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Enhancing the aromatic selectivity of cyclohexane aromatization by CO_(2)coupling

Frontiers of Chemical Science and Engineering 2023年第11期17卷 1801-1808页

作者： Xiangxiang Ren Zhong-Pan Hu Jingfeng Han Yingxu Wei Zhongmin Liu National Engineering Research Center of Lower-Carbon Catalysis Technology Dalian National Laboratory for Clean EnergyiChEM(Collaborative Innovation Center of Chemistry for Energy Materials)Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China

Improving the aromatic selectivity in the alkane aromatization process is of great importance for its practical utilization but challenge to make because the high H/C ratio of alkanes would lead to a serious hydrogen transfer process and a large amount of light ***,CO_(2)is introduced into the cyclohexane conversion process on the HZSM-5 zeolite,which can improve the aromatic *** optimizing the reaction conditions,an improved aromatic(benzene,toluene,xylene,and C9+)selectivity of 48.2%can be obtained at the conditions of 2.7 MPa(CO_(2)),450℃,and 1.7 h^(−1),which is better than that without CO_(2)(aromatic selectivity=43.2%).In situ transmission Fourier transform infrared spectroscopy spectra illustrate that many oxygenated chemical intermediates(e.g.,carboxylic acid,anhydride,unsaturated aldehydes/ketones or ketene)would be formed during the cyclohexane conversion process in the presence of CO_(2).13C isotope labeling experimental results demonstrate that CO_(2)can enter into the aromatics through the formation of oxygenated chemical intermediates and thereby improve the aromatic *** study may open a green,economic,and promising way to improve the aromatic selectivity for alkane aromatization process.

关键词： aromatics carbon dioxide aromatization coupling reaction ZSM-5 zeolite

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Coupling CO_(2)reduction with ethane aromatization for enhancing catalytic stability of iron-modified ZSM-5

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Journal of Energy Chemistry 2022年第3期31卷 210-217,I0007页

作者： Zhenhua Xie Elaine Gomez Dong Wang Ji Hoon Lee Tiefeng Wang Jingguang G.Chen Department of Chemical Engineering Columbia UniversityNew YorkNY 10027USA Chemistry Division Brookhaven National LaboratoryUptonNY 11973USA Department of Chemical Engineering Tsinghua UniversityBeijing100084 BeijingChina

The shale gas revolution and the carbon-neutrality goal are motivating the landscape toward the synthesis of value-added chemicals or fuels from underutilized ethane with the assistance of greenhouse gas CO_(2).Combining ethane aromatization with CO_(2)reduction offers an opportunity to directly produce liquid products for facile separation,storage,and *** the present work,Fe/ZSM-5 catalysts showed promise in the simultaneous CO_(2)reduction and ethane aromatization at atmospheric pressure and 873 *** catalysts were further investigated using X-ray diffraction(XRD)and X-ray absorption fine structure(XAFS)measurements under in-situ conditions,indicating that most of Fe species existed in the form of Fe oxides and a portion of Fe was incorporated into the ZSM-5 framework generating Lewis acid *** types of Fe species remained almost unchanged under reaction conditions,contributing to an enhanced aromatization activity of Fe/*** effects of CO_(2)and steam on the acid sites and in turn aromatization activity were also investigated by transient studies,which exhibited a reversible modification ***,CO_(2)was identified to be critical to enhance coke resistance and in turn catalyst *** work highlights the feasibility of using CO_(2)to assist the upgrading of abundant ethane from shale gas to aromatics over non-precious Fe-based zeolite catalysts.

关键词： Ethane CO_(2) aromatization Fe-modified ZSM-5

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Characterizing Post-PKS Modifications of 16-Demethyl-rifamycin Revealed Two Dehydrogenases Diverting the aromatization Mode of Naphthalenic Ring in Ansamycin Biosynthesis

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Chinese Journal of Chemistry 2022年第13期40卷 1553-1558页

作者： Ting-Yan Han Kai Zhang Gong-Li Tang Qiang Zhou State Key Laboratory of Bio-organic and Natural Products Chemistry Shanghai Institute of Organic ChemistryChinese Academy of Sciences345 Lingling RoadShanghai 200032China School of Chemistry and Materials Science Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of Sciences1Sublane XiangshanHangzhouZhejiang 310024China

The anti-tuberculous rifamycins belong to naphthalenic ansamycin based on the structure of aromatic ***,we explored the post-polyketide synthase(PkS)modifications in the biosynthesis of 16-demethyl-rifamycins via gene knockout,complementation and in vitro enzyme *** collective evidences showed that i)the aromatization of 8-hydroxyl-7,8-dihydronaphtoquinone was accomplished by the combined action of two dehydrogenases,Rifs and Rif;i)the acetylation and methylation of the macrocycle was carried out on naphthoquinone intermediates in preference to naphthol,by Rif-Orf20 and Rif-Orf14,respectively ii)the presence of Rifs/T homologs in ansamycin biosynthetic gene clusters corresponds to the dehydrogenation aromatization mode of *** findings cast new insights into the naphthalene formation and post-PkS modification of ansamycins.

关键词： Ansamycin Natural products Biosynthesis Dehydrogenation aromatization

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aromatization over nanosized Ga-containing ZSM-5 zeolites prepared by different methods:Effect of acidity of active Ga species on the catalytic performance

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Journal of Energy Chemistry 2017年第4期26卷 768-775页

作者： Yujun Fang Xiaofang Su Xuefeng Bai Wei Wu Gaoliang Wang Linfei Xiao Anran Yu National Center for International Research on Catalytic technology Key Laboratory of Chemical Engineering Process&Technology for High-efficiency ConversionCollege of Heilongjiang ProvinceSchool of Chemistry and Material SciencesHeilongjiang UniversityHarbin 150080HeilongjiangChina

Nanosized Ga-containing ZSM-5 zeolites were prepared via isomorphous substitution and impregnation followed by characterized using various techniques. The catalytic performance of the zeolites for the aromatization of 1-hexene was investigated. The results indicate that isomorphous substitution promotes the incorporation of Ga heteroatoms into the framework along with the formation of extra-framework GaO;species（[GaO;]a） that have stronger interactions with the negative potential of the framework. In addition, based on the Py-IR results and catalytic performance, the [GaO;]aspecies with stronger Lewis acid sites produced a better synergism with moderate Br?nsted acid sites and thus improved the selectivity to aromatic compounds. However, the impregnation results in the formation of Ga;O;phase and small amounts of GaO;species that are mainly located on the external surface（[GaO;];）, which contribute to weaker Lewis acid sites due to weaker interactions with the zeolite framework. During 1-hexene aromatization, the nanosized Ga isomorphously substituted ZSM-5 zeolite samples（Gax-NZ5） exhibited better catalytic performance compared to the impregnated samples, and the highest aromatic yield（i.e.,65.4 wt%） was achieved over the Ga4.2-NZ5 sample, which contained with the highest Ga content.

关键词： Nanosized ZSM-5 zeolite Isomorphous substitution Impregnation Active gallium species aromatization

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aromatization and isomerization of methylcyclohexane over Ni catalysts supported on different supports

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Green Energy & Environment 2019年第1期4卷 75-82页

作者： Ye Song Wei Lin Xingcui Guo Linlin Dong Xindong Mu Huiping Tian Lei Wang Research Institute of Petroleum Processing SINOPEC CASKey Laboratory of Bio-based Materials Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of Sciences

In this work, nickel metal supported on different supports(SiO_2, Al_2O_3, ZSM-5) were prepared by spraying nickel nitrate on the supports and calcined at 873 K. Then, they were characterized by XRD, XRF, N_2 adsorption–desorption, NH_3-TPD, MCH-TPD, H_2-TPR, and pyridine-FTIR,and tested as catalysts for the dehydrogenation aromatization and isomerization of methylcyclohexane(MCH) under the conditions of S-Zorb catalytic adsorption desulfurization(T ? 673 K, P ? 1.5 MPa, WHSV ? 5 h^(-1)). The H2-TPR results showed that the interaction of NiO with support decreased in the order of NiO/ZSM-5-Fe aromatization of *** was found that a direct correlation existed between the gasoline components yields, cracking activity and the total number of different supports acid sites measured by NH_3-TPD tests. Higher total acidity of ZSM-5 resulted in gasoline loss because of higher cracking activity of MCH. The number of total acid sites of NiO/ZSM-5-Fe decreased and the medium strong Br€onsted acid sites necessary for MCH isomerization increased after the modification of ZSM-5 by iron metal. So, NiO/ZSM-5-Fe exhibited enhanced MCH conversion, aromatic and isomerization yields when compared to NiO/ZSM-5 and other Ni-based catalysts. This study shows that NiO/ZSM-5-Fe catalyst may be possible to be integrated into the S-Zorb system achieving the recovery of the octane number of gasoline.

关键词： Modified ZSM-5 Methylcyclohexane aromatization Octane number

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aromatization of virgin olive oil by seeds of Pimpinella anisum using three different methods:Physico-chemical change and thermal stability of flavored oils

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Grain & Oil Science and Technology 2021年第3期4卷 108-124页

作者： Youssef Moustakime Zakaria Hazzoumi Khalid Amrani Joutei Faculty of Science and Technology of Fez University of Sidi Mohamed Ben AbdellahFez 3000Morocco

Knowing that flavored products would increase the use of olive oil by non-traditional consumers and enhance the added value of this valuable agricultural product,the virgin olive oil(VOO)was flavored with the seeds of Pimpinella anisum(Green anise)using three different methods:classic maceration,ultrasonic assisted maceration and direct addition of the essential oil(EO).These methodswere compared under two main criteria:time and level of *** physico-chemical parameters and the thermal stability of flavored oils prepared by the three methods were determined by AOAC titration method and GC–MS analysis so as to compare the aromatization effect of the three *** trans-anethole is the major component of the EO of anise seeds as well as the indicator of the level of ***/MS analysis results of the flavored oils showed that the diffusion of trans-anethole in the flavored oil by direct addition of EO was very important(36.3%of the total volatile fraction of the flavored oil)in comparison to the oil flavored by ultrasonic assisted maceration or classic maceration(respectively 26.59%and 23.85%).These different aromatization methods ensure an improvement in the quality of VOO with an enrichment in polyphenols estimated at 35%in the case of ultrasonic flavored oil,an increase in the content of carotenoids and chlorophylls(67%and 21%respectively)in the event of aromatization by classic maceration,and a decrease in specific absorbency at 232 nmestimated at 29%during aromatization by addition of EO as well as a decrease in the peroxide value estimated at 26%in oil flavored by classic maceration unlike in oil flavored by ultrasoundwhich has seen an increase of around 20%.The aromatization was able to maintain the stability of the oils and its qualification as VOO with a gain in induction time in the case of treatment at 60℃ estimated at 29 and 27.5 d respectively in oils flavored by addition of EO and by conventional maceration,an improvement resist

关键词： aromatization Virgin olive oil Essential oil of Pimpinella anisum Classic maceration Ultrasonic assisted maceration Thermal stability Phenolic compounds

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Co-feeding with DME:An effective way to enhance gasoline production via low temperature aromatization of LPG

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Journal of Energy Chemistry 2013年第5期22卷 755-760页

作者： Xiangxue Zhu Yuzhong Wang Xiujie Li Hongbing Li Peng Zeng Jie An Fucun Chen Sujuan Xie Hongping Lan Dawei Wang Shenglin Liu Longya Xu Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Fushun Petrochemical Company CNPC Liaoning Branch Company China Huanqiu Contracting and Engineering Corporation Guangxi Yuchai Petrochemical CO.LTD

The aromatization of light alkenes in liquefied petroleum gas (LPG) with and without dimethyl ether (DME) addition in the feed was investigated on a modified ZSM-5 *** results showed that under the given reaction conditions the selectivity of alkenes to high-octane gasoline blending components was markedly enhanced and the formation of propane and butanes was greatly suppressed with the addition of *** was also found that the distribution of C5+ components was changed a lot with DME addition into the LPG *** formation of branched hydrocarbons (mainly C6 C8 i-paraffin) and multi-methyl substituted aromatics,which are high octane number gasoline blending components,was promoted significantly,while the content of n-paraffins and olefins in C5+ components was decreased obviously,indicating that in addition to the oligomerization,cracking,hydrogen-transfer and dehydrogenation-cyclization of alkenes,the methylation of the formed aromatics and olefins intermediates also plays an important role in determining the product distribution due to the high reactivity of surface methoxy groups formed by *** this process,in combination with the syngas-to-methanol/DME technology,provides an alternative way to the production of high-octane gasoline from coal,natural gas or renewable raw materials.

关键词： aromatization gasoline alkene butene dimethyl ether co-feeding ZSM-5

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Coking kinetics and influence of reaction-regeneration on acidity, activity and deactivation of Zn/HZSM-5 catalyst during methanol aromatization

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Journal of Energy Chemistry 2015年第1期24卷 108-118页

作者： Guiquan Zhang Xin Zhang Ting Bai Tengfei Chen Wentao Fan School of Chemical Engineering Northwest University

The coking kinetics and reaction-regeneration on Zn/HZSM-5 （Zn/HZ） catalyst in the conversion of methanol to aromatics were investigated. The highest initial benzene, toluene and xylene （BTX） yield of ca. 67.7% was obtained on fresh Zn/HZ catalyst, which showed the worst catalytic stability. The cycle of reaction-regeneration significantly modified the texture and acidity of Zn/HZ catalyst, which in turn affected its catalytic performance and coking behavior in methanol conversion to BTX. The residual carbon located on the surface of Zn/HZ catalyst led to the decrease of acid sites and the change on the acid sites distribution, which played an important roles on its activity and deactivation. It was found that the high B/L ratio and the low total acid sites concentration of the Zn/HZ catalyst favored to the high BTX yield and good catalytic stability in methanol conversion.

关键词： methanol aromatization reaction-regeneration acidity deactivation

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Pt supported on Zn modified silicalite-1 zeolite as a catalyst for n-hexane aromatization

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Journal of Energy Chemistry 2019年第7期28卷 96-103页

作者： Guodong Liu Jiaxu Liu Ning He Shishan Sheng Guiru Wang Hongchen Guo Department of Catalytic Chemistry and Engineering&State Key Laboratory of Fine Chemicals Dalian University of TechnologyDalian 116012LiaoningChina State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina

Platinum(Pt)supported on Zinc(Zn)modified silicalite-1(S-1)zeolite(denoted as Pt-Zn/S-1)was prepared by using a wetness-impregnation method and applied in the n-hexane aromatization reaction for the first *** Lewis and Bronsted acid sites were detected in Pt-Zn/S-1 catalyst by means of FT-IR adsorption of NH3 experiment,which were identified as mostly weak and medium ***,Pt and Zn species showed strong interaction,as revealed by the TPR(Temperature-programmed reduction)and XPS(X-ray photoelectron spectroscopy)***-Zn/S-1 catalyst exhibited excellent aromatization function rather than isomerization and cracking side reactions in the conversion of *** experimental study showed that 75.6%of n-hexane conversion and 76.8%of benzene selectivity were obtained over Pt0.1-Zn60/S-l catalyst at 550℃ and under atmospheric *** spectroscopy tests and pulse experimental results,it was concluded that the n-hexane aromatization over Pt-Zn/S-1 catalyst follows a metal-acid bifunctional ***,with the assistance of Zn,the electron-deficient Pt species in Pt-Zn/S-1 showed good sulfur tolerance performance.

关键词： Silicalite-1 zeolite Pt-Zn/Silicalite-1 n-Hexane aromatization Sulfur-resistance

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Promoted effect of zinc–nickel bimetallic oxides supported on HZSM-5 catalysts in aromatization of methanol

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Journal of Energy Chemistry 2017年第3期26卷 540-548页

作者： Yanming Jia Junwen Wang Kan Zhang Wei Feng Shibin Liu Chuanmin Ding Ping Liu College of Chemistry and Chemical Engineering Taiyuan University of Technology State Key Laboratory of Coal Conversion Institute of Coal Chemistry of CAS

Zn/ZSM-5（NZ2） and Zn/Ni/ZSM-5（NZ3） as the catalysts for methanol to aromatics（MTA） were synthesized by a simple ultrasonic impregnation. The textural and acid properties of all catalysts were characterized using XRD, HRTEM, NH;-TPD, Py-IR, XPS, XRF and TG techniques. The XRD and HRTEM results showed that the basic zeolite structures were not affected much with the incorporation of Zn and Ni species. However, great changes have taken place in acid properties. The Py-IR and XPS results indicated that the Zn-Lewis acid sites（ZnOH;species）, which have stronger interaction with the zeolite framework compared with ZnO species, were generated at the expense of B acid sites with the incorporation of zinc species. Moreover, the product analysis results showed that the incorporation of zinc species promoted the primary aromatization by enhancing the dehydroaromatization and suppressing the cracking and subsequent H-transfer reaction. Furthermore, the addition of Ni species well inhibited the loss of zinc species by converting partial ZnO species to ZnOH;species, and thus improved the aromatization activity and catalyst stability. The catalytic performance results showed that the NZ3 possess higher conversion of methanol in a longer time and lower average rate of coke formation compared with NZ2. In addition,the NZ3 also exhibited the highest yield of BTX as the reaction proceeds.

关键词： Zn/Ni/ZSM-5 Acid properties Methanol aromatization

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