abstract
The nonionic Type V deep eutectic solvent (DESs) thymol + menthol is experimentally and computationally studied aiming to clarify the relation between its liquid phase structure and its thermodynamic nonideality. H-1 NMR, Raman, and X-ray scattering analysis of the thymol + menthol system, supported by molecular dynamics simulations, show complex intermolecular interactions dominated by sterically hindered H-bonded clusters. For temperatures greater than or equal to room temperature, a quasi-linear evolution of the eutectic system properties between the pure compounds is observed, suggesting the absence of a magic stoichiometric composition in the eutectic solvent. However, temperature dependent Raman spectroscopy indicates a notable increase in thymol-menthol H-bonding as temperatures approach the eutectic point. This study shows that nonionic Type V DESs present an important temperature-dependent nonideality originating from the change in the intermolecular H-bonding with temperature. These findings have significant implications for the design and growing application of Type V DESs.
subject category
Chemistry, Multidisciplinary; Green & Sustainable Science & Technology; Engineering, Chemical
authors
Schaeffer, N; Abranches, DO; Silva, LP; Martins, MAR; Carvalho, PJ; Russina, O; Triolo, A; Paccou, L; Guinet, Y; Hedoux, A; Coutinho, JAP
our authors
Dinis O. Abranches
Assistant Researcher
Liliana Patrocínio da Silva
Collaborator
Nicolas Schaeffer
Assistant Researcher
Pedro J. Carvalho
Assistant ProfessorGroups
G4 - Renewable Materials and Circular Economy
G6 - Virtual Materials and Artificial Intelligence
Projects
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
acknowledgements
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the Foundation for Science and Technology/MCTES. The NMR spectrometers are part of the National NMR Network (PTNMR) and are partially supported by Infrastructure Project No. 022161 (cofinanced by FEDER through COMPETE 2020, POCI and PORL and FCT through PIDDAC). L.P.S. acknowledges FCT for her Ph.D. grant (SFRH/BD/135976/2018). N.S. acknowledges the national funds (OE), through FCT-Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. Access to the SAXS-Lab at the University of Rome Sapienza and kind support from Dr. A. Del Giudice are acknowledged. This work has been partially supported by a University of Rome Sapienza grant (RG11715C7CC660BE).