Benzoyl peroxide (BPO), historically, due to its wide applications around the world, has caused many serious fire and explosion accidents. In this paper, in order to prevent such accidents, thermal hazard analyses of synthesis of benzoyl peroxide were studied. Firstly, in order to obtain thermal hazard coefficients, the exothermic processes with different alkaline solutions were studied by RC1e (Reaction Calorimeter). The alkaline solutions are NaOH, NH 4 HCO 3 and Na 2 CO 3 , respectively. Secondly, the thermal decomposition of BPO product was studied by PHI-TECⅡto analysis the thermal stability. Finally, the possibility of runaway reactions and thermal risks of synthetic process were evaluated according to the Stoessel criticality diagram. In the first stage, the test results of the reaction heat (Δ H m ), heat release rate ( q r ) and adiabatic temperature rise (Δ T ad ) with different alkaline solutions were NaOH > Na 2 CO 3  > NH 4 HCO 3 . In the second stage, according to the analysis of experimental data, the heat release rate of reaction with NH 4 HCO 3 solution was the slowest, while the Maximum Temperature of the Synthesis Reaction ( MTSR ) and the adiabatic temperature rise (Δ T ad ) were lowest when using Na 2 CO 3 solution. The time needed to reach the maximum reaction rate under the adiabatic condition ( TMR ad ) was 0.83 h when using NaOH solution. The temperature was 38.24 °C when TMRad is 24 h ( T D24 ). The evaluation results of the process showed that the risks of reactions with NaOH solution or NH 4 HCO 3 solution were not acceptable. Only the risk of the reaction with Na 2 CO 3 solution was acceptable. Therefore, the safety level of synthesis of benzoyl peroxide can be significantly improved by using Na 2 CO 3 solution. Research in this paper can not only improve the safety level of BPO reaction and storage processes, but also provide technical support for stability criterion of BPO decomposition reaction.

Thermal hazard analyses for the synthesis of benzoyl peroxide

2-Ethylhexyl nitrate (EHN) is an important material, which is produced by concentrated HNO3–H2SO4 nitration process. But EHN is not a stable material, especially mixed with acids. To analyze the stability of EHN with concentrated acid under serious condition, four samples (pure EHN, concentrated sulfuric acid with EHN, concentrated nitric acid with EHN, and mixed acid with EHN) and three acids (sulfuric acid, nitric acid, and mixed acid) were measured by differential scanning calorimeter (DSC) and accelerating rate calorimeter (ARC) in this paper. The results indicated that concentrated sulfuric acid, concentrated nitric acid, and mixed acid all could decrease the onset decomposition temperature of EHN, especially concentrated sulfuric acid. DSC results also showed that the heat of EHN decomposition with nitric acid is larger than other samples. Based on ARC data, the kinetic parameters and T
 D24 (temperature at which TMR
 ad is 24 h) were calculated. The activation energy and T
 D24 of the EHN with acids, especially with concentrate sulfuric acid, were much lower than the pure EHN. It can be concluded that acids could decrease the stability of EHN and that is an important reason for frequent accidents.

Thermal stability of 2-ethylhexyl nitrate with acid

Cyclohexanone peroxide, a crucial organic peroxide used as a curing agent or an initiator in free radical polymerization, is produced through a reaction of cyclohexanone with hydrogen peroxide in the presence of nitric acid as the catalyst. For this study, we used reaction calorimeter, differential scanning calorimetry, and accelerating rate calorimeter to evaluate the thermal hazard characteristics of cyclohexanone peroxide synthesis and the thermal stability of cyclohexanone peroxide. The overall kinetic parameters of the peroxide reaction, which were calculated based on the Levenberg–Marquardt algorithm, were validated using experimental data. By combining the maximum temperature of the synthesis reaction that was corrected by the yield and temperature, at which time to the maximum rate under adiabatic decomposition conditions was equal to 24 h, criticality classes were depicted to assess the cooling failure scenario of the peroxide reaction. This study enhances our understanding of the peroxide reaction and presents safer operating conditions and design protection measures for a safer and greener chemical industry.

Thermal hazard evaluation of cyclohexanone peroxide synthesis

Research on the thermal history’s influence on the thermal stability of EHN and NC

Heterogeneous benzaldehyde nitration in batch and continuous flow microreactor

2-Ethylhexyl nitrate (2-EHN), an important additive to diesel fuel, is produced from the nitration of iso-octanol with HNO3–H2SO4 mixed acid. In this study, the differential scanning calorimeter (DSC), accelerating rate calorimeter (ARC) and reaction calorimeter were used to analyze the thermal stability of 2-EHN and the thermal hazard of iso-octanol nitration. Four samples with different ratios of 2-EHN to mixed acid were tested using DSC. The results indicated that more mixed acid could catalyze the decomposition of 2-EHN. Three samples were tested using ARC and the results showed that sample 4 contained the lowest onset temperatures, TD8 and TD24. This shows that there is a higher probability of triggering the decomposition of the product 2-EHN from the iso-octanol nitration process. This conclusion was verified using RC1e tests at different temperatures. The RC1e experiments also indicated that the overall heat generation of these reactions was considerably large despite the high yields of the nitration process at 45 °C and 55 °C. This heat generation makes these semi-batch processes difficult to control, especially on a pilot or plant scale. Based on the maximum temperature of the synthesis reaction (MTSR) corrected by the yield, the only acceptable semi-batch process is the nitration reaction at 10 °C.

Li-Ping Chen

Papers

Thermal hazard evaluation for iso-octanol nitration with mixed acid