检索结果-南通市图书馆

Methane dehydroaromatization–A study on hydrogen use for catalyst reduction, role of molybdenum, the nature of catalyst support and significance of Bronsted acid sites

引用

Journal of Energy Chemistry 2019年第7期28卷 20-32页

作者： Vaidheeshwar Ramasubramanian Hema Ramsurn Geoffrey L.Price Russell School of Chemical Engineering The University of Tulsa

Methane dehydroaromatization was studied over Mo/SiO2 and Mo/HZSM-5 with different Mo loadings(2, 5, 10 wt%) at 973 K and 1023 K in a recirculating batch reactor. H2 pretreatment at 1023 K prior to methane activation has significantly improved the catalyst activity with increase in Mo loading and reduced the induction time on benzene formation in both Mo/SiO2 and Mo/HZSM-5. 10 wt% Mo/HZSM-5 gave a maximum methane conversion of 19% and ~67% benzene selectivity at 1023 K. The XRD analysis of used catalysts revealed that the Mo O3 species were converted to β-Mo2C phase. Studies on Mo/SiO2 catalysts showed that benzene was formed even in the absence of acidic zeolite sites. Reactions of ethylene in the presence of pure silica, HZSM-5 and in a blank reactor revealed that conversion of ethylene to aromatics was similar in case of the blank reactor and silica. Thus, it is believed that molybdenum carbide sites act as active sites only for C–H bond activation of methane and ethylene formation. Even though, ethylene can undergo subsequent oligomerization without any catalytic aid to form benzene at973 K and above addition of acidic zeolites improved the selectivity of benzene.

关键词： Methane dehydroaromatization HZSM-5 Silica Molybdenum loading H2 pretreatment Acidic function

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Improved Performance of W/HZSM-5 Catalysts for dehydroaromatization of Methane

引用

Journal of Natural Gas Chemistry 2004年第3期13卷 148-159页

作者： Nor Aishah Saidina Amin Kusmiyati Department of Chemical Engineering Faculty of Chemical and Natural Resources EngineeringUniversiti Teknologi Malaysia 81310 UTM Skudai Johor Malaysia.Department of Chemical Engineering Faculty of Chemical and Natural Resources EngineeringUniversiti Teknologi Malaysia 81310 UTM Skudai Johor Malaysia.

The dehydroaramatization of methane over W-supported ZSM-5 with varying degrees of Li+ ion-exchanged catalysts was studied with and without oxygen at 1073 K and atmospheric pressure. Catalyst activity and stability were found to be influenced by the catalyst acidity related to Bronsted acid sites and by the presence of oxygen in the feed. The NH3-TPD and FTIR-pyridine results demonstrated that partially exchanged of H+ ions by Li+ into the W/HZSM-5 catalysts could be used to control the amount of strong acid sites on the catalyst surface. Without oxygen, the 3WHLi-Z (5:1) catalyst that has strong acid sites equal to nearly 74% of the original strong acid sites in the parent HZSM-5 exhibited the highest methane conversion and selectivity towards aromatics. However, the catalyst deactivated in a five hour period. In the presence of oxygen, the catalyst activity and stability could be improved further. The results of this study revealed that a suitable amount of strong Bronsted acid sites as well as oxygen addition in the feed increased the catalyst activity and stability. The 3WHLi-Z(5:1) catalyst exhibited improved performance in the dehydroaromatization of methane.

关键词： dehydroaromatization methane W-supported ZSM-5 partial ion exchange H+ ion Li ion catalyst activity catalyst stability catalyst acidity oxygen presence improved performance

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Metal-Free Synthesis of Benzo[a]phenanthridines from Aromatic Aldehydes,Cyclohexanones,and Aromatic Amines

引用

Chinese Journal of Chemistry 2022年第3期40卷 365-370页

作者： Pingyu Jiang Zhifei Shan Shanping Chen Quanyuan Wang Shuxin Jiang Haolin Zheng Guo-Jun Deng Key Laboratory for Green Organic Synthesis and Application of Hunan Province Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of EducationCollege of ChemistryXiongtan UniversityXiangtanHunon 411105China Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates(South China University of Technology) GuangzhouGuangdong 510640China

A three-component synthesis of benzo[a]phenanthridines from aromatic aldehydes,cyclohexanones,and aromatic amines has been developed,which is mediated by KI/DMSO/camphorsulfonic acid to afford a variety of functionalized benzo[a]phenanthridines in satisfactory *** present strategy provides a biaryl motif ortho to the nitrogen atom which has the potential to be used as ligand by further *** the advantages of readily available starting materials,transition-metal-free conditions,gram-scale synthesis,and broad substrate scope,this three-component protocol provides an efficient approach for the preparation of diverse benzo[a]phenanthridines.

关键词： Nitrogen heterocycles Multicomponent reactions dehydroaromatization Cyclization Metal-free

来源：

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

Methane Direct Conversion on Mo/ZSM-5 Catalysts Modified by Pd and Ru

引用

Journal of Natural Gas Chemistry 2006年第2期15卷 82-86页

作者： Priscila Dias Sily Fabio Bellot Noronha Fabio Barboza Passos Departamento de Engenharia Química Universidade Federal FluminenseRua Passo da Pátria156 Niterói -RJ CEP 24210-240Brazil Instituto Nacional de Tecnologia Av. Venezuela 82Rio de Janeiro -RJ CEP 20081-312Brazil Departamento de Engenharia Química Universidade Federal FluminenseRua Passo da Pátria156 Niterói-RJ CEP 24210-240Brazil

The effect of addition of Ru and Pd to Mo/HZSM-5 catalysts used in the dehydroaromatization of methane was investigated. Catalytic tests and temperature-programmed oxidation results showed that Pd-based catalysts were more selective to naphthalene and suffered strong deactivation. The presence of Ru improved the activity and stability, with a decrease in the carbonaceous deposit probably because of a mechanism of protection of the Mo2C surface.

关键词： methane Pd Ru Mo ZSM-5 dehydroaromatization

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Basic Engineering of a Two-Stage Process for Co-Upgrading Natural Gas and Petroleum Coke

引用

Advances in Chemical Engineering and Science 2015年第2期5卷 129-133页

作者： Jorge Laine Maria Tosta Centro de Química Instituto Venezolano de Investigaciones Científicas Caracas Venezuela

This communication highlights the possibility of using a novel two-stage process for the co-upgrading of natural gas and petroleum coke into liquid hydrocarbons. The first stage consists of the catalytic dehydroaromatization of methane characterized by producing hydrogen and aromatics: benzene, naphtalene, toluene, etc. The non-reacted methane plus hydrogen and aromatics produced in the first stage are directed to the second stage to react with the petroleum coke. Basic engineering analysis of proposed two-stage process suggests light petroleum production of 160,000 bbl/day from 20,000 ton/day of petroleum coke actually by-produced from Venezuelan Orinoco’s heavy oil belt. Residual coke should be volatiles free therefore useful as a calcined coke.

关键词： dehydroaromatization Natural Gas Petroleum Coke Co-Upgrading

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：