Thermodynamics of Ionic Liquid Precursors. 1-Bromobutane and Its Isomers

Abstract

The heat capacity and parameters of fusion of 1-bromobutane (BuBr) were measured in the temperature range (5 to 370) K using adiabatic calorimetry. The thermodynamic functions for the compound in the crystal and liquid states were calculated from these data. On the basis of the experimental spectroscopic data and the results of quantum-chemical calculations, the ideal-gas properties for BuBr were calculated by methods of statistical thermodynamics. The obtained entropy S m o(g; 298.15 K) = 366.9 J·K–1·mol–1 is in excellent agreement with the value 367.0 ± 1.2 J·K–1·mol–1 obtained from the experimental data. The ideal-gas thermodynamic properties were also calculated for isomeric bromobutanes and 1-butyl-3-methylimdiazolium bromide ionic liquids that allowed us to find the changes of thermodynamic properties in the reactions of synthesis of 1-butyl-3-methylimidazolium bromide isomers. The literature data on the enthalpies of formation for isomeric bromobutanes were collected, and the recommended values were developed. It was demonstrated that the synthesis of ionic liquids from bromoalkanes and 1-methylimidazole in the gas phase, unlike the liquid-phase reaction, is not a thermodynamically favorable process. It possesses more positive enthalpy changes and more negative entropy changes compared to the synthesis in the liquid phase.

Formation Enthalpies of C3 and C4 Brominated Hydrocarbons: Bringing Together Classical Thermodynamics, Modern Mass Spectrometry, and High-Level Ab Initio Calculations

“…The majority of data sources considered here have measurements of the enthalpy-related properties for the target compounds as their main objectives. In some cases, however, additional useful information can be obtained as a byproduct of seemingly unrelated data such as reaction calorimetry for inorganic or organometallic systems. , …”

“…In some cases, however, additional useful information can be obtained as a byproduct of seemingly unrelated data such as reaction calorimetry for inorganic or organometallic systems. 125,148 Holm 92,144 reported the enthalpies of two reactions involving organic magnesium bromides RMgBr in diethyl ether Et 2 O, which he described as…”

“…3) kJ•mol −1 at T = 298.15 K if one uses the idealgas model of Paulechka et al 125 for both isomers. The derived gas-phase enthalpy of formation of 2-bromobutane was combined with the isomerization enthalpy to obtain an additional experimental Δ f H m °(1-bromobutane) in the gas phase.…”

Ionic Liquids: Differential Scanning Calorimetry as a New Indirect Method for Determination of Vaporization Enthalpies

“…For example, with the values C p 1 = 162.1 ± 0.6 J•K −1 •mol −1 for 1-butyl bromide, 25 C p 1 = 147.2 ± 0.6 J•K −1 •mol −1 for MeIm, 26 and…”

“…For example, with the values C p 1 = 162.1 ± 0.6 J·K –1 ·mol –1 for 1-butyl bromide, C p 1 = 147.2 ± 0.6 J·K –1 ·mol –1 for MeIm, and C p 1 = 308.7 ± 1.0 J·K –1 ·mol –1 for [C 4 mim]­[Br], the value Δ r C p,m = −(0.6 ± 1.3) J·K –1 ·mol –1 was estimated. Similar results were also obtained for other alkyl bromides: all Δ r C p,m values were negative and of the order of 1 J·K –1 ·mol –1 .…”