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Mapping out the reaction network of humin formation at the initial stage of fructose dehydration in water

Green Energy & Environment 2024年第6期9卷 1016-1026页

作者： Xing Fu Yexin Hu Ping Hu Hui Li Shuguang Xu Liangfang Zhu Changwei Hu Key Laboratory of Green Chemistry and Technology Ministry of EducationCollege of ChemistrySichuan UniversityChengduSichuan610064China State Key Laboratory of Southwestern Chinese Medicine Resources Innovative Institute of Chinese Medicine and PharmacyChengdu University of Traditional Chinese MedicineChengduSichuan611137China

The formation of humins hampers the large-scale production of 5-hydroxymethylfurfural(HMF)in biorefinery.Here,a detailed reaction network of humin formation at the initial stage of fructose-to-HMF dehydration in water is delineated by combined experimental,spectroscopic,and theoretical studies.Three bimolecular reaction pathways to build up soluble humins are demonstrated.That is,the intermolecular etherification of β-furanose at room temperature initiates the C12 path,whereas the C-C cleavage of a-furanose at 130-150℃ leads to C11 path,and that of open-chain fructose at 180℃ to C11' path.The successive intramolecular dehydrations and condensations of the as-formed bimolecular intermediates lead to three types of soluble humins.We show that the C12 path could be restrained by using HCl or AlCl_(3) catalyst,and both the C12 and C110 paths could be effectively inhibited by adding THF as a co-solvent or accelerating heating rate via microwave heating.

关键词： Carbohydrates 5-hydroxymethylfurfural reaction network Soluble humins Tautomer

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Insights into the reaction network and Mechanism of Green Aerobic Oxidative Esterification of Methacrolein over Different Heterogeneous Catalysts

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China Petroleum Processing & Petrochemical Technology 2021年第3期23卷 1-11页

作者： Li Chenhao Xia Changjiu Liu Yujia Huang Kaimeng Peng Xinxin Liu Jinsheng Lin Min Zhu Bin Luo Yibin Shu Xingtian State Key Laboratory of Catalytic Materials and reaction Engineering Research Institute of Petroleum ProcessingSINOPECBeijing 100083

The oxidative esterification of methacrolein(MAL)is an important way to prepare high-valued methyl methacrylate(MMA),but this process is ultra-complex due to the high reactivity of both C=O and C=C bonds in MAL molecule.In order to further improve MMA selectivity,the reaction network and relevant mechanisms have been proposed and profoundly investigated in this paper.Five kinds of fundamental reactions are involved in this process,including(a)the acetal reaction;(b)the aerobic oxidation of hemiacetal;(c)the alkoxylation of C=C double bond;(d)the Diels-Alder reaction;and(e)the hydrogenation reaction of unsaturated double bond.Among them,the Diels-Alder reaction of MAL is non-catalyzed,and the Brönsted acid sites or the Lewis acid sites favor promoting acetal reaction of MAL with methanol,while the alkoxylation of C=C bond with methanol is enhanced under alkaline condition.In particular,by employing the Pd-based catalysts,hydrogenation products are formed in alkaline methanol solution,hence with lower than those obtained by the Au-based catalysts.Notably,it is necessary to match the hemiacetal fromation and aerobic oxidation of hemiacetal,which is relevant with the amount and strength of acid and redox sites.Consequently,this work can provide a good guidance for the further design of both catalysts and processes in future.

关键词： methacrolein oxidative esterification mechanism reaction network methyl methacrylate

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Computer generation of detailed reaction networks in hydrocracking of Fischer-Tropsch wax

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Chinese Journal of Chemical Engineering 2022年第1期35卷 342-349页

作者： Jingjing Wang Wei Zhao Kunpeng Song Hongwei Xiang Liping Zhou Yong Yang Yongwang Li State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China National Energy Center for Coal to Liquids Synfuels China Co.Ltd.Huairou DistrictBeijing 101400China University of Chinese Academy of Sciences Beijing 100049China

Fischer-Tropsch synthesis(FTS)wax is a mixture of linear hydrocarbons with carbon number from C7 to C70+.Converting FTS wax into high-quality diesel(no sulfur and nitrogen contents)by hydrocracking technology is attractive in economy and practicability.Kinetic study of the hydrocracking of FTS wax in elementary step level is very challenging because of the huge amounts of reactions and species involved.Generation of reaction networks for hydrocracking of FTS wax in which the chain length goes up to C70 is described on the basis of Boolean adjacency matrixes.Each of the species(including paraffins,olefins and carbenium ions)involved in the elementary steps is represented digitally by using a(N+3)N matrix,in which a group of standardized numbering rules are designed to guarantee the unique identity of the species.Subsequently,the elementary steps are expressed by computer-aided matrix transformations in terms of proposed reaction rules.Dynamic memory allocation is used in species storage and a characteristic vector with nine elements is designed to store the key information of a(N+3)N matrix,which obviously reduces computer memory consumption and improves computing efficiency.The detailed reaction networks of FTS wax hydrocracking can be generated smoothly and accurately by the current method.The work is the basis of advanced elementary-step-level kinetic modeling.

关键词： Hydrocracking Fischer-Tropsch synthesis wax Boolean adjacency matrixes reaction network

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Iodine-promoted reaction network for the direct synthesis of 4-aryl-2-aminothiazoles via integration of two domino sequences

Iodine-promoted reaction network for the direct synthesis of...

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中国化学会全国第十一届有机合成化学学术研讨会

作者： Wei-jian Xue An-xin Wu College of Chemistry Central China Normal University

Although a broad range of organic unit reactions have been developed for the construction of organic compounds,most of these reactions are incompatible with each other and cannot be conducted in the same flask as one-pot procedures.The concept of reaction networks has been developed to address this issue of incompatibility,where multiple chemical reactions can be conducted in a single pot.This novel methodology provides an efficient strategy for the synthesis of complex compounds from simple and readily available starting materials.Using this particular strategy,a series of optimum conditions were identified for the convergent integration of a series of domino reactions into one-pot processes,including a self-sorting domino reaction,a focused domino reaction,and a self-labor domino reaction.Herein,we have developed a facile method for the synthesis of 4-aryl-2-aminothiazoles derivatives from simple and readily available aromatic ketones and thiourea.

关键词： reaction network Iodine-promoted Aminothiazoles Domino reaction

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reaction decoupling in thermochemical fuel conversion and technical progress based on decoupling using fluidized bed

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Carbon Resources Conversion 2018年第2期1卷 109-125页

作者： Zhennan Han Sulong Geng Xi Zeng Shipei Xu a Ping An Jiguang Cheng Jun Yang Feng Li Suyi Zhang Miao Liu Guoqing Guan Guangwen Xu State Key Laboratory of Multi-phase Complex System Institute of Process EngineeringChinese Academy of SciencesBeijing 100190People’s Republic of China Institute of Industrial Chemistry and Energy Technology Shenyang University of Chemical TechnologyShenyang 110142People’s Republic of China Luzhoulaojiao Group Co.Ltd Luzhou 646000People’s Republic of China Department of Renewable Energy Institute of Regional InnovationHirosaki University2-1-3 MatsubaraAomori 030-0813Japan

Thermochemical conversion of fuels via pyrolysis/carbonization,cracking,gasification and combustion has to involve a number of individual reactions called attribution reactions to form an intercorrelated reaction network for any conversion process.By separating one or some attribution reactions from the others to decouple their interactions existing in the reaction network,the so-called reaction decoupling enables a better understanding of the complex thermal conversion process and further the optimization of the conditions for attribution reactions as well as the entire conversion process to realize advanced performances.The dual bed conversion and two-stage conversion are the two representative types of fuel conversion technologies developed in recent years based on reaction decoupling.Many technical advantages have been proven for such decoupling fuel conversion technologies,such as poly-generation of products,low-cost production of high-grade products,elimination of undesirable products or pollutants,easy operation and control,and so on.The treated fuels with decoupling conversion technologies mainly include solid biomass and coal,as well as liquid petroleum oil.This paper is devoted to reiteration of the reaction decoupling concept and further to reviewing the research,developments and successful applications of several decoupling fuel conversion technologies of two such types by using fluidized bed as their major reactors.

关键词： reaction decoupling Fuel conversion reaction network Fluidized bed Dual bed Two-stage

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Cross-interaction of volatiles from co-pyrolysis of lignin with pig manure and their effects on properties of the resulting biochar

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Biochar 2021年第3期3卷 391-405页

作者： Chao Li Yifan Sun Lijun Zhang Changxu Wang Shu Zhang Qiaoling Li Leilei Xu Xun Hu School of Material Science and Engineering University of JinanJinan 250022People’s Republic of China Joint International Research Laboratory of Biomass Energy and Materials Co-Innovation Center of Efficient Processing and Utilization of Forest ResourcesCollege of Materials Science and EngineeringNanjing Forestry UniversityNanjing 210037China Technology Center China Tobacco Fujian Industrial CompanyXiamen 361021FujianPeople’s Republic of China School of Environmental Science and Technology Nanjing University of Information Science and TechnologyNanjing 210000People’s Republic of China

Biomass and pig manure have distinct compositions and the co-pyrolysis of them has gained much attention.However,the influence of volatiles interaction on the properties of the char was still unclear.In this study,lignin was selected as the model component of biomass with pig manure for co-pyrolysis at 600°C.The results indicate that volatiles from co-pyrolysis promoted re-condensation reaction,resulting in the higher char yield(48.0%in co-pyrolysis versus 31.0%in pyrolysis of single manure)and the formation of more aromatics in bio-oil.The co-pyrolysis also facilitated the dehydrogenation and dehydration reactions,which accounted for the elimination of oxygen and nitrogen contents and thus a higher carbon content(64.7%in the co-pyrolysis versus the averaged value of 46.4%from the pyrolysis of single feedstock),higher crystallinity and thermal stability of the char.The in-situ diffuse reflection infrared Fourier transform spectroscopy(DRIFTS)characterization results demonstrated that the functionalities abundances of char with temperature was influenced by volatiles interaction via accelerating the carbonization reaction.In addition,the high heating value(HHV)of char was obviously improved by cross-interaction of volatiles during co-pyrolysis(24.4 MJ/Kg in co-pyrolysis versus averaged value of 15.1 MJ/Kg from single pyrolysis),implying that the co-pyrolysis enhanced the energy density of the resulting char.

关键词： Co-pyrolysis Lignin and pig manure Volatiles interaction Char properties reaction network

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Kinetic model for hydroisomerization reaction of C_(8)-aromatics

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Frontiers of Chemical Science and Engineering 2008年第1期2卷 10-16页

作者： Ouguan XU Hongye SU Xiaoming JIN Jian CHU Zhijiang College Zhejiang University of TechnologyHangzhou 310024China National Key Laboratory of Industrial Control Technology Institute of Advanced Process ControlZhejiang UniversityHangzhou 310027China

Based on the reported reaction networks,a novel six-component hydroisomerization reaction net-work with a new lumped species including C_(8)-naphthenes and C_(8)-paraffins is proposed and a kinetic model for a commercial unit is also developed.An empirical catalyst deactivation function is incorporated into the model accounting for the loss in activity because of coke forma-tion on the catalyst surface during the long-term opera-tion.The Runge-Kutta method is used to solve the ordinary differential equations of the model.The reaction kinetic parameters are benchmarked with several sets of balanced plant data and estimated by the differential vari-able metric optimization method(BFGS).The kinetic model is validated by an industrial unit with sets of plant data under different operating conditions and simulation results show a good agreement between the model predic-tions and the plant observations.

关键词： C_(8)-aromatics hydroisomerization reaction network kinetic model catalyst deactivation function parameter estimation

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