Exploring new protic ionic liquids: From synthesis to fundamental properties
Doktorsavhandling, 2023

The ionic liquid community frequently leverages the selling point that more than a million new ionic liquids could conceivably be created. Nonetheless, the number of commercially available compounds is orders of magnitude lower. This highlights the fact that only a small number of all possible ionic liquids are actively being researched, a reality particularly noticeable in the niche field of protic ionic liquids. In such a scenario, research focusing on the development of even a small number of viable alternatives to the popular alkylammonium- and imidazolium-based cations could potentially have a big impact, by paving the way for the synthesis of new families of ionic liquids. However, for these new alternatives to be widely used by the community, they must be easy to synthesize and have desirable properties.

In this thesis, I discuss the challenges that I have encountered and the lessons that I have learned while trying to explore the chemical space of protic ionic liquids. This exploration started with the development of a procedure for the synthesis of pure and dry protic ionic liquids, which was used to make new triazolium-based protic ionic liquids. Additionally, this first work highlights the importance of using air-free techniques to analyze these hygroscopic compounds. Later, these insights were used to develop a new setup for the determination of ionic conductivity in ionic liquids. The latter was used in conjunction with pulsed-field gradient nuclear magnetic resonance diffusion experiments and density functional theory experiments to understand the differences in transport properties between triazolium- and imidazolium-based protic ionic liquids. Finally, we once again turned our attention to the imidazolium cation and explored how simple modifications to its electronic structure, by means of functionalization with electron-withdrawing groups, can enhance its acidity, and how that affects the properties of these nitro- and cyano-functionalized protic ionic liquids.

This thesis aims to highlight the importance of developing new methods for the synthesis and analysis of protic ionic liquids, as well as to explore how computational modeling can be used to rationalize the observed differences in the physicochemical properties of these compounds.

thermal analysis

acidity

transport properties

DFT

Protic ionic liquids

KA-salen, Kemigården 4, Chalmers.
Opponent: Tamar Greaves, RMIT University, Australia.

Författare

Eduardo Maurina Morais

Chalmers, Kemi och kemiteknik, Tillämpad kemi

E. Dahlqvist, E. M. Morais and A. Martinelli. Enhancing the acidity of imidazolium protic ionic liquids by nitro- and cyano-functionalization

Protic ionic liquids are organic salts made by reacting certain acids and bases. What sets them apart from regular salts, which have very high melting temperatures (801 °C for table salt, NaCl, for example), is that protic ionic liquids can be liquid at room temperature. This makes them quite attractive for a series of applications that benefit from their highly ionic environment. One renewable energy technology that might benefit from advances in this field of research is the H2/O2 fuel cell technology (a device that uses hydrogen gas and air to produce electricity, generating only water as a by-product). Although these ionic liquids hold a lot of promise to improve the performance of these devices, there are still many challenges to be addressed before these compounds can be widely adopted. How should these compounds be made? How do we properly analyze them? Can computational chemistry models help us understand the properties of these protic ionic liquids? Dealing with these challenges has been the goal of this thesis work. These questions have led to an exploration of new types of protic ionic liquids and the development of procedures for making them purer and drier and to determine their properties.

Drivkrafter

Hållbar utveckling

Fundament

Grundläggande vetenskaper

Infrastruktur

C3SE (Chalmers Centre for Computational Science and Engineering)

Ämneskategorier

Materialkemi

Annan kemi

Teoretisk kemi

Organisk kemi

Den kondenserade materiens fysik

Styrkeområden

Materialvetenskap

ISBN

978-91-7905-960-6

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 5426

Utgivare

Chalmers

KA-salen, Kemigården 4, Chalmers.

Online

Opponent: Tamar Greaves, RMIT University, Australia.

Mer information

Senast uppdaterat

2023-11-16