对二氯苄-聚乙烯咪唑型聚合离子液体的制备及对煤焦油中苯酚的吸附性能

以1-乙烯咪唑和1,4-对二氯苄为原料, 通过自由基聚合和季铵化交联反应, 制得了一种新型聚合离子液体吸附剂——聚乙烯基苄基咪唑氯(P[VBnim]Cl), 并用元素分析、 凝胶渗透色谱、 红外光谱、 扫描电子显微镜、 物理吸附分析仪及热重分析等方法对其组成、 结构、 颗粒形貌、 比表面积、 孔结构及热稳定性进行了表征. 结果表明, P[VBnim]Cl 结构中对二氯苄与乙烯咪唑的摩尔比约为1∶3; 产物为米黄色蓬松粉末, 易吸水, 其初始颗粒直径为50~80 nm, 比表面积为13.86 m²/g, 平均孔径9.94 nm, 属于介孔结构材料, 初始热分解温度为274 ℃, 具有较好的热稳定性. 同时, P[VBnim]Cl对中低温煤焦油模型油中的苯酚具有优异的吸附性能, 其吸附能力是活性炭的2~10倍, 该吸附剂用乙酸乙酯再生后, 吸附效果仍然较好, 可以循环使用.

Synthesis of 1,4-Bis(chloromethyl)benzene Crosslinked Poly(vinyl imidazolium) and Its Adsorptivity for Phenol from Coal Tar†

A new poly ionic liquid(PIL) type adsorbent, poly(vinyl-benzyl-imidazolium) chloride(P[VBnim]Cl) was prepared facilely with overall yield above 75% through free radical polymerization of 1-vinylimidazole at 70 ℃ and cross-linking of the resulting polymer with 1,4-bis(chloromethyl) benzene via quaternization reaction in dimethylformamide(DMF) solvent. The as-prepared PIL was analyzed and characterized with respect to composition, structure, morphology and thermal stability by elemental analysis, gel permeation chromatography(GPC), Fourier transform infrared spectroscopy(FTIR), scanning electron microscope(SEM), physical absorption instrument and thermal gravimetric analysis/differential scanning calorimetry(TGA/DSC) technique. The molar ratio of 1,4-bis(chloromethyl) benzene to 1-vinylimidazole is about 1∶3 in P[VBnim]Cl. The P[VBnim]Cl is a beige and fluffy fine powder with primary particle size of 50—80 nm, being mesoporous material with specific surface area 13.86 m²/g and average pore size 9.94 nm. The PIL exhibits good thermal stability with its initial decomposition temperature being about 274 ℃. Adsorptivity for phenol from the model oil of low temperature coal tar was also studied. The P[VBnim]Cl was proved as an excellent adsorbent, being 2 to 10 times superior to the conventional active carbon at fixed other conditions. The excellent adsorptive property is mainly attributed to the chemical adsorption of the IL constituents at dilute phenol concentrations as well as the physical adsorption at higher phenol concentrations due to the porous architecture of P[VBnim]Cl. The used P[VBnim]Cl adsorbent can be regenerated easily with ethyl acetate, and used repeatedly with good adsorptivity.