Efficient N-formylation of carbon dioxide and amines with alkanolamine as eco-friendly catalyst under mild conditions. (March 2023)

• Record Type: Journal Article
• Authors: Wen, Qin; Yuan, Xuexin; Zhou, Qiqi; Yang, Hai-Jian; Jiang, Qingqing; Hu, Juncheng; Guo, Cun-Yue
• Is Part Of: Journal of CO₂ utilization. Volume 69(2023)
• Publication Date: 2023-03
• Subjects: Carbon dioxide reduction -- N-formylation -- Alkanolamines -- Wide substrates application -- Selectivity; Carbon dioxide -- Periodicals; Carbon dioxide -- Environmental aspects -- Periodicals; Carbon dioxide mitigation -- Periodicals; Carbon dioxide; Carbon dioxide -- Environmental aspects; Carbon dioxide mitigation; Periodicals; 628.53205
• DOI: 10.1016/j.jcou.2023.102398
• Languages: English
• ISSNs: 2212-9820

Abstract

Abstract: The catalytic fixation of greenhouse gas CO2 has been a hot topic of research, in which the reduction and functionalization of CO2 is important for application. In present work, cheap and readily available alkanolamines were used as efficient catalysts with phenylsilanes as reducing agents to achieve the N-formylation reaction by constructing C-N bonds via the reaction between CO2 and amines (aliphatic or aromatic amines) under mild conditions (40℃and 0.1 MPa). Further studies showed that present catalytic system has wide substrates application. Mono-N-formylated compounds were obtained as main products with good to high yields for all amines. It is worthy noted that for p-aminobenzylamine containing two amino groups as substrate, both amino groups are formylated and N-formylation reaction occurs mainly in aliphatic amine with high electron cloud density. Scale-up research has been performed effectively with high conversion of amine (80%) to obtain the mono-formylated product selectively. Finally, the mechanism of the reaction between amine and CO2 is proposed via control experiments and spectra verification. Systematic mechanism studies have revealed that after polarization by polar solvent DMSO, N-methyldiethanolamine activates CO2 by forming internal salts, which are subsequently reduced by phenylsilanes to formoxysilane intermediates and finally to form N-formylated products. Graphical Abstract: ga1 Highlights: Cheap alcohol amines were proved to be efficient catalysts for CO2 reduction. N-formylation reactions were carried out under 40 ℃ and 0.1 MPa with high selectivity. These catalysts exhibited wide substrates application (aliphatic or aromatic amines). Scale-up research has been performed effectively with high conversion and selectivity. The mechanism is proposed via control experiments and spectra verification.