Indonesia Conference Directory

The role of anion and alkyl chain length of cation on the thermophysical properties of imidazolium-based ionic liquid have been studied. The data were obtained from references and the NIST database. The studied parameters consist of melting temperature (Tm), glass transition temperature (Tg), decomposition temperature (Td), and enthalpy of fusion (∆Hm). The variations of Tm with anions in [C16Mim][A] with A= Br, Cl, BF4, PF6, and TFO are generally decreased with increasing anion radius, except for A= PF6, due to strong hydrogen bonds for the sake of an F atom. The values of critical temperatures (Tm, Tg, and Td) generally show a strong variation with the number of carbon atom or alkyl chain length (the number of n in [CnMim][A] for A = BF4, NTf2, and PF6). The variation of Tm in the number of n shows the non-monotonous variations. This characteristic is the result of the combination of interaction potentials in the crystalline and liquid phases. The variation of Tg in the number of n shows even-odd alternation, presumably due to competition between electrostatic and van der Waals forces. Many kinds of ILs have a relatively high value of Td, which means that it can be kept in the liquid state above 400 °C, which makes them have excellent catalytic activity and dynamic properties. The variation of Td with n looks different with Tm. It is seemingly that the variation of ∆Hm with n follows the Tm. This behavior in accordance with the thermodynamic relation between ∆Hm, Tm, and entropy (S) of the system.