Mechanism of the propagation step in the anionic polymerization of styrene

1980 ◽  
Vol 45 (4) ◽  
pp. 1047-1055 ◽  
Author(s):  
Miroslav Kašpar ◽  
Jiří Trekoval
Keyword(s):  
Experimental Data ◽  
Induction Period ◽  
Anionic Polymerization ◽  
Reactive Intermediate ◽  
Coordination Polymerization ◽  
Kinetic Dependence ◽  
Mathematical Solution ◽  
Slow Reaction

The paper is dealing with an investigation of the kinetic dependence of the propagation step in the anionic coordination polymerization of styrene in benzene at 303 K with "living" oligostyryllithium as initiator at the onset of the reaction. A short but distinct induction period was found, indicating a preceding slow reaction leading to the formation of a reactive intermediate, which behaves as the initiator of the reaction. Using results obtained in the first paper of this series, a new mechanism of propagation has been suggested, the mathematical solution of which is correlated with experimental data.

scholarly journals Multi-Electron-Transfer Catalysts Needed for Artificial Photosynthesis

2012 ◽  
Vol 1387 ◽  
Author(s):  
James Vickers ◽  
Hongjin Lv ◽  
Petro F. Zhuk ◽  
Yurii V. Geletii ◽  
Craig L. Hill
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Electron Transfer ◽  
Catalytic Activity ◽  
Induction Period ◽  
Water Oxidation ◽  
Fuel Production ◽  
Oxygen Ligand ◽  
Visible Light Driven ◽  
Simple Kinetic Model

ABSTRACTWe report a study on catalytic water oxidation by cobalt in oxygen ligand environments because such systems are as promising as any in the water oxidation component of solar fuel production. We have re-examined the catalytic activity of Co(II) in aqueous solution using either [Ru(bpy)3]3+ as a stoichiometric oxidant or in visible-light-driven reactions with persulfate as a sacrificial electron acceptor. In both systems a distinctive induction period is observed. A simple kinetic model is proposed that describes the experimental data well. The presence of an induction period is explained by relatively slow formation of the true catalyst from aquacobalt(II).

A study of sensitized explosions. VI. Experimental observations on the hydrogen-oxygen reaction sensitized by nitrosyl chloride

1941 ◽  
Vol 177 (971) ◽  
pp. 411-420 ◽  
Keyword(s):  
Induction Period ◽  
Ignition Temperature ◽  
Catalyst Concentration ◽  
Mercury Vapour ◽  
Nitrosyl Chloride ◽  
Induction Periods ◽  
Slow Reaction ◽  
Two Systems ◽  
Mercury Vapour Lamp ◽  
Oxygen Reaction

Small amounts of nitrosyl chloride lower the ignition temperature of 2H 2 + O 2 mixtures by over 200° C, the efficiency of this substance in this respect being slightly greater than nitrogen peroxide. At a given temperature the ignition is confined between a lower and an upper concentration of catalyst, outside which only slow reaction occurs. Both the slow reaction and the ignition are preceded by an induction period, the length of which passes from large values through a minimum to further large values as the catalyst concentration is increased, and which, in contrast to the H 2 -O 2 -NO 2 system, is unaffected by irradiation with light from a mercury-vapour lamp. The induction periods and limits depend on the pressure and temperature of reactants in a very similar way to the induction periods and limits of the H 2 -O 2 -NO 2 system described in Part V. The similarity of the two systems extends to the effect of non-reactant gases in quenching the ignition, the quenching pressures being of the same magnitude in both systems. A difference is, however, found in that these foreign gases shorten the induction period in this system whereas they lengthen it in the H 2 -O 2 -NO 2 system.

scholarly journals Anionic Polymerization of ε-Caprolactam under the Influence of Water: 2. Kinetic Model

2020 ◽  
Vol 4 (1) ◽  
pp. 8 ◽  
Author(s):  
Rainer Wendel ◽  
Philipp Rosenberg ◽  
Michael Wilhelm ◽  
Frank Henning
Keyword(s):  
Experimental Data ◽  
Kinetic Model ◽  
Reaction Kinetics ◽  
Water Content ◽  
Anionic Polymerization ◽  
Polyamide 6 ◽  
External Influences ◽  
Influence Of Water ◽  
Kinetics Of

The reaction kinetics of anionic polymerization for the production of anionic polyamide 6 (aPA6) are widely understood. It is also known that this reaction is very sensitive to external influences such as water. This paper analyzes and quantifies the influence of water on the reaction of ε-caprolactam to anionic polyamide 6. A kinetic model is developed in which the reactive molecules of the activator and catalyst are defined as variables and the concentrations of activator and catalyst as well as water content are considered. A model for the calculation of the reaction kinetics is established and validated with experimental data. The developed model can be used to predict the influence and compensation of water by addition of surplus activator and catalyst during the polymerization of ε-caprolactam.

Interpretation of Microstructure of Poly-Isoprene and Polybutadiene Obtained in Anionic Polymerization

1967 ◽  
Vol 40 (3) ◽  
pp. 883-894 ◽  
Author(s):  
K. F. O'Driscoll ◽  
T. Yonezawa ◽  
T. Higashimura
Keyword(s):  
Experimental Data ◽  
Anionic Polymerization ◽  
Quantitative Model ◽  
Relative Reactivity ◽  
Mo Calculations ◽  
Model Based ◽  
Polymer Microstructures ◽  
Lcao Mo

Abstract A mechanism is proposed for the anionic homopolymerization of the diene monomers isoprene and butadiene. This mechanism qualitatively explains how the various polymer microstructures occur. A quantitative model based on this mechanism is treated by LCAO-MO calculations which include the effect of the counterion on the propagating chain. The results of the calculations are then compared with experimental data on microstructure and relative reactivity in hydrocarbon and tetrahydrofuran solvents. In every instance the comparisons give correct, semiquantitative agreement between calculation and experiment.

EFFECT OF PREHEATING TIME ON THE INACTIVATION OF PHOSPHATASE IN MILK*

1951 ◽  
Vol 14 (4) ◽  
pp. 131-133 ◽  
Author(s):  
S. A. Lear ◽  
H. G. Foster
Keyword(s):  
Experimental Data ◽  
Heat Effect ◽  
Line Heating ◽  
Mathematical Solution ◽  
Straight Line ◽  
Individual Effects ◽  
Mathematical Equations ◽  
The Individual ◽  
Canning Industry

The authors consider the incongruities encountered when the phosphatase test is applied to milk and offer a practical mathematical solution for some of them. Experiments are described wherein it was possible to evaluate the individual effects of the preheating, holding and cooling segments of the heating (pasteurizing) curve on the inactivation of phosphatase in milk. Thus experimental data were obtained that satisfied the requirements of the mathematical equations used currently in the food canning industry to calculate the total lethal heat effect of a process. The authors report that when one minute preheating time with straight line heating is used, it will contribute 0.40 percent and 29.91 percent of the total lethal heat respectively when the holding temperatures are 146.3° F and. 163.4° F.

scholarly journals Anionic Polymerization Using Flow Microreactors

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1532 ◽  
Author(s):  
Yusuke Takahashi ◽  
Aiichiro Nagaki
Keyword(s):  
Anionic Polymerization ◽  
Cationic Polymerization ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Polymer Chemistry ◽  
Revolutionary Change ◽  
Coordination Polymerization ◽  
Flow Microreactor ◽  
Extensive Flow ◽  
Flow Microreactors

Flow microreactors are expected to make a revolutionary change in chemical synthesis involving various fields of polymer synthesis. In fact, extensive flow microreactor studies have opened up new possibilities in polymer chemistry including cationic polymerization, anionic polymerization, radical polymerization, coordination polymerization, polycondensation and ring-opening polymerization. This review provides an overview of flow microreactors in anionic polymerization and their various applications.

scholarly journals APPLICATION FOR CALCULATING THE PARAMETERS OF A GAS SENSOR FROM THE EXPERIMENTAL KINETIC DEPENDENCE OF RESPONSE

2021 ◽  
Vol 2 (133) ◽  
pp. 26-32
Author(s):  
Alexander Tonkoshkur ◽  
Andrey Lozovsky
Keyword(s):  
Experimental Data ◽  
Gas Sensors ◽  
Data Entry ◽  
The Internet ◽  
Computational Algorithms ◽  
Kinetic Dependence ◽  
Textual Information ◽  
Spreadsheet Program ◽  
Software Packages ◽  
Internal Sources

The elements of the structure and user interface of a specialized application for processing experimental data and calculating the parameters of gas sensors, based on the concept of using various software, packages and media are presented that are most effective at each stage. The application provides such service functions as data entry using Excel spreadsheet program; calculations in the mathematical package "Mathcad"; test item examples of using computational algorithms and providing the necessary textual information from internal sources and the Internet.

scholarly journals Kinetic parameter estimation for solid octogen-containing explosive according to ODTX-experiments

2018 ◽  
pp. 53-59
Author(s):  
Y. S. Zuev ◽  
N. I. Karmanov ◽  
E. V. Nedospasova
Keyword(s):  
Experimental Data ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Parameter Estimation ◽  
Kinetic Parameter ◽  
Induction Period ◽  
Software Package ◽  
Analysis Software ◽  
Element Analysis ◽  
Kinetic Parameter Estimation

The study introduces a method for estimating kinetic parameters for the LX -10 explosive. The method includes the use of analytical dependence for the induction period, by which the experimental data are processed, and the ANSYS CFD finite element analysis software package. Satisfactory agreement between the calculated and experimental data was obtained.

Microdiffraction Patterns of Small Metallic Particles II; Theoretical Analysis

1982 ◽  
Vol 40 ◽  
pp. 668-669
Author(s):  
A. Gómez ◽  
P. Schabes-Retchkiman ◽  
M. José-Yacamán ◽  
T. Ocaña
Keyword(s):  
Experimental Data ◽  
Electron Diffraction ◽  
Theoretical Analysis ◽  
Size Range ◽  
Dynamical Theory ◽  
Metallic Particles ◽  
Splitting Effect

The splitting effect that is observed in microdiffraction pat-terns of small metallic particles in the size range 50-500 Å can be understood using the dynamical theory of electron diffraction for the case of a crystal containing a finite wedge. For the experimental data we refer to part I of this work in these proceedings.

Evidence for ordered Fe3Ni

1987 ◽  
Vol 45 ◽  
pp. 216-217
Author(s):  
K.B. Reuter ◽  
D.B. Williams ◽  
J.I. Goldstein
Keyword(s):  
Experimental Data ◽  
Martensitic Transformation ◽  
Electron Diffraction ◽  
Room Temperature ◽  
Direct Evidence ◽  
Transformation Product ◽  
Iron Meteorites ◽  
X Ray ◽  
Ni Content ◽  
Temperature Transformation

In the Fe-Ni system, although ordered FeNi and ordered Ni3Fe are experimentally well established, direct evidence for ordered Fe3Ni is unconvincing. Little experimental data for Fe3Ni exists because diffusion is sluggish at temperatures below 400°C and because alloys containing less than 29 wt% Ni undergo a martensitic transformation at room temperature. Fe-Ni phases in iron meteorites were examined in this study because iron meteorites have cooled at slow rates of about 10°C/106 years, allowing phase transformations below 400°C to occur. One low temperature transformation product, called clear taenite 2 (CT2), was of particular interest because it contains less than 30 wtZ Ni and is not martensitic. Because CT2 is only a few microns in size, the structure and Ni content were determined through electron diffraction and x-ray microanalysis. A Philips EM400T operated at 120 kV, equipped with a Tracor Northern 2000 multichannel analyzer, was used.

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