Kinetic Study on Acrylic Acid Polymerisations in Isopropanol

The radical polymerisation of acrylic acid is largely concentration dependent and affected by the type of the surrounding solvent. This work investigates reaction rate constants, the activation energy, heat flux and the molecular weight in the industrially relevant synthesis of low molecular mass acrylic acid polymers in 2‑propanol. The polymerisations were carried out isothermally in an RC1e calorimeter with inline Raman spectroscopy for monomer concentration monitoring. For a non-neutralised acrylic acid in isopropanol (150 g/L), a monomer reaction order of 1.73 ± 0.15, an activation energy of 58.6 ± 0.8 kJ/mol (0.5 mol% AIBN) and 88.5 ± 1.5 kJ/mol (1.0 mol% AIBN), and a reaction enthalpy of 66.4 ± 4.8 kJ/mol could be shown. This data is in accordance with the literature values for acrylic acid polymerisation in water. In addition, linear correlations between the respective reaction parameters and the molecular weight for customised polymer synthesis in the range from 1.2 to 1.7 × 104 g/mol could be established. In comparison with aqueous acrylic acid polymerisation, it was found that the reaction rate constants in isopropanol were slower by a factor of approximately 10 under similar reaction conditions.

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Reactions of thiyl radicals with phenothiazines and other antioxidants in aqueous solutions. A pulse radiolysis study

Canadian Journal of Chemistry ◽

10.1139/v90-211 ◽

1990 ◽

Vol 68 (8) ◽

pp. 1376-1382 ◽

Cited By ~ 7

Author(s):

Manohar Lal ◽

H. S. Mahal

Keyword(s):

Molecular Weight ◽

Ascorbic Acid ◽

Aqueous Solutions ◽

Rate Constants ◽

Pulse Radiolysis ◽

Reaction Rate ◽

Mercaptopropionic Acid ◽

Molecular Weights ◽

Reaction Rate Constants ◽

Thiyl Radicals

Reaction rate constants of thiyl radicals with phenothiazines, promethazine (PMZ), chlorpromazine (CPZ), prochlorperazine (PPZ), trimeperazine tarterate (TPZ), and other antioxidants, e.g., ascorbic acid and 2,2-azinobis(3-ethyl benzthiazoline-6 sulphonate) (ABTS) have been estimated using pulse radiolysis technique. In general they are quite high (108–109 M−1 s−1). The k values for cysteine, cysteamine, mercaptoethanol, and mercaptopropionic acid with similar structures and molecular weights are more or less similar for PMZ, CPZ, and PPZ.Rate constants are lower in value for [Formula: see text] radicals of phenothiazines showing that they are dependent upon the structure and the molecular weight of the compound.Rate constants are the same whether the thiyl radicals are generated from thiols or their corresponding disulphides. The k values for chlorine-containing phenothiazines, chlorpromazine, and prochlorperazine are higher than those of promothazine Keywords: pulse radiolysis, thiyl radicals, phenothiazines, ABTS, ascorbic acid.

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Finding of kinetic characteristics of the process co-gasification of heavy coal tars with lignite and walnut shell

Chemistry, Technology and Application of Substances ◽

10.23939/ctas2020.02.046 ◽

2020 ◽

Vol 3 (2) ◽

pp. 46-52

Author(s):

D. Yu. Bilets ◽

◽

D. V. Miroshnichenko ◽

P. V. Karnozhitskiy ◽

Yu. V. Nikolaichuk ◽

...

Keyword(s):

Activation Energy ◽

Flow Rate ◽

Rate Constants ◽

Reaction Rate ◽

Walnut Shell ◽

Kinetic Characteristics ◽

Reaction Rate Constants ◽

Gasification Process

Studied of co-gasification of heavy coal tars with lignite and walnut shell in the temperature ranged from 400 to 500 °С, the flow rate of oxidand (air) ranged from 0,0005 to 0,004 m3/min. It is established that the weigth loss of the sample mixtures in the gasification process has a S-shaped. Mathematical and graphical dependences of the influence of oxidant flow rate on the values of reaction rate constants and activation energy of gasification of experimental mixtures were developed.

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Dissolution kinetics of sepiolite from Eskisehir (Turkey) in hydrochloric and nitric acids

Clay Minerals ◽

10.1180/claymin.1990.025.2.06 ◽

1990 ◽

Vol 25 (2) ◽

pp. 207-215 ◽

Cited By ~ 19

Author(s):

H. Cetisli ◽

T. Gedikbey

Keyword(s):

Activation Energy ◽

Acid Concentration ◽

Rate Constants ◽

Reaction Rate ◽

Dissolution Kinetics ◽

Particle Sizes ◽

Initial Particle ◽

Reaction Rate Constants ◽

Apparent Activation Energies ◽

Kinetics Of

AbstractDissolution kinetics of sepiolite from Eskisehir (Turkey) have been investigated at various temperatures and particle sizes using dilute hydrochloric and nitric acids. Dissolution reaction rate constants were calculated and apparent activation energies were dependent on acid concentration. For both acids, apparent activation energy values reached a minimum of ∼11 kcal/mol at an acid concentration of 0·75 M. For the second-order reaction which is independent of the acid concentration, the activation energy was 14·5 kcal/mol for both acids. The reaction rate constants were proportional to the acid concentrations, and inversely proportional to the square-root of the initial particle radii of the sepiolite.

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Study on detoxification property of alkaline-modified MoO42--H2O2 decontaminants against PhSMe under subzero environment

E3S Web of Conferences ◽

10.1051/e3sconf/202126702061 ◽

2021 ◽

Vol 267 ◽

pp. 02061

Author(s):

Shaohua Wei ◽

Hongpeng Zhang ◽

Haiyan Zhu ◽

Lianyuan Wang ◽

Jing Liang ◽

...

Keyword(s):

Activation Energy ◽

Rate Constants ◽

Oxidation Rate ◽

Oxidation Reaction ◽

Reaction Rate ◽

Reaction Rate Constants ◽

Relative Ratio ◽

Reaction Activation Energy ◽

Oxidation Reaction Rate

The decontaminant activated by MoO42- (MoO42--H2O2) suitable for subzero environment shows strong oxidizing ability and weak nucleophilicity due to its acid. In this paper, in order to improve nucleophilicity and retain oxidation of MoO42--H2O2 as far as possible, NH3 and NaOH were used as alkaline modifiers, and PhSMe was used as a simulant of HD to study the oxidation rate and products of sulfides by alkaline-modified MoO42--H2O2 below zero. Results showed that the reaction rate constants decreased with the increase of pH in both NH3 and NaOH modified MoO42--H2O2 at -20°C, and the relative ratio of sulfone to sulfoxide increased especially at pH>9. The reaction activation energy Ea of PhSMe oxidation in the alkaline-modified MoO42--H2O2 decontaminants was lower than that in the MoO42--H2O2 decontaminant, which indicated that the sensitivity of the oxidation reaction rate to temperature in MoO42--H2O2 was reduced after modification.

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