The thermokinetic parameters were investigated for cumene hydroperoxide (CHP), di-tert-butyl peroxide (DTBP), and tert-butyl
peroxybenzoate (TBPB) by non-isothermal kinetic model and isothermal kinetic model by differential scanning calorimetry (DSC)
and thermal activity monitor III (TAM III), respectively. The objective was to investigate the activation energy (Ea) of CHP, DTBP, and TBPB applied non-isothermal well-known kinetic equation to evaluate the thermokinetic parameters by DSC.
We employed TAM III to assess the thermokinetic parameters of three liquid organic peroxides, obtained thermal runaway data,
and then used the Arrhenius plot to obtain the Ea of liquid organic peroxides at various isothermal temperatures. In contrast, the results of non-isothermal kinetic algorithm
and isothermal kinetic algorithm were acquired from a highly accurate procedure for receiving information on thermal decomposition
characteristics and reaction hazard. 相似文献
The exothermic decomposition of cumene hydroperoxide (CHP) in cumene liquid was characterized by isothermal microcalorimetry,
involving the thermal activity monitor (TAM). Unlike the exothermic behaviors previously determined from an adiabatic calorimeter,
such as the vent sizing package 2 (VSP2), or differential scanning calorimetry (DSC), thermal curves revealed that CHP undergoes
an autocatalytic decomposition detectable between 75 and 90°C. Previous studies have shown that the CHP in a temperature range
higher than 100°C conformed to an nth order reaction rate model. CHP heat of decomposition and autocatalytic kinetics behavior were measured and compared with
previous reports, and the methodology and the advantages of using the TAM to obtain an autocatalytic model by curve fitting
are reported. With various autocatalytic models, such as the Prout-Tompkins equation and the Avrami-Erofeev rate law, the
best curve fit among models was also investigated and proposed. 相似文献
Abstract The application of electrochemical detection to the high performance liquid chromatographic determination of organic peroxides has been studied. The use of a buffered mobile phase was found to be critical to the successful analysis of samples containing hydroperoxides. Using amperometric detection, mixtures of peroxide containing compounds were readily determined. The sensitivity of the amperometric detector was in the one nanogram range for both benzoyl peroxide and cumene hydroperoxide. Polar-ographic detection was found to be a highly reproducible method for the analysis of samples containing peroxides as components of mixtures in the range of 5-2000 ng. The peroxide containing compounds determined in this manner were t-butyl hydroperoxide, cumene hydroperoxide, and 13-hydroperoxy-9(Z)-11(E)-octadecadien-oic acid. The polarographic detection system was used to obtain observed half-wave potentials for the peroxides under different chromatographic conditions. These observations correlated closely with literature results on the polarography of these compounds. 相似文献
Organic peroxides have been widely used in industries and are known to be self-reactive chemicals. In this paper, thermal
and infrared spectroscopic analyses were carried out to obtain a better understanding of the thermally hazardous behavior
of cumene hydroperoxide (CHP) with cumene solvent. The temperature and heat flow profiles of different concentrations of CHP
at scanning and isothermal conditions were measured with a small scale reaction calorimeter. Furthermore, probe type in situ infrared spectroscopic measurements were performed and the reaction mechanism will be discussed in regards to both energy
release and product identification. 相似文献
Studies on the thermal decompositions of diamyl peroxide (DAPO), dicumyl peroxide (DCPO), and tert-butyl cumyl peroxide (TBCP) were conducted by DSC. Heat of decomposition, exothermic onset point, and chemical kinetics were determined and compared to those data of di-tert-butyl peroxide (DTBP), a model compound for studying thermokinetics of organic peroxide and standardization of a calorimeter. Similarities and differences of decomposition mechanisms between these organic peroxides were proposed and verified. Kinetics on decomposition of uni-molecular reaction via these similar alkoxyl radials accompanying β C–C bond scission were discussed and compared to the results from ab initio calculations. The ranking of thermal stability on dialkyl peroxides is determined to be in the following sequence: DCPO < TBCP < DAPO < DTBP. This rate-determining step in thermal decomposition of dialkyl peroxides possessed an average eigenvalue of log A at about 13.1 ± 1.2. Activation energy on the thermal decomposition of these peroxides was calculated to be 139.5 ± 14.4 kJ mol?1. 相似文献
In recent years, organic peroxides, including methyl ethyl ketone peroxide (MEKPO) and cumene hydroperoxide (CHP), have often caused thermal runaway reactions, fires, and thermal explosions worldwide. Under normal circumstances, H2O and dry fire-extinguishing chemicals are often employed to eliminate fire situations. We evaluated the thermal runaway reaction for MEKPO and CHP mixed with H2O and dry fire-extinguishing chemicals by differential scanning calorimetry, and thermal runaway reaction for CHP mixed with dry fire-extinguishing chemicals by vent sizing package 2. The results showed that ABC dry chemical, BC dry chemical, and XBC dry chemical all caused the decomposition of MEKPO to occur at lower onset temperature and H2O caused the ΔHd of MEKPO to become higher. On the other hand, H2O and XBC dry chemical induced the decomposition of CHP to occur at lower onset temperature as well as lower thermal explosion temperature. The maximum of self-heating rate ((dT/dt)max) and the maximum pressure-rise rate ((dP/dt)max) of CHP mixed with dry fire-extinguishing chemicals were measured lower than CHP alone. The results indicated that MEKPO and CHP are highly hazardous when mixed with H2O and some dry fire-extinguishing chemicals. In view of loss prevention, the results can be useful references for fire fighters dealing with thermal upsets in chemical plants. 相似文献
The oxidation to hydroperoxide of poly(arylene ethylenes) (PAE) by oxygen carried out in solutions at 80–110°C. The effect of initiating additions and the nature of solvent relative to the content of hydroperoxide groups in oxidized PAE were investigated. The oxidation to hydroperoxides in PAE occurs at the methylene groups, and the synthesized hydroperoxides are secondary peroxides. The decomposition of PAE hydroperoxides in toluene and chlorobenzene at concentrations of 0.006–0.03 mole/l. for hydroperoxide in the presence and absence of N-phenyl-α-naphthylamine (PNA) was studied. The decomposition of one hydroperoxide has been studied in the presence of cobaltous and manganese resinates and of PNA in chlorobenzene at 30–50°C. The addition of PNA to a chlorobenzene solution of PAE hydroperoxide containing cobaltous or manganese resinate accelerates the hydroperoxide decomposition, reduces the activation energy, and changes the reaction order from the second-order to first-order. The synthesized hydroperoxides initiate the radical polymerization of styrene and methyl methacrylate. The initiating activity of one of the synthesized hydroperoxides of PAE for polymerization of styrene (60°C) in the presence and absence of activating addition of manganese resinate was also evaluated. 相似文献
A series of pentaerythritol diphosphites (PEDP) was used to study the effect of structure on the decomposition of 1-methyl-1-phenylethyl hydroperoxide (cumene hydroperoxide, CHP) in chlorobenzene under nitrogen at 75°C. Whilst pentaerythritol diphosphites with bonds: react in a strictly stoichiometric reaction with cumene hydroperoxide, forming phosphates, we propose that pentaerythritol diphosphites and thiophosphates with bonds: react with cumene hydroperoxide by a different mechanism. The active heteroatom is sulphur which, through the formation of a catalytically active species, causes rapid decomposition of the hydroperoxide which is studied by measuring infra-red spectra using FTIR techniques. 相似文献
Decomposition of cumene hydroperoxide into free radicals in aqueous and organic media in the presence of cationic surfactants at 37°C is studied by the method of inhibitors using quercetin as an acceptor of radicals. It is found that cationic surfactants catalyze the decomposition of cumene hydroperoxide into radicals, the catalytic effect in an organic medium being higher than that in an aqueous solution. Catalytic action of surfactants greatly depends on the counterion nature. Cetyltrimethylammonium chloride has the highest catalytic activity. Characteristics of surface activity of some cationic surfactants and hydroperoxides are obtained. 相似文献
Over 90% of the cumene hydroperoxide (CHP) produced in the world is applied in the production of phenol and acetone. The additional
applications were used as a catalyst, a curing agent, and as an initiator for polymerization. Many previous studies from open
literature have verified and employed various aspects of the thermal decomposition and thermokinetics of CHP reactions. An
isothermal microcalorimeter (thermal activity monitor III, TAM III), and a thermal dynamic calorimetry (differential scanning
calorimetry, DSC) were used to resolve the exothermic behaviors, such as exothermic onset temperature (T0), heat power, heat of decomposition (ΔHd), self-heating rate, peak temperature of reaction system, time to maximum rate (TMR), etc. Furthermore, Fourier transform
infrared (FT-IR) spectrometry was used to analyze the CHP products with its derivatives at 150 °C. This study will assess
and validate the thermal hazards of CHP and incompatible reactions of CHP mixed with its derivatives, such as acetonphenone
(AP), and dimethylphenyl carbinol (DMPC), that are essential to process safety design. 相似文献
The kinetics of the reactions of H 2 O 2 and of methyl, ethyl, tert -butyl, and cumene hydroperoxides with I m were investigated in the presence and absence of molybdate as catalyst. These results were utilized to develop an analytical method for the simultaneous determination of H 2 O 2 and organic hydroperoxides in aqueous solutions. The total amount of H 2 O 2 and organic hydroperoxides can be determined by the spectrophotometric measurement of $ {\rm I}_3^ - $ formed quantitatively during 30 min of heating at 60°C. Catalase selectively decomposes H 2 O 2 in solutions containing organic hydroperoxides. The total amount of the latter can therefore be determined iodometrically after H 2 O 2 decomposition. In the oxidation of leuco crystal violet to crystal violet by H 2 O 2 and organic hydroperoxides, horseradish peroxidase exerts similar activities in the reactions involving methyl and ethyl hydroperoxides and H 2 O 2 , but its activity is much lower with tert -butyl and cumene hydroperoxide. It was observed that acetate buffer is unsuitable for pH adjustment in this type of hydroperoxide determination in consequence of the slow oxidation of the dye in the blank solution. 相似文献
The thermal decomposition of cumene hydroperoxide (CHP) by the metal complex, 2,2′-thiobis(4-tert-octylphenolato)n-butylamine (Cyasorb UV 1084), in hexane solution and in the temperature range 27–70°, has been examined. The complex is an effective hydroperoxide decomposer at a molar ratio of [CHP]/[complex] = 0.19; at higher molar ratios, an induction period is present. The peroxidolytic effect increases with temperature rise and is attributed to a homolytic mechanism at low ratios of hydroperoxide to complex and to an ionic mechanism when the former is in excess. Kinetic analysis of the data yielded rate constants of 1.06 × 10−5sec−1 at 27° and 2.38 × 10−3sec−1 at 200°, at low ratios of CHP to complex, highlighting the efficiency of the process at high temperatures. The latter, coupled with the observed antioxidant behaviour of this metal complex in polypropylene during both processing and photooxidative conditions, lead to the conclusion that hydroperoxide decomposition must play an important role in the stabilising action of Cyasorb UV 1084 in this polymer. 相似文献
Fluorescence quenching experiments indicate that energy transfer occurs from cumene excited at 254 nm to cumene hydroperoxide. Quantum yields show that the sensitized decomposition of the hydroperoxide occurs quantitatively and that 2-phenylpropanol-2 is the main photoproduct. In the presence of oxygen, this process plays a dominant role in the initiation of the photo-oxidation. When benzophenone is excited to the first triplet state by irradiation at 365 nm in the presence of cumene hydroperoxide, phosphorescence quenching experiments and laser flash photolysis suggest that an exciplex is formed. This exciplex dissociates into cumylperoxy and ketyl radicals in such a way that 80% of the excited ketone molecules are transformed into the corresponding pinacol. In the presence of oxygen, benzophenone primarily initiates the photo-oxidation of cumene by hydrogen abstraction but, as cumene hydroperoxide is formed, formation and reaction of the exciplex become progressively more and more important. The photochemical behaviour a fluorenone is quite different from that of benzophenone. The sensitized decomposition of cumene hydroperoxide occurs in the presence of that ketone. Surprisingly, fluorenone also initiates the photo-oxidation of cumene; the mechanism of that reaction is discussed. The whole set of results provides a sound basis for the interpretation of the photo-oxidation of polystyrene in various conditions. 相似文献
In petrochemistry, dicumyl peroxide (DCPO) is used in various resins for improving physical properties, which was produced
by cumene hydroperoxide (CHP) with oxidization reaction, redox reaction, and dehydration reaction. The reactant, CHP, is a
typical organic hydroperoxide and has been intrinsically unstable and reactive due to its bivalent -O-O- structure which can
be broken readily with bond-dissociation energy. This sequence on sensitive study aimed at the thermal hazard evaluation for
the reactive and incompatible characteristics of CHP mixed with various inorganic alkaline solutions. Differential scanning
calorimetry (DSC) and vent sizing package 2 (VSP2) were used to analyze the thermal hazards and runaway reaction of redox
system, such as decomposition of CHP in cumene solution and CHP react with inorganic alkaline solutions, exothermic onset
temperature, peak power, heat of decomposition of dynamic scanning tests, adiabatic self-heating rate, pressure rise rate,
maximum temperature, maximum pressure of reaction system, etc. The results of the tests have proven helpful in establishing
safe handling, storage, transportation, and disposal guidelines. 相似文献
HPLC along with FT-IR technique was used to study the formation of organic peroxides in the Cl2-ethane-air photoreaction system. Ethyl hydroperoxide (CH3CH21OOH, EHP) and peroxyacetic acid ( CH3C(O)OOH, PAA) were conformed to be the peroxide product in the reaction system. In addition, methyl hydroperoxide (CH3OOH, hydroxymethyl hydroperoxide (HOCH2OOH, HMHP) and two unidentified organic peroxides were detected for the first time. EHP and were the dominant peroxide products.
The identification of HMHP showed that Criegee biradical CH2OO may be formed as an intermediate in the oxidation of ethane. Simulation results showed that photooxidation of ethane may
make substantial contribution to source of organic peroxides in the atmosphere. 相似文献
HPLC along with FT-IR technique was used to study the formation of organic peroxides in the Cl2-ethane-air photoreaction system. Ethyl hydroperoxide (CH3CH21OOH, EHP) and peroxyacetic acid ( CH3C(O)OOH, PAA) were conformed to be the peroxide product in the reaction system. In addition, methyl hydroperoxide (CH3OOH, hydroxymethyl hydroperoxide (HOCH2OOH, HMHP) and two unidentified organic peroxides were detected for the first time. EHP and were the dominant peroxide products. The identification of HMHP showed that Criegee biradical CH2OO may be formed as an intermediate in the oxidation of ethane. Simulation results showed that photooxidation of ethane may make substantial contribution to source of organic peroxides in the atmosphere. 相似文献
The interaction of fillers and pigments with free radical initiators has been studied. Clay minerals have a marked influence on both the rate and the mechanism of the decomposition of peroxides and hydroperoxides. Kaolinite is a particularly effective catalyst and causes rapid decomposition even at room temperature. The reaction of cumene hydroperoxide with kaolinite is first-order in peroxide and the rate constant is proportional to the ratio of clay to hydroperoxide. From a study of the products of the reaction and the influence of solvent on the decomposition, a mechanism involving an intramolecular rearrangement or closely associated ion pairs has been proposed. The application of these results to polymer filler composites is discussed. 相似文献
The reactions of the copper (II) chelates of norephedrine (I), N-methylnorephedrine (II), N-ethylnorephedrine (III), and N-n-butylnorephedrine (IV) with benzoyl peroxide, cumene hydroperoxide, and 2,2′-diphenyl-1-picrylhydrazyl have been studied. Only the chelates of N-alkyl-substituted norephedrines enter into the reactions with free radicals, while their reactivity increases with the length of the alkyl substituent in the amino group of the ligand. The decomposition of cumene hydroperoxide was catalyzed by all four chelates; the catalytic efficiency increases in the order I<II<III < IV. 相似文献