Molecular-Level Insights into the Oxidative Degradation of Grafted Amines

Authors

  • Dr. Asieh Ahmadalinezhad,

    1. Department of Chemistry, Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario, K1N 6N5 (Canada)
    Search for more papers by this author
  • Dr. Ritesh Tailor,

    1. Department of Chemistry, Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario, K1N 6N5 (Canada)
    Search for more papers by this author
  • Prof. Abdelhamid Sayari

    Corresponding author
    1. Department of Chemistry, Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario, K1N 6N5 (Canada)
    • Department of Chemistry, Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario, K1N 6N5 (Canada)
    Search for more papers by this author

Abstract

The oxidative degradation of CO2 adsorbents consisting of amine-grafted pore-expanded mesoporous MCM-41 silica was investigated. The adsorbents were treated under flowing air at various temperatures, and the degree of deactivation was evaluated through the measurement of their CO2 adsorption capacity prior and subsequent to exposure to air. To decipher the chemical structure of surface species upon air-deactivation of grafted amines, a solvent extraction procedure was developed using a deuterated basic solution. The obtained solutions were analyzed by a variety of 1D and 2D NMR spectroscopy techniques, such as 29Si, 13C, 1H, [1H,15N] HMBC, [1H,13C] HMQC, COSY and DOSY. The surface species generated by oxidative degradation of amine-grafted silica were found to contain functional groups such as imine, amide and carboxylic groups. Several structural units were conclusively demonstrated.

Ancillary