电喷雾质谱对TiO_(2)光催化选择性氧化苄胺反应机理研究

Study on the mechanism of TiO_(2)photocatalytic selective oxidation of benzylamine by electrospray ionization mass spectrometry

电喷雾电离质谱技术(ESI-MS)无需样品预处理,直接对反应进行实时取样、离子化并进行分析,可以快速、准确地捕捉反应过程中寿命较短的中间体和产物,并进行在线实时监测。基于此,以光催化选择性氧化苄胺生成亚胺反应为例,通过搭建常压质谱在线反应监测装置,对2,2,6,6-四甲基哌啶氧化物(TEMPO)辅助的TiO_(2)光催化苄胺氧化反应进行了原位、在线的监测。结果表明,常压质谱技术可以准确识别出TEMPO参与反应过程中的中间体,从而揭示TEMPO辅助TiO_(2)光催化苄胺氧化反应的反应机理。TiO_(2)纳米材料可以利用光能激发电荷对,在反应中产生活性氧化物种,从而促进氧化还原反应的进行。TEMPO作为助催化剂,在反应中可以作为氧化剂参与反应过程,促进光催化反应中的电子转移过程,从而提高反应效率和选择性。

Electrospray ionization mass spectrometry(ESI-MS)technology can directly sample,ionize,and analyze reactions in real-time without sample pretreatment,enabling rapid and accurate capture of short-lived intermediates and products during the reaction process,and enabling online real-time monitoring.Taking the photocatalytic selective oxidation of benzylamine to imine as an example,an atmospheric pressure mass spectrometry online reaction monitoring device was built to perform in situ and online monitoring of 2,2,6,6-tetramethylpiperidine oxide(TEMPO)-assisted TiO_(2)photocatalytic oxidation of benzylamine.Through this experiment,atmospheric pressure mass spectrometry technology can accurately identify the intermediates involved in the reaction process with TEMPO,thus revealing the mechanism of TEMPO-assisted TiO_(2)photocatalytic oxidation of benzylamine.TiO_(2)nanomaterials can utilize light to excite charge carriers and generate active oxidative species in the reaction,thus promoting the redox reaction.TEMPO,as an auxiliary catalyst,can participate in the reaction process as an oxidant,promote the electron transfer process in the photocatalytic reaction,and thereby improve the efficiency and selectivity of the reaction.