Metal-Free Catalytic Conversion of Veratryl and Benzyl Alcohols through Nitrogen-Enriched Carbon Nanotubes

C Pub Date : 2024-01-26 DOI:10.3390/c10010013
Neeraj Gupta, Ilaria Barlocco, O. Khavryuchenko, Alberto Villa
{"title":"Metal-Free Catalytic Conversion of Veratryl and Benzyl Alcohols through Nitrogen-Enriched Carbon Nanotubes","authors":"Neeraj Gupta, Ilaria Barlocco, O. Khavryuchenko, Alberto Villa","doi":"10.3390/c10010013","DOIUrl":null,"url":null,"abstract":"Nitrogen-rich carbon nanotubes NCNT700 and NCNT800 were prepared using the chemical vapor deposition method (CVD). The catalysts were characterized via high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) analysis. Both the catalysts were found to have an inverted cup-stack-like morphology. The XPS analysis revealed that the catalysts are rich in pyridinic sites with variable amounts of nitrogen on their surface. The NCTN700, with a higher nitrogen content and more pyridinic sites on its surface, was found to be a good catalyst for the oxidation of benzyl and veratryl alcohols into respective aldehydes. It was observed that toluene and 4-methyl veratrole were also produced in this reaction. The amount of toluene produced was as high as 21%, with 99% conversion of benzaldehyde in the presence of NCNTs-700. The mechanistic pathway was revealed through DFT studies, where the unusual product formation of aromatic alkanes such as toluene and 4-methyl veratrole was explained during the reaction. It was astonishing to observe the reduced product in the reaction that proceeds in the forward direction in presence of a peroxide (tert-butyl hydroperoxide, TBHP). During the computational analysis, it was revealed that the reduced product observed in the reaction did not appear to proceed through a direct disproportionation reaction. Rather, the benzyl alcohol (the reactant) used in the reaction may undergo oxidation by releasing the hydrogen radicals. The hydrogen atoms released during the oxidation reaction appear to have been trapped on pyrrolic sites on the surface of catalyst and later transferred to the reactant molecules to produce toluene as a side product.","PeriodicalId":9397,"journal":{"name":"C","volume":"72 4","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"C","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.3390/c10010013","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0

Abstract

Nitrogen-rich carbon nanotubes NCNT700 and NCNT800 were prepared using the chemical vapor deposition method (CVD). The catalysts were characterized via high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) analysis. Both the catalysts were found to have an inverted cup-stack-like morphology. The XPS analysis revealed that the catalysts are rich in pyridinic sites with variable amounts of nitrogen on their surface. The NCTN700, with a higher nitrogen content and more pyridinic sites on its surface, was found to be a good catalyst for the oxidation of benzyl and veratryl alcohols into respective aldehydes. It was observed that toluene and 4-methyl veratrole were also produced in this reaction. The amount of toluene produced was as high as 21%, with 99% conversion of benzaldehyde in the presence of NCNTs-700. The mechanistic pathway was revealed through DFT studies, where the unusual product formation of aromatic alkanes such as toluene and 4-methyl veratrole was explained during the reaction. It was astonishing to observe the reduced product in the reaction that proceeds in the forward direction in presence of a peroxide (tert-butyl hydroperoxide, TBHP). During the computational analysis, it was revealed that the reduced product observed in the reaction did not appear to proceed through a direct disproportionation reaction. Rather, the benzyl alcohol (the reactant) used in the reaction may undergo oxidation by releasing the hydrogen radicals. The hydrogen atoms released during the oxidation reaction appear to have been trapped on pyrrolic sites on the surface of catalyst and later transferred to the reactant molecules to produce toluene as a side product.
通过富氮碳纳米管实现藜芦醇和苄醇的无金属催化转化
采用化学气相沉积法(CVD)制备了富氮碳纳米管 NCNT700 和 NCNT800。通过高分辨率透射电子显微镜(HRTEM)和 X 射线光电子能谱(XPS)分析对催化剂进行了表征。结果发现,两种催化剂都具有倒杯叠层状形态。XPS 分析表明,催化剂表面富含不同数量氮的吡啶位点。发现氮含量较高且表面吡啶位点较多的 NCTN700 是苯甲醇和藜芦醇氧化成相应醛类的良好催化剂。据观察,在这一反应中还产生了甲苯和 4-甲基藜芦。在 NCNT-700 的存在下,苯甲醛的转化率为 99%,甲苯的生成量高达 21%。通过 DFT 研究揭示了机理途径,解释了反应过程中形成甲苯和 4-甲基藜芦等芳香烃的不寻常产物。令人惊讶的是,在过氧化物(叔丁基过氧化氢,TBHP)存在的情况下,在反应中观察到了正向进行的还原产物。在计算分析过程中发现,在反应中观察到的还原产物似乎并不是通过直接歧化反应进行的。相反,反应中使用的苯甲醇(反应物)可能通过释放氢自由基而发生氧化。氧化反应中释放出的氢原子似乎被截留在催化剂表面的吡咯啉位点上,随后转移到反应物分子中,生成副产品甲苯。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 求助全文
来源期刊
C
C
自引率
0.00%
发文量
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信