Thermal hazard assessment of the thermal stability of acne cosmeceutical therapy using advanced calorimetry technology

Thermal hazards of benzoyl peroxide and its derived process products through theoretical thermodynamics assessment and different calorimetric technologies.

Benzoyl peroxide (BPO) is a typical organic peroxide widely used in food processing, particularly flour bleaching. Due to the unstable nature of the oxygen-oxygen bond in BPO, it readily reacts under even mid-low-temperature conditions. Lower concentrations of BPO are also potentially explosive, even when combined with acid or alkaline additives. Given the history of both potential and documented industrial accidents, this study investigates the thermal stability of various BPO concentrations when mixed with acid or alkaline solutions. In addition, differential and integral kinetic models were applied to verify that the apparent activation energy data from the differential scanning calorimetry experiments were valid. The results of autocatalysis reactions and nth-order reaction simulations presented characteristics consistent with the experimental findings. The findings in this paper can be used as a reference for BPO products that are mediated with either an acid or an alkaline solution during production, storage, transportation, or use.

Evaluation of multiple reactions in dilute benzoyl peroxide concentrations with additives using calorimetric technology

To explore the thermal hazard of tert-butyl peracetate (TBPA), various instruments were applied to investigate the synthesis and decomposition of TBPA. Reaction calorimeter (RC1e) was used to analyze the exothermic characteristics during synthesis of TBPA in acid and alkaline medium, respectively. The thermal parameters, such as adiabatic temperature rise (ΔTad,r) and maximum temperature of the synthesis reaction (MTSR), were calculated for assessing the thermal hazard of TBPA synthesis. Differential scanning calorimetry (DSC) and Phi-TEC II adiabatic calorimeter were used to understand thermal characteristics of TBPA decomposition. According to the exothermic curves from the interruption and rescanning experiments and isothermal experiments by DSC, TBPA decomposed following the nth-order law. Thermal parameters of TBPA decomposition at different heating rates were obtained from non-isothermal experiments and the corresponding apparent activation energy (Ea) was calculated by Kissinger method and Starink method. Phi-TEC II was, in turn, used to obtain the thermokinetic parameters of TBPA decomposition under adiabatic conditions. The thermokinetic parameters, such as Ea, the pre-exponential factor (A) and reaction order (n), were used to calculate the time to maximum rate under adiabatic conditions (TMRad) and TD24 (Temperature at which TMRad is 24.0 h). To further understand the decomposition process, thermal decomposition products were studied using gas chromatography/mass spectrometry (GC/MS). Then the reaction scheme of TBPA decomposition was proposed. The thermal hazard of TBPA synthesis was evaluated according to the risk matrix and the Stoessel criticality diagram. Results shows that compared to synthesis in acid medium, TBPA synthesis in alkaline medium was preferred. However, the operating conditions of synthesis also need to be redesigned to improve the process safety level. These studies were considered to have potential applications in inherently safer operating measures and safer storage and transportation.

Process safety evaluation of the synthesis of tert-butyl peracetate

The present paper deals with thermal runaway risk of esterification reaction in semibatch reactor. It identifies thermal runaway conditions for the esterification of 2-butanol (2B) and propionic anhydride (PA) with sulfuric acid (SA). The autocatalytic kinetic model of esterification of 2B and PA with SA was obtained by the experiments. A new boundary diagram was proposed for the autocatalytic parallel reactions. Then, the combined boundary diagram considering the target temperature and maximum allowable temperature was used to define the critical conditions for the thermal runaway. The conditional probability of thermal runaway for esterification of 2B and PA with SA was calculated by Monte Carlo simulations.

Thermal Runaway Risk of Semibatch Processes: Esterification Reaction with Autocatalytic Behavior

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.

Yong Zhang

Papers

Thermal hazard analyses for the synthesis of benzoyl peroxide