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Due to their numerous properties as an advanced or specialized material, ionic liquids (ILs) have found an increasingly wide utilization in many fields. Moreover, mixtures of ILs can further improve their correlative properties. Therefore, it is significant that the thermal stability and exothermic behaviour of IL binary mixtures were studied. In this work, two typical representative imidazole ILs ([BMIM]BF4 and BMIM[NO3]) were selected, and their binary mixture thermal stability and thermal decomposition process of visualization were investigated by simultaneous thermogravimetric analyser (STA). Furthermore, their binary mixture exothermic behaviour and decomposition products were obtained by differential scanning calorimetry (DSC) and thermogravimetry coupled with Fourier transform infrared spectroscopy (TG-FTIR), respectively. The compound mode of imidazolium-based IL binary mixtures was divided into three categories: the molar fraction (7:3, 1:1, and 3:7) of parent pure ILs. We found that TG curves trend of IL binary mixtures was consistent with their parent pure ILs. Compared with TG curves, DSC curves of IL mixtures demonstrated that the behaviours of heat absorption and heat release at greater than 700.0 K in mixtures were different from their parent pure ILs. According to the infrared spectrum of gas products, the oxygen-containing functional group in BMIM[NO3] is likely to have some influence on the second-stage decomposition of sample 1#. Systematic thermal analysis results provided a significant reference for the exothermic behaviours and thermal degradation process of imidazolium-based ionic liquid binary mixture and a feasible research route for further investigations into the thermal decomposition characteristics of IL mixtures. [ABSTRACT FROM AUTHOR]

Imidazole ionic liquids (ILs) have broad application prospects in batteries and other fields. Researching the thermal decomposition features of ILs holds paramount importance for the application in battery electrolyte. 1-allyl-3-methylimidazole nitrate ionic liquid (IL) as a new functional IL, and its related thermal decomposition properties are unknown. In this paper, the thermal decomposition peculiarities of 1-allyl-3-methylimidazole nitrate IL were systematically analyzed by thermogravimetric analyzer, differential scanning calorimetry, and accelerating rate calorimeter techniques, and the relevant thermodynamic parameters and thermal decomposition models were derived. In addition, 1-allyl-3-methylimidazole nitrate IL possesses strong thermal runaway characteristics and the risk of thermal runaway is also evaluated. The main gaseous products formed by the pyrolysis of 1-allyl-3-methylimidazole nitrate IL was detected and analyzed by thermogravimetry-Fourier transform infrared spectroscopy and thermogravimetric-photoionization mass spectrometry techniques. The results showed that flammable gas, toxic gas, and asphyxiating gas are formed during the pyrolysis of 1-allyl-3-methylimidazole nitrate IL. This study lays a theoretical foundation for the safe application and the formulation of corresponding safety protection measures of 1-allyl-3-methylimidazole nitrate IL. [ABSTRACT FROM AUTHOR]

In plastic industry, liquid organic peroxides are prevailingly used to manufacture polymer materials. Unfortunately, a corresponding diversity of thermal hazards about instrument damage, fire, explosion, economic loss, and even casualty is engendered. This study focused on the comprehensive investigation to detect the specific thermal reactions and decomposition characteristics of tert-butyl (2-ethylhexyl) monoperoxy carbonate (TBEC) which is commonly used as polymerization initiator. First, simultaneous thermogravimetric analyzer was used to record the data in dynamic heating experiments and two mass loss stages were observed of TBEC. To further estimate the thermal stability of TBEC, differential scanning calorimetry was adopted to collect the thermokinetic parameters. Moreover, Flynn–Wall–Ozawa and ASTM E698-16 kinetic methods were applied for calculating the apparent activation energy of TBEC with different conversion rates. Then, thermogravimetric analyzer and FTIR spectrometer were utilized to detect the gaseous decomposition products of TBEC. The results show that TBEC is a Class 2 hazardous substance with high explosion hazard. The gaseous decomposition product of TBEC is tert-butyl alcohol, carbon dioxide, and 2-ethylhexanol. Furthermore, numerical simulation was employed to obtain the time to maximum rate under the adiabatic conditions of TBEC which can provide a predictive model for the industry. On the other hand, the explosion possibility of TBEC was assessed via oxygen balance. The findings of this study can provide the thermal hazard information of TBEC under upset scenarios and used to develop an instruction system to peter the related incidents. [ABSTRACT FROM AUTHOR]

Polystyrene is a multifunctional plastic used to manufacture consumables with a wide range of applications. Some azo compounds can produce free radicals when heated, which can be used as initiators for styrene polymerization. However, thermal runaway could occur during the styrene bulk polymerization initiated by azodiisobutyronitrile (AIBN) due to the release of a large amount of heat. To obtain thermal hazard properties, differential scanning calorimetry (DSC) and accelerating rate calorimetry (ARC) were applied to this investigation. The DSC experimental results showed that the extrapolated onset temperature and exothermic peak temperature decreased gradually after adding the initiator, which indicated initiator AIBN promoted the polymerization. ARC experiment decoded dynamic thermal parameters such as apparent activation energy, adiabatic temperature rise, initial runaway temperature, maximum temperature and polymerization heat of the hybrid system. Finally, the experimental and calculation results showed that the heat released by the polymerization reaction was basically unchanged at different heating rates; as the initiator concentration increases, the heat released by the polymerization reaction also increases, the polymerization temperature is controllable below 35.1 ℃. These results are critical for reducing the risk of loss of control and designing intrinsically safer styrene production, storage and transport processes. [ABSTRACT FROM AUTHOR]

4,4′-Azobis (4-cyanovaleric acid) (ACVA) is known as a kind of water-soluble azo initiator which was widely used in the radical polymerization process. As same as other azo compounds, ACVA may also trigger thermal runaway accidents at high temperatures due to its specific –N=N– structure. To qualify its pyrolysis characteristics, thermogravimetric analysis and differential scanning calorimetry were applied to this investigation, moreover, the TGA-FTIR combination technology was used in the product analysis part. The results showed that ACVA has a complex decomposition process, there are four mass loss stages during its pyrolysis, the heat release mainly occurred in the first and final decomposition stage and the heat flux in the middle stages was very disordered. Different decomposition stages were accompanied by different decomposition products, and some of them were considered toxic, such as HCN and CH4. Thermokinetic parameters such as apparent activation energy (Ea) were also calculated in this paper by using Kissinger–Akahira–Sunose (KAS) method. Surprisingly, ACVA has the lowest Ea (91 kJ mol−1) and the highest heat release (4706 J g−1) compared with some commonly used azos, which means it will more easily suffer a serious runaway accident. All these studies can give us a comprehensive understanding of the thermal decomposition of ACVA to prevent accidents. [ABSTRACT FROM AUTHOR]

With the continuous development of battery technology, there are new research investments in materials of various parts. In the field of electrolytes, ionic liquids (IL) are considered to be excellent electrolytes and have been widely studied in distinct energy fields. However, it is necessary to pay attention to the safety characteristics of ionic liquids at high temperature due to the application of energy. Still, there is little research on the reaction and kinetics of ionic liquids. To ensure the safety of ionic liquids, such as high temperature, the common ionic liquid 1-hexyl-3-methylimidazolium nitrate ([Hmim] NO3) was selected for analysis. The exothermic mode is obtained from the data of differential scanning calorimetry. The basic reaction parameters of [Hmim] NO3 were determined with thermodynamic equation simulation. For ionic liquids in the actual situation, consider adding a heat balance model to estimate its temperature change pattern and determine the hazard temperature and related safety parameters. Temperature changes were assessed by constructing 25.0 g and 50.0 g packages to simulate material reactions and heat transfer in the external environment. The results showed that [Hmim] NO3 had shorter TMRad and TCL (< 1 day) when the temperature was above 200 °C. [ABSTRACT FROM AUTHOR]

Organic peroxides, due to temperature manipulation failure and/or manner disturbances, had been probable to lead to the prevalence of runaway phenomena, even fire, and explosion. Cumene hydroperoxide (CHP), is a traditional liquid organic peroxide for industrial purposes and is applied as a free radical initiator for polymerization reactions in the petrochemical industry. Its utilization in the industrial processes had certain potential safety hazards. In this work, linearly ramped thermal decomposition in CHP was performed using differential scanning calorimetry under a nitrogen atmosphere. Kinetic analysis is made using data from the ramped measurements with two integral strategies (Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose). The gaseous products of thermal decomposition in CHP are investigated via thermal gravimetric evaluation coupled with Fourier transform infrared spectroscopy and gas chromatography/mass spectrometry. Combined with the experimental results, the possible decomposition path of CHP is discussed. This makes up the gap of unclear decomposition mechanism of CHP in inert atmosphere, and has important reference significance for its industrial production and application. [Display omitted] [ABSTRACT FROM AUTHOR]

Di-tert-butyl peroxy-hexahydro terephthalate (HTP-65W), a newly developed organic peroxide, has been used in manufacturing acrylonitrile–butadiene–styrene copolymer and as an initiator in the polymerization. However, few studies focus on the thermal hazards of HTP-65W. The purpose of this study was to investigate the thermal decomposition phenomenon of HTP-65W under different conditions via calorimetric technologies and simulation. According to simultaneous thermogravimetric analyzer curves, two mass loss stages were detected at about 79 °C and around 64–72% mass loss happened in the first stage. Furthermore, the real view system was used to observe the apparent physical phenomenon like color and state change in HTP-65W during the reaction. Utilizing accelerating rate calorimeter and adiabatic kinetic method, the exothermic phenomena occurred at around 75 °C. The apparent activation energy (Ea) and rate constant of reaction under adiabatic conditions were 172.0 kJ mol−1 and 4.0 × 1025 mol L−1 s−1. Through differential scanning calorimetry and kinetics simulation, an exothermic peak appeared between 87 and 168 °C caused by the thermal decomposition of HTP-65W, and the Ea calculated using Flynn–Wall–Ozawa and Friedman methods were 143.4 and 128.4 kJ mol−1, respectively. To prevent thermal loss prevention accidents, time to maximum rate under adiabatic condition was obtained as 24 h under 63.9 °C and self-accelerating decomposition temperature was 61 °C for 50 kg package size of HTP-65W. Results of this study can support to prevent the potential thermal hazards of HTP-65W happened during storage, transportation, and manufacturing process. [ABSTRACT FROM AUTHOR]

2,2′-Azobis[2-(2-imidazolin-2-yl) propane] dihydrochloride (AIBI) is a class of initiators that share water-soluble features, which was widely employed in the chemical polymerization industry. The merits of AIBI are that it can conduct smooth, stable, and controllable decomposition reaction and initiate polymerization efficiently at low temperature and concentration. Unfortunately, due to the high formation enthalpy and through a large amount of gas release, AIBI has high-potential thermal hazards. Therefore, the thermal behavior of the whole decomposition process is analyzed through series of simultaneous thermogravimetric analyzer and differential scanning calorimetry tests coupled with the advanced thermal investigation. It is found that AIBI would rapidly decompose and abruptly release an enormous amount of heat in the range of 170 to 180 °C, but with only 10% mass loss in this period. These thermal parameters can be used to describe the thermal stability of AIBI, thus effectively preventing the thermal hazard and loss of control of AIBI in the process of production, transportation, and storage. [ABSTRACT FROM AUTHOR]

The polymerization industry has existed for many years. The advancement of industrial technology is contributed to the related synthesis and application of enduring polymer operation. Organic peroxide (OP) initiators have been used and applied to practical industrial processes which may cause a runaway reaction due to their self-reactive property. OPs have been used for a long time and studied in the related literature. However, there are still emerging OPs that have recently been applied to these processes, and there are few related studies. To ensure the thermal safety of OPs in the process of production, transportation, and storage, the common OP initiator such as dicumyl peroxide (DCPO) was selected to be investigated. First, thermal decomposition characteristics under non-isothermal and adiabatic conditions of DCPO were acquired by differential scanning calorimetry. Second, combined calorimetry with pseudo-adiabatic and isothermal conditions can determine the process of thermal hazards and basic reaction patterns. The gleaned data can input into a mathematical model to evaluate the basic thermal hazards for DCPO, respectively. In addition, based on simulated thermal explosion models and kinetic parameters, hazardous properties of storage and transport can also be acquired. The results show that the DCPO has prominent hazard properties on thermal and explosive hazards in process conditions which should pay much attention to temperature during storage and transportation. [ABSTRACT FROM AUTHOR]

4-Amino-1,2,4-triazole picrate (4-ATPA) is a type of ionic liquids, as well as an explosive with sound thermal stability and low mechanical sensitivity. However, under upset conditions such as high temperature and pressure, an unpredictable explosion would occur and result in huge casualties and property losses. The purpose of this research was to evaluate the thermal hazard and runaway reaction of 4-ATPA through high-pressure differential scanning calorimetry and accelerating rate calorimeter. The kinetic parameters of decomposition reaction under non-isothermal and different pressure conditions were calculated based on the experiment results. Experimental results showed that the β and test pressure had no effect on the amount of heat release. Adiabatic experiments indicated that 4-ATPA had a high onset temperature at 196.8 °C. The maximum self-heating rate (3567.9 °C min−1) and pressure rise rate (202.0 bar min−1) revealed the vulnerability of 4-ATPA to suffer a disastrous explosion. Moreover, the apparent activation energy and pre-exponential factor were evaluated as 110.2 kJ mol−1 and 1.8 × 10−15 s−1 by ASTM E698 method. The correctness of the thermodynamic calculation formula under adiabatic conditions is verified by ARC tests. Finally, the thermal hazard risk of 4-ATPA was classified as unacceptable based on the risk classification criteria. [ABSTRACT FROM AUTHOR]

Azo compounds used in catalytic reactions often exhibit self-reactivity and high exothermicity. Severe fires and explosions can occur if the stage of change in the reaction (e.g., in an endothermic process or cooling system) is weaker than in a fractional heat release process. To guarantee the thermal safety of azo initiator in the production process, azobisdimethylvaleronitrile (ABVN), a normally applied azo in polymerization, was selected for the study. The basic thermal hazards of ABVN were obtained by simulating the exothermic curves of ABVN with differential scanning calorimetry technique, and the self-accelerating decomposition temperature (SADT) was calculated by combining the kinetics of the reaction. Analyzing the impact of different packaging conditions on SADT, values were verified with simulation methods performed with the packaging of 25.0 kg and 50.0 kg of ABVN. The results showed that the SADT was lower than 50 °C. Therefore, it is essential to establish a style of computing that can more rapidly determine the value of SADT, avoiding time-consuming and costly large-scale experiments. [ABSTRACT FROM AUTHOR]

Azo compounds, which are commonly used in radical polymerization reactions, readily demonstrate their self-reactive properties. Because of their sensitive thermal decomposition properties, azo compounds have been responsible for many accidents. To avoid unexpected thermal decomposition in the workplace, information about the thermal stability and other properties of azo compounds should be provided to on-site personnel in industries that use these materials. In this study, the target substance, 2,2'-azobis-(2,4-dimethylvaleronitrile) (ABVN), is shown to have a higher reactivity than other azo compounds, and its thermal decomposition characteristics are discussed based on a literature review and results from differential scanning calorimetry (DSC) and accelerating rate calorimetry (ARC). A thermokinetic analysis of ABVN is conducted using DSC and ARC data. The results can provide process-control data and explain the effects of thermal runway for ABVN. In addition, based on applied numerical methods, critical runaway temperatures, stable temperatures, and the required heat dissipation rate for the prevention of the thermal runaway reactions are calculated using a process deviation analysis. The results show that the reactant quantities and the process parameters must be strictly controlled to achieve the desired reaction. [ABSTRACT FROM AUTHOR]

1,3-Dimethylimidazolium nitrate ([Mmim]NO 3), an ionic liquid, is a versatile and novel solvent for the petrochemical industry. Nevertheless, under high temperature conditions or thermal upset scenarios, [Mmim]NO 3 can be decomposed in a manner that produces an explosion or other serious safety problems. The aim of this research was to investigate the thermal stability of [Mmim]NO 3 by simultaneous thermogravimetric analyzer and high pressure differential scanning calorimetry. Isothermal experiments indicated that [Mmim]NO 3 would be decomposed at a temperature substantially lower than the onset temperature. A pseudo-zero-order rate expression was applied to characterize the thermal decomposition kinetics of [Mmim]NO 3 , and related thermokinetic parameters were further obtained. Moreover, the temperature at which the thermal decomposition of ILs reached 10.0% for a given time of 10.0 h (T 0.1/10h) was defined to assess the long-term thermal stability, which can be used as the maximum operating temperature of [Mmim]NO 3. The results of this study may provide relevant processes for safer control based on the thermal hazard assessment of [Mmim]NO 3. [ABSTRACT FROM AUTHOR]

Di(2,4-dichlorobenzoyl) peroxide (DCBP), classified as a diacyl peroxide, is commonly used in silicone rubber manufacturing as a crosslinking agent, vulcanizing agent, and polymerization initiator. However, its reactivity or incompatibility may negatively affect safety requirements and concerns during chemical reactions. This study was conducted to investigate the properties of DCBP by using differential scanning calorimetry and a literature review. Specifically, thermal decomposition behavior of DCBP was examined by combining simulations with thermal analysis methods to analyze the foundation of thermokinetics, such as the peak temperature, heat of decomposition, and apparent activation energy of DCBP. Based on parameters obtained from the calculations, this investigation was integrated with thermal explosion theory, which represents a major advancement in the comprehension of behavior between heat release and heat transfer to the surroundings incorporated into a single differential equation, and a decision was made from a criticality criterion simultaneously. [ABSTRACT FROM AUTHOR]

Thermogravimetry and differential scanning calorimetry (DSC) were used to investigate the thermal stability of four nitrate-based ionic liquids. The variations of thermal behavior for different numbers or lengths of alkyl substituents for imidazolium cations were analyzed systematically. Long-term stability and operating temperature for 1.0% mass loss during 10 h (T0.01, 10 h) were estimated using model-free perdition methodologies. The results of T0.01, 10 h were predicted to be 78.73 and 81.59 °C for [Bim][NO3] and [Mim][NO3], respectively. The apparent activation energy (Ea) was obtained using four isoconversional methods at various heating rates through DSC experiments. This study confirmed that [Bim][NO3] and [Mim][NO3] decomposed swiftly, and the gaseous products can result in ignition and continuous combustion. [ABSTRACT FROM AUTHOR]

Azo compounds (azos) are vital basic initiators used in chemical plants that also possess thermally active properties. Azos may trigger serious accidents because of their intense exothermicity. We applied a specific method to characterize the reaction kinetics of azos using data from differential scanning calorimetry (DSC). Specifically, this method was used to analyse the thermal decomposition of 2,2-azobis(2-methylbutyronitrile) (AMBN). The exothermic peak temperature, exothermic final temperature, and heat of decomposition were determined. The data obtained from the experiments were utilized to predict the self-accelerating decomposition temperature, control temperature, and emergency temperature. Experiments conducted to explore the runaway phenomenon of AMBN during the overall decomposition process interfered with the thermal analysis studies. We utilized a process simulation model to mimic the decomposition of AMBN, ensuring that the simulation results were realistic and practical. The results are worthy of being applied to thermal analysis, for example, for application in proactive loss prevention. [ABSTRACT FROM AUTHOR]

Azo compounds, which readily show self-reactive traits, are extensively used in solution radical polymerization. If the phase of reaction is changed, such as in an endothermic process is weaker than in the exothermic decomposition process, it may cause serious fires and explosions. To ensure thermal safety of azo initiators in the process of creation, the commonly used oil-soluble azo initiators, 2,2′-azobis-(2-methylbutyronitrile), or so-called AMBN, are chosen to be explored. In this study, thermal decomposition characteristics under non-isothermal were obtained using differential scanning calorimetry. The composed data can be input into an equation such as isoconversional differential method with advanced thermal analysis technique to evaluate the cardinal thermal hazard for AMBN thermokinetic. [ABSTRACT FROM AUTHOR]

Numerous fires and explosions have occurred in chemical industries in Taiwan. In addition to considerable damage to equipment, such accidents cause environmental damage and even social turmoil, and they remind us of the importance of industrial process safety. Many of these accidents involve organic peroxides, which become extremely labile or unstable if they contact acids, bases, or other incompatibles. This study established thermokinetic and thermal safety parameters by differential scanning calorimetry and a thermal activity monitor III for cumene hydroperoxide (CHP) and its incompatibles. For the first time, this study reports the first real-time observation of the reaction of CHP with sulfuric acid by thermal imaging camera, which was used to determine the rate of heat evolution and recognize the degree of hazard present during thermal incidents. [ABSTRACT FROM AUTHOR]

Azo compounds (azos) are radical polymerization initiators due to an azo group in the molecule. The molecular structure of the bivalent-N-N-composition is a weak bond which can release a significant amount of heat and toxic gas via thermal decomposition under high ambient temperature. This sequence on sensibility study aimed at the thermal hazard evaluation for the reactive and incompatible characteristics of azo compounds mixed with acid or alkaline solutions. To realize the thermal stability of azobis dimethylvaleronitrile (ABVN) during the process, transportation, and storage, we used differential scanning calorimetry and thermal activity monitor III to analyze the inherent safety properties and potential hazards. Isothermal and non-isothermal scanning tests were performed to compare the exothermic behaviors in a thermal decomposition process. Moreover, the thermal reactivity properties obtained via vent sizing package 2 were applied for evaluation, and the effects of thermal runaway reactions hazard were compared for ABVN with incompatibilities under the adiabatic conditions. These results are critically important in reactor design for producing and using azos to improve feeding safety, especially under thermal upsets. [ABSTRACT FROM AUTHOR]

In addition to organic peroxides, azo compounds are important basic initiators applied in chemical plants. In general, these compounds decompose at lower temperatures than aldehydes, ketones, and ethers, some of which decompose unimolecularly at higher temperatures so that the first products are not as stable due to the bivalent -N=N- composition, which has very active characteristics. In this study, thermal stability tests of two azo compounds, 2,2′-azobis (2-methylbutyronitrile) and 2,2′-azobis-(2-4-dimethylvaleronitrile), were evaluated via differential scanning calorimetry to determine the apparent exothermic onset temperature ( T), heat of decomposition (Δ H), and apparent exothermic peak temperature ( T) for intrinsic thermal safety analysis. Following the dynamic tests, vent sizing package 2 (VSP2) was employed to determine the maximum pressure ( P), maximum temperature ( T), maximum self-heating rate [(d T/d t)], maximum pressure rise rate [(d P/d t)], and adiabatic time to maximum rate [( TMR)] under a credible case. Finally, we attempted to obtain the apparent activation energy ( E) and pre-exponential factor ( A) during decomposition via a non-isothermal approach through Flynn-Wall-Ozawa equation and the approximate solution for the design of safer reaction conditions with greater efficiency when azo compounds are used as initiators. As a whole, a prudent approach for the integration of thermal hazard data was developed that is necessary and useful for determining a proactive emergency response procedure associated with industrial applications on azo compounds during thermal upsets. [ABSTRACT FROM AUTHOR]

A new approach was used to monitor the autocatalytic reaction of benzoyl peroxide (BPO) by non-isothermal and isothermal kinetic models constructed using differential scanning calorimetry and thermal activity monitor III analyses, respectively. Autocatalytic reactions generally start slowly and then accelerate as the reactant is consumed and the autocatalyst is produced. Consequently, an autocatalytic reaction may require special design considerations to avoid certain upset conditions, such as runaway exothermic reactions. We conducted a thermal hazard analysis of various products, including benzoic acid, benzene, and phenol, which were deliberately selected and individually mixed with BPO to investigate their thermal hazards. Model fitting can be applied to predict the amount of time required to achieve the maximum rate under isothermal conditions at any temperature of interest. The proposed procedure was effective and accurate for evaluating the autocatalytic reaction of BPO. [ABSTRACT FROM AUTHOR]

In addition to polypropylene, acrylonitrile, and carbonyl alcohol, propylene oxide is the fourth major derivative among propylene derivatives and one of the important basic organic chemicals. A thermal stability test of catalyst, methanol, and hydrogen peroxide (H2O2) was conducted via differential scanning calorimetry (DSC). Propylene epoxidation with H2O2 over catalyst, methanol, and propylene evenly mixed by specific pressure was carried out, and then the runaway reaction under adiabatic conditions was further simulated by the vent sizing package 2 (VSP2) to measure temperature and pressure data with respect to time of the runaway excursion. Finally, the apparent activation energy of H2O2 and propylene oxide reaction was obtained via temperature variation equation to evaluate the degree of potential hazard in industry. [ABSTRACT FROM AUTHOR]

Having two active peroxide groups, 1,1-bis( tert-butylperoxy)cyclohexane (BTBPC) has a certain degree of thermal instability. It is usually used as an initiator in a chemical process, and therefore, careless operation could result in severe accidents. This study emphasized the runaway reactions of BTBPC 70 mass% (4.5-5.2 mg), the relevant thermokinetic parameters, and the thermal safety parameters. Differential scanning calorimetry was used to evaluate the above-mentioned thermokinetic parameters, using four low heating rates (0.5, 1, 2, and 4 °C min) combined with kinetic simulation method. The results indicated that apparent exothermic onset temperature ( T), apparent activation energy ( E), and heat of decomposition (Δ H) were ca. 118 °C, 156 kJ mol, and 1,080 kJ kg, respectively. In view of process loss prevention, at the low heating rates of 0.5, 1, 2, and 4 °C min, storing BTBPC 70 mass% below 27.27 °C is a more reassuring approach. [ABSTRACT FROM AUTHOR]

To accomplish an effective analysis of adsorption, the strong acid dye from aqueous solution of sodium alginate (SA) and multi-walled carbon nanotubes (MWCNTs) composite gel beads were used as important parameters. Differential scanning calorimetry (DSC) was used to measure the heat of breakdown reaction. The experimental conditions were set at 0.5, 1, 2, 4, and 8 °C min, and the temperature range was 30-300 °C. The heating rates and the temperature range were set as follows: Four kinds of proportion in this experiment contained 2 SA % w/v (SA), 0.03, 0.09, 0.18, 0.36 % w/v (MWCNTs), and 10 % w/v calcium chloride, respectively. Four samples, 5, 6, 7, 8, and 9 mg, were used to detect the experimental data. It contributed to understanding the reaction for the distinctive MWCNTs. With the thermokinetic data by isoconversional approach obtained from advanced kinetics and technology solutions (AKTS), the related thermal safety information can be obtained from the thermal reaction of MWCNTs. Valuable parameters, such as activation energy ( E) and heat of decomposition, can be applied in operation, including adsorption and desorption processes. After DSC tests, and under the four compositions of SA/MWCNTs, at different heating rates of 0.5, 1, 2, 4, and 8 °C min, primarily we found that when the heating rate was increased, exothermic onset temperature would increase gradually. After analyzing E value by isoconversional kinetics, we learned that in four different adsorption compositions, SA/MWCNTs (161.20 kJ mol) was the minimum. Among them, the highest value was SA/MWCNTs (220.48 kJ mol). However, in this study, for SA/MWCNTs compositions we found that E value will drop in the final material SA/MWCNTs. Accordingly, if the ratio of SA and calcium chloride was fixed, then different compositions of the MWCNTs would affect adsorption efficiency of SA/MWCNTs and E variation. [ABSTRACT FROM AUTHOR]

The decomposition of organic peroxides by their relatively weak oxygen linkage and hydroperoxide radical in the presence of reaction solution is one of the thermal hazards for triggering a runaway reaction. Runaway incidents may occur in oxidation reactors, vacuum condensation reactors, tank lorries, or storage tanks. In NFPA 432 organic peroxides in NFPA 432 are classified as flammable. The exothermic behaviors of solid organic peroxides, dicumene peroxide, benzoyl peroxide, and lauroyl peroxide, were determined by differential scanning calorimetry (DSC), and vent sizing package 2 (VSP2). Relevant data detected by DSC provided thermal stability information, such as exothermic onset temperature ( T), maximum heat-releasing peak ( T), and heat of decomposition (Δ H). VSP2 was used to perform the bench scale situation for pushing the expected or unexpected reaction to undergo runaway reaction. Onset temperature, maximum pressure, self-heating rate ((d T d t)), and pressure-release rate ((d P d t)) were therefore obtained and explained. These results are essentially crucial in process design for an inherently safer approach. [ABSTRACT FROM AUTHOR]

Liquid organic peroxides have been broadly employed in the process industries such as tert-butyl peroxy-2-ethyl hexanoate (TBPO). This study investigated the thermokinetic parameters of TBPO, a typical liquid organic peroxide, by isothermal kinetic algorithms and non-isothermal kinetic algorithms with thermal activity monitor III, and differential scanning calorimetry, respectively. An attempt has been made to determine the thermokinetic parameters by simulation software, such as exothermic onset temperature ( T), maximum temperature ( T), decomposition (∆ H), activation energy ( E), self-accelerating decomposition temperature, and isothermal time to maximum rate (TMR). A liquid thermal explosion model was established for a reactor containing liquid organic peroxide of interest. From experimental results, liquid organic peroxides' optimal conditions for avoiding a violent runaway reaction of storage and transportation were created. [ABSTRACT FROM AUTHOR]

• A new method was developed to study the thermal hazard of imidazole ILs. • The decomposition mechanism of ILs in different atmospheres was not affected. • The selected imidazole ILs released more heat in an oxidising atmosphere. • The decomposition products of the selected imidazole ILs were reductive. • The deflagration characteristics of the products of ILs should be fully considered. Ionic liquids (ILs), as a type of salt that is liquid at room temperature, break the entrenched views on salt when it was proved that some of them could be ignited. In this research, an innovative method was used to evaluate the thermal stability of such special salts and speculated their ignition mechanism based upon gas analysis. Four typical representative imidazole ILs (BMIMBF 4 , BMIMDCN, BMIMNO 3 , and BMIMOAc) were selected, and their thermal decomposition characteristics and thermal effect were obtained by simultaneous thermogravimetric analyser (STA) and differential scanning calorimetry (DSC), respectively. Furthermore, their decomposition products were investigated by thermogravimetry coupled with Fourier-transform infrared spectroscopy (TG-FTIR). It is noteworthy that they behaved diversely in DSC experiments and exhibited a radically different thermal effect in their decomposition. In addition, there exists positive feedback in the mechanism of the exothermic phenomenon of selected ILs in the air. Nevertheless, TG curves of four selected ILs were almost the same under air or nitrogen conditions. Series TG-FTIR experiments confirmed that the initial decomposition products of BMIMBF 4 and BMIMDCN under air or nitrogen are extremely different. The decomposition products of BMIMNO 3 and BMIMOAc in the air atmosphere have more oxidative products than nitrogen. The results denoted that the thermal decomposition mechanism of the four selected ILs in the air were the same as under nitrogen. The reducibility of the decomposition products induced the peculiar thermal effects of these imidazole ILs under the different gas environments. This study was innovative in researching the thermal effect and mechanism of imidazole ILs' decomposition and provided certain safety guidance for the process safety and loss prevention of imidazole ILs. [ABSTRACT FROM AUTHOR]

Azo-peroxyester, a multifunctional elemental energetic material, has low efficiency when indirectly acting on the target product in a reaction. If azo-peroxyester is dissolved in an appropriate solvent, the yield is greatly improved. With the aim of perfecting the safety of diethyl azodicarboxylate (DEAD) in industrial process applications, this study evaluated the inherent safety of DEAD when dissolved in different reagents by using differential scanning calorimetry and a thermal activity monitor III. The thermokinetic parameters, exothermic onset temperature (T o), time to maximum rate under isothermal conditions (TMR iso), and apparent activation energy (E a), were determined in order to reveal factors influencing the reaction mechanism. Comparing with pure DEAD, T 0 was lower when DEAD was dissolved in three ionic liquids: 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium tetrafluoroborate, and 1-butyl-3-methylimidazolium bis(trifluoromethyl)sulfonyl)imide. Additionally, E a and TMR iso were considerably higher, indicating there was an improvement in both efficiency and thermal safety of DEAD for the reaction process. These results support the applications of DEAD in industrial process safety, and set a foundation for future laboratory investigation. • Multiple heating approaches were used to evaluate the inherent thermal safety of DEAD when dissolved in different solvents. • T o , TMR iso , and E a were used to determine factors influencing the reaction mechanism. • By integrating DSC and TAM III data, differing effects of the solvents on thermal decomposition of DEAD were obtained. • Thermal hazards were identified when DEAD was dissolved in MeCN, MeOH, or EtOAC. • [BMIM][BF 4 ] and [BMIM][NTf 2 ] are ideal solvents for DEAD in terms of proactive loss prevention measures. [ABSTRACT FROM AUTHOR]

Ionic liquids are extensively used in pharmaceutical, chemical and aerospace fields, and sometimes used in high temperature environments. Investigating the pyrolysis hazard characteristics and mechanism of ionic liquids is significant. 1-Hexyl-2,3-dimethylimidazolium nitrate ([Hmmim][NO 3 ]) as a new versatile ionic liquid has been systematically studied in this paper. The pyrolysis characteristics of [Hmmim][NO 3 ] in different conditions are researched by using thermogravimetric analyzer, differential scanning calorimetry and accelerating rate calorimeter technologies. Main thermodynamic parameters, safety parameters, and reaction pattern of [Hmmim][NO 3 ] pyrolysis process are acquired. The severity degree and possibility of [Hmmim][NO 3 ] runaway reaction is evaluated, which may result in serious damage to the plant. The microscopic mechanism of [Hmmim][NO 3 ] pyrolysis has been explored comprehensive utilization thermogravimetry-flourier transform infrared spectroscopy, thermogravimetric-photoionization mass spectrometry and quantum-chemical simulation. The primary noxious gas and reaction steps leading to the thermal hazards of [Hmmim][NO 3 ] are confirmed. This research provides a theoretical basis for improving the intrinsic safety of [Hmmim][NO 3 ] application and formulating corresponding safety preventive measures. [ABSTRACT FROM AUTHOR]