Reaction Mechanism Study and Analysis Method of Aerobic Oxidation of Benzyl Alcohol to Benzaldehyde with Amphoteric Water-Soluble Catalyst

Abstract

The invention discloses a reaction mechanism research and analysis method for the aerobic oxidation of benzyl alcohol to benzaldehyde by an amphoteric water-soluble catalyst. II / TEMPO catalytic system catalyzed the oxidation of alcohols to aldehydes in alkaline aqueous solution and studied the reaction mechanism. The calculation results show that: the zwitterionic nature of the catalyst has no effect on the alcohol oxidation reaction; the catalytic reaction mechanism includes catalyst activation, substrate oxidation and catalyst regeneration steps; the conversion efficiency is calculated based on the energy span model (TOF=3.89h ‑1 ) and experimental measurement results (TOF=5.40h ‑1 ) consistent. The rate-determining step is the substrate oxidation step, that is, the process of hydrogen atom transfer from alkoxide to oxygen atom of TEMPO. By exploring the reaction mechanism of the catalytic system, not only can the reaction process be observed, but also provide a theoretical basis for the design of new and efficient catalysts.

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