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Chinese Journal of Chemical Engineering 2021年第3期34卷 10-16页

作者： Changjie Lu Weiqiang Tang Zijiang Dou Peng Xie Xiaofei Xu Shuangliang Zhao State Key Laboratory of Chemical Engineering and School of Chemical Engineering East China University of Science and TechnologyShanghai 200237China Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology and School of Chemistry and Chemical Engineering Guangxi UniversityNanning 530004China

It is important to study the solvent effect on keto-enol tautomerism that has applications in many areas of chemical *** this work,we use a multiscale reaction density functional theory(Rx DFT)to study the keto-enol tautomerism and isomerization of pyruvic *** results show that both effects of solvation and water assistance could reduce the reaction *** water molecule participates the reaction as a catalyst to accept/give the protons with forming a hexagonal ring in the transition *** a result of this temporary and intermediate hexagonal ring,the solute configuration undergoes a small variation during the reaction,giving a diminished contribution to the intrinsic reaction free *** solvent distribution shows a local ordering behavior near the solute that also reduces the contribution of solvation effect to the reaction *** assistance plays a major role in both pre-reaction and postreaction *** terms of the driving force for the reaction,the effects of both solvation and water assistance are important.

关键词： Solvent effect Reaction density functional theory Pyruvic acid tautomerism Isomerization

Study on the tautomerism of an Indoline Spiropyran in Compressed CO_2 and Ethanol Mixture

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Chinese Chemical Letters 1999年第8期10卷 689-690页

作者： Xi Feng ZHANG Qiang SUI Bu Xing HAN Hai Ke YAN Yan Qiao WANG (Institute of Chemistry. Chinese Academy of Sciences, Beijing 100080) Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

Thermodynamic and kinetic properties of the tautomerism of an indoline spiropyran in compressed CO2-ethanol mixture were studied by UV-Vis spectroscopy at 298.15 K, 303. 15 K, and 308.15 K. It was found that the compo... 详细信息

关键词： Compressed CO_2 ethanol indoline spiropyran tautomerism

Influence of Temperatures on the tautomerism of the N-（1H- Imidazoline-2-yl）-lH-benzimidazol-2-amine and Investigation of Its Electrochemical Behaviour

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Chinese Journal of Chemistry 2012年第2期30卷 400-404页

作者： Servi, Suleyman Genc, Murat Saydam, Sinan Department of Chemistry Faculty of Science University of Firat TR-23119 Elazig Turkey Department of Chemistry Faculty of Science and Art University of Adiyaman TR-02040Adiyaman Turkey

Synthesis of N-（1H-imidazoline-2-yl）-lH-benzimidazol-2-amine was carried out under microwave irradiation （MWI） conditions. Dynamic 1H NMR investigation of N-（lH-imidazoline-2-yl）-lH-benzimidazol-2-amine compound was reported at temperature range of 223--333 K in DMF-d7. Some physical parameters, such as coalescence temperature （Tc）, the free energy of activation （△G＊） and rate constant （k） values were calculated from its IH NMR spectra at various temperatures. Electrochemical feature of this compound was investigated by cyclic （CV） and square wave voltammetry （SWV）.

关键词： benzimidazole tautomerism dynamic NMR cyclic voltammetry

ab Initio Calculation on tautomerism of Pyrazolin-5-ones

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Chinese Journal of Structural Chemistry 1996年第1期15卷 9-11页

作者： Sun Ren-An Wang Chang-Sheng Yang Zhong-Zhi(Department of Chemistry, Liaoning Normal Universijy, Dalian, 116029)M. Vincent, I. H. Hillier (Department of Chamistry,Manchester University, England) Department of Chemistry Liaoning Normal University Dalian 116029 Department of Chemistry Manchester University United Kingdom

The relative stability of tautomers on pyrazolin-5-ones in gas phase and in solution is studied theoretically by STO-6-31G** +CI ab initio method and the reaciton field continuum model. the results obtained in our wor... 详细信息

关键词： ab initio calculation tautomerism pyrazolin-5-ones

Applying density functional theory on tautomerism in 3,4- dihydropyrimidin-2(1H)-ones

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Frontiers of Chemistry in China 2011年第2期6卷 142-146页

作者： Asadollah FARHADI Mohammad Ali TAKASSI Faculty of Science University of Petroleum Technology AhwazAhwaz 61981-44471Iran

In the present study,the density functional theory(DFT)and Gibbs free energy calculations were performed to investigate the stability and tautomerism of C4-substituted-3,4-dihydropyrimidin-2(1H)-*** different forms are possible for the ethyl 3,4-dihydropyrimidinones(ethyl 4-aryl-6-methyl-3,4-dihydropyrimidin-2(1H)-one-5-carboxylates,ethyl 4-aryl-2-hydroxy-6-methyl-1,4-dihydropyrimidine-5-carboxylates and ethyl 4-aryl-2-hydroxy-6-methyl-3,4-dihydropyrimidine-5-carboxylates)forms that the most stable form is ethyl 4-aryl-6-methyl-3,4-dihydropyrimidin-2(1H)-one-5-carboxylates(keto-form).The obtained data showed that the substitution on the C4-substitut position can be effective on the equilibrium constant(K_(eq)).

关键词： Gibbs free energy density functional theory(DFT) tautomerism dihydropyrimidin-2(1H)-ones Keto-Form

Ab Initio Study on the tautomerism of Thioformamide Between Its Thione and Thiol Forms

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Chemical Research in Chinese Universities 1991年第3期7卷 201-203页

作者： Zhao Chengda, Chen Xiaofeng and Chen Bin (Department of Chemistrty, Northeast Normal University, Changchun)

Introduction Thioformamide plays an important role in the organic and biochemical processes. Up to now, there are some reports on the static state study of its thione and thiol form tautumors, but few papes on the mechanism of tautomerism between these two tautomors. Since this tautomerism equilibrium may model the proton shift isomerization of thionucleic acid bases approximately, the theoretical study on the mechanism and dynamics of such a process has important significance.

关键词： Ab initio IRC Thioformamide tautomerism

Thiosemicarbazones Synthesized from Acetophenones: tautomerism, Spectrometric Data, Reactivity and Theoretical Calculations

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International Journal of Analytical Mass Spectrometry and Chromatography 2019年第2期7卷 19-34页

作者： Belén Gastaca Hernán Rubén Sánchez Fiorella Menestrina Maricel Caputo María de las Mercedes Schiavoni Jorge Javier Pedro Furlong Laboratory of Organic Compounds Studies (LADECOR) Department of Chemistry Facultad de Ciencias Exactas National University of La Plata La Plata Argentina Institute of Physics of Liquids and Biological Systems (IFLySIB CONICET) National University of La Plata La Plata Argentina Laboratory of Research and Development of Analytical Methods (LIDMA) Department of Chemistry Facultad de Ciencias Exactas National University of La Plata La Plata Argentina

Tautomeric forms of Thiosemicarbazones have been investigated by spectrometric methods, their chemical reactivity and theoretical calculations of the relative tautomers stabilities. The mass spectral fragmentation of thiosemicarbazones synthesized from acetophenones has been studied by CG/MS. The analysis of the corresponding spectra shows not only the regular fragmentation mechanisms but homolytic ruptures from even-electron species. 1H NMR spectra exhibit signals for the most intense open thioketo tautomeric structure, although when using TFA a ring structure is observed in the corresponding tautomeric equilibrium. Density Functional Theory calculations (DFT) also provide evidence to support the experimental observations by GC-MS and 1H NMR. Methylation reactions give support to the occurrence of the thioenol tautomeric form which would be the second most abundant according to the Density Functional Theoretical calculations.

关键词： Thiosemicarbazones tautomerism MS NMR Theoretical Calculations

Explanation of tautomerism and Isomerization in Terms of the Magnetic Field

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Journal of Chemistry and Chemical Engineering 2016年第2期10卷 96-98页

作者： Aibassov Yerkin Yemelyanova Valentina Tussupbayev Nessipbay Shakieva Tatyana Yerzhanova Zhadyra Bulenbayev Maxat Blagikh Evgeniy Research Institute of New Chemical Technologies and Materials Kazakh National University Al-Farabi Almaty 005012 Kazakhstan

A study of the influence of magnetic field on the tautomerism, the authors proposed a new method for predicting possible new intra- and intermolecular rearrangements due to tautomerism. The authors have proposed a gen... 详细信息

关键词： tautomerism isomerism benzidine rearrangement magnetic field.

Interaction of TATB with Cu and Cu^(+1). A DFT study

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Defence Technology（防务技术） 2019年第1期15卷 27-37页

作者： Lemi Türker Middle East Technical University Department of Chemistry

Symmetric triaminotrinitrobenzene known as TATB decomposes in contact with some heavy metals,such as copper. Presently, TATB and some of its important tautomers are subjected to B3LYP/6-31G(d,p) level of treatment. Some molecular orbital energies have been obtained and compared. Then. interaction of these species with Cu and Cu^+ are investigated. Although TATB has been found to be affected little by either Cu or Cu^+, undergoing only some bond length changes and/or distortions, the resonance-assisted tautomers having one to three aci groups decompose by the influence of Cu atom. In each case, only one N-OH bond rupture occurs.

关键词： Triaminitrinitrobenzene TATB tautomerism Copper DFT Pull-push

Revelation of bimolecular tautomerization induced by the concerted and radical interactions in lignin pyrolysis

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Journal of Energy Chemistry 2023年第9期84卷 1-10页

作者： Wen-luan Xie Bin Hu Wen-ming Zhang He-long Li Guo-yong Song Ji Liu Qiang Lu National Engineering Research Center of New Energy Power Generation North China Electric Power UniversityBeijing 102206China Beijing Key Laboratory of Lignocellulosic Chemistry Beijing Forestry UniversityBeijing 100083China Suzhou Institute of North China Electric Power University Suzhou 215123JiangsuChina

Bimolecular interactions play crucial roles in lignin *** tautomerization of key intermediates has a significant impact on the formation of stable products,whereas bimolecular tautomerization has been rarely *** the present work,the bimolecular tautomerization mechanism induced by both concerted and radical interactions was proposed and carefully confirmed.A characteristicβ-O-4 lignin dimer,2-phenoxy-1-phenylethanol(α-OH-PPE),was used as the model compound to reveal two representative keto-phenol and enol-keto tautomerism mechanisms,based on theoretical calculations combined with pyrolysis *** results indicate that the unimolecular tautomerism as the rate-determining step limits product generation,due to fairly high energy *** the free hydroxy compounds and radicals derived from initial pyrolysis can further initiate bimolecular tautomerism reactions through the one-step concerted hydroxyl-assisted hydrogen transfer(hydroxylAHT)and two-step radical hydrogen abstraction interactions,*** alleviating and even avoiding the large ring tension of tautomerism,the unstable tautomers(2,4-cyclohexadienone and1-hydroxy styrene)can be rapidly tautomerized into stable phenol and acetophenone with the help of intermolecular *** from the significant advantage of retro-ene fragmentation in breaking theβ-O-4 bond to form tautomers,a large amount of stable phenolic and ketone products can be generated following bimolecular tautomerization in the pyrolysis ofβ-O-4 linked lignin.

关键词： Lignin pyrolysis Interaction mechanism tautomerism Hydroxyl-assisted hydrogen transfer Radical chain reaction