Double H-bonds multimer absorbent design for H₂S absorption

A double H-bonds multimer absorbent for hydrogen sulfide (H₂S) absorption was designed via intermolecular self-assembly using 1,8-Diazabicyclo-[5.4.0]-undec-7-ene (DBU) and ethylene glycol (EG) under the guidance of quantum chemical calculation (QCC). The formation mechanisms of multimer absorbents and the absorption mechanisms between those absorbents and H₂S were explored by QCC and experiments. It was found that the formed multimer absorbent at the DBU/EG molar ratio of 1:2 has two intermolecular H-bonds with different strengths between DBU and EG, which can combine with H₂S via strong intermolecular forces. Furthermore, the characteristics analysis of multimer absorbents and complexes confirmed the above mechanisms. Experimental results indicated that the DBU-2EG has a higher H₂S solubility of 5.8 mol/kg multimer absorbent with a low viscosity value of 15.12 mPa·s at 25 °C and better regeneration performance. The multimer absorbent exhibits great potential in the H₂S capture process.