Effect of Lengths of Substituents in Imidazolium Groups on the Preparation of Imidazolium-Salt-Type Ionic Liquids Containing Polyhedral Oligomeric Silsesquioxane Structures

DOI PDF Web Site 6 Citations 36 References

Search this article

Abstract

<jats:title>Abstract</jats:title> <jats:p>Hydrolytic condensation of organotriethoxysilanes containing imidazolium groups [(CH3CH2O)3Si(CH2)3(C3H3N2)R] with substituents of different lengths (i.e., R = -(CH2)3CH3, -(CH2)2CH3, -CH2CH3, -CH3, and -H) was performed using the superacid bis(trifluoromethanesulfonyl)imide (HNTf2) as a catalyst in a water/methanol (1:19, v/v) mixed solvent. When R was -(CH2)3CH3, -(CH2)2CH3, or -H, room temperature ionic liquids (RT-ILs) containing polyhedral oligomeric silsesquioxane (POSS) structures (BuIm-POSS-IL, PrIm-POSS-IL, and HIm-POSS-IL) were successfully prepared. The glass-transition temperatures (Tgs) of these ILs were −33.2 °C, −31.8 °C, and −14.4 °C, respectively, and they presented no melting temperatures (Tms), indicating that they are amorphous compounds. In addition, their fluidities were visually observed above 5 °C, 10 °C, and 30 °C, respectively. Conversely, although EtIm-POSS-IL, which is prepared from (CH3CH2O)3Si(CH2)3(C3H3N2)CH2CH3, took more than two weeks to crystallize, it is a crystalline compound. The crystallized EtIm-POSS-IL exhibited a Tm of 59.0 °C, a Tg of −32.6 °C, and a flow temperature of ca. 60 °C. Furthermore, MeIm-POSS-IL prepared from (CH3CH2O)3Si(CH2)3(C3H3N2)CH3 in our previous study is a crystalline POSS with a Tm of 106 °C and a flow temperature of ca. 100 °C. Based on the above results, when R is a long alkyl chain or H, RT-ILs containing POSSs with amorphous structures can be prepared. In addition, these ILs exhibit high pyrolysis temperatures (&gt;420 °C).</jats:p>

Journal

Citations (6)*help

See more

References(36)*help

See more

Related Projects

See more

Keywords

Details 詳細情報について

Report a problem

Back to top