Imperfect mixing as a dominant factor leading to stochastic behavior: A new system exhibiting crazy clock behavior

László Valkai, A. Horváth

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

It is clearly demonstrated that the arsenous acid-periodate reaction displays crazy-clock behavior when a statistically meaningful number of kinetic runs are performed under "exactly the same" conditions. Both extensive experimental and numerical simulation results gave convincing evidence that the stochastic feature of the title reaction originates from the imperfection of the mixing process, and neither local random fluctuation nor initial inhomogeneity alone is capable of explaining adequately the observed phenomena. Imperfect mixing is manifested - in practice - in the unintentional and inherent formation of dead volumes where the concentration of the reactants may even significantly differ from the ones measured in the case of a completely uniform concentration distribution, and the system may spend enough time there under imperfectly mixed conditions to complete the nonlinear chemical process. Furthermore, it is also shown that a more efficient mixing, i.e. a smaller dead volume size and shorter residence time being spent in the dead volume, does not necessarily mean Landolt times are smaller than the one measured under completely homogeneous conditions. Evidently, the "initial" concentration of the reagents in the dead volume - and of course in the rest of the solution - greatly influences the Landolt time to be measured in the case of an individual kinetic run and may therefore show either positive or negative deviation from the Landolt time for the completely homogeneous state. As a result, less efficient mixing may either accelerate or decelerate the rate of a nonlinear autocatalytic reaction at a macroscopic volume level.

Original languageEnglish
Pages (from-to)14145-14154
Number of pages10
JournalPhysical Chemistry Chemical Physics
Volume20
Issue number20
DOIs
Publication statusPublished - Jan 1 2018

Fingerprint

clocks
Clocks
Kinetics
kinetics
Display devices
reagents
inhomogeneity
Defects
Computer simulation
deviation
acids
defects
simulation

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

Imperfect mixing as a dominant factor leading to stochastic behavior : A new system exhibiting crazy clock behavior. / Valkai, László; Horváth, A.

In: Physical Chemistry Chemical Physics, Vol. 20, No. 20, 01.01.2018, p. 14145-14154.

Research output: Contribution to journalArticle

@article{c5c4d223a9c44f20901af9bbca97de3e,
title = "Imperfect mixing as a dominant factor leading to stochastic behavior: A new system exhibiting crazy clock behavior",
abstract = "It is clearly demonstrated that the arsenous acid-periodate reaction displays crazy-clock behavior when a statistically meaningful number of kinetic runs are performed under {"}exactly the same{"} conditions. Both extensive experimental and numerical simulation results gave convincing evidence that the stochastic feature of the title reaction originates from the imperfection of the mixing process, and neither local random fluctuation nor initial inhomogeneity alone is capable of explaining adequately the observed phenomena. Imperfect mixing is manifested - in practice - in the unintentional and inherent formation of dead volumes where the concentration of the reactants may even significantly differ from the ones measured in the case of a completely uniform concentration distribution, and the system may spend enough time there under imperfectly mixed conditions to complete the nonlinear chemical process. Furthermore, it is also shown that a more efficient mixing, i.e. a smaller dead volume size and shorter residence time being spent in the dead volume, does not necessarily mean Landolt times are smaller than the one measured under completely homogeneous conditions. Evidently, the {"}initial{"} concentration of the reagents in the dead volume - and of course in the rest of the solution - greatly influences the Landolt time to be measured in the case of an individual kinetic run and may therefore show either positive or negative deviation from the Landolt time for the completely homogeneous state. As a result, less efficient mixing may either accelerate or decelerate the rate of a nonlinear autocatalytic reaction at a macroscopic volume level.",
author = "L{\'a}szl{\'o} Valkai and A. Horv{\'a}th",
year = "2018",
month = "1",
day = "1",
doi = "10.1039/c8cp01156g",
language = "English",
volume = "20",
pages = "14145--14154",
journal = "Physical Chemistry Chemical Physics",
issn = "1463-9076",
publisher = "Royal Society of Chemistry",
number = "20",

}

TY - JOUR

T1 - Imperfect mixing as a dominant factor leading to stochastic behavior

T2 - A new system exhibiting crazy clock behavior

AU - Valkai, László

AU - Horváth, A.

PY - 2018/1/1

Y1 - 2018/1/1

N2 - It is clearly demonstrated that the arsenous acid-periodate reaction displays crazy-clock behavior when a statistically meaningful number of kinetic runs are performed under "exactly the same" conditions. Both extensive experimental and numerical simulation results gave convincing evidence that the stochastic feature of the title reaction originates from the imperfection of the mixing process, and neither local random fluctuation nor initial inhomogeneity alone is capable of explaining adequately the observed phenomena. Imperfect mixing is manifested - in practice - in the unintentional and inherent formation of dead volumes where the concentration of the reactants may even significantly differ from the ones measured in the case of a completely uniform concentration distribution, and the system may spend enough time there under imperfectly mixed conditions to complete the nonlinear chemical process. Furthermore, it is also shown that a more efficient mixing, i.e. a smaller dead volume size and shorter residence time being spent in the dead volume, does not necessarily mean Landolt times are smaller than the one measured under completely homogeneous conditions. Evidently, the "initial" concentration of the reagents in the dead volume - and of course in the rest of the solution - greatly influences the Landolt time to be measured in the case of an individual kinetic run and may therefore show either positive or negative deviation from the Landolt time for the completely homogeneous state. As a result, less efficient mixing may either accelerate or decelerate the rate of a nonlinear autocatalytic reaction at a macroscopic volume level.

AB - It is clearly demonstrated that the arsenous acid-periodate reaction displays crazy-clock behavior when a statistically meaningful number of kinetic runs are performed under "exactly the same" conditions. Both extensive experimental and numerical simulation results gave convincing evidence that the stochastic feature of the title reaction originates from the imperfection of the mixing process, and neither local random fluctuation nor initial inhomogeneity alone is capable of explaining adequately the observed phenomena. Imperfect mixing is manifested - in practice - in the unintentional and inherent formation of dead volumes where the concentration of the reactants may even significantly differ from the ones measured in the case of a completely uniform concentration distribution, and the system may spend enough time there under imperfectly mixed conditions to complete the nonlinear chemical process. Furthermore, it is also shown that a more efficient mixing, i.e. a smaller dead volume size and shorter residence time being spent in the dead volume, does not necessarily mean Landolt times are smaller than the one measured under completely homogeneous conditions. Evidently, the "initial" concentration of the reagents in the dead volume - and of course in the rest of the solution - greatly influences the Landolt time to be measured in the case of an individual kinetic run and may therefore show either positive or negative deviation from the Landolt time for the completely homogeneous state. As a result, less efficient mixing may either accelerate or decelerate the rate of a nonlinear autocatalytic reaction at a macroscopic volume level.

UR - http://www.scopus.com/inward/record.url?scp=85047637438&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85047637438&partnerID=8YFLogxK

U2 - 10.1039/c8cp01156g

DO - 10.1039/c8cp01156g

M3 - Article

AN - SCOPUS:85047637438

VL - 20

SP - 14145

EP - 14154

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

SN - 1463-9076

IS - 20

ER -