Change In Reaction Rate Research Articles

Physicochemical properties and esterolytic reactivity of oxime functionalized surfactants in pH-responsive mixed micellar system

We present a comprehensive study of the aggregation properties of zwitterionic micelles of oxime-functionalized surfactants and their mixed micellar systems with conventional cationic CTABr and nonionic Tween® 80 surfactants. Analysis of the micellar effects on the reaction rates toward activated esters is also completed. Specifically, aggregation properties of micelles of amphiphilic 1-alkyl-3-methyl-2-(oximinomethyl)imidazolium and 1-alkyl-3(1-oximinoethyl)pyridinum bromides (alkyl=CnH2n+1, where n=12, 16) and their mixed micellar systems with CTABr and Tween® 80 have been investigated. The changes in micellar properties and reaction rates toward 4-nitrophenyl esters of diethyl phosphoric (NPDEP), diethyl phosphonic (NPDEPN), and toluenesulphonic (NPOTos) acids, with increase of pH ensuring deprotonation of specific oximate moiety, have been studied. We focused on the changes of micellar properties of mixed micelles depending on the mixture composition and the deprotonation degree of the functional oximate group. The critical micelle concentration (cmc) values, degrees of counterion binding (β), and size of micellar aggregates were obtained using surface tension measurements, dynamic light scattering method, bromide selective electrode, and by solubilization of hydrophobic dye Orange OT. The surface excess concentration (Гmax, μmol/m2), minimum area per molecule (Amin), interaction parameters (βm), standard Gibbs free energy of adsorption (ΔGadso) and micellization (ΔGmo), and excess free energy of micellization (ΔGex) have been evaluated. Micellar effects of the systems studied on the acyl transfer reaction rates were shown to increase with higher fraction of deprotonated oxime and can be treated in the framework of a pseudophase partitioning model. These results provide new information on (i) control the reactivity of the organized molecular systems and (ii) elaboration the basis for designing pH-responsive supramolecular assemblies.

Effect of hydrogen and propylene on the hydrogen peroxide decomposition over Pt, PtO and Au catalysts

The decomposition of hydrogen peroxide (H2O2) on Pt, PtO and Au catalysts has been investigated in the presence of nitrogen, propylene and hydrogen. H2O2 formation on the catalyst is known to be a key intermediate step for the direct synthesis of propylene oxide (PO) from hydrogen, propylene and oxygen. Therefore, during this reaction, H2O2 is in contact with the catalyst on which it is produced, propylene and hydrogen. In this work we investigate the effect of the simultaneous presence of a metal catalyst (Pt, Au) and these gases on the H2O2 decomposition. The presence of hydrogen favors the decomposition of H2O2 over all the studied catalysts. This is attributed to the combination of direct decomposition and hydrogenation reactions. Furthermore, hydrogen changes the catalyst from an oxidized to a more metallic state accelerating the H2O2 decomposition. We also observed the positive effect of propylene on decreasing the decomposition activity of Pt and Au. The experimental results were used to estimate reaction rate constants. The obtained rate constants hinted to changes of the catalyst during the decomposition as the main reason for reaction rate changes. This was confirmed to happen for Pt but not for the Au catalyst. The decrease of H2O2 decomposition on Au in the presence of propylene is due to their interaction where propylene blocks the Au active sites responsible for the H2O2 decomposition.

31 P magnetization transfer magnetic resonance spectroscopy: Assessing the activation induced change in cerebral ATP metabolic rates at 3 T.

PurposeIn vivo 31P magnetic resonance spectroscopy (MRS) magnetization transfer (MT) provides a direct measure of neuronal activity at the metabolic level. This work aims to use functional 31P MRS‐MT to investigate the change in cerebral adenosine triphosphate (ATP) metabolic rates in healthy adults upon repeated visual stimuli.MethodsA magnetization saturation transfer sequence with narrowband selective saturation of γ‐ATP was developed for 31P MT experiments at 3 T.ResultsUsing progressive saturation of γ‐ATP, the intrinsic T1 relaxation times of phosphocreatine (PCr) and inorganic phosphate (Pi) at 3 T were measured to be 5.1 ± 0.8 s and 3.0 ± 1.4 s, respectively. Using steady‐state saturation of γ‐ATP, a significant 24% ± 14% and 11% ± 7% increase in the forward creatine kinase (CK) pseudo‐first‐order reaction rate constant, k 1, was observed upon visual stimulation in the first and second cycles, respectively, of a paradigm consisting of 10‐minute rest followed by 10‐minute stimulation, with the measured baseline k 1 being 0.35 ± 0.04 s−1. No significant changes in forward ATP synthase reaction rate, PCr/γ‐ATP, Pi/γ‐ATP, and nicotinamide adenine dinucleotide/γ‐ATP ratios, or intracellular pH were detected upon stimulation.ConclusionThis work demonstrates the potential of studying cerebral bioenergetics using functional 31P MRS‐MT to determine the change in the forward CK reaction rate at 3 T. Magn Reson Med 79:22–30, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Dynamic reservoir-condition microtomography of reactive transport in complex carbonates: Effect of initial pore structure and initial brine pH

We study the impact of brine acidity and initial pore structure on the dynamics of fluid/solid reaction at high Péclet numbers and low Damköhler numbers. A laboratory μ-CT scanner was used to image the dissolution of Ketton, Estaillades, and Portland limestones in the presence of CO2-acidified brine at reservoir conditions (10MPa and 50°C) at two injected acid strengths for a period of 4h. Each sample was scanned between 6 and 10 times at ∼4μm resolution and multiple effluent samples were extracted. The images were used as inputs into flow simulations, and analysed for dynamic changes in porosity, permeability, and reaction rate. Additionally, the effluent samples were used to verify the image-measured porosity changes.We find that initial brine acidity and pore structure determine the type of dissolution. Dissolution is either uniform where the porosity increases evenly both spatially and temporally, or occurs as channelling where the porosity increase is concentrated in preferential flow paths. Ketton, which has a relatively homogeneous pore structure, dissolved uniformly at pH=3.6 but showed more channelized flow at pH=3.1. In Estaillades and Portland, increasingly complex carbonates, channelized flow was observed at both acidities with the channel forming faster at lower pH. It was found that the effluent pH, which is higher than that injected, is a reasonably good indicator of effective reaction rate during uniform dissolution, but a poor indicator during channelling. The overall effective reaction rate was up to 18 times lower than the batch reaction rate measured on a flat surface at the effluent pH, with the lowest reaction rates in the samples with the most channelized flow, confirming that transport limitations are the dominant mechanism in determining reaction dynamics at the fluid/solid boundary.

Coal type identification based on the emission spectra of a furnace flame

This paper presents a novel method of identifying coal type based on mechanistic methods. The ratio of the resonance line spectrum of a luminous flame and the continuous spectrum at the same wavelength eliminates the influence of temperature on spectral intensity. The atomic line spectra of Na and K are typical and significant over continuous flame spectra. The concentrations of elemental Na and K in the flame are exclusively relative to coal type and composition. Using an experimental furnace and charge-coupled device (CCD) optical spectrometer apparatus, the continuous spectra and atomic line spectra of Na and K elements were sampled from coal flames in real time. An empirical fitting method was used to simplify the formulas of absorption strength and flame temperature calculation, and rational solutions were obtained by using an iterative algorithm. Due to the change in reaction rate and absorption by soot particles, the relative contents of Na and K in a flame vary with the temperature and absorption strength. Arrhenius’s equation for temperature compensation was adopted. Compensation for soot density in the furnace was also satisfied by an exponential expression. At any one sampling position, the compensation parameters were identical for all coal types. After compensation for temperature and density of soot particles, the relative strength of the Na and K signals and the ratio between them uniquely matched the coal type burnt in various conditions. The results were replicated and verified in various conditions, and the response time of the system was of the order of seconds.

A coupled thermal decomposition model for coal particle pyrolysis

Based on the porous structure of coal, a coupled thermal decomposition model is developed to describe the coal pyrolysis process more fully and truly. It not only incorporates specific surface change in reaction rate during conversion, but also couples chemical reaction rate happened on pore surfaces with internal diffusion rate of the gaseous product. To validate the applicability of the model, three kinds of coal pyrolysis experiments were carried out. The results show that the model is suitable for all the three stages of coal pyrolysis, which realizes the unification of mechanisms in low-, middle- and high-temperature stages. One set of activation energy and pre-exponential factor is calculated for each stage of coal pyrolysis according to the slope and intercept of the corresponding fitting line. With these kinetic parameters, the numerical solution of this model is obtained. Compared the numerical solution with experimental values, the good agreement between them is observed, which validates the reliability of the model.

Thermophoresis effects on gas-particle phases flow behaviors in entrained flow coal gasifier using Eulerian model

A numerical model based on the Eulerian–Eulerian two-fluid approach is used to simulate the gasification of coal char inside an entrained flow gasifier. In this model, effects of thermophoresis of coal char particles are thoroughly investigated. The thermophoresis is due to the gas temperature gradient caused by absorptedheat of coal char gasification. This work, firstly, calculates the gas temperature gradient and thermophoretic force at 1100°C,1200°C,1300°C and 1400°C wall temperatures. Then, the changes of particle volume fraction and velocity in the gasifier are studied in the simulation with thermophoresis or not. The results indicate that considering the particle thermophoresis has some effects on the calculation of particle volume fraction in the gasifier, especially at wall temperature of 1400°C, and the maximum particle volume fraction variance ratio reaches up to 1.38% on wall surface of the gasifier. These effects are mainly caused by large gas temperature gradient along the radial direction of the gasifier. For the particle velocity, the changes are small but can be observable along radial direction of the gasifier, which has good agreement with the distributions of radial gas temperature gradient and thermophoretic force. These changes above may have certain effects on gasification reaction rates in this Eulerian model. So the change of gasification reaction rates in the simulation with thermophoresis or not is studied finally.

Effect of the fuel/air mixture concentration distribution on the dynamics of a low-emission combustor

An investigation of the low-emission premixed combustion in a conventional combustor is presented. The main problem encountered is the pressure fluctuations induced under certain operating conditions of the combustor. Low-emission operation of the combustor was studied numerically and experimentally. The effect of the concentration distribution at the outlet from the mixing zone on the position and macrostructure of the flame and the combustion stability was investigated at various excess air factors corresponding various GTU loads. It is demonstrated that, for a given excess air factor, there exists the concentration profile such that the interaction of the flame front with dominating flow structures results in excitation of the low-frequency combustion instability. The factors responsible for high-amplitude pressure fluctuations are examined. It is shown that the combustion stability can be estimated using a calculated criterion. Its direct relationship with pressure fluctuation amplitudes is described. The effect of the air pressure in a combustor on the flame macrostructure and the combustion stability was studied. It is shown that an increase in the combustor pressure has no considerable effect on the processes in the combustor. However, a change in the chemical reaction rates affects the stable combustion boundary. In this case, the combustion stability is achieved with higher nonuniformity of the fuel-air mixture entering the combustion zone. The experimental boundaries of stable combustion envelope at an air pressure of 350 and 1500 kPa are presented.

DEPENDENCE OF X-RAY BURST MODELS ON NUCLEAR REACTION RATES

ABSTRACT X-ray bursts are thermonuclear flashes on the surface of accreting neutron stars, and reliable burst models are needed to interpret observations in terms of properties of the neutron star and the binary system. We investigate the dependence of X-ray burst models on uncertainties in (p, γ), (α, γ), and (α, p) nuclear reaction rates using fully self-consistent burst models that account for the feedbacks between changes in nuclear energy generation and changes in astrophysical conditions. A two-step approach first identified sensitive nuclear reaction rates in a single-zone model with ignition conditions chosen to match calculations with a state-of-the-art 1D multi-zone model based on the Kepler stellar evolution code. All relevant reaction rates on neutron-deficient isotopes up to mass 106 were individually varied by a factor of 100 up and down. Calculations of the 84 changes in reaction rate with the highest impact were then repeated in the 1D multi-zone model. We find a number of uncertain reaction rates that affect predictions of light curves and burst ashes significantly. The results provide insights into the nuclear processes that shape observables from X-ray bursts, and guidance for future nuclear physics work to reduce nuclear uncertainties in X-ray burst models.

INFLUENCE OF MECHANICAL MICRO-DEFECTS ON THE LOCAL POLARIZATION IN DEVICES BASED ON FERROELECTRICS

The results of theoretical and experimental studies of the effect of the charged micro-defects on a local reversal in the polarized ferroelectric materials. Domain circuit formation given near the surface of charged defects, the surface temperature distribution of the reaction rate and concentration of solute at the surface of the ferroelectric during enteral studies. The changes of amplitude versus frequency wave oscillations and changes in the rate of reaction in the vicinity of the instability microdefect fluctuations, as well as the evolution of the self-oscillation mode, stable and unstable oscillation modes, taking into account features of the fine structure of the hysteresis loop of the local piezoelectric response due to the proximity of the defects. Experimental verification showed that the pulsed electrophysical effects on ferroelectric sample energy is consumed less, but the effect is higher.

Multi-objective shadow prices point at principles of metabolic regulation

Perturbations in environmental and intracellular conditions often lead to changes across all cellular layers, from transcription to metabolism. Regulatory mechanisms are key to mediating these changes to maintain homeostasis and to ensure viability. Since changes in metabolic reaction rates are partly due to perturbations in metabolite concentrations, it is expected that metabolites with large effect on those reaction rates which govern metabolic functionality are tightly regulated. The extent of metabolic regulation has been quantified by the sensitivity of an individual metabolic function to changes in metabolite concentrations, in particular by shadow prices in the constraint-based modeling framework. However, the system-wide characterization of the extent to which metabolite concentrations are regulated in the more realistic scenario of multiple contending tasks remains elusive. Here we examine multi-objective shadow prices for the central carbon metabolism of Escherichia coli whose reaction rates are shaped by several contending metabolic functions. We determine shadow prices for sampled solutions of the Pareto front, which characterizes the space of multi-objective optima, for three contending metabolic functions that provide the best agreement with 13C-labeling experiments. By analyzing the parts of the Pareto front closest to the experimentally determined flux phenotypes, we show that E. coli operates in the vicinity of an area of the Pareto front which facilitates robust and efficient regulation. In addition, we find significant associations between features of the transcriptional regulatory network and the sensitivity of E. coli's metabolic functionality to changes in metabolite concentrations. We demonstrate that the structural constraints of the metabolic network together with data on condition-specific flux phenotypes can be effectively used to dissect metabolic regulation on a system-wide level.

Modelling the role of CtfA/B in reverse shift continuous culture experiments of Clostridium acetobutylicum

In continuous phosphate-limited conditions, under pH control from high pH (pH ≳ 5.2) to low pH (pH ≲ 5.2), the metabolism of the Gram-positive bacterium Clostridium acetobutylicum,switches from acid to solvent production. Three main enzymes are responsible for the shift, acetoacetate decarboxylase (Adc), alcohol dehydrogenase (AdhE1/2) and a CoA-transferase (CtfA/B), which are produced in increased quantities during solventogenesis. A two-population model, Millat et al. (2013) and fitted to such ‘forward’-shift data, can explain this, as well as observed changes in optical density immediately following the shift: an acidogenic subpopulation is washed out and a solventogenic subpopulation grows in its place, each with distinct physiologies and proteomes. We fit this model to a ‘reverse’-shift experiment, where the pH is increased from solventogenic to acidogenic conditions. We find corresponding changes in reaction rates, with AdhE1 and Adc production falling, as in the ‘forward’ experiments; however, for CtfA/B, the best fit surprisingly arises from the same level of production in both conditions. We propose experiments that would test whether this is a model artefact or accurately reflects cultures shifted in this reverse direction, and, if true, may suggest that over-expressing CtfA/B in both solventogenic and acidogenic conditions could improve the efficiency of fermentation.

Reservoir condition imaging of reactive transport in heterogeneous carbonates using fast synchrotron tomography — Effect of initial pore structure and flow conditions

We investigate the impact of initial pore structure and velocity field heterogeneity on the dynamics of fluid/solid reaction at high Péclet numbers (fast flow) and low Damköhler number (relatively slow reaction rates). The Diamond Lightsource Pink Beam was used to image dissolution of Estaillades and Portland limestones in the presence of CO2-saturated brine at reservoir conditions (10MPa and 50°C representing ~1km aquifer depth) at two flow rates for a period of 2h. Each sample was scanned between 51 and 94 times at 4.76-μm resolution and the dynamic changes in porosity, permeability, and reaction rate were examined using image analysis and flow modelling.We find that the porosity can either increase uniformly through time along the length of the samples, or may exhibit a spatially and temporally varying increase that is attributed to channel formation, a process that is distinct from wormholing, depending on initial pore structure and flow conditions. The dissolution regime was structure-dependent: Estaillades with a higher porosity showed more uniform dissolution, while the lower porosity Portland experienced channel formation. The effective reaction rates were up to two orders of magnitude lower than those measured on a flat substrate with no transport limitations, indicating that the transport of reactant and product is severely hampered away from fast flow channels.

Performance of Ni/Si-pillared clay catalytic extrudates for benzene hydrogenation reaction

Ni supported on Si-pillared montmorillonite systems have been prepared and studied as catalysts for the test reaction of benzene hydrogenation. The Ni/Si-pillared clay catalytic systems were characterized as to their crystallographic structure, specific surface area, specific volume and apparent density. Their reactivity was evaluated over a temperature range of 70–150°C under atmospheric pressure, in a differential bench scale reactor, and compared with other Ni catalysts supported on conventional carriers, such as γ-Al2O3 and Vycor. Apart from the intrinsic catalytic rates, the effect of both internal and external mass transfer limitations was also studied for particle sizes commonly used in industrial praxis. The change of the overall reaction rates with particle size was investigated. The mass transfer effects were examined for diluted catalytic beds of three extrudate sizes and diffusional limitation within the particles were decoupled from external mass transfer resistances. Particle diffusional limitations and their dependence on process temperature and particle porosity were determined and discussed.

Chlorine Dioxide–Iodine–Acetylacetone Oscillation Reaction Investigated by UV–Vis and Online FTIR Spectrophotometric Methods

In order to study the chemical oscillatory behavior and mechanism of a new chlorine dioxide–iodine–acetylacetone reaction system, a series of experiments were carried out by using UV–Vis and online FTIR spectrophotometric methods. The initial concentrations of acetylacetone, chlorine dioxide, iodine, sulfuric acid, and the pH value have considerable influence on the oscillations observed at wavelength of 350 nm for the starch–triiodide ion complex (\({\text{QI}{_{3}^-}}\)). There is a pre-oscillatory or induction stage, the amplitude and the number of oscillations are associated with the initial concentration of reactants. Equations were obtained for the starch–triiodide ion complex (\({\text{QI}{_{3}^-}}\)) reaction rate change with reaction time and the initial concentrations in the oscillation stage. The oscillation reaction can be accelerated by increasing the reaction temperature. The apparent activation energies at the induction stage and the oscillation stage are 45.64 and 12.39 kJ·mol−1, respectively. The intermediates were detected by the online FTIR analysis. Based upon the experimental data in this work and in the literature, a plausible reaction mechanism was proposed for the oscillation reaction.

Interplay of reaction and pore diffusion during cobalt-catalyzed Fischer–Tropsch synthesis with CO2-rich syngas

For cobalt-catalyzed Fischer–Tropsch synthesis (FTS), a model was developed to analyze numerically the reaction–diffusion performance in catalyst particles. The model is based on a mesoporous particle and is valid for CO2-free and -rich syngas. The kinetic parameters of all three relevant reactions, CO hydrogenation to C2+ hydrocarbons as well as CH4 and CO2 hydrogenation (mainly) to CH4, were derived at intrinsic conditions (dp=150μm). Thereafter, the effective kinetics considering pore diffusion limitations were derived by using a homemade catalyst in 5mm diameter. From the data measured, a kinetic approach for conversion of CO2 inside the catalyst particle was developed. The experimentally derived Langmuir–Hinshelwood type rate expressions and a variable chain growth parameter α, dependent on temperature and syngas ratio, were implemented into the model. Furthermore, the change of the local reaction rates and selectivities, as a consequence of changing syngas ratio due to diffusion limitation is taken into account. The simulated data of effective kinetics and selectivities are in agreement with the measured data. The simulation predicts that CO2 is only converted in the CO-free core region of large catalyst particles at high temperatures and strong pore diffusion limitations. For CO2 converts mainly to CH4 (selectivity 95%C), a slightly increased overall methane selectivity is expected indicating consumption of CO2. However, this effect was not measurable even with 5mm particles at high temperatures as methanation of CO2 occurs only to a minor extent even at pronounced diffusion limited conditions and is negligible at industrial conditions.

Hard carbon nanoparticles as high-capacity, high-stability anodic materials for Na-ion batteries

Hard carbon nanoparticles (HCNP) were synthesized by the pyrolysis of a polyaniline precursor. The measured Na+ cation diffusion coefficient (10−13–10−15cm2s−1) in the HCNP obtained at 1150°C is two orders of magnitude lower than that of Li+ in graphite (10−10–10−13cm2s−1), indicating that reducing the carbon particle size is very important for improving electrochemical performance. These measurements also enable a clear visualization of the stepwise reaction phases and rate changes which occur throughout the insertion/extraction processes in HCNP, The electrochemical measurements also show that the nano-sized HCNP obtained at 1150°C exhibited higher practical capacity at voltages lower than 1.2V (vs. Na/Na+), as well as a prolonged cycling stability, which is attributed to an optimum spacing of 0.366nm between the graphitic layers and the nano particular size resulting in a low-barrier Na+ cation insertion. These results suggest that HCNP is a very promising high-capacity/stability anode for low cost sodium-ion batteries (SIBs).

(99)Tc(VII) Retardation, Reduction, and Redox Rate Scaling in Naturally Reduced Sediments.

An experimental and modeling study was conducted to investigate pertechnetate (Tc(VII)O4(-)) retardation, reduction, and rate scaling in three sediments from Ringold formation at U.S. Department of Energy's Hanford site, where (99)Tc is a major contaminant in groundwater. Tc(VII) was reduced in all the sediments in both batch reactors and diffusion columns, with a faster rate in a sediment containing a higher concentration of HCl-extractable Fe(II). Tc(VII) migration in the diffusion columns was reductively retarded with retardation degrees correlated with Tc(VII) reduction rates. The reduction rates were faster in the diffusion columns than those in the batch reactors, apparently influenced by the spatial distribution of redox-reactive minerals along transport paths that supplied Tc(VII). X-ray computed tomography and autoradiography were performed to identify the spatial locations of Tc(VII) reduction and transport paths in the sediments, and results generally confirmed the newly found behavior of reaction rate changes from batch to column. The results from this study implied that Tc(VII) migration can be reductively retarded at Hanford site with a retardation degree dependent on reactive Fe(II) content and its distribution in sediments. This study also demonstrated that an effective reaction rate may be faster in transport systems than that in well-mixed reactors.

Effect of Co-solutes on Template-Directed Nonenzymatic Replication of Nucleic Acids.

The widely acknowledged 'RNA world' theory pertains to how life might have chemically originated on early Earth. It presumes the existence of catalytic RNAs, which were also capable of storing and propagating genetic information. Substantial research has gone into understanding how enzyme-free reactions of nucleic acids might have led to the formation of such catalytic RNA polymers. However, most of these studies involved reactions that were performed in aqueous systems devoid of any "background" molecules. This scenario is not a true representation of the complex chemical environment that might have been prevalent on prebiotic Earth. In the present study, we analyzed the effect of co-solutes ("background" molecules) on the rate and accuracy of template-directed nonenzymatic replication of RNA, in a putative RNA world. Our results suggest that presence of co-solutes in the reaction affects the addition of purine monomers across their cognate template base. Reduction in the rate of these 'fast' cognate addition reactions resulted in an apparent increase in the frequency of mismatches in the presence of co-solutes. However, reactions that involved the addition of a mismatched base were not notably affected. Such a scenario could have led to an accrual of mutations during the propagation of functional sequences on early Earth, unless the relevant sequences were separated from the bulk reaction milieu by some limiting boundary structure (e.g., a membrane). In general, our results suggest that the presence of co-solutes could have affected certain prebiotic reaction rates to a larger extent than others. Even modest changes in nonenzymatic replication reaction rates could have eventually resulted in the accumulation of greater variation in RNA sequences over prolonged time periods. It, therefore, is pertinent to account for the chemical complexity intrinsic to prebiotic environments while studying relevant nonenzymatic reactions.

Sodium chlorite – iodide – acetylacetone oscillation reaction investigated by UV-Vis spectrophotometry

A new sodium chlorite – iodide – acetylacetone chemical oscillatory reaction has been studied by the UV-Vis spectrophotometric method. The initial concentrations of acetylacetone, sodium chlorite, iodide, and sulfuric acid and the pH value have great influence on the oscillation observed at a wavelength of 570 nm for the starch–triiodide complex. There is a pre-oscillatory or induction stage and the amplitude and number of oscillations depend on the initial concentration of the reactants. Equations for the starch–triiodide complex reaction rate change with reaction time and the initial concentrations in the oscillation stage were obtained. The induction time decreases linearly with the initial concentration of acetylacetone or sodium chlorite but increases linearly with the initial concentration of sulfuric acid. The oscillation reaction can be accelerated by increasing the reaction temperature. The apparent activation energies at the induction stage and the oscillation stage were 61.02 and 61.36 kJ/mol, respectively, indicating that the two stages have similar reaction mechanisms. Generating the enol isomer by keto–enol tautomerism is an important step to constrain the time of the induction period.