scholarly journals Reaction Rate Models for the Thermal Decomposition of Ibuprofen Crystals

2014 ◽  
Vol 04 (02) ◽  
pp. 71-78 ◽  
Author(s):  
Sundaram Ramukutty ◽  
Esakki Ramachandran
Keyword(s):  
Thermal Decomposition ◽  
Reaction Rate

Thermal Decomposition Kinetics of Glyphosate (GP) and its Metabolite Aminomethylphosphonic Acid (AMPA)

2019 ◽  
Author(s):  
Milad Narimani ◽  
Gabriel da Silva
Keyword(s):  
Thermal Decomposition ◽  
Reaction Rate ◽  
Decomposition Kinetics ◽  
Rate Theory ◽  
Thermal Decomposition Mechanism ◽  
Treatment Processes ◽  
Aminomethylphosphonic Acid ◽  
Reaction Rate Theory ◽  
Decomposition Chemistry ◽  
Kinetics Of

Glyphosate (GP) is a widely used herbicide worldwide, yet accumulation of GP and its main byproduct, aminomethylphosphonic acid (AMPA), in soil and water has raised concerns about its potential effects to human health. Thermal treatment processes are one option for decontaminating material containing GP and AMPA, yet the thermal decomposition chemistry of these compounds remains poorly understood. Here, we have revealed the thermal decomposition mechanism of GP and AMPA by applying computational chemistry and reaction rate theory methods. <br>

Cavitation-induced Reactions in Pure Substituted Benzenes

1972 ◽  
Vol 50 (11) ◽  
pp. 1743-1750 ◽  
Author(s):  
G. K. Diedrich ◽  
P. Kruus ◽  
L. M. Rachlis
Keyword(s):  
Thermal Decomposition ◽  
Low Temperature ◽  
Bond Dissociation Energy ◽  
Dissociation Energy ◽  
Cavitation Bubble ◽  
Reaction Rate ◽  
Substituted Benzenes ◽  
Thermal Reactions ◽  
Initiation Reaction ◽  
Low Temperature Pyrolysis

The formation of polymers has been observed on exposure of pure substituted benzenes to ultrasound intense enough to cause cavitation. The products have some of the characteristics of the char obtained from low temperature pyrolysis of hydrocarbons. They are difficult to dissolve, melt above 300 °C, and give a large broad e.p.r. signal. A crude correlation between bond dissociation energy and the reaction rate suggests that the initiation reaction is a thermal decomposition in a cavitation bubble. The phenomenon is compared to radiolysis and thermal reactions.

Thermal Decomposition and Isomerization of Furfural and 2-Pyrone: A Theoretical Kinetic Study

2020 ◽  
Author(s):  
Saddam Al-Hammadi ◽  
Gabriel da Silva
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Study ◽  
Gas Phase ◽  
Quantum Chemical ◽  
Reaction Rate ◽  
Rate Theory ◽  
Reaction Rate Theory ◽  
Reaction Channels

We have studied the decomposition and isomerization of furfural in the gas-phase using quantum chemical and statistical reaction rate theory techniques. This work uncovers a variety of new reaction channels...

Effect of Co-precursor Maliec Anhydride on the Thermal Decomposition of Acetyl Ferrocene: A Reaction Kinetic Analysis

2019 ◽  
Vol 9 (1) ◽  
pp. 22-35
Author(s):  
Bratati Das ◽  
Ashis Bhattacharjee
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Reaction Mechanism ◽  
Kinetic Analysis ◽  
Reaction Rate ◽  
Reaction Kinetic ◽  
Step Process ◽  
Probable Reaction Mechanism ◽  
Probable Reaction ◽  
Reaction Atmosphere

Background: Thermal decomposition of iron-bearing organometallic complex acetyl ferrocene, (C5H4COCH3)Fe(C5H5), leads to hematite (α-Fe2O3) nanoparticles. Presence of maliec anhydride, C4H2O3 as co-precursor during thermal decomposition modifies the size of the particles as well as the quantity of the reaction product significantly. Objective: Kinetic analysis of the solid-state thermal reaction of acetyl ferrocene in the presence of varying amount of co-precursor maliec anhydride under inert reaction atmosphere has been studied in order to understand the reaction mechanism involved behind the formation of hematite and the role of co-precursor in the reaction process. For this purpose, reaction kinetic analysis of three mixtures of acetyl ferrocene and maliec anhydride has been carried out. Methods: Thermogravimetry under non-isothermal protocol with multiple heating rates has been employed. The data are analyzed using model-free iso-conversional kinetic techniques to estimate the activation energy of reaction and reaction rate. The most-probable reaction mechanism has been identified by master plot method. The kinetic triplets (activation energy, reaction rate, most probable reaction mechanism function) have been employed to estimate the thermodynamic triplets (ΔS, ΔH and ΔG). Observations: Acetyl Ferrocene (AFc) undergoes thermal decomposition in a four-step process leaving certain residual mass whereas maliec anhydride (MA) undergoes complete mass loss owing to melting followed by evaporation. In contrast, the (AFc1-x-MAx) mixtures undergo thermal decomposition through a two-step process, and the decompositions are completed at much lower temperatures than that in AFc. The estimated activation energy and reaction rate values are found strongly dependent on the extent of conversion as well as on the extent of mixing. Introduction of MA in the solid reaction atmosphere of AFc in one hand reduces the activation energy required by AFc to undergo thermal decomposition and the reaction rate, while on the other hand varies the nature of reaction mechanism involved. Results: The range of reaction rate values estimated for the mixtures indicate that the activated complexes during Step-I of thermal decomposition may be treated as ‘loose’ complex whereas ‘tight’ complex for the Step-II. From the estimated entropy values, thermal process of (AFc1-x-MAx) mixture for Steps I and II may be interpreted as ‘‘slow’’ stage. Conclusion: Variation of Gibb’s free energy with the fraction of maliec anhydride in the mixtures for Step-I and II indicate that the thermal processes of changing the corresponding activated complexes are non-spontaneous at room temperature.

Fast synthesis of MoO3-x and its catalytic effect on the thermal decomposition of ammonium perchlorate based molecular perovskite (DAP-4)

2021 ◽  
Author(s):  
Xiaoxia Li ◽  
Shuaida Zhu ◽  
Qi Jia ◽  
Haixia Zhao ◽  
Yuqi Cao ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Ammonium Perchlorate ◽  
Reaction Rate ◽  
Decomposition Reaction ◽  
Reaction Rate Constant ◽  
Structure Characterization ◽  
Maximum Heat ◽  
Maximum Heat Release ◽  
Positive Effect ◽  
Fast Synthesis

Abstract: In this work, we proved that MoO3-x has a positive effect on the thermal decomposition of ammonium perchlorate based molecular perovskite (H2dabco)[NH4(ClO4)3] (DAP-4). MoO3-x was prepared by heat-treatment, and the morphology, structure and thermal decomposition performance were characterized. The morphology and structure characterization results showed that MoO3-x was an irregular layered structure material, and Mo element was mainly in the +6 chemical valence state, with a small amount of Mo5+. Thermal analysis results showed that the thermal decomposition peak temperature of DAP-4 was effectively reduced from 394.4 °C to 353.7 °C, 321.4 °C, and 312.5 °C in the presence of 1 %, 5 %, and 10 % MoO3-x, respectively. It is particularly worth noting that the maximum heat release rate of the DAP-4/10 % MoO3-x mixture was increased by 4.9 times compared with pure DAP-4. Through the two classic thermal decomposition kinetic methods, Kissinger and Starink, the reliable kinetic parameters of DAP-4/MoO3-x were obtained. The increase of the reaction rate constant k indicated that the maximum thermal decomposition reaction rate of DAP-4 was effectively improved. This work provided a feasible technology for using MoO3-x as an effective catalyst to improve the thermal performance of DAP-4.

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