ISIS Neutron and Muon Source Data Journal

Microheterogeneity structure of water-dimethylformamide (DMF) mixtures

Abstract: Some binary liquid mixtures display ?microheterogeneity? (MH), where molecular clustering of each component is observed on the microscale, but on the macroscale the components are fully miscible. This is suggested to be the reason behind certain mixture characteristics, such as non-ideal thermodynamic quantities and water activity. Our overarching project aims to investigate how the structure of binary solvent mixtures influences the outcome of solute recrystallisation. The groups prior work using MH water-acetonitrile mixtures has shown that solute-solute and solute-solvent interactions change with the occurrence of solvent clustering. Water-DMF mixtures have been chosen for this experiment, as MD simulations suggest these mixtures show MH. Water, DMF and mixtures are valuable solvents in industrial synthesis and recrystallisation, hence it is important to know how these solvents are structured so we can link structure to experimental outcomes. We propose to investigate mixtures at 15, 35 & 50 mole% DMF as this will provide a wide compositional range to gauge clear differences in the solution structure. 7 isotopic substitutions will be used to differentiate between DMF and water hydrogen atoms, totalling to 21 samples. Assuming 4 hours per sample and 2 hours per standard, we request 5 days of beamtime on NIMROD. This will (dis-)prove the existence of molecular clustering and provide a baseline for future experiments investigating these mixtures with solute.

Principal Investigator: Dr Katharina Edkins
Experimenter: Miss Abbie Madden
Local Contact: Dr Tom Headen
Experimenter: Dr Benjamin Vella
Experimenter: Mr Alexander Park

DOI: 10.5286/ISIS.E.RB2510442

ISIS Experiment Number: RB2510442

Publisher: STFC ISIS Neutron and Muon Source

Data format: RAW/Nexus
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Data Citation

The recommended format for citing this dataset in a research publication is as:
[author], [date], [title], [publisher], [doi]

For Example:
Dr Katharina Edkins et al; (2025): Microheterogeneity structure of water-dimethylformamide (DMF) mixtures, STFC ISIS Neutron and Muon Source, https://doi.org/10.5286/ISIS.E.RB2510442

Data is released under the CC-BY-4.0 license.