[bmim]OH和[A336][FeCl_4]混合离子液体氧化吸收硫化氢

Oxidation absorption of H_2S by [bmim]OH and [A336][FeCl_4] mixed ionic liquids

为了降低非水相催化氧化硫化氢体系的运行成本,将碱性的氢氧化1-丁基-3-甲基咪唑([bmim]OH)离子液体与价格较低的酸性三辛基甲基铵四氯铁酸盐([A336][FeCl_4])离子液体分别按照0.2∶1、0.5∶1、0.8∶1、1∶1和2∶1的比例混合,用所得到的混合离子液体进行硫化氢氧化吸收实验,系统研究了混合离子液体的水溶性、密度、红外光谱、黏度和酸性强度等性能,并对其硫容和反应产物进行了分析。研究结果表明:(1)[A336]FeCl_4季铵盐离子液体的酸性强度和价格均低于[bmim]Fe Cl4离子液体,可以降低离子液体非水相催化氧化硫化氢体系的成本;(2)混合离子液体不仅同时具有[bmim]OH和[A336][FeCl_4]的骨架结构,且其p H值、黏度和硫容均随[bmim]OH量的增加而增加;(3)混合离子液体明显弱于[A336][FeCl_4]离子液体的酸性强度,有利于硫化氢的吸收,其黏度随温度上升而剧烈下降的性质有利于中、高温脱硫。结论认为,当[bmim]OH/[A336][FeCl_4]的物质的量之比在0.5∶1~1∶1时,可以构建成本较低、酸性适中、黏度较低、硫容较高的中、高温脱硫体系。

For the purpose of reducing the operating cost of a non-aqueous desulfurization system, the mixed ionic liquids were prepared by blending the basic 1-butyl-3-methylimidazolium hydroxide（[bmim]OH） with the cheap acidic tricaprylylmethylammonium tetrachloroferrate（[A336][FeCl4]） in the ratio of 0.2： 1, 0.5 ： 1, 0.8： 1, 1： 1 and 2 ： 1, respectively, and then they were used for H2S oxidation absorption experiments. Accordingly, the properties of the mixed ionic liquids were researched systematically, including water solubility, density, IR spectrum, viscosity and acidic strength, and their sulfur capacity and reaction products were analyzed. And the following research results were obtained. First, the acidic strength and price of [A336][FeCl4] quaternary ammonium ionic liquid are lowered than those of [bmim][FeCl4] ionic liquid, so its adoption can reduce the cost of ionic-liquid non-aqueous desulfurization system. Second, the mixed ionic liquids have the frameworks of both [bmim]OH and [A336][FeCl4], and their p H,viscosity and sulfur capacity increase with the increase of [bmim]OH. Third, the acidic strength of mixed ionic fluids is much lower than that of [A336][FeCl4] ionic liquid, and it is beneficial to H2S absorption. Moreover, its viscosity decreases dramatically with the increase of temperature, which is favorable for desulfurization at medium and high temperature. In conclusion, the medium-high temperature desulfurization system with the characteristics of lower cost, moderate acidity, lower viscosity and higher sulfur capacity can be developed when the molar ratio of [bmim]OH to [A336][FeCl4] is in the range of 0.5： 1-1 ： 1.