Investigation of the surface interactions of selected amides with mesoporous silica using FTIR spectroscopy and hyperspectral imaging

Abstract

The adsorption of eight structurally different secondary and tertiary amides (N-ethyl formamide, N-methyl-propionamide, N-cyclohexyl formamide, N-tert-Butyl-formamide, N-Methyl-benzamide, N-Pentyl-benzamide, N,N-dimethyl acetamide and N,N-diethyl dodecanamide) from carbon tetrachloride solution on mesoporous silica (MS) material was investigated by kinetic FTIR spectroscopic measurements. Of the tested amides, N-methyl-propionamide showed the highest affinity for the MS material. The results indicate that tertiary amides show low affinity for the surface interaction with MS while the affinity of secondary amides decreases with the increase in the volumeof substituents. This result is correlated to the capability of amide N-H to participate in hydrogen bonding with the MS surface. Results of FTIR spectroscopy evidence the presence of amides adsorbed on the surface of MS while the analysis of hyperspectral images reveals the possibility of constructing effective qualitative hyperspectral sensors for amides based on MS as a sensing substrate.