CAJ | 학술논문

1-烷基-3-甲基咪唑双三氟甲基磺酰胺型离子液体([Cnmim][NTf2])被认为是最有希望用于核燃料循环中的分离试剂之一,虽然其化学结构在辐照过程中变化不大,但在受到γ辐照后会发生明显的变色,因此有必要研究该类离子液体的变色原因.本文以60Co为辐照源,系统研究了辐照后不同C(1)-烷基链长和咪唑环上C(2)位上的H被甲基取代后离子液体的紫外-可见(UV-Vis)吸收光谱行为,并结合辐照后离子液体荧光光谱和质谱的变化,分析了导致该类离子液体辐照后颜色加深的原因.结果表明,随着咪唑环上C(1)―烷基链长度和剂量增大,离子液体颜色加深;而C(2)位上的H被甲基取代后颜色明显变浅.辐照后咪唑型离子液体的变色主要来自于辐照后产生的烷基侧链含双键的咪唑阳离子,咪唑阳离子二聚体和含氟咪唑化合物.此外,γ辐照引起咪唑阳离子易发生π-π堆积,而聚集态含量增加也会引起颜色加深.
1-완기-3-갑기미서쌍삼불갑기광선알형리자액체([Cnmim][NTf2])피인위시최유희망용우핵연료순배중적분리시제지일,수연기화학결구재복조과정중변화불대,단재수도γ복조후회발생명현적변색,인차유필요연구해류리자액체적변색원인.본문이60Co위복조원,계통연구료복조후불동C(1)-완기련장화미서배상C(2)위상적H피갑기취대후리자액체적자외-가견(UV-Vis)흡수광보행위,병결합복조후리자액체형광광보화질보적변화,분석료도치해류리자액체복조후안색가심적원인.결과표명,수착미서배상C(1)―완기련장도화제량증대,리자액체안색가심;이C(2)위상적H피갑기취대후안색명현변천.복조후미서형리자액체적변색주요래자우복조후산생적완기측련함쌍건적미서양리자,미서양리자이취체화함불미서화합물.차외,γ복조인기미서양리자역발생π-π퇴적,이취집태함량증가야회인기안색가심.
Ionic liquids 1-alkyl-3-methylbis(trifluoromethylsulfonyl)imide ([Cnmim] [NTf2]) are promising separating reagents in the nuclear fuel cycle. Their chemical structure changes slightly when exposed toγradiation, but the apparent darkening of [Cnmim][NTf2] occurs at low dose. This radiation-induced darkening of [Cnmim][NTf2] should be investigated further. To understand the effect of radiation on [Cnmim][NTf2], we systematical y studied the influences of the length of the C(1)―alkyl chain and substitution of C(2)―H on the UV-Vis spectra of irradiated [Cnmim][NTf2]. Fluorescence and mass spectra of [Cnmim][NTf2] al owed the possible colored products to be determined. The darkening of [Cnmim][NTf2] is more obvious as the length of the C(1)―alkyl chain and absorbed dose increase, but it is weakened effectively after methylation at the C(2)-position of the imidazole ring. The dominant colored products are possibly imidazolium cations containing double bonds, dimers of imidazolium cations and fluorinated imidazolium compounds. Imidazolium cations could aggregate through π-π stacking after γ-irradiation, and the associated states may also play a role in darkening these ionic liquids.