellent catalytic performance was attributed to the presence of stable coordination bonds between the molybdenum oxide and copper complex, which resulted in the formation of easily accessible Mo species with high electropositivity. In addition, the copper complex also acted as an active site for the activation of t-BuOOH, thus im- proving these copper complex-modified polyoxometalates. 展开更多
关键词 Supramolecular compound Molybdenum oxide cluster Copper complex Olefin Epoxidation
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Visible light promoted difunctionalization reactions of alkynes 被引量:4
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作者 Xiang Ren Zhan Lu 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第7期1003-1019,共17页
Visible light promoted difunctionalization of alkynes is reviewed. The difunctionalization reaction is achieved by different reagents. Radicals such as carbon(sp3), carbon(sp2), and other heteroatom(P, S, N, Se, O, an... Visible light promoted difunctionalization of alkynes is reviewed. The difunctionalization reaction is achieved by different reagents. Radicals such as carbon(sp3), carbon(sp2), and other heteroatom(P, S, N, Se, O, and halide) radicals initiated by visible light can undergo radical addition to a carbon-carbon triple bond. Upon further transformation, the desired difunctionalized products are obtained. Some organometallic complexes can be activated by visible light;the difunctionalization of alkynes is catalyzed by these species. Other reagents like 1,3-dipole precursors could also react with alkynes to give difunctionalization products;here, the 1,3-dipole derivatives are obtained by visible light photocatalysis. So far, the strategy has been succeeded in the formation of C–C bonds and C–X bonds. Several valuable chemical skeletons have been constructed under mild conditions. However, high regio-and stereoselectivities in some direct difunctionalization methodologies are yet to be achieved. 展开更多
关键词 Visible light photocatalysis Difunctionalization CYCLIZATION ALKYNE Redox catalyst
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Solvothermal synthesis of Co-substituted phosphomolybdate acid encapsulated in the UiO-66 framework for catalytic application in olefin epoxidation 被引量:4
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作者 Dianwen Hu Xiaojing Song +4 位作者 Shujie Wu Xiaotong Yang Hao Zhang Xinyu Chang Mingjun Jia 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第2期356-366,共11页
Hybrid composites of phosphomolybdic acid@UiO-66(PMo12@UiO-66)and Co-substituted phosphomolybdic acid@UiO-66(PMo11Co@UiO-66)were synthesized using the direct solvothermal method.A variety of characterization results d... Hybrid composites of phosphomolybdic acid@UiO-66(PMo12@UiO-66)and Co-substituted phosphomolybdic acid@UiO-66(PMo11Co@UiO-66)were synthesized using the direct solvothermal method.A variety of characterization results demonstrated that phosphomolybdic acid(PMo12)or Co-substituted phosphomolybdate acid(PMo11Co)clusters are uniformly dispersed in the cages of Zr-based metal-organic UiO-66 frameworks.The catalytic properties of these hybrid composites were investigated by applying the epoxidation of olefins with tert-butyl hydroperoxide as the oxidant.Compared to PMo12@UiO-66,PMo11Co@UiO-66 showed a much higher catalytic activity and was simply recovered by filtration and reused for at least ten runs without significant loss of catalytic activity.Particularly,PMo11Co@UiO-66 can efficiently convert cyclic olefins like limonenes to epoxides,and its selectivity to 1,2-limonene oxide reached 91%in the presence of a radical inhibitor such as hydroquinone.The excellent catalytic activity and stability of the hybrid composite PMo11Co@UiO-66 are mainly attributed to the uniform distribution of highly active PMo11Co units within the smaller cages of UiO-66,to the suitable surface polarity of the hybrid composite for facilitating the access of reagents and solvent,and to the strong interface-interactions between the polyoxometalate and the UiO-66 framework. 展开更多
关键词 POLYOXOMETALATE Metal-organic frameworks OLEFINS EPOXIDATION Solvothermal synthesis
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Tandem Lewis acid catalysis for the conversion of alkenes to 1,2‐diols in the confined space of bifunctional TiSn‐Beta zeolite 被引量:4
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作者 Qifeng Lei Chang Wang +4 位作者 Weili Dai Guangjun Wu Naijia Guan Michael Hunger Landong Li 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第7期1176-1184,共9页
The generation of multifunctional isolated active sites in zeolite supports is an attractive method for integrating multistep sequential reactions into a single‐pass tandem catalytic reaction.In this study,bifunction... The generation of multifunctional isolated active sites in zeolite supports is an attractive method for integrating multistep sequential reactions into a single‐pass tandem catalytic reaction.In this study,bifunctional TiSn‐Beta zeolite was prepared by a simple and scalable post‐synthesis approach,and it was utilized as an efficient heterogeneous catalyst for the tandem conversion of alkenes to 1,2‐diols.The isolated Ti and Sn Lewis acid sites within the TiSn‐Beta zeolite can efficiently integrate alkene epoxidation and epoxide hydration in tandem in a zeolite microreactor to achieve one‐step conversion of alkenes to 1,2‐diols with a high selectivity of>90%.Zeolite confinement effects result in high tandem rates of alkene epoxidation and epoxide hydration as well as high selectivity toward the desired product.Further,the novel method demonstrated herein can be employed to other tandem catalytic reactions for sustainable chemical production. 展开更多
关键词 Tandem catalysis Confinement effect ZEOLITE Alkene epoxidation Epoxide hydration
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Quantum Chemistry of PAHs Thermal Cracking with Different Hydrogenation Degree 被引量:2
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作者 Wang Chunlu Zhou Han +2 位作者 Dai Zhenyu Zhao Xiaoguang Zhao Yi 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2013年第2期63-66,共4页
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 differ... 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. 展开更多
关键词 heavy oil PAHS thermal cracking ring cleavage molecular modeling DFT
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Hydrothermal synthesis and catalytic performance of bulky titanium silicalite-1 aggregates assembled by bridged organosilane 被引量:4
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作者 Li Chen Teng Xue +4 位作者 Jian Ding Hai Hong Wu Kun Zhang Peng Wu Ming‐Yuan He 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第2期275-282,共8页
A facile and effective method to synthesize TS‐1zeolite aggregates has been presented.The crystallization of silanized seeds and nanocrystallites led to large and irregular TS‐1zeolite aggregates ranging from5to40μ... A facile and effective method to synthesize TS‐1zeolite aggregates has been presented.The crystallization of silanized seeds and nanocrystallites led to large and irregular TS‐1zeolite aggregates ranging from5to40μm in size,based on the special sol‐gel chemistry of bridged organosilane.Epoxidation of1‐hexene and cyclohexene was used as a probe reaction to investigate the catalytic performance of the resulting materials.These TS‐1zeolite aggregates possessed both the conventional nanoparticle properties of TS‐1zeolites and variable surface hydrophilic/hydrophobic features,which enhanced the catalytic properties of hydroperoxides for alkene epoxidation.Moreover,the large aggregates effectively simplified the separation procedure during preparation and catalytic reactions. 展开更多
关键词 Bridged organosilane TS‐1 seeds TS‐1 nanocrystallites Zeolite aggregation Alkene epoxidation
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Bio-toxicity Effect of Polycyclic Aromatic Hydrocarbons Pyrene on Arabidopsis thaliana
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作者 尹冬雪 苏玉红 乔敏 《Agricultural Science & Technology》 CAS 2011年第6期818-822,共5页
[Objective] The aim was to study the effects of polycyclic aromatic hydrocarbons(PAHs)pyrene on the physiology and biochemistry of plant.[Method] Taking model plant A.thaliana as material,the effects of 4-ring PAHs ... [Objective] The aim was to study the effects of polycyclic aromatic hydrocarbons(PAHs)pyrene on the physiology and biochemistry of plant.[Method] Taking model plant A.thaliana as material,the effects of 4-ring PAHs pyrene stress on A.thaliana growth were studied,as well as the changes of antioxidant enzyme activity and ultrastructure in leaves.[Result] Under pyrene stress,the root growth of A.thaliana was enhanced under low concentration but was inhibited under high concentration.Trichomes of A.thaliana leaves distorted with the increase of pyrene concentration.Under 0.25 mmol/L of pyrene stress for 28 d,the photosynthetic process of A.thaliana was inhibited,and chlorophyll content in A.thaliana leaves decreased significantly.With the increase of pyrene concentration,the activity of peroxidase(POD),superoxide dismutase(SOD)and ascorbate peroxidase(APX)in A.thaliana leaves increased significantly,while catalase(CAT)activity went up firstly and then went down.In addition,average H2O2 content in A.thaliana leaves under different pyrene concentrations were higher than that of control.Meanwhile,damaged ultrastructures of few chloroplasts in A.thaliana leaves under pyrene stress were observed,and photosynthesis was inhibited significantly.[Conclusion] The study could provide references for the toxic mechanism of PAHs on plant and plant selection in the phytoremediation of PAHs contaminated soil. 展开更多
关键词 Polycyclic aromatic hydrocarbons PYRENE Arabidopsis thaliana Antioxidant enzyme
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Identification of nitrogen-polyaromatic compounds in asphaltene from co-processing of coal and petroleum residue using chromatography with mass spectrometry 被引量:3
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作者 Pingping Zuo Wenzhong Shen 《International Journal of Coal Science & Technology》 EI 2017年第3期281-299,共19页
Abstract Asphaltene, from co-processing of coal and petroleum residues is one of the most precious and complex molecular mixtures existing, with tremendous economic relevance. Asphaltene was separated by Soxhlet extra... Abstract Asphaltene, from co-processing of coal and petroleum residues is one of the most precious and complex molecular mixtures existing, with tremendous economic relevance. Asphaltene was separated by Soxhlet extraction with methylbenzene and then divided into three parts by distillation. Gas chromatography (GC) and high-performance liquid chromatography (HPLC) were coupled with quadrupole time-of-flight mass spectrometry (Q-TOF MS) to separate and characterize organic nitrogen species in the distillates of asphaltene at molecular level. Molecular mass of compounds was mainly distributed from 150 to 600 ~t. Number of rings plus double bonds (rdb) and synchronous fluorescence spectra indicated that most of the organonitrogen compounds (NPAC) contained heterocyclic aromatic rings, including pyridines, anilines, quinolins, pyrroles, carbazoles and indoles plus various alkyl groups. Constant-wavelength synchronous fluo- rescence spectrometry (CWSFS) indicated NPAC with 2-3 rings were the main structures of organonitrogen compounds and the corresponding structural information was proposed. Some organic nitrogen isomers were separated and identified by atmospheric pressure chemical ionization (APCI) GC-Q-TOF MS and electrospray ionization (ESI) HPLC-Q-TOF MS. The methodology applied here contained chromatographic injection of the diluted sample using conventional columns sets and Data Analysis 4.2 software. Identifying molecular structures provides a foundation to understand all aspects of coal- derived asphaltene, enabling a first-principles approach to optimize resource utilization. 展开更多
关键词 Co-processing of coal and petroleum residue ·Asphlatene · Heterocyclic aromatic rings · GC-Q-TOF MS ·HPLC-FL-Q-TOF MS
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Enantioselective epoxidation of olefins with hydrogen peroxide catalyzed by bioinspired aminopyridine manganese complexes derived from L-proline 被引量:2
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作者 Wenfang Wang Qiangsheng Sun +1 位作者 Chungu Xia Wei Sun 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第9期1463-1469,共7页
Three chiral aminopyridine ligands derived from L-proline were prepared. Careful evaluation of the corresponding aminopyridine manganese complexes in asymmetric epoxidation of olefins revealed a broad substrate scope ... Three chiral aminopyridine ligands derived from L-proline were prepared. Careful evaluation of the corresponding aminopyridine manganese complexes in asymmetric epoxidation of olefins revealed a broad substrate scope in the presence of 0.2 mol% manganese complex and 0.5 equiv. 2,2-dimethylbutyric acid, with aqueous hydrogen peroxide as an oxidant. A variety of olefins including styrenes, chromenes, and cinnamamides were transformed successfully into the target epoxides with moderate to excellent enantioselectivity(yield up to 95%, ee up to 99%). 展开更多
关键词 AMINOPYRIDINE ligand Manganese Asymmetricep oxidation HYDROGENPEROXIDE OLEFIN
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Optimization of Ultrasonic Extraction and Clean-up Protocol for the Determination of Polycyclic Aromatic Hydrocarbons in Marine Sediments by High-performance Liquid Chroma-tography Coupled with Fluorescence Detection 被引量:1
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作者 PENG Xuewei YAN Guofang +3 位作者 LI Xianguo GUO Xinyun ZHOU Xiao WANG Yan 《Journal of Ocean University of China》 SCIE CAS 2012年第3期331-338,共8页
The procedures of ultrasonic extraction and clean-up were optimized for the determination of polycyclic aromatic hydrocarbons (PAHs) in marine sediments. Samples were ultrasonically extracted, and the extracts were pu... The procedures of ultrasonic extraction and clean-up were optimized for the determination of polycyclic aromatic hydrocarbons (PAHs) in marine sediments. Samples were ultrasonically extracted, and the extracts were purified with a miniaturized silica gel chromatographic column and analyzed with high performance liquid chromatography (HPLC) with a fluorescence detector. Ultrasonication with methanol-dichloromethane (2:1, v/v) mixture gave higher extraction efficiency than that with dichloromethane. Among the three elution solvents used in clean-up step, dichloromethane-hexane (2:3, v/v) mixture was the most satisfactory. Under the optimized conditions, the recoveries in the range of 54.82% to 94.70% with RSDs of 3.02% to 23.22% for a spiked blank, and in the range of 61.20% to 127.08% with RSDs of 7.61% to 26.93% for a spiked matrix, were obtained for the 15 PAHs studied, while the recoveries for a NIST standard reference SRM 1941b were in the range of 50.79% to 83.78% with RSDs of 5.24% to 21.38%. The detection limits were between 0.75 ng L-1 and 10.99 ng L-1for different PAHs. A sample from the Jiaozhou Bay area was examined to test the established methods. 展开更多
关键词 ultrasonic extraction marine sediment polycyclic aromatic hydrocarbon high performance liquid chromatography
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Carbcations Chemistry: β-Methyl Shift--A New Rearrangement of the Carbcations Bridged Alicyclic Hydrocarbons
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作者 Evheniy Bagrii 《Journal of Chemistry and Chemical Engineering》 2014年第8期772-777,共6页
Results of researches on study of the kinetics and isomerization mechanism of the alkyladamantanes in the presence of the heterogeneous catalysts of the acid type are considered as detection and experimental proof of ... Results of researches on study of the kinetics and isomerization mechanism of the alkyladamantanes in the presence of the heterogeneous catalysts of the acid type are considered as detection and experimental proof of a new intramolecular rearrangement of the carbcations bridged alicyclic hydrocarbons--2,4-moving of the methyl groups (β-methyl shift). The proof of realization of such rearrangement is direct and primary formation 1,4-dimethyladamantane from 1,2-dimethyladamatane, passing a formation stage of the thermodynamic much stable 1,3-dimethyladamantane; direct formation 1,3,6-trimethyladamantane from 1,3,4-trimethyladamantane, excepting a formation stage 1,3.5-trimethyladamantane, and also other isomers which formation is impossible to explain by means of known 1,2-methyl shift (a-methyl shift). 展开更多
关键词 Alkyladamantanes ISOMERIZATION alicyclic hydrocarbons carbcations intramolecular rearrangement 2 4-moving methyl groups.
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The Study of Pollution of PAHs (Polycyclic Aromatic Hydrocarbons) in AI-Hilla River, Iraq by Using Bioindicator Freshwater Crab (Sesarma boulengeri Caiman)
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作者 Jasim M. Salman Atheer S. N. AI-Azawey Fikrat M. Hassan 《Journal of Life Sciences》 2014年第4期351-357,共7页
The present study was used freshwater Crab (Sesarma boulengeri Caiman) as bioindicator to measured the PAHs levels in AI-Hilla River, Iraq, during the period from March 2010 to February 2011. Crab samples were colle... The present study was used freshwater Crab (Sesarma boulengeri Caiman) as bioindicator to measured the PAHs levels in AI-Hilla River, Iraq, during the period from March 2010 to February 2011. Crab samples were collected from two sites on the AI-Hilla River. Sixteen of PAils compounds were identified seasonally in these samples. High mean value was (72.06 μg/g), recorded by Dibenzo (a, h) anthracene (DbA) in Site 1 and low mean value was (0.36 μg/g) recorded by Anthracene (Ant) in Site 2. The study showed a clear variation in PAHs concentration independent from the seasons and locations. Site 1 recorded high value of HMW (high molecular weight) and LMW (low molecular weight) more than Site 2. The present study revealed that all PAHs compounds were from Pyrogenic Origin. Seven carcinogenic PAHs (cPAHs) were recorded in crab tissues that were collected from the AI-Hilla River. The TEF (toxicity equivalency factor) was calculated to toxicity equivalent crab concentration. From the results, the fresh water Crab Sesarma boulengeri is a good bioindicator to water pollution by PAHs. 展开更多
关键词 Polycyclic aromatic hydrocarbons fresh water crab carcinogenic PAHs environmental health BIOINDICATOR Euphrates River AI-Hilla River.
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Curing Mechanism of Condensed Polynuclear Aromatic Resin and Thermal Stability of Cured Resin 被引量:1
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作者 Li Shibin Sun Qiqian +2 位作者 Wang Yuwei Wu Mingbo Zhang Zailong 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2015年第2期9-16,共8页
In order to improve the thermal stability of condensed polynuclear aromatic(COPNA) resin synthesized from vacuum residue, 1,4-benzenedimethanol was added to cure COPNA resin. The curing mechanism was investigated by p... In order to improve the thermal stability of condensed polynuclear aromatic(COPNA) resin synthesized from vacuum residue, 1,4-benzenedimethanol was added to cure COPNA resin. The curing mechanism was investigated by proton nuclear magnetic resonance spectrometry, solid carbon-13 nuclear magnetic resonance spectrometry and Fourier transform infrared spectroscopy. Microstructures of the uncured and the cured COPNA resins were studied by scanning electron microscopy and X-ray diffractometry. The thermal stability of COPNA resins before and after curing was tested by thermogravimetric analysis. The element composition of the cured COPNA resin heated at different temperatures was analyzed by an element analyzer. The results showed that the uncured COPNA resin reacted with the cross-linking agent during the curing process, and the curing mechanism was confirmed to be the electrophilic substitution reaction. Compared with the uncured COPNA resin, the cured COPNA resin had a smooth surface, well-ordered and streamlined sheet structure with more crystalline solids, better molecular arrangement and orientation. The weight loss process of the uncured and cured COPNA resins was divided into three stages. Carbon residue of the cured COPNA resin was 41.65% at 600 ℃, which was much higher than 25.02% of the uncured COPNA resin, which indicated that the cured COPNA resin had higher thermal stability. 展开更多
关键词 condensed polynuclear aromatic resin SYNTHESIS vacuum residue CURING thermal stability
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ZnO/SiO_2-modified rare-earth-metal ternary catalyst bearing quaternary ammonium salts for synthesis of high molecular weight poly (propylene carbonate) 被引量:2
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作者 Ruihua Cheng Yujie Zhou +1 位作者 Qiaoli Hou Boping Liu 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第8期1303-1310,共8页
A modified rare-earth-metal catalyst system combined with quaternary ammonium salts(QASs) as cocatalysts was investigated in the alternating copolymerization of CO_2/propylene oxide(PO) to produce poly(propylene ... A modified rare-earth-metal catalyst system combined with quaternary ammonium salts(QASs) as cocatalysts was investigated in the alternating copolymerization of CO_2/propylene oxide(PO) to produce poly(propylene carbonate)(PPC). In the presence of ZnO/SiO_2, the ZnEt_2-glycerine-Y(CCl_3OO)_3 catalyst presented higher activity for CO_2/PO copolymerization, as well as a higher molecular weight of polycarbonate, while maintaining the high carbonate content originating from the neat ZnEt_2-glycerine-Y(CCl_3OO)_3 catalyst. In the presence of QASs bearing different halide anions(F., Cl., and Br.), the type of the halide anion had a strong influence on the activity of the catalyst for CO_2/PO alternating copolymerization. Only tetramethylammonium fluoride(TMAF) could promote the alternating copolymerization without increasing the by-product. Combined the ZnO/SiO_2 catalyst and TMAF, the catalytic activity for CO_2/PO polymerization increased dramatically compared to the basic ternary catalyst system. The improved catalyst system produced a polymer with a high carbonate unit level equivalent to that of the polycarbonate produced by the basic ZnEt_2-glycerine-Y(CCl_3OO)_3 catalyst system. 展开更多
关键词 CO2/epoxide copolymerization Rare‐earth‐metalcatalyst ZnO‐modifiedsilica gel Quaternaryammoniumsalt MOLECULARWEIGHT
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Chemical Effects of CO2 Concentration on Soot Formation in Jet-stirred/Plug-flow Reactor
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作者 张引弟 娄春 +2 位作者 刘德华 李勇 阮龙飞 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2013年第11期1269-1283,共15页
Soot formation was investigated numerically with CO2 addition in a jet-stirred/plug-flow reactor (JSR/PFR) C2H4/OJN2 reactor (C/O ratio of 2.2) at atmospheric pressure. An updated Kazakov mechanism empha- sizes th... Soot formation was investigated numerically with CO2 addition in a jet-stirred/plug-flow reactor (JSR/PFR) C2H4/OJN2 reactor (C/O ratio of 2.2) at atmospheric pressure. An updated Kazakov mechanism empha- sizes the effect of the O2/CO2 atmosphere instead of an O2/N2 one in the premixed flame. The soot formation was taken into account in the JSR/PFR for C2H4/O2/N2. The effects of CO2 addition on soot formation in different C2H4/O2/CO2/N2 atmospheres were studied, with special emphasis on the chemical effect. The simulation shows that the endothermic reaction CO2 + H - CO + OH is responsible of the reduction of hydrocarbon intermediates in the CO2 added combustion through the supplementary formation of hydroxyl radicals. The competition of CO2 for H radical through the above forward reaction with the single most important chain branching reaction H + O2, ' O + OH reduces significantly the fuel burning rate. The chemical effects of CO2 cause a significant increase in residence time and mole fractions of CO and OH, significant decreases in some intermediates (H, C2H2), polycyclic aromatic hydrocarbons (PAHs, C6H6 and CI6H10, etc.) and soot volume fraction. The CO2 addition will leads to a decrease by only about 5% to 20% of the maximum mole fractions of some C3 to Clo hydrocarbon intermediates. The sensitivity analysis and reaction-path analysis results show that C2H4 reaction path and products are altered due to the CO2 addition. 展开更多
关键词 fuel enrichment carbon dioxide kinetics modeling soot formation jet-stirred/plug-flow reactor
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Phytoremediation of PAH-Contaminated Sediments by Potamogeton Crispus L. with Four Plant Densities
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作者 孟凡波 迟杰 《Transactions of Tianjin University》 EI CAS 2015年第5期440-445,共6页
In order to investigate the effect of plant density ofPotamogeton crispus L. on the remediation of sedi- ments contaminated by polycyclic aromatic hydrocarbons, a 54-day experiment with four plant densities (642, 1 6... In order to investigate the effect of plant density ofPotamogeton crispus L. on the remediation of sedi- ments contaminated by polycyclic aromatic hydrocarbons, a 54-day experiment with four plant densities (642, 1 604, 2 567 and 3 530 plants/m^2) was conducted. The results showed higher plant density with slower plant growth rate. Surface area per plant was the most sensitive root parameter to plant density. At the end of the 54-day experi- ment, planting P. crispus enhanced the dissipation ratios of phenanthrene and pyrene in sediments by 6.5%-26,2% and 0.95%-13.6%, respectively. The dissipation increment increased with increasing plant density. Plant uptake accounted for only a small portion of the dissipation increments. Furthermore, P. crispus could evidently improve sediment redox potentials, and strong positive correlations between root surface area and the redox potential as well as between the redox potentials and the dissipation ratios of phenanthrene and pyrene were obtained, indicating that the oxygen released by the roots ofP. crispus might be the main mechanism by which P. crispus enhanced the dis- sipation of PAHs in sediments. 展开更多
关键词 polycyclic aromatic hydrocarbons (PAHs) PHYTOREMEDIATION plant density Potamogeton crispus L. SEDIMENTS
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Catalytic Cracking of Cycloparaffins Admixed with Olefins:2. Single-Event Microkinetic(SEMK) Assessment 被引量:1
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作者 Xue Gaoping Weng Huixin +1 位作者 Joris W.Thybaut Guy B.Marin 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2014年第2期84-90,共7页
The developed SEMK model is used to provide an insight into the contribution of individual reactions in the cracking of methylcyclohexane as well as the site coverage by various carbenium ions. The preferred reaction ... The developed SEMK model is used to provide an insight into the contribution of individual reactions in the cracking of methylcyclohexane as well as the site coverage by various carbenium ions. The preferred reaction pathways for the conversion of methylcyclohexane are hydride transfer reactions followed by PCP-isomerizations, deprotonation and endocyclic β-scission, accounting for 61%, 22% and 12% of its disappearance, respectively, at 693 K and 30% conversion of methylcyclohexane. Protolysis plays a minor role in the cracking of methylcyclohexane. Once cyclic diolefins are formed, all of them can be instantaneously transformed to aromatics, which are easily interconverted via disproportionation. Judging from the carbenium ion concentrations it is evident that, at the investigated operating conditions, less than 5% of the acid sites are covered by carbenium ions, less than 2% of which corresponds to cyclic type species including allylic ones. 展开更多
关键词 catalytic cracking single-event microkinetic model cycloparaffin OLEFIN site coverage by carbenium ions
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EPR and DFT Study of the Polycyclic Aromatic Radical Cations from Friedel-Crafts Alkylation Reactions
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作者 Tao Wang An-an Wu +1 位作者 Li-guo Gao Han-qing Wang 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2009年第1期51-56,共6页
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... 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. 展开更多
关键词 Electron paramagnetic resonance Eelectron-nuclear double resonance Density functional theory Polycyclic aromatic radical cation
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Synthesis and Mollucicidal Activity of Some New Bicyclic and Polycyclic Pyrimidine Derivatives
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作者 Mohamed Abdel-Megid Mohamed Abdel-Hamid Awas +2 位作者 Magdy Seada Kamelia Mohamed Elmhdy Mortta Mohamed Elsayed 《Journal of Chemistry and Chemical Engineering》 2010年第5期41-53,共13页
Hydrazinolysis ofethylthiopyrimidine derivative 2 gave 2-hydrazinopyrimidine 3 which used as a convenient precursor for the synthesis of pyrazolylpyrimidines, hydrazones and pyrimidotriazines. Also, treatment of 2 wit... Hydrazinolysis ofethylthiopyrimidine derivative 2 gave 2-hydrazinopyrimidine 3 which used as a convenient precursor for the synthesis of pyrazolylpyrimidines, hydrazones and pyrimidotriazines. Also, treatment of 2 with ethyl chloroacetate yielded N^-carbethoxymethyl-2-ethylthio-pyrimidine 15, which on reaction with ethyl carbazate and hydrazine hydrate afforded pyrimidotriazine and imidazopyrimidine, respectively. Chlorination of 2 using phosphorous oxycbloride yielded 4-chloropyrimidine 18, which reacted with some heterocyclic compounds having vicinal amino cyano groups to give some new polynuclear heterocyclic system. Also, the effect of some active methylene compounds on 18 was also studied. Some of the newly synthesized compounds were tested as mollucicidal agents against Biomphlaria alexandrina snails that caused intestinal bilharzias, the national problem in Egypt. 展开更多
关键词 Pyrazolylpyrimidines pyrimidotriazines imidazopyrimidines pyrimidopyrimidines mollucicidal activity.
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