Fundamental concepts in chemical kinetics

Schmitz, Guy; Lente, Gábor

doi:10.1007/s40828-019-0096-1

Cited by 19 publications

(5 citation statements)

References 20 publications

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“…The reaction rate, i.e., the rate at which α cures (dα/dt), is expressed in Equation ( 4). α can also be expressed as the degree of curing [43,44]. The area of the total calorific value was integrated over time to analyze the change in the curing degree over time.…”

Section: Comparison Of Odor Intensities and Voc Emissions For Dpetmp ...mentioning

confidence: 99%

Effect of Synthetic Low-Odor Thiol-Based Hardeners Containing Hydroxyl and Methyl Groups on the Curing Behavior, Thermal, and Mechanical Properties of Epoxy Resins

et al. 2023

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A novel thiol-functionalized polysilsesqioxane containing hydroxyl and methyl groups was synthesized using a simple acid-catalyzed sol–gel method to develop an epoxy hardener with low odor, low volatile organic compound (VOC) emissions, and fast curing at low temperatures. The synthesized thiol-based hardeners were characterized using Fourier transform infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis (TGA), and gel permeation chromatography and compared with commercially available hardeners in terms of odor intensity and VOC emissions using the air dilution olfaction method and VOC analysis. The curing behavior and thermal and mechanical properties of the epoxy compounds prepared with the synthesized thiol-based hardeners were also evaluated. The results showed that synthetic thiol-based hardeners containing methyl and hydroxyl groups initiated the curing reaction of epoxy compounds at 53 °C and 45 °C, respectively. In contrast, commercial thiol-based hardeners initiated the curing reaction at 67 °C. Additionally, epoxy compounds with methyl-containing synthetic thiol-based hardeners exhibited higher TGA at a 5% weight loss temperature (>50 °C) and lap shear strength (20%) than those of the epoxy compounds with commercial thiol-based hardeners.

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Section: Comparison Of Odor Intensities and Voc Emissions For Dpetmp ...mentioning

confidence: 99%

Effect of Synthetic Low-Odor Thiol-Based Hardeners Containing Hydroxyl and Methyl Groups on the Curing Behavior, Thermal, and Mechanical Properties of Epoxy Resins

et al. 2023

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“…Equation ( 3) is the most commonly used form of TST, which omits complex considerations of the partition functions of the reactant and the activated complex, and thus does not take into account the motion over the saddle point [72]. This equation is presented in the simplest form (apart from the temperature) with a single frequency variable ν:…”

Section: Discussionmentioning

confidence: 99%

Elements of Transition-State Theory in Relation to the Thermal Dissociation of Selected Solid Compounds

Mianowski,

Radko,

Bigda

2024

Energies

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An analysis was carried out on the thermal dissociation of selected inorganic salts according to Transition-State Theory (TST). For this purpose, two possibilities were compared in the context of rate constants: in the first case using the Arrhenius constant directly from TST, and in the second, using the thermodynamic equilibrium constant of the reaction/process of active state formation. The determined relationships are presented in the form of temperature profiles. It was established that TST applies to reactions for which there is a formally and experimentally reversible reaction, in the literal sense or catalytic process. The importance of the isoequilibrium temperature, which results from the intersection of the thermodynamic temperature profile and the Gibbs free energy of activation, was demonstrated. Its values close to the equilibrium temperature are indicative of more dynamic kinetic qualities. As part of the discussion, the Kinetic Compensation Effect (KCE) was used to observe changes in the entropy of activation by comparing two kinetic characteristics of the same reaction. Enthalpy–Entropy Compensation (EEC) was shown to be the same law as KCE, just expressed differently. This was made possible by TST, specifically the entropy of activation at isokinetic temperature, by which the perspective of the relationship of energy effects changes.

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“…Equilibrium constants depend on the ionic strength and consequently the kinetic constants also depend on it [24]. It is not possible to take this effect exactly into account but we note that most monovalent ions have an activity coefficient  near 0.70-0.75 in the range of ionic strengths of most of our experiments (0.1 to 0.2 M) and we use values of the kinetic constants estimated if  ~ 0.7.…”

Section: Appendix Rate Constantsmentioning

confidence: 99%

“…However, many reactions of Table I are not elementary and the use of this principle may be open to criticism. We have offered another proof introducing the concept of quasi-elementary reaction [24]. It is defined as a reaction with a well-defined stoichiometry and rate orders corresponding to this stoichiometry.…”

Section: Introductionmentioning

confidence: 99%

Kinetics and mechanism of I(+ 3) reactions and consequences for other iodine reactions

Schmitz

Furrow

2022

Reac Kinet Mech Cat

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This article presents new kinetic studies of the disproportionation of I(+3) and of its oxidation by H2O2. It also provides an update of the previously proposed model for reactions of iodine compounds with oxidation numbers from -1 to +5 with each other and with H2O2.This model explains the kinetics of several reactions, including the oxidation of iodine by H2O2. We show that the reduction of HOI by H2O2 results from HOI + H2O2  HOOI + H2O followed by the reversible reaction HOOI  I -+ H + + O2. An analysis of previous measurements of the kinetic constant k(HOI + H2O2) explains the large differences between the values proposed in the literature and gives k(HOI + H2O2) = 6 M -1 s -1 . The reversibility of the reaction HOOI  I -+ H + + O2 suggests a new explanation for the effect of oxygen on the Bray-Liebhafsky reaction. H2O2 would oxidize HOOI by a radical mechanism. ManuscriptClick here to access/download;Manuscript;Studies of I(+3) reac revised.docx Click here to view linked References

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Fundamental concepts in chemical kinetics

Cited by 19 publications

References 20 publications

Effect of Synthetic Low-Odor Thiol-Based Hardeners Containing Hydroxyl and Methyl Groups on the Curing Behavior, Thermal, and Mechanical Properties of Epoxy Resins

Effect of Synthetic Low-Odor Thiol-Based Hardeners Containing Hydroxyl and Methyl Groups on the Curing Behavior, Thermal, and Mechanical Properties of Epoxy Resins

Elements of Transition-State Theory in Relation to the Thermal Dissociation of Selected Solid Compounds

Kinetics and mechanism of I(+ 3) reactions and consequences for other iodine reactions

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