Experimental and Theoretical Thermodynamic Study of Distillable Ionic Liquid 1,5-Diazabicyclo[4.3.0]non-5-enium Acetate

Abstract

A thermochemical study of the protic ionic liquid 1,5-diazabicyclo­[4.3.0]­non-5-enium acetate ([DBNH]­[OAc]), a prospective cellulose solvent considered for the Ioncell-F process, was carried out. The heat capacities of 1,5-diazabicyclo[4.3.0]­non-5-ene (DBN) and [DBNH]­[OAc] were measured by differential scanning calorimetry (DSC) at 223–323 and 273–373 K temperature ranges, respectively. The enthalpies of fusion and synthesis reaction of [DBNH]­[OAc] were measured by DSC and reaction calorimetry, respectively. The gas-, liquid-, and solid-phase enthalpies of formation of [DBNH]­[OAc] and DBN were determined using calorimetric and computational methods. The enthalpy of vaporization of [DBNH]­[OAc] was estimated from the formation enthalpies. The activity coefficients at infinite dilution of 17 and the enthalpies of solution at infinite dilution of 25 organic solutes in [DBNH]­[OAc] were measured by gas chromatography and solution calorimetry methods, respectively. The obtained data will be used in the design and optimization of the Ioncell-F process.

Solvent Welding and Imprinting Cellulose Nanofiber Films Using Ionic Liquids

“…In these cases, the IL yielded a more compact surface for macrofibers (filter paper) and patterned surfaces for nanofibers (CNF), see Figure 9. 33 , and it was mixed with 5% w/w of gamma-valerolactone (GVL) an effective reported co-solvent for biomass dissolution 67,68 . The welding dipping procedure was performed with the mixture at room temperature.…”

“…On the other hand, as mentioned previously, the cation plays a synergistic effect on cellulose dissolution. When the side chain length of alkyl groups or the symmetry of cations increased, the dissolution rate of cellulose in ILs decreased, because of the increase of viscosity and the decrease of H-bond acidity 27,33 it more favorable to dissolve in the IL 27,30,32 .…”

“…Chloride-containing ILs solubilize cellulose through the establishment of hydrogen bonds; meanwhile, for ILs containing acetate anions the hydrogen bonding is accompanied by the conjugation of cellulosic reducing ends (at C2 for imidazolium cation); therefore, the anion and cation have shown to possess a synergistic effect [27][28][29][30][31] . The more basic acetate containing ILs reacts with oligocellulose reducing end groups to a much greater extent than the homologous ILs containing the chloride anion, suggesting that this reaction is likely dependent on the basicity of the anion 32 29,33 .…”

Limitations of Cellulose Dissolution and Fiber Spinning in the Lyocell Process Using [mTBDH][OAc] and [DBNH][OAc] Solvents

“…On the other hand, separating IL-water systems via the evaporation of the latter has already provided promising results (Parviainen et al 2015;King et al 2011;Ostonen et al 2016). Originally, thermal treatments were studied for the distillation, and consequently purification, of ILs.…”

Dissolution and Hydrolysis of Bleached Kraft Pulp Using Ionic Liquids

“…However, initial toxicity results suggest that there are no major toxicity issues related to the typical ILs used for cellulose dissolution [18,19,20]. ILs are currently used in cellulose products’ technologies, paying attention to ILs recovery/recyclability, which in some cases might be performed by distillation [21,22,23]. On the other hand, previous works have reported CNC synthesis by ILs.…”