The Synthesis Of Quaternary Ammonium Ionic Liquid And Study On Their Solubility Of H₂s

As there were some disadvantages in the old desulphurization process, the new desulfurization method was studied using the quaternary ammonium ionic liquid. A series of quaternary ammonium ionic liquids were synthesized, using which the desulfurization process and the recycle of the ionic liquids were studied.21 kinds of quaternary ammonium ionic liquids were synthesized using caprolactam, urea, glycine, L-alanine or L-valine and tetrabutyl ammonium fluoride, tetrabutyl ammonium chloride, tetrabutyl ammonium bromine,1-butyl bromide-1,4-diazabicyclo(2,2,2)octane or choline chloride respectively.The quaternary ammonium ionic liquids were chosen as the absorbent, by comparing the mole fraction solubility of H2S in the quaternary ammonium ionic liquids. The result indicates that caprolactam tetrabutyl ammonium halogen ionic liquids are the best. Since the influence of halogen on the mole fraction solubilities of H2S ionic liquids was not obvious. Considering the economic and environmental benefits, caprolactam tetrabutyl ammonium bromide ionic liquid was performed. Caprolactam tetrabutyl ammonium bromide ionic liquid was chosen as the absorbent, and was confirmed the optimum conditions for desulphurization process.After the ionic liquid was reused 5 times the solubility of H2S in the ionic liquid had not obvious change. Zn/Fe-IL ternary system was prepared by mixing the caprolactam tetrabutyl ammonium bromide ionic liquid, ZnCl2 and FeCl3·6H2O at room temperature. The optimum conditions of desulphurization process were investigated in Zn/Fe-IL ternary system.The caprolactam tetrabutyl ammonium bromide ionic liquid has good desulphurization performance. It is easy to recycle elemental sulfur in the Zn/Fe-IL ternary system.