| In recent years,the chemical industry has developed rapidly and the number of organic peroxides has been increasing year by year,which has improved the convenience of people’s lives.However,organic peroxides also have many potential safety hazards due to their special structure of oxygen-oxygen bond(O-O).The main harmful properties of organic peroxides are oxidizing,sensitive to heat,releasing a large amount of heat and generating free radicals.Many countries have promulgated corresponding management regulations for the hazardous characteristics of organic peroxides,but still cannot prevent the occurrence of related accidents such as combustion and explosion caused by organic peroxides due to thermal decomposition or fire.Therefore,the thermal safety of organic peroxides has gradually become an important issue.Studying the hazardous properties of organic peroxides will help prevent thermal explosions and reduce property losses and casualties caused by organic peroxides.This article takes three typical organic peroxide as examples(tert-butyl peroxide hexahydroterephthalate(HTP-65W),benzoyl peroxide(BPO),and dicumyl peroxide(DCP))to study the thermal decomposition characteristics and hazards of organic peroxides.The related conclusions are listed as follows:Simultaneous thermogravimetric analyzer and differential scanning calorimetry are used to analyze the relative thermal decomposition characteristics of the three organic peroxides under dynamic heating condition.The results show that HTP-65W,DCP and BPO all have two mass loss stages.For HTP-65W,the first mass loss stage is dominant,which corresponds to the first exothermic peak in the heat flow experiments,the reason for this phenomenon is the thermal decomposition of HTP-65W.The thermal decomposition activation energies of three organic peroxides are calculated using FWO and KAS methods.It is known that DCP has the worst thermal stability and is prone to thermal decomposition reactions.The thermal stability of HTP-65W and BPO are similar.Differential scanning calorimetry with pressure-maintaining system is used to explore the effect of pressure on the decomposition of various three organic peroxides.The test selected four pressures of 0.50,0.75,1.00 and 1.50 MPa respectively.The test results show that the increase of pressure has no significant effect on the exothermic peak of DCP.Compared with the data under normal pressure,there is no significant change in the initial decomposition temperature and peak temperature of DCP.But another endothermic peak appears immediately after the exothermic peak,which may be caused by the evaporation of products produced by the thermal decomposition of DCP.The results of BPO show that when the pressure increases to 1.0 and 1.5 MPa,the endothermic peak before the exothermic peak in the decomposition curve of BPO disappears,indicating that BPO decomposes directly in the solid state under high pressures.The accelerating rate calorimeter is used to simulate the adiabatic runaway reaction of three organic peroxides.It is found that HTP-65W starts the self-accelerate decomposition reaction at a lower temperature.Compared with the other two organic peroxides,the thermal stability of HTP-65W is poor.And a large amount of gas products produced during the decomposition process,resulting a sharp rise of pressure in system,showing a strong explosiveness.At the same time,according to the "Fine Chemical Reaction Safety Risk Assessment Guidelines",it is found that the thermal runaway reaction of HTP-65W is a conditional acceptance risk,and the risk level is moderate.Corresponding measures can be taken to reduce safety risks according to the guidance.Figure[23]Table[21]Reference[109]... |
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