Pentaethylphenol (Not 2,6-di-tert-butyl-4-ethylphenol) verified as the primary product of guaiacol ethanol alkylation reaction

IF 5.2 2区化学 Q1 CHEMISTRY, APPLIED

Catalysis Today Pub Date : 2024-09-26 DOI:10.1016/j.cattod.2024.115081

Yushuai Sang , Mingze Yang , Cedric Agyingi, Yongdan Li

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引用次数: 0

Abstract

Guaiacol ethanol alkylation (GEA), a model reaction of lignin solvolysis, has been intensively investigated. However, the product identification with gas chromatograph-mass spectrometer (GC-MS) was wrong due to the defect of the GC-MS databases. In this work, the main product was isolated with a flash chromatography technique and analyzed with ¹H NMR and was identified as ethyl fully substituted phenol (or pentaethylphenol), which is contrary to the reported 2,6-di-tert-butyl-4-ethylphenol in previous literature. The NMR analysis of the entire product mixture further confirms that the product only contains ethyl substituted molecules, with no existence of isopropyl or tert-butyl substituted products. The byproducts, including ethyl partially substituted phenols, i.e., tetraethylphenol and triethylphenol, ethyl partially substituted guaiacol, 2-ethoxyphenol, and pentaethylbenzene, were also speculated based on the MS spectra. These findings rectify a long-standing error in product identification and may offer critical insights for mechanism investigations.

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经证实五乙基苯酚（不是 2,6-二叔丁基-4-乙基苯酚）是愈创木酚乙醇烷基化反应的主要产物

愈创木酚乙醇烷基化反应（GEA）是木质素溶解的一个模型反应，已被深入研究。然而，由于气相色谱-质谱（GC-MS）数据库的缺陷，用气相色谱-质谱（GC-MS）鉴定产物时出现了错误。在这项工作中，利用闪蒸色谱技术分离出了主要产物，并用 1H NMR 进行了分析，确定其为乙基全取代苯酚（或五乙基苯酚），这与之前文献中报道的 2,6-二叔丁基-4-乙基苯酚相反。对整个产品混合物的核磁共振分析进一步证实，该产品只含有乙基取代的分子，不存在异丙基或叔丁基取代的产品。根据质谱图还推测出了副产物，包括乙基部分取代的苯酚，即四乙基苯酚和三乙基苯酚、乙基部分取代的愈创木酚、2-乙氧基苯酚和五乙苯。这些发现纠正了产品鉴别中长期存在的错误，并可能为机理研究提供重要启示。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Catalysis Today 化学-工程：化工

CiteScore

11.50

自引率

3.80%

发文量

573

审稿时长

2.9 months

期刊介绍： Catalysis Today focuses on the rapid publication of original invited papers devoted to currently important topics in catalysis and related subjects. The journal only publishes special issues (Proposing a Catalysis Today Special Issue), each of which is supervised by Guest Editors who recruit individual papers and oversee the peer review process. Catalysis Today offers researchers in the field of catalysis in-depth overviews of topical issues. Both fundamental and applied aspects of catalysis are covered. Subjects such as catalysis of immobilized organometallic and biocatalytic systems are welcome. Subjects related to catalysis such as experimental techniques, adsorption, process technology, synthesis, in situ characterization, computational, theoretical modeling, imaging and others are included if there is a clear relationship to catalysis.