Abstract:

A series of acidic deep eutectic solvents (DESs) EMIES/nC₉H₁₀O₂（n=0.25, 0.5, 1, 2, 4） were synthesized by simply heating the mixture of 1-ethyl-3-methylimidazolium ethylsulfate (EMIES) and 3-phenylpropionic acid (C₉H₁₀O₂). The structure of EMIES/nC₉H₁₀O₂ was determined by FTIR, ¹H NMR and TGA characterization. The extraction-oxidation desulfurization system was developed to remove sulfides from model oil using EMIES/nC₉H₁₀O₂ as the extractant and catalyst, H₂O₂ as the oxidation. The influences of raw material ratio, reaction temperature, O/S ratio, amount of DESs and different sulfide on the desulfurization performance were investigated. The experimental results demonstrated the optimal reaction conditions were molar ratio of EMIES to C₉H₁₀O₂ of 1∶1, temperature of 50℃, O/S ratio of 8, the amount of DESs of 1.5 g and 5 ml model oil. Removal rate of DBT, 4, 6-DMDBT and BT reached 94.8%, 91.6% and 46.4%, respectively, under the optimal condition. The DESs can be reused for 6 times without significant decrease in activity. In addition, the desulfurization mechanism of the oxidation-extraction desulfurization system was discussed.

Key words: solvent extraction, recovery, catalysis, deep eutectic solvents

摘要：

通过简单加热1-乙基-3-甲基咪唑硫酸乙酯（EMIES）离子液体和3-苯丙酸（C₉H₁₀O₂）的混合物，制备了一系列酸性低共熔溶剂EMIES/nC₉H₁₀O₂（n=0.25,0.5,1,2,4）。通过FTIR，¹H NMR和TGA的表征，确定EMIES/nC₉H₁₀O₂的结构。以该低共熔溶剂为催化剂和萃取剂，H₂O₂为氧化剂，组成氧化-萃取脱硫体系，用于脱除模拟油中的硫化物。考察了原料配比、反应温度、氧硫比（O/S）、低共熔溶剂加入量和不同硫化物对脱硫性能的影响。结果表明，在EMIES和C₉H₁₀O₂摩尔比为1∶1，反应温度为50℃，O/S比为8，低共熔溶剂加入量为1.5 g和模拟油5 ml的反应条件下，二苯并噻吩、4,6-二甲基二苯并噻吩和苯并噻吩的脱除率分别为94.8%、91.6%和46.4%。低共熔溶剂可循环使用6次，活性无明显下降。此外，对该氧化-萃取脱硫体系的脱硫机理进行了探讨。

关键词: 溶剂萃取, 回收, 催化剂, 低共熔溶剂