{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,24]],"date-time":"2026-09-24T11:04:22Z","timestamp":1790247862300,"version":"4.1.0"},"reference-count":38,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2026,9,24]],"date-time":"2026-09-24T00:00:00Z","timestamp":1790208000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Dielectric relaxation of n-propanol and isopropanol was examined by radio-frequency measurements at seven fixed frequencies (0.3\u201332 MHz) over +20 to \u2212160 \u00b0C and by openCOSMO-RS calculations. Apparent characteristic times were assigned from dielectric-loss maxima and analyzed with Arrhenius and Eyring formalisms. Nine temperature scans were available for each sample, obtained with three independent measuring capacitors and three repeat scans per capacitor. Capacitor-specific Arrhenius fits gave apparent activation energies of 21.30 \u00b1 0.16 kJ mol\u22121 (SD; 95% CI of the mean 20.91\u201321.69) for n-propanol and 21.99 \u00b1 0.16 kJ mol\u22121 (95% CI 21.60\u201322.38) for isopropanol. A conservative Welch comparison of the three independent-capacitor estimates gave \u0394Ea = 0.687 kJ mol\u22121 (95% CI 0.332\u20131.042, p = 0.0058). Although this sub-kJ difference is statistically distinguishable in the cell-level analysis, it is not considered to have mechanistic significance because systematic temperature uncertainty and unresolved spectral overlap are not included in that comparison. Eyring activation enthalpies are 19.60 \u00b1 0.15 and 20.23 \u00b1 0.15 kJ mol\u22121 (SD), respectively. Entropy and Gibbs-energy values are reported only as apparent quantities under \u03ba = 1. openCOSMO-RS yields liquid-to-n-hexane infinite-dilution transfer enthalpies of 30.5 and 28.0 kJ mol\u22121. These transfer quantities include hydrogen bonding and nonspecific solvation, dispersion, and packing contributions and are therefore not identified with hydrogen-bond enthalpies. Literature calorimetry gives lower neat-alcohol hydrogen-bonding enthalpy magnitudes of approximately 17 kJ mol\u22121. Kirkwood factors above unity indicate strong static orientational correlation. Because the seven-frequency window does not independently resolve the Debye and structural \u03b1 processes, the kinetic parameters are interpreted as effective descriptors of the dominant dielectric-loss process rather than mode-specific barriers.<\/jats:p>","DOI":"10.3390\/molecules31193405","type":"journal-article","created":{"date-parts":[[2026,9,24]],"date-time":"2026-09-24T10:16:28Z","timestamp":1790244988000},"page":"3405","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Dielectric Relaxation and Equilibrium Thermodynamic Descriptors in Propanol Isomers: Radio-Frequency Measurements and openCOSMO-RS Analysis"],"prefix":"10.3390","volume":"31","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6252-1512","authenticated-orcid":false,"given":"Samir","family":"Azizov","sequence":"first","affiliation":[{"name":"Institute of Physics PLE, Ministry of Science and Education of the Republic of Azerbaijan, H. Javid Avenue, 131, Baku AZ-1073, Azerbaijan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9696-2199","authenticated-orcid":false,"given":"Tarana","family":"Nurubeyli","sequence":"additional","affiliation":[{"name":"Institute of Physics PLE, Ministry of Science and Education of the Republic of Azerbaijan, H. Javid Avenue, 131, Baku AZ-1073, Azerbaijan"},{"name":"Risk Assessment and Management Research Center, Azerbaijan University of Architecture and Construction, Baku AZ-1073, Azerbaijan"},{"name":"Department of Physics and Electronics, Khazar University, Mahsati Str. 41, Baku AZ-1096, Azerbaijan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kamala","family":"Khalilova","sequence":"additional","affiliation":[{"name":"Institute of Physics PLE, Ministry of Science and Education of the Republic of Azerbaijan, H. Javid Avenue, 131, Baku AZ-1073, Azerbaijan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"data-curation","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"}]},{"given":"Nazakat","family":"Kerimli","sequence":"additional","affiliation":[{"name":"Department of Medical and Biological Physics Department, Azerbaijan Medical University, Samad Vurgun St.167, Baku AZ-1022, Azerbaijan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"software","vocabulary":"credit"}]},{"given":"Gunay M.","family":"Iskenderova","sequence":"additional","affiliation":[{"name":"Institute of Physics PLE, Ministry of Science and Education of the Republic of Azerbaijan, H. Javid Avenue, 131, Baku AZ-1073, Azerbaijan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-4766-5299","authenticated-orcid":false,"given":"Asim","family":"Abdulla","sequence":"additional","affiliation":[{"name":"Department of Electronics and Energy Engineering, Nakhchivan State University, A. Aliyev 11, Nakhchivan AZ-7000, Azerbaijan"},{"name":"Department of Electrical and Electronics Engineering, Zonguldak B\u00fclent Ecevit University, 67100 Zonguldak, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"project-administration","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"}]},{"given":"Gultamam","family":"Ganizade","sequence":"additional","affiliation":[{"name":"Institute of Physics PLE, Ministry of Science and Education of the Republic of Azerbaijan, H. Javid Avenue, 131, Baku AZ-1073, Azerbaijan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"data-curation","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6906-5211","authenticated-orcid":false,"given":"Ijabika","family":"Sardarova","sequence":"additional","affiliation":[{"name":"Department of Elektronics and Automation, Azerbaijan State Oil and Industry University, Azadliq Avenue, 20, Baku AZ-1010, Azerbaijan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"visualization","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0009-0000-5699-3054","authenticated-orcid":false,"given":"Orxan","family":"Aliyev","sequence":"additional","affiliation":[{"name":"Institute of Physics PLE, Ministry of Science and Education of the Republic of Azerbaijan, H. Javid Avenue, 131, Baku AZ-1073, Azerbaijan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"data-curation","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"}]},{"given":"Sajara","family":"Nabieva","sequence":"additional","affiliation":[{"name":"Institute of Physics PLE, Ministry of Science and Education of the Republic of Azerbaijan, H. Javid Avenue, 131, Baku AZ-1073, Azerbaijan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"data-curation","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"}]},{"given":"Afet","family":"Karimova","sequence":"additional","affiliation":[{"name":"Institute of Physics PLE, Ministry of Science and Education of the Republic of Azerbaijan, H. Javid Avenue, 131, Baku AZ-1073, Azerbaijan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"software","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0296-1131","authenticated-orcid":false,"given":"Jeyhun","family":"Guliyev","sequence":"additional","affiliation":[{"name":"Institute of Physics PLE, Ministry of Science and Education of the Republic of Azerbaijan, H. Javid Avenue, 131, Baku AZ-1073, Azerbaijan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"13473","DOI":"10.1021\/jp206665w","article-title":"Hydrogen Bonding and Molecular Aggregates in Liquid Methanol, Ethanol, and 1-Propanol","volume":"115","author":"Gereben","year":"2011","journal-title":"J. Phys. Chem. B"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"18739","DOI":"10.1039\/C7CP02884A","article-title":"The origin of the Debye relaxation in liquid water and fitting the high-frequency excess response","volume":"19","author":"Elton","year":"2017","journal-title":"Phys. Chem. Chem. Phys."},{"key":"ref_3","unstructured":"B\u00f6ttcher, C.J.F., and Bordewijk, P. (1978). Theory of Electric Polarization, Vol. II: Dielectrics in Time-Dependent Fields, Elsevier."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1016\/j.physrep.2014.07.005","article-title":"Structure and dynamics of monohydroxy alcohols\u2014Milestones towards their microscopic understanding, 100 years after Debye","volume":"545","author":"Gainaru","year":"2014","journal-title":"Phys. Rep."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1294","DOI":"10.1021\/j100888a033","article-title":"Microwave Absorption and Molecular Structure in Liquids. LXII. The Three Dielectric Dispersion Regions of the Normal Primary Alcohols","volume":"69","author":"Garg","year":"1965","journal-title":"J. Phys. Chem."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"258303","DOI":"10.1103\/PhysRevLett.105.258303","article-title":"Nuclear-Magnetic-Resonance Measurements Reveal the Origin of the Debye Process in Monohydroxy Alcohols","volume":"105","author":"Gainaru","year":"2010","journal-title":"Phys. Rev. Lett."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2960","DOI":"10.1021\/acs.jpcb.0c10970","article-title":"Is a Dissociation Process Underlying the Molecular Origin of the Debye Process in Monohydroxy Alcohols?","volume":"125","author":"Soszka","year":"2021","journal-title":"J. Phys. Chem. B"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"058201","DOI":"10.1103\/PhysRevLett.132.058201","article-title":"Hydrogen Bonding Exchange and Supramolecular Dynamics of Monohydroxy Alcohols","volume":"132","author":"Cheng","year":"2024","journal-title":"Phys. Rev. Lett."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"L043403","DOI":"10.1103\/yvnc-2tmw","article-title":"Molecular Dynamics Insights into the Debye Process of 1-Propanol","volume":"113","author":"Gabriel","year":"2026","journal-title":"Phys. Rev. E"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"098201","DOI":"10.1103\/PhysRevLett.130.098201","article-title":"Molecular Mechanism of the Debye Relaxation in Monohydroxy Alcohols Revealed from Rheo-Dielectric Spectroscopy","volume":"130","author":"Patil","year":"2023","journal-title":"Phys. Rev. Lett."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"144503","DOI":"10.1063\/1.4823998","article-title":"Dynamics of glass-forming liquids. XVII. Dielectric relaxation and intermolecular association in a series of isomeric octyl alcohols","volume":"139","author":"Singh","year":"2013","journal-title":"J. Chem. Phys."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1484","DOI":"10.1063\/1.1748105","article-title":"Dielectric Relaxation in Glycerol, Propylene Glycol, and n-Propanol","volume":"19","author":"Davidson","year":"1951","journal-title":"J. Chem. Phys."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1756","DOI":"10.1063\/1.1740575","article-title":"Dielectric Properties of Liquid Ethanol and 2-Propanol","volume":"23","author":"Hassion","year":"1955","journal-title":"J. Chem. Phys."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"4634","DOI":"10.1063\/1.1346635","article-title":"Effects of induced steric hindrance on the dielectric behavior and H bonding in the supercooled liquid and vitreous alcohol","volume":"114","author":"Johari","year":"2001","journal-title":"J. Chem. Phys."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"10789","DOI":"10.1063\/1.1620996","article-title":"The cooperative dynamics of the H-bond system in 2-propanol\/water mixtures: Steric hindrance effects of nonpolar head group","volume":"119","author":"Sato","year":"2003","journal-title":"J. Chem. Phys."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1016\/B978-0-444-64235-6.50003-6","article-title":"COSMO-RS: From Quantum Chemistry to Fluid Phase Thermodynamics","volume":"43","author":"Klamt","year":"2018","journal-title":"Comput. Aided Chem. Eng."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"114250","DOI":"10.1016\/j.fluid.2024.114250","article-title":"Predicting Solvation Free Energies for Neutral Molecules in Any Solvent with openCOSMO-RS","volume":"589","author":"Nevolianis","year":"2025","journal-title":"Fluid Phase Equilib."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"113472","DOI":"10.1016\/j.fluid.2022.113472","article-title":"An open source COSMO-RS implementation and parameterization supporting the efficient implementation of multiple segment descriptors","volume":"560","author":"Gerlach","year":"2022","journal-title":"Fluid Phase Equilib."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"e1338","DOI":"10.1002\/wcms.1338","article-title":"The COSMO and COSMO-RS Solvation Models","volume":"8","author":"Klamt","year":"2018","journal-title":"WIREs Comput. Mol. Sci."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"2224","DOI":"10.1021\/j100007a062","article-title":"Conductor-like Screening Model for Real Solvents: A New Approach to the Quantitative Calculation of Solvation Phenomena","volume":"99","author":"Klamt","year":"1995","journal-title":"J. Phys. Chem."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1132","DOI":"10.1002\/poc.977","article-title":"Calorimetric determination of hydrogen-bonding enthalpy for neat aliphatic alcohols","volume":"18","author":"Solomonov","year":"2005","journal-title":"J. Phys. Org. Chem."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"881","DOI":"10.1002\/qsar.200630152","article-title":"Enthalpy of Solvation Correlations for Gaseous Solutes Dissolved in Benzene and in Alkane Solvents Based on the Abraham Model","volume":"26","author":"Mintz","year":"2007","journal-title":"QSAR Comb. Sci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"3292","DOI":"10.1063\/1.455883","article-title":"The dielectric relaxation of mixtures of water and primary alcohol","volume":"90","author":"Mashimo","year":"1989","journal-title":"J. Chem. Phys."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"117489","DOI":"10.1016\/j.jphotochem.2026.117489","article-title":"Integrated experimental and DFT investigation of temperature-dependent dielectric relaxation and optical properties in the chlorobenzene\u2013iodobenzene\u2013n-hexane ternary system","volume":"482","author":"Hasanova","year":"2026","journal-title":"J. Photochem. Photobiol. A Chem."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"085002","DOI":"10.1088\/1361-6501\/abfd68","article-title":"Low Loss Dielectric Measurements in the Frequency Range 1\u201370 MHz by Using a Vector Network Analyser","volume":"32","author":"Gregory","year":"2021","journal-title":"Meas. Sci. Technol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"727","DOI":"10.1109\/TDEI.2006.1667730","article-title":"A review of RF and microwave techniques for dielectric measurements on polar liquids","volume":"13","author":"Gregory","year":"2006","journal-title":"IEEE Trans. Dielectr. Electr. Insul."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1329","DOI":"10.1109\/19.963206","article-title":"Improved calibration of impedance analyzers for measurements on highly conductive liquids","volume":"50","author":"Grosse","year":"2001","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"124501","DOI":"10.1063\/1.4868556","article-title":"Liquid 1-propanol studied by neutron scattering, near-infrared, and dielectric spectroscopy","volume":"140","author":"Matic","year":"2014","journal-title":"J. Chem. Phys."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"269","DOI":"10.1063\/1.1139320","article-title":"Precise measurement of dielectric properties at frequencies from 1 kHz to 100 MHz","volume":"58","author":"Kakimoto","year":"1987","journal-title":"Rev. Sci. Instrum."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"373","DOI":"10.1134\/S1063783425600980","article-title":"Electronic Structure and Dielectric Functions of GaInS3 from Ab Initio and Experimental Studies","volume":"67","author":"Jahangirli","year":"2025","journal-title":"Phys. Solid State"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"74","DOI":"10.1021\/je970136l","article-title":"Limiting Activity Coefficients in Alcohol-Containing Organic Solutions from Headspace Gas Chromatography","volume":"43","author":"Asprion","year":"1998","journal-title":"J. Chem. Eng. Data"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1086","DOI":"10.1063\/1.474456","article-title":"Dynamics of glass-forming liquids. III. Comparing the dielectric \u03b1- and \u03b2-relaxation of 1-propanol and o-terphenyl","volume":"107","author":"Hansen","year":"1997","journal-title":"J. Chem. Phys."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1389","DOI":"10.1063\/1.1700767","article-title":"High Frequency Dispersion in n-Propanol","volume":"20","author":"Cole","year":"1952","journal-title":"J. Chem. Phys."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"e70716","DOI":"10.1002\/pat.70716","article-title":"Influence of Polymer Matrix Polarity on Dielectric Relaxation and AC Conduction in Silicon\u2013Polymer Thin Composites","volume":"37","author":"Nurubeyli","year":"2026","journal-title":"Polym. Adv. Technol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"11170","DOI":"10.1063\/1.1811072","article-title":"Dynamics of glass-forming liquids. IX. Structural versus dielectric relaxation in monohydroxy alcohols","volume":"121","author":"Wang","year":"2004","journal-title":"J. Chem. Phys."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"911","DOI":"10.1063\/1.1750343","article-title":"The dielectric polarization of polar liquids","volume":"7","author":"Kirkwood","year":"1939","journal-title":"J. Chem. Phys."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"107","DOI":"10.1063\/1.1749604","article-title":"The Activated Complex in Chemical Reactions","volume":"3","author":"Eyring","year":"1935","journal-title":"J. Chem. Phys."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"273","DOI":"10.1016\/0021-9614(69)90047-0","article-title":"The thermodynamic properties of solutions of normal and branched alcohols in benzene and n-hexane","volume":"1","author":"Brown","year":"1969","journal-title":"J. Chem. Thermodyn."}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/31\/19\/3405\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,24]],"date-time":"2026-09-24T10:17:44Z","timestamp":1790245064000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/31\/19\/3405"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,24]]},"references-count":38,"journal-issue":{"issue":"19","published-online":{"date-parts":[[2026,10]]}},"alternative-id":["molecules31193405"],"URL":"https:\/\/doi.org\/10.3390\/molecules31193405","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,24]]}}}