In recent years, there has been an increasing concern about the effects
of toxic chemicals in the environment. In response to this concern,
there is a growing impetus to develop chemical manufacturing
processes which can reduce or eliminate the use or generation of
hazardous substances. Within this aspect of green chemistry, in this
Thesis, Ionic Liquids (ILs) and Deep Eutectic Solvents (DESs) have been
tested as greener alternatives in different chemical processes.
In a first stage, the capability of using ILs as solvents for citrus
essential oil deterpenation by liquid-liquid extraction was investigated.
The liquid-liquid equilibria of ternary systems limonene + linalool + IL
were determined. Results were analysed in terms of the solute
distribution ratio and selectivity, allowing to draw conclusions about
the influence of the structure of the ILs in these thermodynamic
parameters. Experimental data were correlated by means of the NRTL
and UNIQUAC equations.
To evaluate the capability of some ILs to act as surfactants in
Enhanced Oil Recovery, two of these salts showing surfactant behaviour
were tested. Liquid-liquid equilibria of ternary systems water + IL + ndodecane
were determined. Winsor Type III systems were found, and
the interfacial tensions between phases were measured to prove the
ability of these salts to reduce the water – oil interfacial tension.
Physical and transport properties of the phases involved, such as
density and viscosity, were also experimentally measured.
In a last stage, an introductory study on the processing of
lignocellulosic biomass with DESs was carried out. Different renewable
DESs were prepared from hydrogen bond donor and hydrogen bond
acceptor starting materials. Solubility tests of pine wood and wheat
straw in these solvents were carried out.
From the thermodynamic studies that were carried out in this
Thesis, it turns out that designer solvents can be used to develop
greener and/or more efficient chemical processes.
