{"title":"Mixing Laws and Chemical Reaction Mechanisms for Predicting the LBV of CH4/CSC Gases Premixed Flame","authors":"Yu Liu, Mengmeng Luo, Xiaoxiao Chen, Wen Zeng, Fuchao Tian, Yuntao Liang","doi":"10.1002/kin.70023","DOIUrl":"https://doi.org/10.1002/kin.70023","url":null,"abstract":"<div>\u0000 \u0000 <p>Coal spontaneous combustion (CSC) process releases a large number of combustible gases, which bring threat to the combustion and explosion of mine methane (CH<sub>4</sub>). Under the action of CSC, the combustion characteristics of CH<sub>4</sub> will undergo significant changes. In the current work, the laminar burning velocity (LBV) of CH<sub>4</sub>/CSC gases mixed flame was obtained in a constant volume chamber (CVC) under an initial pressure of 0.1 MPa and an initial temperature of 300 K over a wide equivalence ratio range of 0.7–1.3 with three kinds of CSC gases mixing ratios. The effects of CSC gases addition on the LBV of CH<sub>4</sub> were analyzed first. And then, four kinds of mixing laws were used to predict the LBV of CH<sub>4</sub>/CSC gases mixed flame. In addition, six kinds of detailed reaction mechanisms were used to calculate the LBV of CH<sub>4</sub>/CSC gases mixed flame. Results show that the mixing of all kinds of CSC gases increases the LBV of CH<sub>4</sub>, and <i>T</i> mixing law is more suitable for predicting the LBV of CH<sub>4</sub> mixed with CSC gases in the second stage, while the modified and simplified USC 2.0 mechanism can predict the LBV of CH<sub>4</sub> mixed with CSC gases well in all three stages.</p>\u0000 </div>","PeriodicalId":13894,"journal":{"name":"International Journal of Chemical Kinetics","volume":"58 3","pages":"71-85"},"PeriodicalIF":1.6,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146136641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Complex Effect of Ascorbic Acid on the H2O2–SCN−–OH−–Cu2+–Type Chemical Oscillators—Experimental Studies and Numerical Modeling","authors":"Mateusz Thomas, Marek Orlik","doi":"10.1002/kin.70021","DOIUrl":"https://doi.org/10.1002/kin.70021","url":null,"abstract":"<div>\u0000 \u0000 <p>The complex effect of L-ascorbic acid on the oscillatory course of the Orbán–Epstein system, in which the Cu<sup>2+</sup>-catalyzed oxidation of thiocyanate ions with hydrogen peroxide occurs, was investigated. Our studies involved both the original and EDTA-perturbed system, analyzed in previous works. Potentiometric and spectrophotometric measurements were supported by numerical modeling of the proposed schemes of interaction of L-ascorbic acid with the components of the system. In this way the kinetic mechanism of the effect of EDTA on the Orbán–Epstein system, based on the idea of excess production of <span></span><math>\u0000 <semantics>\u0000 <msubsup>\u0000 <mi>HO</mi>\u0000 <mn>2</mn>\u0000 <mo>•</mo>\u0000 </msubsup>\u0000 <annotation>${mathrm{HO}}_2^ bullet $</annotation>\u0000 </semantics></math> radicals, enhancing the negative feedback loop in the oscillation cycle, was confirmed. The eventual involvement of other radicals, as, for example, OS(O)CN<sup>•</sup> is possible, but kinetically indistinguishable from that of <span></span><math>\u0000 <semantics>\u0000 <msubsup>\u0000 <mi>HO</mi>\u0000 <mn>2</mn>\u0000 <mo>•</mo>\u0000 </msubsup>\u0000 <annotation>${mathrm{HO}}_2^ bullet $</annotation>\u0000 </semantics></math> species. The novel observation of the slowdown of oscillatory dynamics upon increasing concentrations of L-ascorbic was explained in terms of removal of HO<sub>2</sub>Cu(OH)<sub>2</sub><sup>−</sup> intermediate from reaction medium, presumably by the reduction of the central copper ion to elemental copper.</p>\u0000 </div>","PeriodicalId":13894,"journal":{"name":"International Journal of Chemical Kinetics","volume":"58 1-2","pages":"42-55"},"PeriodicalIF":1.6,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145831500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Further Mechanistic Orientation on the Oxidation of Sustainable Pectin Polysaccharide by Permanganate Ion in Acidic Media","authors":"Refat M. Hassan, Samia M. Ibrahim","doi":"10.1002/kin.70022","DOIUrl":"https://doi.org/10.1002/kin.70022","url":null,"abstract":"<div>\u0000 \u0000 <p>The kinetics of oxidation of pectin by acidic permanganate was studied at higher concentrations of pectin, previously. Consequently, the pseudo-first order plots of (ln (Abs. vs. time) were deviated from linearity. The results were interpreted in terms of two-stage reactions. Therefore, the results and postulated reaction mechanism were faced some debates which means that the redox reaction needs a further investigation. We expected that deviation may be attributed to the use of pectin of high concentration which leads to the creation of some complicated intermediates. These formed complexes may tend to retard the reaction rates and, hence, the noticed deviation from linearity. Therefore, in the present work pectin substrate of low concentrations was applied to check the linearity of pseudo first-order plots. Fortunately, all curves obtained from all plots were found to be fairly linear. This result was considered as evidence to support our expectation. Again, the experimental observations revealed second order rate constants in [H<sup>+</sup>] on contrary to that reported previously. Such diversity and contrariety observed may indicate the complexity and non-complementary nature of the present redox system. The activation parameters calculated by the least-squares method from the temperature dependency of the second-order rate constants were found to be ∆H<sup>≠</sup> = 52.67 kJ/mole, ∆S<sup>≠</sup> = –65.54 J/mole K, ∆G<sup>≠</sup> = 71.90 kJ/mole and E<sup>≠</sup> = 55.36 (±0.2–2.0 kJ/mole), respectively. However, the results obtained agreed with both inner and outer-sphere mechanism, a simultaneous two-electron change in one step of inner-sphere nature was suggested to be the more preferable pathway route for the electron-transfer. Speculated reaction mechanisms based on the experimental observations and the evaluated kinetic parameters were postulated and a pertinent discussion is presented.</p>\u0000 </div>","PeriodicalId":13894,"journal":{"name":"International Journal of Chemical Kinetics","volume":"58 1-2","pages":"56-65"},"PeriodicalIF":1.6,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145831499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nadia Sebbar, Henning Bockhorn, Dimosthenis Trimis
{"title":"A Computational Study of the Oxidation of the Phenanthryl Radical C14H9•: Thermochemistry and Possible Reaction Pathways","authors":"Nadia Sebbar, Henning Bockhorn, Dimosthenis Trimis","doi":"10.1002/kin.70020","DOIUrl":"https://doi.org/10.1002/kin.70020","url":null,"abstract":"<p>In this computational study, the reaction of the phenanthryl radical C<sub>14</sub>H<sub>9</sub>• (A<sub>3</sub>•) with molecular and atomic oxygen as part of the reaction mechanism of the oxidation of phenanthrene is investigated. Pathways resulting from the A<sub>3</sub>• + <sup>3</sup>O<sub>2</sub> and A<sub>3</sub>• + O reaction systems are examined using DFT quantum chemistry calculations. The energetics of the involved intermediates, products, and transition state structures are determined, as well as the kinetics of possible reaction pathways. Similar to the oxidation of smaller systems (A<sub>1</sub>• (phenyl) or A<sub>2</sub>• (naphthyl)), the addition of <sup>3</sup>O<sub>2</sub> to the phenanthryl radical A<sub>3</sub>• results in a peroxy radical C<sub>14</sub>H<sub>9</sub>OO• (A<sub>3</sub>OO•) with some 50 kcal mol<sup>−1</sup> of energy released, allowing further propagation and/or chain branching reactions. Standard enthalpies of formation as well as entropies and heat capacities are calculated using DFT methods (B3LYP, M06, APFD). Similar to the oxidation of the naphthyl radical, six primary subsequent pathways for the stabilized peroxy A<sub>3</sub>OO• are investigated with barriers below the energy of the starting point A<sub>3</sub>• + <sup>3</sup>O<sub>2</sub>. The reaction channels were investigated down to the next smaller PAH-radical (naphthyl A<sub>2</sub>•) and the corresponding reaction products. Important exothermic chain branching reactions are taking place, and several unsaturated oxygenated hydrocarbon intermediates are identified and determined. For the identified pathways, kinetic parameters based on canonical transition state theory (CTST) are calculated and reported in this study.</p>","PeriodicalId":13894,"journal":{"name":"International Journal of Chemical Kinetics","volume":"58 1-2","pages":"18-41"},"PeriodicalIF":1.6,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/kin.70020","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145831549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Kinetics and Equilibrium Studies on the Adsorption Performance of Methylene Blue onto Terracotta Clay","authors":"Rirhandzu Mhlarhi, Wasiu Babatunde Ayinde, Joshua Nosa Edokpayi","doi":"10.1002/kin.70019","DOIUrl":"https://doi.org/10.1002/kin.70019","url":null,"abstract":"<p>Methylene blue (MB), a toxic, carcinogenic, and persistent dye, has constantly contaminated aquatic systems, posing serious risks to human health and environmental safety. In this study, the potential of natural raw terracotta clay, herein termed (RTC), to effectively sequester cationic MB dye from aqueous solution was evaluated. Effects of variations in sorption time (5–180 min), adsorbent dosage (0.01–1.0 g), initial adsorbate concentration (2–50 mg/L), adsorbate pH (2–12), temperature (298–323 K), and water chemistry were investigated for its successful removal in batch experiments. The optimum pH for MB adsorption was attained at 10. The kinetic data were best fit by the pseudo-second-order model, while the Langmuir isotherm model justified the state of equilibrium data. RTC achieved a maximum adsorption capacity of 23.10 mg/g at 298 K. Thermodynamics investigations revealed that the reactions were viable, spontaneous, and exothermic. The clays’ characterization revealed that it was crystalline and mesoporous. Furthermore, RTC demonstrated consistent performance in removing MB from aqueous solution over five consecutive regeneration cycles, indicating its good reusability. RTC is thus suited for the cost-effective and environmental friendliness removal of MB from aqueous solutions.</p>","PeriodicalId":13894,"journal":{"name":"International Journal of Chemical Kinetics","volume":"58 1-2","pages":"3-17"},"PeriodicalIF":1.6,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/kin.70019","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145831486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amira Ali Mohammed Makoof Zabanoot, Fatima Mahad Said Issa Al Amri, Hanan Nooh Bilal Al Hamir, Lubna Musallam Ahmed Al Hadhri, Miysam Yaslam Al Abd Al-Hadhrami, Selvaraju Sivamani
{"title":"Adsorption of Hexavalent Chromium on Raw and Activated Cassava Rhizome: Kinetic Analysis Using Mechanistic and Empirical (Regression and ANN) Models","authors":"Amira Ali Mohammed Makoof Zabanoot, Fatima Mahad Said Issa Al Amri, Hanan Nooh Bilal Al Hamir, Lubna Musallam Ahmed Al Hadhri, Miysam Yaslam Al Abd Al-Hadhrami, Selvaraju Sivamani","doi":"10.1002/kin.70017","DOIUrl":"https://doi.org/10.1002/kin.70017","url":null,"abstract":"<div>\u0000 \u0000 <p>Heavy metals adsorption by adsorbents prepared from natural materials is a low-cost, effective method for their removal from aqueous environments. This study aims to investigate the kinetic studies on the adsorption of hexavalent chromium from its aqueous solution on raw and activated cassava rhizome. The coarse and fine raw cassava rhizome powder was activated by thermal (drying), pyrolysis, 1% (v/v) acetic acid, and 1% (w/v) KOH solutions. The batch adsorption studies were carried out by varying time (0–60 min) with adsorption capacity (meq/g) as a dependent variable. Adsorption capacity increased with an increase in time up to 40 min and then remained constant for all adsorbents with variation in adsorption capacity from 1.5 to 2.1 meq/g in the order of fine pyrolysis > fine thermal > fine acid = coarse pyrolysis > fine alkali = coarse thermal > coarse acid > coarse alkali > raw fine > raw coarse. Then, the effect of time on adsorption capacity data was fit to mechanistic models of pseudo-first, pseudo-second, zeroth, and half-order kinetics. Adsorption of hexavalent chromium on raw coarse and fine cassava rhizome powder followed pseudo-first-order kinetics. Also, the data were fit to empirical models based on regression and neural network, and the goodness of model fit was evaluated using the correlation coefficient (<i>R</i>). Regression analysis indicates the optimal fit with an <i>R</i> value of 0.9948 when the effect of time on adsorption capacity was investigated. Neural network analysis reveals the best fit at an <i>R</i> value of 0.9985. Hence, a higher rate constant for fine particles compared to coarse particles indicates that fine particles have a greater effective surface area and enhanced diffusional properties, facilitating more efficient adsorption, which suggests that the finer particles interact more with the adsorbate, allowing for quicker transport and adsorption processes.</p>\u0000 </div>","PeriodicalId":13894,"journal":{"name":"International Journal of Chemical Kinetics","volume":"57 12","pages":"733-743"},"PeriodicalIF":1.6,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145366274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sonal B. Uplapwar, Umesh Fegade, Tariq Altalhi, Jayashri D. Bhirud
{"title":"Efficient Removal of Basic Fuchsin Dye Using a Novel SnOFe2O3TiO2 Nanocomposite: Synthesis, Characterization, and Adsorption Statistic","authors":"Sonal B. Uplapwar, Umesh Fegade, Tariq Altalhi, Jayashri D. Bhirud","doi":"10.1002/kin.70013","DOIUrl":"https://doi.org/10.1002/kin.70013","url":null,"abstract":"<div>\u0000 \u0000 <p>The present study investigates the adsorption performance of SnOFe<sub>2</sub>O<sub>3</sub>TiO<sub>2</sub> nanocomposite for the removal of Basic Fuchsin (BF) dye from aqueous solution. The nanocomposite was synthesized via the coprecipitation method and characterized using various techniques such as TEM, SAED, and EDAX. TEM images confirmed the nanocomposite's crystalline structure with nanoscale particle sizes, while SAED patterns revealed its polycrystalline nature. EDAX analysis revealed the presence of Ti (54.9%), O (39.5%), Fe (4.8%), and Sn (0.7%), indicating TiO<sub>2</sub> as the dominant phase, with Fe and Sn contributing additional functionalities. Adsorption experiments were conducted to examine the effect of various operational parameters, such as pH, contact time, adsorbent dose, and initial dye concentration. The adsorption capacity increased with pH, reaching a maximum at pH 8.5. The adsorption process followed pseudo-second-order kinetics with a high correlation coefficient (<i>R</i><sup>2</sup> = 0.99), indicating chemisorption as the primary mechanism. The Langmuir isotherm model best described the equilibrium data, with a maximum adsorption capacity (<i>Q</i><sub>max</sub>) of 344.42 mg/g at 25°C. Thermodynamic analysis showed that the adsorption process was spontaneous and exothermic, with a slightly negative enthalpy change (Δ<i>H</i>°) of −0.008314 kJ/mol and a negative Gibbs free energy (Δ<i>G</i>°) of −3.150 kJ/mol at 298 K. The SnOFe<sub>2</sub>O<sub>3</sub>TiO<sub>2</sub> nanocomposite exhibited excellent reusability, retaining over 90.71% of its adsorption capacity after five consecutive cycles of regeneration using a simple desorption process. These results demonstrate the potential of SnOFe<sub>2</sub>O<sub>3</sub>TiO<sub>2</sub> nanocomposite as a highly efficient and sustainable adsorbent for the removal of BF dye from wastewater.</p>\u0000 </div>","PeriodicalId":13894,"journal":{"name":"International Journal of Chemical Kinetics","volume":"57 12","pages":"716-732"},"PeriodicalIF":1.6,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145366414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Performance of the Water-Lean Mixture of 2-Amino-2-Methyl-1,3-Propanediol, Ethylene Glycol, and Propanol in CO2 Separation From Simulated Biogas","authors":"Shaurya Mohan, Prakash D. Vaidya","doi":"10.1002/kin.70012","DOIUrl":"https://doi.org/10.1002/kin.70012","url":null,"abstract":"<div>\u0000 \u0000 <p>AMPD (2-Amino-2-methyl-1,3-propanediol) is a candidate hindered amine for CO<sub>2</sub> separation from biogas. In this study, the performance of water-lean mixtures of AMPD with the organic solvents ethylene glycol (EG) and propanol (PrOH) was explored. Hindered amines load more CO<sub>2</sub>, while organic solvents desorb CO<sub>2</sub> at low temperature. As a result, the proposed mixtures will be useful for improved CO<sub>2</sub> removal from biogas. Thus, CO<sub>2</sub> solubility in the blends AMPD/H<sub>2</sub>O (AMPD = 1 M) and AMPD/EG/PrOH/H<sub>2</sub>O (AMPD = 1 M, EG:PrOH = 1:1, H<sub>2</sub>O = 15 wt.%) was measured at 303, 313, and 323 K. The equilibrium CO<sub>2</sub> partial pressure varied in the 0.05–240 kPa range. Upon replacing water with the chosen organic solvents, the rate of CO<sub>2</sub> desorption in AMPD doubled, and low-temperature regeneration (<i>T</i> = 363 K) was possible. Besides, the heat of CO<sub>2</sub> absorption was lowered too, as evident from the Gibbs–Helmholtz equation. Since these outcomes were encouraging, absorption kinetics were also studied in the fast pseudo-first order reaction regime using the stirred cell technique and rate constants at 308 K were reported. Such water-lean mixtures were hitherto scarcely studied, and we filled this gap in this work.</p>\u0000 </div>","PeriodicalId":13894,"journal":{"name":"International Journal of Chemical Kinetics","volume":"57 12","pages":"705-715"},"PeriodicalIF":1.6,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145366462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of Mixed Micellization Behavior of Gemini Surfactants on Kinetic Hydrolysis of Carboxylate Ester: A Comparative Study With Single Micellization System","authors":"Deepti Tikariha Jangde, Anjali Sinha, Birendra Kumar","doi":"10.1002/kin.70014","DOIUrl":"https://doi.org/10.1002/kin.70014","url":null,"abstract":"<div>\u0000 \u0000 <p>The hydrolysis of carboxylate ester, that is, p-nitrophenyl acetate (PNPA) with α-nucleophiles, such as acetohydroxamic acid (AHA) and benzohydroxamic acid (BHA), has been studied in mixed surfactant systems (CTAB + C<sub>16</sub>-10-C<sub>16</sub>, 2Br<sup>−</sup>; CTPB + C<sub>16</sub>-10-C<sub>16</sub>, 2Br<sup>−</sup>; CTAB + C<sub>16</sub>-12-C<sub>16</sub>, 2Br<sup>−</sup>; and CTPB + C<sub>16</sub>-12-C<sub>16</sub>, 2Br<sup>−</sup>) at pH 8.0 and 27°C. Each reaction proceeded with pseudo-first-order kinetics. The rate of reactions with a system of mixed gemini surfactants has been shown to accelerate noticeably. The gemini mixed system had a higher rate constant than the single surfactant system. Gemini surfactants' spacer length has been tested in single systems, and their rate data are contrasted with those of monomeric surfactants, such as cetytrimethylammonium bromide (CTAB) and cetytriphenylphosphonium bromide (CTPB).</p>\u0000 </div>","PeriodicalId":13894,"journal":{"name":"International Journal of Chemical Kinetics","volume":"57 12","pages":"697-704"},"PeriodicalIF":1.6,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145366268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Kinetics and Thermodynamics of Tautomerization Reactions of 1,1- and 1,2-Ethenediols","authors":"Judith Würmel, John M. Simmie","doi":"10.1002/kin.70011","DOIUrl":"https://doi.org/10.1002/kin.70011","url":null,"abstract":"<p>Tautomerism is a common phenomenon amongst organic molecules with easily interconvertible isomers, which can impact drug action and toxicity. Here we are interested in the enols of carboxylic acids, which are known to be much less stable than their acid counterparts. We are concerned primarily with hydrogen-atom transfer reactions or keto <span></span><math>\u0000 <semantics>\u0000 <mo>⇌</mo>\u0000 <annotation>$rightleftharpoons$</annotation>\u0000 </semantics></math> enol tautomerism in ethenediols leading to acetic acid or glycoaldehyde and in particular the chemical kinetics at low temperatures where quantum mechanical tunneling plays a key role in the rates of reaction. We consider both the direct tautomerization reactions and those that are mediated by a water molecule, where the hydrogen transfer is facilitated by the formation of a low energy pre-reaction complex, and we present energy barriers for conformer isomerizations and hydrogen transfer reactions. We provide thermochemical data, including heats of formation, standard entropy, heat capacity, and enthalpy change for all isomeric forms of molecules under investigation.</p>","PeriodicalId":13894,"journal":{"name":"International Journal of Chemical Kinetics","volume":"57 12","pages":"687-696"},"PeriodicalIF":1.6,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/kin.70011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145366959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}