检索结果-南通市图书馆

hydrogenation of phenylpyruvic acid to phenylalanine catalyzed by Ni-B/SiO_2

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2008年第3期17卷 303-308页

作者： Qunfang Liang Aiqing Zhang Lin Li Key Laboratory of Catalvsis and Materials Science of the State Ethnic Affairs Commission ＆ Ministry of Education College of Chemistry and MateriaLs Science South-Central University for Nationalities Wuhan 430074 Hubei China

Phenylalanine （Phe） is a significant amino acid that cannot be synthesized by human themselves but must be taken from environment. It was initially found that the nanosized amorphous Ni-B/SiO2 alloy prepared by the chemical reduction method was an effective catalyst for the preparation of Phe from phenylpyruvic acid （PPA） by amination and hydrogenation. It has been found that the amorphous Ni-B/SiO2 alloy catalyst exhibits superior activity and selectivity to the traditional catalysts Raney Ni and Urushibara nickel. The effects of reaction time, amounts of catalysts and ammonia solution, reaction temperature, and H2 pressure on the reaction have been investigated systematically. The results indicated that the yield of Phe was 97.9%, and the selectivity for Phe reached 98.9% when the reaction was carried out for 3 h at 333 K and 2.0 MPa of H2 with m（Cat.）： m（PPA） = 0.6 ： 1.0 and n（NH3）： n（PPA） = 3 ： 1. The catalysts were characterized by XRD, AAS, XPS, BET, and TEM, and the relationship between the catalyst structure and the catalytic activity was discussed in detail. It was found that the reason why Ni-B/SiO2 amorphous alloy catalyst was much more active for the preparation of Phe could be accounted for by the presence of electron-rich Ni due to electron donation from alloying B; the smaller size of Ni-B particles, the larger specific surface area of Ni-B/SiO2.

关键词： Ni-B/SiO2 amorphous alloy phenylalanine phenylpyruvic acid hydrogenation catalyst

hydrogenation Properties of Zr Films Under Various Conditions of Hydrogen Plasma

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2002年第6期19卷 775-778页

作者：晏国强罗顺忠等 AppliedIonBeamPhysicsLaboratory InstituteofModernPhysicsFudanUniversityShanghai200433 InstituteofNuclearPhysicsandChemistry ChinaAcademyofEngineeringPhysicsChengdu610003

The hydrogenation properties of Zr samples with and without an Ni overlayer under various plasma conditions were investigated by means of non-Rutherford backscattering and elastic recoil detection analysis. The theoretical maximum hydrogen capacity, 66.7 at%, could be achieved at a hydrogen absolute pressure of ~2 Pa and a substrate temperature of ~393 K for a plasma irradiation of only 10 min; this was significantly greater than that for gas hydrogenation under the same hydrogen pressure and substrate temperature. It was also found that the C and O contamination on the sample surface strongly influences the hydrogenation, and that the maximum equilibrium hydrogen content drops dramatically with the increasing total contamination. In addition, the influence of the Ni overlayer on the plasma hydrogenation is discussed.

关键词： hydrogenation

hydrogenation of Toluidines Catalyzed by Silica-supported Carboxymethylcellulose-platinum Complex

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2004年第2期20卷 176-179页

作者： WANGXin YANGJi-huo HUANGMei-yu JIANGYing-yan DepartmentofChemistry HuazhongUniversityofScienceandTechnologyWuhan430074P.R.China Group4060 InstituteofChemistryChineseAcademyofSciencesBeijing100080P.R.China

The hydrogenation of toluidines catalyzed by silica-supported carboxymethyl cellulose platinum complex forms methylcyclohexlamines in high yields, such as m-toluidine to 3-methylcyclohexylamine, o-toluidine to 2-methylcyclohexylamine, and p-toluidine to 4-methylcyclohexylamine in 97%, 96.7% and 98.2% yields, respectively, at 30 ℃ and under atmospheric hydrogen pressure. The yields were remarkably affected by the Pt content in the complex, the kind of solvent and the reaction temperature. The catalyst was very stable and could be reused several times without remarkable change in the catalytic activity.

关键词： hydrogenation Silica-supported carboxymethyl cellulose-platinum complex Toluidine Methylcyclohexylamine

hydrogenation of the buffer-layer graphene on 6H-SiC （0001）： A possible route for the engineering of graphene- based devices

在线全文

学校读者我要写书评

暂无评论

Nano Research 2015年第3期8卷 839-850页

作者： Yu-Pu Lin Younal Ksari Jean-Marc Themlin Aix-Marseille UniversitY CNRS Universite de Toulon IM2NP UMR 7334 13397 Marseille France

The hydrogenation at various temperatures of the （6√3 ×6√3）R30° reconstruction of SIC（0001）, the so-called buffer layer graphene （BLG）, is investigated. For the BLG, a significant concentration of remaining dangling bonds related to unsaturated Si atoms of the outermost SiC bilayer is evidenced in the inverse photoemission spectra. These dangling bonds give rise to a peak around 1 eV above the Fermi level, associated with the upper single-electron states of a Mott-Hubbard insulator, which vanishes upon hydrogenation. Hydrogen atoms adsorbed at ambient temperature remain covalently bound to BLG （H-BLG） up to temperatures of -500℃. They induce additional C-Si bonds at the BLG/SiC interface that saturate the remaining Si dangling bonds, as evidenced in both IPES and Auger electron spectra. The H-BLG further shows a large energy gap and an excess n-type doping in comparison to the pristine BLG. Upon hydrogen exposure at higher temperature （〉 700 ℃）, hydrogen atoms intercalate at the BLG/SiC interface, inducing the formation of a single layer of quasi-free- standing graphene （QFSG） lying on top of a hydrogenated （√3×√3）R30° reconstruction as supported by IPES. We suggest that the high-stability and the distinct electronic structure of both BLG-derived structures, H-BLG and QFSG, may open a route for the engineering of graphene-based devices.

关键词： graphene hydrogenation photoemissionspectroscopy electronic structure

hydrogenation of Cinnamaldehyde to Cinnamyl Alcohol over An Ultrafine Co-B Amorphous Catalyst

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2002年第2期13卷 107-110页

作者： Xing Fan CHEN He Xing LI Ye Ping XU Ming Hui WANG Department of Chemistry Shanghai Normal UniversityShanghai 200234

A novel Co-B amorphous alloy catalyst in the form of ultrafine particles was prepared by chemical reduction of CoCl2 with aqueous NaBH4, which exhibited excellent activity and selectivity during the hydrogenation of cinnamaldehyde to cinnamyl alcohol in liquid phase. The optimum yield of cinnamyl alcohol was 87.6%, much better than the yield of using Raney Ni, Raney Co and other Co-based catalysts.

关键词： Co-B amorphous catalyst hydrogenation cinnamaldehyde cinnamyl alcohol.

hydrogenation of ortho-nitrochlorobenzene on activated carbon supported platinum catalysts

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2005年第5期6卷 378-381页

作者：蒋成君尹红陈志荣 Department of Chemical and Biochemical Engineering Zhejiang University Hangzhou 310027 China

Platinum/carbon catalyst is one of the most important catalysts in hydrogenation of ortho-nitrochlorobenzene to 2,2′-dichlorohydrazobenzene. The preparation process and the supports of catalysts are studied in this paper. Raw materials and preparation procedure of the activated carbon have great influences on the compositions and surface structure of platinum/carbon catalysts. Platinum catalysts supported on activated carbon with high purity, high surface area, large pore volume and appropriate pore structure usually exhibit higher activities for hydrogenation of ortho-nitrochlorobenzene to 2,2′-dichlorohydrazobenzene. The catalyst prepared from H2PtCl6 with pH=3 shows greater catalytic performance than those prepared under other conditions.

关键词： Platinum/carbon catalyst hydrogenation Ortho-nitrochlorobenzene 2 2′-dichlorohydrazobenzene Activated carbon

hydrogenation of SBS Catalyzed by Immobilized Ru-TPPTS Complex in Polyether Molten Salt

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2005年第3期16卷 338-340页

作者： LiWEI JingYangJIANG YanHuaWANG ZiLinJIN StateKeyLaboratoryofFineChemicals DalianUniversityofTechnologyDalian116012

Catalytic hydrogenation of SBS was performed for the first time in polyether molten salt with Ru/TPPTS complex as catalyst. Experimental results showed that the hydrogenation degree can be enhanced significantly by the addition of triphenylphosphine (TPP). When the molar ratio of TPP, TPPTS and Ru is 2:5:1, 89% hydrogenation degree can be achieved after 12 h under reaction conditions of 5.0 MPa and 150°C. The ionic liquid containing catalyst can be reused three times without obvious changes in the catalytic selectivity and activity.

关键词： hydrogenation SBS ruthenium complex polyether molten salt.

hydrogenation Behavior of Hydrogen Peroxide in a Microreactor

在线全文

学校读者我要写书评

暂无评论

China Petroleum Processing & Petrochemical Technology 2022年第4期24卷 29-35页

作者： Zhu Hongwei Sun Bing Jin Yan Feng Junjie Zhao Chenyang Yan Junjie Jiang Jie Xu Wei SINOPEC Research Institute of Safety Engineering Co. Ltd.Qingdao 266071 State Key Laboratory of Heavy Oil Processing China University of Petroleum Qingdao 266580

The hydrogenation of hydrogen peroxide is an unwanted side reaction in the direct synthesis of hydrogen peroxide and remains a problem to *** mechanism of this reaction has been studied with batch reactors but the slow heat and mass transfer in batch reactors hindered the understanding of its intrinsic *** this study,a microreactor is employed to investigate the parameters that influence the hydrogenation reaction,including flow rate,channel length,hydrogen pressure,solvent composition,and initial hydrogen peroxide *** activity of different catalysts was compared and the hydrogenation law was confirmed,providing guiding information to better control the hydrogenation process.

关键词： hydrogenation hydrogen peroxide microreactor hydrogenation decomposition law catalyst passivation

hydrogenation of Alkylanthraquinone Over Pore-Expanded and Channel-Shortened Pd/SBA-15

在线全文

学校读者我要写书评

暂无评论

Transactions of Tianjin University 2019年第6期25卷 595-602页

作者： Nan Wang Qingqing Ma Enxian Yuan Li Wang Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072China

SBA-15 silica was synthesized by adding normal paraffin and alkyl benzene as swelling agents and using a low-temperature gelation *** was then impregnated on SBA-15,yielding a *** of the catalyst by X-ray diffraction,N2 adsorption/desorption,scanning electron microscopy,transmission electron micrographs,X-ray photoelectron spectroscopy,in situ FTIR,and a hydrogenation test of 2-ethyl-anthraquinone reveal that the addition of C6-C9 normal paraffin and 1,3,5-triisopropylbenzene could enlarge the pore diameter without a significant loss of ordered ***,the length of SBA-15 pore channels decreased ***,the sizes of Pd particles increase as the pore diameter is *** largest pore size(13.6 nm)and short length of pore channels(ca.0.35μm)are achieved by adding *** a result,this catalyst exhibits the highest hydrogenation activity with an approximately 100%improvement,compared with a conventionally synthesized catalyst in the absence of a swelling agent.

关键词： hydrogenation Anthraquinone SBA-15 Swelling agent Hydrogen peroxide