The resource utilization of hydrogen sulfide (H2S) is an important and promising topic in energy chemical engineering. The previous products developed in our group through H2S conversion are sulfur or mercaptan acids. Alternative way to convert H2S is still desirable. Herein, we developed a green and mild method to convert H2S into mercaptan alcohols by the addition reaction with epoxide mediated in tertiary amine-functionalized protic ionic liquids (PILs). Reaction kinetics, substrate scope, and regeneration experiment have all been explored. Almost quantitative conversion of substrates was realized with catalytic loading of PILs at 30 C. Water extraction was used to recycle the catalysts from the reaction system. It is believed that the excellent results, together with its operational simplicity and the ability to successively reuse the catalyst, make this new methodology environmentally benign and cost-effective. The generality of the H2S resource methodology gives it potential for application on an industrial scale.

In view of the environmental hazards caused by SO2, the development of efficient SO2 capture technology has important practical significance. In this work, a low viscosity protic ionic liquids containing imidazole, ether linkage, and tertiary amine structure, was synthesized by acid-base neutralization of tris(3,6-dioxaheptyl)amine (TMEA) and imidazole (Im) for SO2 absorption. The results showed that the solubility of SO2 in [TMEA][Im] reached 12.754 mol·kg-1 at 298.2 K and 100 kPa and the ideal selectivity of SO2/CO2(1/1) and SO2/H2S(1/1) are 141.6 and 11.8 at 100 kPa, respectively. Furthermore, [TMEA][Im] can be reused and the SO2 absorption performance was not significantly reduced after five cycles. In addition, the absorption of low-concentration SO2 (2000 ppm) in [TMEA][Im] was also tested. Further spectroscopic research and thermodynamic analysis suggested that the high SO2 uptake by [TMEA][Im] was caused by the synergistic effect of physical and chemical absorption.

This paper proposes for the first time the preparation of a series of amino acid ionic liquids (AAILs) via one-step hydrolysis of cheap lactams for the capture of CO2. The structures of the prepared AAILs are confirmed using NMR, FTIR, and ESIMS, and their physical properties are also determined. It is found that these AAILs are reversible CO2 absorbents with very high absorption capacities (0.15 to 0.18 g·g1 at 313.2 K and 1.0 bar), better than almost all task-specific ionic liquids reported in literatures. The absorption mechanism is also elucidated to be a combination of 1:1 and 2:1 stoichiometric reaction of AAILs with CO2 from NMR, FTIR, reaction equilibrium thermodynamical modelling (RETM) and quantum calculations. The AAILs have the advantages of simple synthesis, high yield, and using available cheap raw materials. It is believed that this kind of AAILs have great potentials to be used as efficient CO2 absorbents.