Reaction mechanism research and analysis method for amphoteric water-soluble catalyst aerobic oxidation of benzyl alcohol to benzaldehyde

Abstract

The invention discloses a reaction mechanism research and analysis method for amphoteric water-soluble catalyst aerobic oxidation of benzyl alcohol to benzaldehyde. A density functional theory (DFT) is used for research of reaction mechanism of an amphoteric water-soluble CuII / TEMPO catalyst system in catalysis and oxidization of alcohol into aldehyde in an alkaline aqueous solution. The calculation results show that zwitterionic properties of catalysts have no effect on oxidation reaction of the alcohol; the catalytic reaction mechanism includes catalyst activation, substrate oxidation and catalyst regeneration steps; the conversion efficiency (TOF=3.89h-1) is calculated based on an energetic span model and consistent with an experimental measurement result (TOF=5.40h-1). The rate-determining step is the substrate oxidation step, and is a process in which hydrogen atoms are transferred from alkoxide to oxygen atoms of TEMPO. By exploring the reaction mechanism of the catalytic system,the reaction process can be observed, and a theoretical basis is provided for designing a new high-efficiency catalyst.

Description

technical field [0001] The present invention relates to the computational chemistry of the aerobic oxidation of alcohols to aldehydes. More specifically, it relates to an analytical method for the study of the reaction mechanism of the aerobic oxidation of benzyl alcohol to benzaldehyde with an amphoteric water-soluble catalyst. Background technique [0002] The selective oxidation of primary alcohols to the corresponding aldehydes is one of the most important conversion processes in industrial production and fine chemicals. For example, benzaldehyde is widely used in the synthesis of fragrances and fine chemicals. Current approaches to achieve alcohol oxidation require the use of stoichiometric oxidants, such as ruthenium(VIII) oxide, sodium hypochlorite, potassium dichromate, and chromium(VI) oxide, among others. In recent years, significant progress has been made in the GOase biomimetic catalytic system that catalyzes the oxidation of primary alcohols to aldehydes using...

AI Technical Summary

Problems solved by technology

However, so far, most of the experimental studies on the existing Cu-TEMPO biomimetic catalytic system for the aerobic oxidation of primary alcohols using water as a solvent are limited to the consideration of catalytic reaction conditions (reaction temperature, pressure, catalyst dosage), substrate range, etc. and product selectivity, yield and other factors

For the geometric and electronic structure of the active center of the catalyst, the steric and electronic effects of the ligands, the synergistic effect between the ligands, the coordination mode of the central metal Cu ion and the ligand and its bonding characteristics and other factors and the catalytic activity Relationships and reaction mechanisms at the molecular level have been poorly studied, thus limiting the design and synthesis of new catalysts

[0004] In 2011, Pombeiro et al. reported that [(L)Cu II (Hen)(H 2 O)] / TEMPO catalyst system (en: ethylenediamine) [Eur.J.Inorg.Chem.2011,27,4175-4181] is an amphoteric water-soluble catalyst, and can catalyze the oxidation of alcohol to aldehyde in aqueous solution; But whether the nature of the zwitterions will affect the efficiency of the reaction system and the C α The reaction mechanism of this system, such as the activation mechanism of -H, has not been carried out, because it cannot provide a theoretical basis for the design of new and efficient catalysts

Images