Initiation Of Chain Reactions Research Articles

Mechanism of methyl elaidate on the thermal oxidation behavior

The effects of cis–trans isomerization on the oxidation products of oleic acid (composites and structure characterization) were investigated. The reduction of thermal oxidation reaction of methyl elaidate (ME) was 6.72 % lower than that of methyl oleate (MO), and the oxidation products (core aldehydes) first increased and then decreased with the prolongation of thermal oxidation time. ME exhibited better oxidation stability than MO in free radicals, hydroperoxides, double bonds, aldehydes, and glycerides. The oxidation products were mainly 11-oxo-9-undecenoate (initial stage) and methyl 9-oxononanoate (later stage), following the free radical chain reaction mechanism. The H8 in double bond was more easily dehydrogenated in the chain initiation stage than H11, followed by the formation of core aldehyde through three intermediates and two transition states each pathway. ME required a higher energy barrier (1.3–13.6 kJ/mol) than MO reaction, making it more difficult for ME to undergo thermal oxidation reaction. The transition state 4 and 5 were rate determining steps of chain initiation reaction and proliferation reaction, respectively. This study was of great significance to further control the formation of these trans fats and their oxidation products.

Study on the oxidative decomposition mechanism of R1234ye(E): A DFT study

R1234ye(E) is an environmentally friendly working fluid that can be applied in refrigeration, heat pumps, and organic Rankine cycle systems, but it has issues with oxidative decomposition and flammability. Therefore, based on density functional theory, the oxidative decomposition mechanism of R1234ye(E) has been studied. The results indicate that the oxidative decomposition of R1234ye(E) is a typical chain reaction. The first stage is a chain-initiation reaction, where R1234ye(E) generates a large number of free radicals through initial self thermal decomposition reactions and collision reactions with oxygen. The most likely to occur is path 1–2, which is a homolytic reaction with an energy barrier of only 347.91 kJ/mol. The second stage is the chain-propagation reaction, including the reactions between R1234ye(E) and different free radical and subsequent reactions. The most likely to occur is path 5–1, which is a hydrogen abstraction reaction with an energy barrier of only 21.83 kJ/mol. The last stage is the chain-termination reaction, where the intermediates or products of the above reactions continue to react with the active free radicals until they are consumed. When all the reactants and free radicals are consumed and stable products are generated, the oxidative decomposition reaction ends. The research results provide a reference for the safe application of R1234ye(E) and other HFOs working fluids.

Stochastic simulation of hydrogen-oxygen auto-ignition at the microscale.

A hybrid stochastic simulation method is developed to study H2-O2 auto-ignition at the microscale. Simulation results show that the discrete and stochastic characteristics of reaction collisions have notable impacts on the ignition process, particularly in the early stages when only a few radicals exist. The statistical properties of ignition delay time, which reflect the accumulated stochasticity during ignition, are obtained and analyzed for different initial temperatures and total molecular numbers. It is found that the average and standard deviation of ignition delay time increase as the total molecular number decreases, with this phenomenon being particularly pronounced near the crossover temperature. When the total molecular number is sufficiently small, the chain initiation reaction becomes crucial to the stochastic properties, as its average firing time exhibits an inverse proportionality to the total molecular number. As the total molecular number increases, the influence of other chain reactions intensifies, causing the power law relation between standard deviation and total molecular number to shift from -1 power to -0.5 power. Owing to different chain reaction paths for high- and low-temperature auto-ignition, the strongest relative fluctuation occurs near the crossover temperature. A theoretical equation for the standard deviation of ignition delay time is obtained based on dimensional analysis, giving excellent agreement with the simulation results in both high- and low-temperature modes.

Latest Advances in Highly Efficient Dye-Based Photoinitiating Systems for Radical Polymerization.

Light-activated polymerization is one of the most important and powerful strategies for fabrication of various types of advanced polymer materials. Because of many advantages, such as economy, efficiency, energy saving and being environmentally friendly, etc., photopolymerization is commonly used in different fields of science and technology. Generally, the initiation of polymerization reactions requires not only light energy but also the presence of a suitable photoinitiator (PI) in the photocurable composition. In recent years, dye-based photoinitiating systems have revolutionized and conquered the global market of innovative PIs. Since then, numerous photoinitiators for radical polymerization containing different organic dyes as light absorbers have been proposed. However, despite the large number of initiators designed, this topic is still relevant today. The interest towards dye-based photoinitiating systems continues to gain in importance, which is related to the need for new initiators capable of effectively initiating chain reactions under mild conditions. In this paper we present the most important information about photoinitiated radical polymerization. We describe the main directions for the application of this technique in various areas. Attention is mainly focused on the review of high-performance radical photoinitiators containing different sensitizers. Moreover, we present our latest achievements in the field of modern dye-based photoinitiating systems for the radical polymerization of acrylates.

Unraveling the Thermal Oxidation Products and Peroxidation Mechanisms of Different Chemical Structures of Lipids: An Example of Molecules Containing Oleic Acid.

Lipid structures affect lipid oxidation, causing differences in types and contents of volatiles and nonvolatiles in various foods. In this study, the oxidation differences of monoacylglycerol (MAG), triacylglycerol (TAG), phosphatidylethanolamine (PE), and phosphatidylcholine (PC) with oleoyl residues and oleic acid (FA) during thermal treatment were investigated. Volatiles and nonvolatiles were monitored by gas chromatography-mass spectrometry and ultrahigh-performance liquid chromatography-Q-Exactive HF-X Orbitrap Mass Spectrometer, respectively. The results showed that the structures of MAG and TAG could delay the chain initiation reaction. The polar heads of PC and PE remarkably influenced the oxidation rate and the formation of the oxidation products probably due to the hydrogen bonds formed with free radicals. Among the volatile oxidation products, aldehydes, acids, and furans with eight or nine carbon atoms accounted for the majority in FA, MAG, TAG, and PC samples, but PE samples mainly generated ketones with nine or 10 carbon atoms. The formation of nonvolatile products in TAG samples possessed significant stage-specific changes. Fatty acid esters of hydroxy fatty acids were only produced in the free fatty acid oxidation model. The activity of chemical bonds participating in the truncation reaction decreased to both sides from the double bond position.

Deuterium-Reinforced Polyunsaturated Fatty Acids Prevent Diet-Induced Nonalcoholic Steatohepatitis by Reducing Oxidative Stress.

Background and Objectives: Oxidative stress is implicated in the progression of nonalcoholic steatohepatitis (NASH) through the triggering of inflammation. Deuterium-reinforced polyunsaturated fatty acids (D-PUFAs) are more resistant to the reactive oxygen species (ROS)−initiated chain reaction of lipid peroxidation than regular hydrogenated (H−) PUFAs. Here, we aimed to investigate the impacts of D-PUFAs on oxidative stress and its protective effect on NASH. Materials and Methods: C57BL/6 mice were randomly divided into three groups and were fed a normal chow diet, a methionine–choline-deficient (MCD) diet, and an MCD with 0.6% D-PUFAs for 5 weeks. The phenotypes of NASH in mice were determined. The levels of oxidative stress were examined both in vivo and in vitro. Results: The treatment with D-PUFAs attenuated the ROS production and enhanced the cell viability in tert-butyl hydroperoxide (TBHP)−loaded hepatocytes. Concurrently, D-PUFAs decreased the TBHP-induced oxidative stress in Raw 264.7 macrophages. Accordingly, D-PUFAs increased the cell viability and attenuated the lipopolysaccharide-stimulated proinflammatory cytokine expression of macrophages. In vivo, the administration of D-PUFAs reduced the phenotypes of NASH in MCD-fed mice. Specifically, D-PUFAs decreased the liver transaminase activity and attenuated the steatosis, inflammation, and fibrosis in the livers of NASH mice. Conclusion: D-PUFAs may be potential therapeutic agents to prevent NASH by broadly reducing oxidative stress.

Effects of polyglycerol polyricinoleate on the antioxidant pathways of curcumin during the peroxidation of canola oil

Polyglycerol-polyricinoleate (PGPR) and curcumin were added to canola oil in order to evaluate the effects of PGPR on the interfacial performance of curcumin. A combination-model (linear-sigmoidal) was employed for measuring kinetic-indices relevant to the initiation and propagation phases during the peroxidation process. In the presence of curcumin (4.343 mM), the rate constants of formation and decomposition of hydroperoxides (ROOHs) were 2.94 × 10−5 meq.kg and 6.1 × 10−3 min−1, respectively, which significantly decreased compared to the control sample. The antioxidant activity of curcumin (1.086 mM) was 2.07, which increased in the presence of PGPR (2.72). This enhancement was due to a decrease in the participation rate of curcumin molecule (AH) in an undesirable chain-initiation reaction, i.e. AH + ROOH→A●+RO●+H2O. In addition, an analysis of rate equations showed that the electron-transfer mechanism of curcumin was modified in the presence of PGPR, so that the rate of participation was reduced to zero in the undesirable reaction, i.e. A●+RH→AH + R●.

Quantum Chemistry Calculation Study on Chain Reaction Mechanisms and Thermodynamic Characteristics of Coal Spontaneous Combustion at Low Temperatures.

The coal spontaneous combustion phenomenon seriously affects the safety production of coal mines. Aiming at the problem of complex coal molecular structure and incomplete reaction sequences at present, the mechanisms and thermodynamic parameters of coal spontaneous combustion chain reactions were explored by combining experimental detections and molecular simulations. First, the active groups on the surface of coal were obtained by Fourier transform infrared spectroscopy (FTIR), mainly including methyl (−CH3), methylene (−CH2), methyne (−CH), phenolic hydroxyl (−ArOH), alcohol hydroxyl (−ROH), carboxyl (−COOH), aldehyde (−CHO), and ether (−O−), and the coal molecular models containing functional groups and radicals were established. According to the charge density, electrostatic potential, and frontier orbital theories, the active sites and active bonds were obtained, and a series of reactions were given. The thermodynamic and structural parameters of each reaction were explored. In the chain initiation reaction stage, O2 chemisorption and the self-reaction of radicals play a leading role. In this stage, heat gradually accumulates and various radicals begin to generate, where the intramolecular hydrogen transfer reaction of a peroxide radical (−C–O–O·) can produce the key hydroxyl radical (−O·). In the chain propagation reaction stage, O2 and −O· continuously consume active sites to accelerate the reaction sequences and increase the temperature of coal, and index gases such as CO and CO2 generate, causing the chain cycle reactions to gradually form. The chain termination reaction stage is the formation of stable compounds such as ethers, esters, and quinones, which can inhibit the development of chain reactions. The results can further explain the reaction mechanism of coal spontaneous combustion and provide references for the development and utilization of chemical inhibitors.

Pyrolysis behavior and kinetics of sustainable terpenoid hydrocarbon fuel farnesane

Directional synthesis of hydrocarbon fuels using metabolic engineering injects fresh blood into alleviating energy shortage and environmental pollution problems due to its sustainability. Farnesane, a terpenoid multi-branched iso-paraffin derived from sugarcane through metabolic engineering, is expected to be an excellent alternative fuel attracting widespread attention. In this work, the pyrolysis behavior of farnesane was investigated in a tandem μ-reactor equipped with an online GC-MS/FID detection system under pressures of 0.1 and 2.0 MPa and temperature of 773–998 K. The focus of this work is to provide the pyrolysis experimental data of farnesane and analyze the reaction mechanism to support the fuel application demonstration. A detailed kinetic model (285 species and 2903 reactions) was proposed, based on which the energy flow of the reaction network was further analyzed. Rate of production (ROP) and sensitivity (SEN) analysis show that C–C bond scission of farnesane is the important chain initiation reaction. H-abstraction reaction occupies the largest proportion in farnesane consumption, more than 90%. Due to the existence of multiple branched chains, besides small molecular products, 1-alkene is one of the most important product categories, such as 4-methyl-1-hexene, 6-methyl-1-heptene, 2,6-dimethyl-1-heptene, etc. Compared with the n-paraffin pyrolysis, in which ethylene is more easily generated, propene also has a relatively high proportion due to the existence of branched chains during the pyrolysis of farnesane. Benzene and toluene are the major detected aromatic hydrocarbons, which are mainly generated from cyclic precursors by cyclization of alkene radicals and then further occurring isomerization or dehydrogenation reactions. The model can well reproduce the variation trend of the product distribution with temperature and pressure.

Investigation on the flammability limit and limiting oxygen concentration of N2-diluted H2/CO/air mixtures at high temperature and pressure

H2/CO binary mixtures are common, and their combustion characteristics and reaction mechanism are important. Currently, there are few studies on the combustion characteristics of H2/CO mixtures at high temperature and pressure conditions, and they are mainly limited by the test conditions. In this work, a flammability limit test device was used to determine the flammability limit and limiting oxygen concentration of a combustible mixture with a composition of H2/CO = 1:1 at high initial temperature (∼80 °C) and high initial pressure (∼10 MPa) conditions. The effects of temperature and pressure on the flammability limit and limiting oxygen concentration were obtained, and the results showed that the initial temperature and initial pressure expanded the range and reduced the limiting oxygen concentration, which significantly increased the risk of combustion. As the pressure increased, the effect of pressure on the flammability limit and limiting oxygen concentration decreased. In addition, an obvious coupling effect of initial temperature and pressure on the upper flammability limit and the limiting oxygen concentration (<5 MPa) was found. Moreover, kinetic simulations of the CO/H2 mixture were carried out to verify the synergistic oxidation effect, which was explained using chain reaction theory. We found that the chain initiation reactions caused by H2 generated OH products and the heat required for CO oxidation. Lastly, we also observed oxygen competition between CO and H2, which decreased the CO conversion rate as H2 increased.

Experimental and kinetic modeling studies of polyoxymethylene dimethyl ether (PODE) pyrolysis in jet stirred reactor

Polyoxymethylene dimethyl ethers (DMMn) is regarded as a potential alternative fuel for transportation utilization. The jet stirred reactor (JSR) pyrolysis of DMM1−3 was studied at temperatures of 450∼1080 K and pressures of 1.03 atm with the residence time (τ) of 2 s. A gas chromatography/mass spectrometry (GC–MS/FID) was used to detect and provide reliable pyrolysis experimental data. Seven key pyrolysis products were detected and measured in the present work, including fuel, methyl formate, methanol, acetaldehyde, methane, ethane and ethylene. A detailed kinetic model of DMM1−3 pyrolysis was elaborated. Both rate of production (ROP) and sensitivity analysis were performed to reveal the DMM1−3 pyrolysis processes. Results show that the chemical kinetic simulation can reproduce the consumption of fuel and most intermediate species reasonably well. With the increase of n from 1 to 3 inside DMM1−3, the reactivity increases evidently and the initial pyrolysis temperature decreases significantly, which is mainly resulted from different fuel-specific chain initiation reactions of DMM1−3. Methane and methyl formate are two detected key species with relatively significant concentrations. It was revealed that the fuel-specific chain initiation reactions of DMM1−3 can also significantly affect the production and consumption paths of methyl formate. In addition to the major production and consumption paths of formaldehyde, two key competitive channels were found to perform relatively high negative sensitivity to formaldehyde production of DMM2 and DMM3.

Effect of Steric Structure on the Mechanism of Antioxidant Activity of Alkyl Gallates in Soybean Oil Triacylglycerols—A Kinetic Approach

AbstractFrom an interfacial phenomena standpoint, the effect of the alkyl chain length is evaluated on the mechanism of antioxidant activity of gallic acid ester derivatives (methyl, propyl, octyl, dodecyl, and stearyl gallates) in bulk phase oil. A combinational kinetic model is used to estimate the oxidation kinetic parameters, such as induction period, the maximum concentration of lipid hydroperoxides, and critical reverse micelle concentration. These kinetic parameters are estimated much better with the combinational model compared to the tangent method. The nonlinear behavior is observed for inhibitory activities of homologous series of antioxidants in soybean triacylglycerols. In terms of different kinetics parameters, including antioxidant effectiveness and activity, methyl gallate has the highest inhibitory effect during lipid peroxidation. Gallic acid and alkyl gallates are able to protect bulk oils against peroxidation (induction period &gt; 336 h) in terms of the extent of their participation in the main reaction of chain termination and pro‐oxidative side reactions of chain initiation, and anti‐oxidative side reactions of chain propagation.Practical Applications: This work explains the effect of the esterification in the inhibitory activity of alkyl gallates, mechanism action of alkyl gallates in bulk oil systems, antiradical potency as a function of the interfacial phenomena, and free radical chain mechanism, the impact of antioxidant activity on critical reverse micelle concentration of hydroperoxides. Moreover, in this study, it is confirmed that the combinational kinetic model can be employed as a reliable method for determining the oxidation kinetic parameters.

High-temperature decomposition of amorphous and crystalline cellulose: reactive molecular simulations

We study the thermal decomposition of cellulose using molecular simulations based on the ReaxFF reactive force field. Our analysis focuses on the mechanism and kinetics of chain scission, and their sensitivity on the condensed phase environment. For this purpose, we simulate the thermal decomposition of amorphous and partially crystalline cellulose at various heating rates. We find that thermal degradation begins with depolymerization via glycosidic bond cleavage, and that the order of events corresponds to a randomly initiated chain reaction. Depolymerization is followed by ring fragmentation reactions that lead to the formation of a number of light oxygenates. Water is formed mainly in intermolecular dehydration reactions at a later stage. The reaction rate of glycosidic bond cleavage follows a sigmoidal reaction model, with an apparent activation energy of 166 ± 4 kJ/mol. Neither the condensed phase environment nor the heating programme have appreciable effects on the reactions. We make several observations that are compatible with mechanisms proposed for cellulose fast pyrolysis. However, due to the absence of anhydrosugar forming reactions, the simulations offer limited insight for conditions of industrial interest. It remains unclear whether this is a natural consequence of the reaction conditions, or a shortcoming of the force field or its parameter set.Graphic abstract

Thermoacoustic instability analysis of a laminar lean premixed flame under autoignitive conditions

To address engineering challenges encountered in developing advanced gas turbine combustors, theoretical analysis and numerical simulation were performed to investigate the thermoacoustic instability of a laminar lean premixed flame under autoignitive conditions. The analysis was carried out within the scope of weak autoignition tendencies and employed a three-step mechanism, which included the chain-initiation reaction. The numerical simulation was performed as a validation using a skeletal mechanism for diesel fuel under the typical operating conditions of gas turbines. The results showed that the three-step mechanism could qualitatively describe the high-temperature chemistry involved in autoignition and flame propagation. The analysis indicated that the flame propagation speed was accelerated by the accumulation of pre-flame reactions. Under certain conditions, the flame speed showed a linear correlation with the pre-flame length. The results were consistent with the existing literature. In addition, the equilibrium position of the flame oscillation, which was excited by velocity fluctuation, could return to the initial position, and pre-flame reactions could alter the phase delay. These results suggested a new mechanism for thermoacoustic instability because the overall heat release rate fluctuated with the flame front. The flame might amplify, damp, high-pass filter, or low-pass filter the acoustic energy based on the phase difference between the velocity and pressure oscillations.

MBMS study on plasma‐assisted low‐temperature oxidation of n‐heptane and iso‐octane in a flow reactor

AbstractNonequilibrium plasma has a great potential in the lean combustion of gasoline engines. However, fundamental studies on plasma‐assisted combustion on gasoline components are limited. In the present study, Low‐temperature oxidation behaviors for n‐heptane and iso‐octane in a plasma flow reactor were investigated. Species measurements were performed at room temperature and low pressure of 40 mbar using the electron ionization molecular‐beam mass spectrometry (EI‐MBMS). A total of 72 and 57 species were quantified in n‐heptane and iso‐octane oxidation, respectively. Based on measured species data, reaction networks of n‐heptane and iso‐octane in the plasma system were discussed. Particularly, some typical low‐temperature intermediates, such as cyclic ethers, diones, and ketohydroperoxides, were observed, suggesting the applicability of the classical low‐temperature reaction scheme in the plasma system of large hydrocarbons. The results indicate that the major role of plasma discharge on the low‐temperature oxidation of large hydrocarbons is either to breakdown large fuel molecules or to accelerate the chain initiation reactions. We also investigated the parametric effects of voltage, frequency, and residence time on the species pools, and found that the increase of these parameters leads to higher production of intermediates. The whole system reactivity was most sensitive to the plasma voltage. The difference between plasma frequency and residence time on the species formation was found. Moreover, some highly temperature‐sensitive reactions, such as the RO2 → QOOH, proceed at very low temperatures (around 340 K) in the plasma system, which was potentially attributed to the additional energy from plasma‐generated species.

Antioxidant activity and mechanism of inhibitory action of gentisic and \u03b1-resorcylic acids

The antioxidant activity of gentisic (GA) and α-resorcylic (α-RA) acids was investigated by considering their molecular structures in various oxidative environments, including DPPH· scavenging assay, stripped olive and soybean oils, and the corresponding oil-in-water emulsions. The mechanism of action in the oils was evaluated in the presence of different concentrations of the antioxidants at 60 °C, using the kinetic parameters the stabilization factor (F), the oxidation rate ratio (ORR), the activity (A), and the average rate of antioxidant consumption (overline{r}_{{{text{AH}}}}). GA was significantly more potent antioxidant than α-RA in all the environments. Although the less polar α-RA showed better activity in the emulsions rather than in the bulk oils, GA with an ortho-hydroxy structure had higher capacity to scavenge DPPH·, and LOO· in the oils and emulsions. The lower performance of α-RA was attributed to its participation in side reactions of chain initiation (AH + LOOH → A· + L· + H2O) and propagation (A· + LH → AH + L·) as competed with the main chain termination reaction (LOO· + AH → LOOH + A·).

The Legacy of Hermann Staudinger: Covalently Linked Macromolecules

In 1920, at age 39 and the peak of his professional carrier, one of the most distinguished organic chemists of his generation, Hermann Staudinger, claimed that natural and synthetic polymers are covalent macromolecules rather than colloidal aggregates. This idea initiated chain reactions supporting and dismissing the covalent macromolecular concept. The story of his 1953 Nobel Prize in Chemistry is reported here.

A product analysis-based study on the mechanism of inflammable gas explosion suppression

To study the mechanism of the suppressing effect of Expanded Aluminium (EA) on the premixed gas explosion, premixed methane-air and propane-air gases were undergone explosion reaction in the presence of EA in a self-designed closed pipeline with the overpressures and the compositions, rates and sensitivities of products analyzed. The results showed that the 9.5% methane-air and 5% propane-air explosions produced peak pressures decreased by 79.3% and 65.6%, and residual methane and propane contents increased by 270% and 560% respectively than without EA. In addition, the results revealed that the explosions of propane in the presence of EA produced less methane and carbon oxides contents, but more ethylene and propylene contents. The simulation showed that H, O, and OH are the key factors affecting the rate of products. The product compositions, together with other parameters, suggested that EA decreased temperature, inhibited chain initiation and propagation reaction, but facilitated chain termination reaction by advancing and accelerating the gas phase and wall destruction reaction of radicals, especially collisions and concentration of key free radicals. This new research method based on the analysis of explosion products can be used for in-depth research into gas explosion features and shed light on the suppressing mechanism of EA in flammable gas explosion.

Unraveling synergistic effects on pyrolysis reactivity and indene formation in co-pyrolysis of toluene and acetylene

Synergistic effect is one of the most important interactions between different fuel components and is very influential on combustion characteristics such as polycyclic aromatic hydrocarbon (PAH) and soot emissions, pyrolysis/oxidation reactivity and so on. In order to explore the potential synergistic effects between aromatics and open-chained fuels, pure toluene pyrolysis, pure acetylene pyrolysis and co-pyrolysis of toluene and acetylene were investigated in a flow reactor using synchrotron vacuum ultraviolet photoionization mass spectrometry at 1057–1340 K and 1 atm. Mole fractions of fuels and key products including both stable and reactive ones were evaluated. The experimental results indicate that in the co-pyrolysis of toluene and acetylene, the decomposition of both fuels is greatly stimulated and the formation of indene is significantly improved compared to the pyrolysis of pure toluene and pure acetylene. As a result, remarkable synergistic effects can be observed on pyrolysis reactivity and indene formation. A kinetic model for co-pyrolysis of toluene and acetylene was updated from our previous toluene model and was validated against the new data. The modeling analysis reveals that the unimolecular decomposition reaction of toluene producing benzyl radical and H atom is the chain-initiation reaction in both pure toluene pyrolysis and co-pyrolysis of toluene and acetylene. In the pure toluene pyrolysis, the self-combination reaction forming bibenzyl dominates the consumption of benzyl radical and results in strong chain termination. In the co-pyrolysis of toluene and acetylene, instead of the chain-termination reaction, a circulating reaction sequence initiating from the reaction between benzyl radical and acetylene continuously converts toluene and acetylene to indene and H2, which can explain the observed synergistic effects on pyrolysis reactivity and indene formation in the co-pyrolysis of toluene and acetylene.

Influence and assessment of AIBN on thermal hazard under process situations

Free radical polymerization is an effective method for large-scale production of various olefin polymers, in which the initiator is one of the emphases in the study of different chain reaction mechanisms in chemical industry. The azo compounds are widely used in organic synthesis to initiate chain reactions. Azos are divided into different types according to the applicable temperature range. 2,2′-Azobis(2-methylpropionitrile) is suitable for moderate temperatures and well known. In the past, the chemical and free radical reactions of 2,2′-Azobis(2-methylpropionitrile) have been studied. However, the kinetic model and reaction mechanism of initiators under process conditions are still lacking. The thermal hazard characteristics evaluated by process situation of 2,2′-Azobis(2-methylpropionitrile) were discussed in this study. The kinetics analysis on AIBN is based on detailed information including rate constants, reaction orders and activation energies of the decomposition reaction. Simulated heat exchange patterns of initiators between bulk packaging and the environment can be used to collect relevant heat hazard parameters. The results of the analysis are directly related to the storage and transportation safety of the 2,2′-Azobis(2-methylpropionitrile). Finally, a series of evaluation models about the thermal safety of initiators are constructed and analyzed by simulating the runaway modes of the 2,2′-Azobis(2-methylpropionitrile) at different temperatures.