Deep eutectic solvents from 2021 to 2026: A curated DOI-resolved database of selected physicochemical and thermophysical properties

Deep eutectic solvents (DESs) have emerged as one of the most rapidly expanding classes of designer solvents, attracting considerable interest across chemistry, chemical engineering, separation science, electrochemistry, biomass processing, materials science, and pharmaceutical applications. The continuous growth of DES research has generated a vast amount of physicochemical information; however, these data remain dispersed across a large and heterogeneous body of literature, limiting their accessibility, comparability, and reuse. The objective of the present study was to develop a curated, DOI-resolved physicochemical database of DESs reported during the period 2021–2026, focusing on six commonly reported properties: density, viscosity, electrical conductivity, surface tension, refractive index, and melting point. A systematic literature search was performed in Scopus using the query TITLE (“deep eutectic solvents”), yielding 9767 records. A multi-stage triage and prioritization framework was subsequently applied to identify studies containing extractable physicochemical measurements. Data were extracted using a structured JSON-based protocol, followed by DOI resolution, HBA/HBD standardization, DES harmonization, duplicate removal, quality control, and measurement-level database reconstruction. A hierarchical evidence architecture linking all measurements to their original publications through REF_ID and DOI identifiers was implemented. The final database contains 89 DOI-resolved studies, 496 unique DES systems, 64 canonical HBA identities, 124 canonical HBD identities, 234 unique HBA–HBD combinations, and 16,793 physicochemical measurements. Six major physicochemical properties were represented, including density (7304 measurements), viscosity (5782), conductivity (1427), refractive index (1215), surface tension (1024), and melting point (41). The database encompasses a diverse chemical space including choline-based DESs, ammonium-derived DESs, natural deep eutectic solvents (NADESs), hydrophobic DESs, metal-containing DESs, and a broad range of emerging DES systems. Evidence-based ranking further identified the most extensively characterized reference DES systems reported in the contemporary literature. Beyond providing an updated data resource for selected physicochemical and thermophysical DES properties, the database introduces a measurement-level, DOI-resolved, and evidence-traceable framework for DES data integration. Chemical descriptors, biological compatibility metrics, and aqueous-DES behavior are recognized as important complementary data layers and are discussed as future extensions requiring dedicated extraction and validation protocols.