شماره ركورد كنفرانس :
5048
عنوان مقاله :
Molecular Dynamics Simulations of Dynamics and Diffusion Coefficients of Tetrabutylphosphonium Amino Acid Based Room Temperature Ionic Liquids
Author/Authors :
M. H ،Kowsari Department of Chemistry - Isfahan University of Technology - Isfahan, Iran , S ،Alavi Department of Chemistry - Isfahan University of Technology - Isfahan, Iran , B ،Najafi Department of Chemistry - Isfahan University of Technology - Isfahan, Iran , E ،Dehghanpisheh Department of Chemistry - Isfahan University of Technology - Isfahan, Iran , F ،Ranjbar Department of Chemistry - Isfahan University of Technology - Isfahan, Iran , K ،Gholizadeh Department of Chemistry - Isfahan University of Technology - Isfahan, Iran
كليدواژه :
Ionic Liquids , Amino Acid , Molecular dynamics Simulation , Diffusion , Transport Properties
عنوان كنفرانس :
ششمين كنگره بين المللي مهندسي شيمي
چكيده لاتين :
Molecular dynamics simulations are used to study the dynamics and transport properties of 6 [TBP][AA] roomtemperature
ionic liquids composed of the tetrabutylphosphonium ([TBP]+, or [P(C4)4]+) cation with the amino acid
([AA]–) anions, such as glycine ([Gly]–), alanine ([Ala]–), leucine ([Leu]–), aspartic acid ([Asp]–), glutamic acid ([Glu]–
), and glutamine ([Gln]–). The explicit atom force field of Zhou et al. [J. Phys. Chem. B 111, 7078 (2007)] is used in the
simulations. The dynamics of the ionic liquids are characterized by studying the mean-square displacement (MSD) and
the velocity autocorrelation function (VACF) for the centers of mass of the ions at ~ 280 K. The diffusion coefficients
evaluate from the linear slope of MSD(t) functions in the range of 2–4 ns and the cationic transference numbers
estimated for study the contributions of the anions and cations to the transport of charge in these ionic liquids. We
determined the role of the amino acid anion structures on the dynamical behavior of this family of ionic liquids. The
MSD and self-diffusion of relatively heavier [TBP]+ non-planar cation are smaller than that of the lighter amino acids
anions from the Einstein results, except of case of [TBP][Gln] and [TBP][Leu]. The trends in the cationic transference
numbers with different length of alkyl side chain in the amino acid anions are [Gly]- < [Ala]- < [Leu]- and the trends in
the cationic transference numbers with different functional side chain in the amino acid anions are [Asp]- < [Glu]- <
[Gln]-. The trends in the diffusion coefficient for anions with identical cations are [Gly]- > [Ala]- > [Leu]- and [Asp]- >
[Glu]- > [Gln]-. The results for the cases of [Leu]- and [Gln]- have a relatively high uncertainly due to the lower values
of b exponent and relatively higher melting points for these two ILs. The major factor for determining the magnitude
of the self-diffusion is the length of alkyl side chain and the type of functional group in the side chain of the anion of the
amino acid ionic liquids.
