Reversible absorption of SO2 with alkyl-anilines: The effects of alkyl group on aniline and water

SO2 absorption behaviours of N,N-dimethylaniline (DMA), N,N-diethylaniline (DEA), N,N-dibutylaniline (DBA), and N-methyldiphenylamine (MDPA) - were investigated in dry and wet conditions. DMA showed the highest SO2 absorption capacity of 1.5 mol(SO2) mol(Absorbent)(-1) in dry condition, while DBA showed the highest capacity of 1.75 mol(SO2)mol(Absorbent)(-1) in wet condition. Raman analyses revealed that anilines captured SO2 by forming charge transfer complexes in dry condition and the interaction between SO2 and aniline decreased as the steric hindrance of alkyl aniline increased. In contrast, bisulfite-based acid-base salt was formed in the presence of water, and the capacity increased with an increasing basicity of the alkyl aniline. (C) 2018 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.