文献类型：期刊文献

中文题名：氧化铌催化苯甲醇与苯胺N-烷基化反应的研究

英文题名：Catalytic N-Alkylation of Benzyl Alcohol and Aniline on Nb2O5 Catalyst

作者：夏新宇[1];侯善凯[1];郭勇[1];刘晓晖[1];王艳芹[1]

机构：[1]华东理工大学化学与分子工程学院、工业催化研究所、上海市功能性材料化学重点实验室,上海200237

年份：2025

卷号：83

期号：3

起止页码：212

中文期刊名：化学学报

外文期刊名：Acta Chimica Sinica

收录：;WOS:【SCI-EXPANDED(收录号:WOS:001471637600003)】；北大核心:【北大核心2023】；

基金：Project supported by the National Natural Science Foundation of China (Nos. 22072042, 21872050, 21403065) and National Key Research and Development Program of China (No. 2022YFC3902500) .

语种：中文

中文关键词：氧化铌;苯甲醇;苯胺;N-烷基化;SN1

外文关键词：Nb2O5;benzyl alcohol;aniline;N-alkylation;SN1

摘要：通过固体催化剂实现醇的N-烷基化是一条环境友好的胺类化合物合成路线.本工作将水热法制备的氧化铌应用于苯甲醇和苯胺的N-烷基化反应中,与几种金属氧化物和传统的三氯化铝催化剂相比,氧化铌的催化活性最优,苯甲醇转化率100%,N-苄基苯胺收率65.2%.进一步通过反应级数、溶剂和空间位阻效应以及碳正离子的相关实验对氧化铌催化苯甲醇N-烷基化的反应路径和机理进行研究,结果表明反应经历的是苯甲醇生成碳正离子的SN1反应机制.此外,苯甲醇和苯胺的原位红外吸脱附实验证明,氧化铌能活化苯甲醇的C—O键以及苯胺的N—H键,促进了碳正离子的生成以及苯胺N—H键的断裂,从而具有很好的苯甲醇N-烷基化催化活性.
The N-alkylation of alcohols over solid catalysts represents an environmentally benign approach for the synthesis of amine compounds.In this study,niobium oxide synthesized via a hydrothermal method was employed for the N-alkylation of benzyl alcohol with aniline.Compared to various metal oxides and conventional aluminum trichloride catalysts,niobium oxide demonstrated superior catalytic activity,achieving complete conversion of benzyl alcohol(100%)and a 65.2%yield of N-benzylaniline under optimized conditions(180℃,1 MPa N2,4 h).To elucidate the reaction pathway and mechanism of benzyl alcohol N-alkylation over niobium oxide,comprehensive investigations were conducted,including reaction kinetics,solvent polarity effects,steric hindrance studies,and carbocation-trapping experiments.Kinetic analysis revealed a reaction order of 1.04 for benzyl alcohol and 0.008 for aniline,indicating a first-order overall reaction predominantly governed by the alcohol.Solvent polarity significantly influenced the reaction outcome:in toluene(a polar solvent),the yield remained stable at 65.0%,while in nonpolar solvents(cyclohexane and dodecane),the yields drastically decreased to 3.2%and 4.4%,respec-tively.This highlights the critical role of polar media in stabilizing carbocation intermediates.Steric effects were evaluated using diphenylmethanol as a bulky substrate,which surprisingly yielded 77%of the target product,suggesting minimal steric hindrance under the SN1 mechanism.Definitive evidence for carbocation intermediate was obtained through experiments with 1-phenylcyclopropylmethanol,where only products derived from rearranged carbocations were detected.These results demonstrated that the reaction proceeds via the SN1 mechanism involving carbocations generated from benzyl alcohol.Fur-thermore,in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)analysis of benzyl alcohol and aniline revealed that niobium oxide activates the C—O bond of benzyl alcohol and the N—H bond of aniline,facilitating the for-mation of carbocations and the cleavage of the N—H bond of aniline,thereby exhibiting good catalytic activity for benzyl alcohol N-alkylation.The niobium oxide catalyst also exhibited exceptional stability,maintaining its activity even after six cycles.This study not only provides a comprehensive mechanistic understanding of Nb2O5-catalyzed N-alkylation but also establishes a green and practical strategy for sustainable amine synthesis.