High temperature imidazolium ionic polymer for gas chromatography

Abstract

A new main-chain type ionic homopolymer GC stationary phase which has high separation efficiencies for alcohols, phthalates and PAHs and a maximum programmable temperature of 400 C was prepared and studied.Ionic liquids (ILs) are salts with relatively low melting points; they are usually liquid around ambient temperature. ILs have recently attracted a lot of interest due to their unique properties. Their minuscule vapor pressure and inflammability make them ''green'' solvents, in contrast to conventional organic solvents. Moreover, other properties such as solubility, conductivity, and thermal stability can be tuned by changing the substituted functional groups or the combination of cations and anions. These properties make ionic liquids multi-functional and designable. Detailed descriptions of these properties can be found in Ref. 1-7.Recently, Armstrong et al. demonstrated a series of ionic liquids as the stationary phases for gas chromatography. The ionic liquids have many properties that match the requirements of GC stationary phase, including high solubility, thermal stability, chemical stability, viscosity, wettability, and most important of all, the designability. Many successful applications and detailed discussions are available in the literature. [8][9][10] However, in spite ionic liquids normally having high thermal stability, they are still not comparable to some of the conventionally thermal-stable stationary phases. It could be due to the ion evaporation or decomposition under high temperature. Polymerized ionic liquids or ionic liquid polymers (PILs) show great promise. Ions are tethered to the backbone of the polymer. Despite the loss of ion mobility, the mechanical strength of the whole substrate increases as the does thermal stability. 11,12 The comb-like imidazolium based ionic liquid polymers show a decomposition temperature ranging from 280-380 C. More recently, Armstrong et al. demonstrated a series of

Poly(alkylimidazolium bis(trifluoromethylsulfonyl)imide)‐Based Polymerized Ionic Liquids: A Potential High‐Performance Lubricating Grease

“…Preparation of IL‐Based Lubricants : The synthesis method of PImC 6 NTf 2 was in accordance with that by Ho et al[14a], and BIm 5 ‐(NTf 2 ) 2 was synthesized with a similar method as reported by Gusain et al[5a] and Zeng et al[5b]. After vacuum drying at 80 °C for 12 h, the two ILs were stored at room temperature of 25 ± 3 °C.…”

“…Recently, Zhang et al and Bapat et al synthesized copolymerized PILs as lubricant additives which remarkably improved tribological properties in selected base oils. However, PILs generally have a higher melting point than conventional MILs and DILs, and are often present in solid form at room temperature to lose the fluidity of the lubricant, which prevents them to be directly used as lubricants . To our best knowledge, until now there is no work on the lubrication performance of PILs as base lubricant or lubricating grease.…”

“…It was reported that PImC 6 NTf 2 has relatively lower melting point of just 65 °C and has high thermal stability (with a decomposition temperature around 450 °C). [14a,18] A small amount of DILs named 1,1′‐(pentane‐1,5‐diyl)‐bis(3‐butylimidazolium) bis(trifluoromethylsulfonyl)imide (BIm 5 ‐(NTf 2 ) 2 ) was added to PImC 6 NTf 2 to decrease the crystallization temperature and improve the lubricating properties. The lubricating properties of PImC 6 NTf 2 and its mixture with BIm 5 ‐(NTf 2 ) 2 were investigated under severe operating conditions including high pressure (up to 3.5 GPa) and high temperature (200 °C).…”

Polycyclic aromatic hydrocarbons as model solutes for carbon nanomaterials in ionic liquids

“…An IL-based technology can also be used to design special HPLC columns to separate PAH chiral compounds. 47 Various studies of PAHs in IL solutions have been reported, mainly in the scope of extraction applications, such as microextraction, [48][49][50][51][52][53] analytical techniques 54 such as chromatography [55][56][57] or environmental issues. 56,58 In microextraction processes, ILs act as fiber modifiers and the resulting materials are used to extract PAH analytes with higher resolution.…”

Polymeric Ionic Liquids Derived from L-Valine for the Preparation of Highly Selective Silica-Supported Stationary Phases in Gas Chromatography

“…At high temperatures, uniform IL-coated silica columns can experience film disruption leading to a decrease in the analyte retention times and efficiency. In this regard, polymerized ionic liquids (PILs) can provide the required answers, maintaining the excellent thermal stability of the columns, and combining the main features of an ionic liquid and the typical polymer properties such as improved mechanical stability and processability [ 39 , 40 , 41 , 42 ]. Furthermore, in recent years, Anderson et al reported the development of cross-linked polymeric ionic liquid stationary phases for GC with higher thermal stability (up to 380 °C) [ 43 ] than the columns coated with the monocationic or dicationic ILs with similar structures [ 44 ].…”