KINETICS OF THE THERMAL DECOMPOSITION OF HYDROGEN PEROXIDE VAPOR

1957 ◽  
Vol 35 (4) ◽  
pp. 283-293 ◽  
Author(s):  
Paul A. Giguère ◽  
I. D. Liu
Keyword(s):  
Activation Energy ◽  
Hydrogen Peroxide ◽  
Thermal Decomposition ◽  
Frequency Factor ◽  
Reaction Rates ◽  
Appreciable Effect ◽  
Phase Reaction ◽  
Glass Rods ◽  
Surface Decomposition ◽  
Hydrogen Peroxide Vapor

The rates of thermal decomposition of hydrogen peroxide vapor were measured by the static method at low pressures (0.2 to 20 mm. Hg), over the temperature range 300°–600 °C., in carefully cleaned glass vessels. The reaction was of the first order with respect to time and the final products were only water and oxygen. Around 400 °C. the character of the reaction changed gradually from heterogeneous (surface effects, low activation energy) to homogeneous (reproducible rates in various vessels). With initial pressures of about 10 mm. Hg the experimental rates above 400° lead to an apparent activation energy of 43 kcal. and a frequency factor of 1010.7. After correction for the residual surface decomposition, the rate equation becomes[Formula: see text]in good agreement with the accepted value for the O—O bond dissociation energy. The reaction rates increased regularly with pressure.Packing the reaction vessels with glass rods and adding various gases (including nitric oxide and propylene) had no appreciable effect on the gas-phase reaction. Deuterium peroxide vapor decomposed at the same rate as hydrogen peroxide under comparable conditions. The results may be explained adequately by the following non-chain mechanism for the uncatalyzed decomposition:[Formula: see text]

THE THERMAL DECOMPOSITION OF HYDROGEN PEROXIDE VAPOR

1968 ◽  
Author(s):  
K. R. Bilwakesh ◽  
W. A. Strauss ◽  
R. Edse ◽  
E. S. Fishburne
Keyword(s):  
Hydrogen Peroxide ◽  
Thermal Decomposition ◽  
Hydrogen Peroxide Vapor

THE THERMAL DECOMPOSITION OF HYDROGEN PEROXIDE VAPOUR. II.

1947 ◽  
Vol 25b (2) ◽  
pp. 135-150 ◽  
Author(s):  
Paul A. Giguère
Keyword(s):  
Activation Energy ◽  
Hydrogen Peroxide ◽  
Thermal Decomposition ◽  
Low Temperatures ◽  
Hydrocyanic Acid ◽  
Quartz Surface ◽  
First Order ◽  
Acid Washing ◽  
Reaction Vessels ◽  
Low Pressures

The decomposition of hydrogen peroxide vapour has been investigated at low pressures (5 to 6 mm.) in the temperature range 50° to 420 °C., for the purpose of determining the effect of the nature and treatment of the active surfaces. The reaction was followed in an all-glass apparatus and, except in one case, with one-litre round flasks as reaction vessels. Soft glass, Pyrex, quartz, and metallized surfaces variously treated were used. In most cases the decomposition was found to be mainly of the first order but the rates varied markedly from one vessel to another, even with vessels made of the same type of glass. On a quartz surface the decomposition was preceded by an induction period at low temperatures. Fusing the glass vessels slowed the reaction considerably and increased its apparent activation energy; this effect was destroyed by acid washing. Attempts to poison the surface with hydrocyanic acid gave no noticeable result. The marked importance of surface effects at all temperatures is considered as an indication that the reaction was predominantly heterogeneous under the prevailing conditions. Values ranging from 8 to 20 kcal. were found for the apparent energy of activation. It is concluded that the decomposition of hydrogen peroxide vapour is not very specific as far as the nature of the catalyst is concerned.

THE THERMAL DECOMPOSITION OF STYRENE–BUTADIENE POPCORN POLYMER

1950 ◽  
Vol 28b (1) ◽  
pp. 5-16
Author(s):  
C. A. Winkler ◽  
J. Halpern
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Linear Relation ◽  
Frequency Factor ◽  
Thermal Reaction ◽  
Cross Linking ◽  
First Order ◽  
Bond Scission ◽  
Styrene Butadiene ◽  
Kinetics Of

At temperatures of the order of 250 °C., popcorn polymer undergoes decomposition to soluble polymer. The reaction is catalyzed by peroxides present in the popcorn when the latter is formed. These peroxides may be removed by extracting the polymer with benzene. The kinetics of both the catalyzed and purely thermal solubilization reactions were investigated. The rates of both reactions are first order, the catalyzed degradation having a higher activation energy and a higher frequency factor. The rate of the thermal reaction decreases and its activation energy increases with increasing butadiene content of the polymer. A linear relation between the activation energy and the log of the frequency factor, for the decomposition of popcorn polymers of different butadiene contents, was observed. The results indicate that the rate of solubilization is determined by the activation energy of the bond scission process, and is independent of the degree of cross-linking of the polymer.

scholarly journals Thermogravimetric and Kinetic Analysis of Melon (Citrullus colocynthis L.) Seed Husk Using the Distributed Activation Energy Model

2015 ◽  
Vol 15 (1) ◽  
pp. 77-89 ◽  
Author(s):  
Bemgba Bevan Nyakuma
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Kinetic Analysis ◽  
Biomass Conversion ◽  
Clean Energy ◽  
Frequency Factor ◽  
Energy Model ◽  
Distributed Activation Energy Model ◽  
Solid Biofuel ◽  
Seed Husk

Abstract This study seeks to characterize the thermochemical fuel properties of melon seed husk (MSH) as a potential biomass feedstock for clean energy and power generation. It examined the ultimate analysis, proximate analysis, FTIR spectroscopy and thermal decomposition of MSH. Thermogravimetric (TG) analysis was examined at 5, 10, 20 °C/min from 30-800 °C under nitrogen atmosphere. Subsequently, the Distributed Activation Energy Model (DAEM) was applied to determine the activation energy, E, and frequency factor, A. The results revealed that thermal decomposition of MSH occurs in three (3) stages; drying (30-150 °C), devolatization (150-400 °C) and char degradation (400-800 °C). Kinetic analysis revealed that the E values fluctuated from 145.44-300 kJ/mol (Average E = 193 kJ/mol) while A ranged from 2.64 × 1010 to 9.18 × 1020 min-1 (Average E = 9.18 × 1019 min-1) highlighting the complexity of MSH pyrolysis. The fuel characterization and kinetics of MSH showed it is an environmentally friendly solid biofuel for future thermal biomass conversion.

scholarly journals Calculation of Kinetic Parameters of the Thermal Decomposition of Residual Waste of Coniferous Species: Cedrus Deodara

2018 ◽  
Vol 21 (2) ◽  
pp. 75-80 ◽  
Author(s):  
Alok Dhaundiyal ◽  
Muammel M. Hanon
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Kinetic Parameters ◽  
Frequency Factor ◽  
Inert Atmosphere ◽  
Kissinger Method ◽  
Heating Rates ◽  
Cedrus Deodara ◽  
Coniferous Species ◽  
Competitive Reactions

Abstract This paper deals with pyrolysis decomposition of Cedrus deodara leaves with the help of thermogravimetric analysis (TGA). Experiments are performed in the presence of inert atmosphere of nitrogen. Experiments are conducted at three different heating rates of 5 °C∙min-1, 10 °C∙min-1 and 15 °C∙min-1 within temperature range of 35 °C to 700 °C. Arrhenius parameters such as activation energy and frequency factor are estimated by Flynn Wall and Ozawa (FWO), Kissinger-Akahira-Sonuse (KAS) and Kissinger. The activation energy and frequency factor calculated by using Kissinger method are 67.63 kJ∙mol-1 and 15.06 . 104 min-1 respectively; whereas the averaged values of the same parameters through FWO and KAS methods are 89.59 kJ∙mol-1 and 84.748 kJ∙mol-1, 17.27 . 108 min-1 and 62.13 . 107 min-1 respectively. Results obtained through Kissinger method represent the actual values of kinetic parameters. Conversely, FWO and KAS methods reflect the apparent values of kinetic parameters, as they are highly influenced by the overlapping of competitive reactions occur during pyrolysis.

THE GAS PHASE REACTION OF METHYL RADICALS WITH HEXAFLUOROACETONE

1957 ◽  
Vol 35 (10) ◽  
pp. 1216-1224 ◽  
Author(s):  
G. O. Pritchard ◽  
E. W. R. Steacie
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Gas Phase ◽  
Steric Factor ◽  
Phase Reaction ◽  
Methyl Radicals ◽  
Kcal Mole ◽  
Gas Phase Reaction

The photolytic and thermal decomposition of azomethane in the presence of hexafluoroacetone produces small amounts of fluorinated products, mainly fluoroform. The mechanism of this and related reactions is discussed. It is concluded that the proposed reaction.[Formula: see text]has an activation energy of about 6 kcal./mole, with a steric factor of about 10−5.

scholarly journals The thermal decomposition of hydrogen peroxide vapour

1946 ◽  
Vol 185 (1001) ◽  
pp. 207-224 ◽  
Keyword(s):  
Hydrogen Peroxide ◽  
Thermal Decomposition ◽  
Water Vapour ◽  
Surface Reaction ◽  
High Pressures ◽  
Reaction Rates ◽  
Bimolecular Reaction ◽  
Temperature Range ◽  
Low Pressures ◽  
Absolute Reaction

The decomposition of hydrogen peroxide vapour at pressures less than 1 mm. in silica vessels has been investigated, mainly at 80° C, but also over the temperature range 15-140° C. Oxygen at low pressures was found to have no appreciable influence on the rate of decomposition; water vapour retarded the rate slightly. The reaction was predominantly a surface one. In one vessel, the decomposition was bimolecular with respect to the peroxide pressure, the rate being given by k [H 2 O 2 ] 2 /(1+ b [H 2 O]) 2 in another, the bimolecular reaction of the final stages at low peroxide pressures was preceded by one of order approximately 0.7 at the high pressures. Higher pressures of oxygen and nitrogen retarded the decomposition appreciably. At higher pressures of water vapour, a pronounced periodicity in rate was evident. The apparent heat of activation over the temperature range investigated was not constant, being calculated as 4200 cal. from rates at 15 and 70° C and 8400 cal. from rates at 80 and 140° C. On the assumption that the lower value more nearly represents the surface reaction, the velocity of decomposition, calculated for 1 mm. pressure of peroxide at 50° C by the theory of absolute reaction rates, was 0.70 x 10 13 mol.cm. -2 sec. -1 , in agreement with the experimental value of 0.76 x 10 13 mol.cm. -2 sec. -1 .

SECOND-ORDER UNIMOLECULAR KINETICS IN THE THERMAL DECOMPOSITION OF HYDROGEN PEROXIDE VAPOR

1958 ◽  
Vol 36 (9) ◽  
pp. 1308-1319 ◽  
Author(s):  
W. Forst
Keyword(s):  
Hydrogen Peroxide ◽  
Thermal Decomposition ◽  
Initial Pressure ◽  
Critical Energy ◽  
Order Rate Constant ◽  
Second Order ◽  
Static Method ◽  
Experimental Conditions ◽  
First Order ◽  
Hydrogen Peroxide Vapor

The thermal decomposition of hydrogen peroxide vapor has been reinvestigated by the static method as a function of initial pressure at pressures up to 22 mm Hg, and in the presence of inert gas (helium, oxygen, and water) up to 100 mm Hg. In each case the apparent first-order rate constant increased linearly with pressure. It is demonstrated that under the present experimental conditions the pyrolysis of hydrogen peroxide shows behavior typical of an elementary unimolecular reaction in its low-pressure, second-order region. The reaction was accompanied by a heterogeneous decomposition which in the presence of foreign gas became inhibited. Helium was used as inhibitor over the temperature range 430–470 °C, which permitted calculating the activation energy for activation with peroxide and with helium. The results can be satisfactorily accounted for by assuming a critical energy of 47–50 kcal and five effective classical oscillators for activation with peroxide and three with helium, provided deactivation occurs on every collision. Kinetic evidence against this assumption is briefly discussed.

Kinetics and mechanisms of the thermal decomposition of ethane - II. The reaction inhibited by nitric oxide

1961 ◽  
Vol 260 (1300) ◽  
pp. 103-113 ◽  
Keyword(s):  
Nitric Oxide ◽  
Activation Energy ◽  
Thermal Decomposition ◽  
Induction Period ◽  
Volume Ratio ◽  
Frequency Factor ◽  
Inflexion Point ◽  
Kcal Mole ◽  
First Order ◽  
Pressure Time

The pressure-time curves for the decomposition of ethane when fully inhibited by nitric oxide have initially a point of inflexion. The initial rates are proportional to the first power of the pressure at higher pressures, and to the 3/2 power at lower pressures; the rates at the inflexion point are proportional to the pressure to a power which is slightly greater than unity. The acti­vation energy corresponding to the initial rates in the first-order region was found to be 77∙5 kcal/mole, and the frequency factor 3∙12 × 10 15 s -1 . The reaction was slightly inhibited by increasing the surface: volume ratio, and the induction period disappeared on addition of ethylene. The facts are shown to be consistent with a mechanism in which initiation occurs by the reaction NO + C 2 H 6 → C 2 H 5 + HNO, which is estimated to have an activation energy of 52 kcal. At the beginning of the reaction and at lower pressures termination is con­sidered to occur by H + HNO → H 2 + NO; as ethylene accumulates the ratio [C 2 H 5 ]/[H] increases and the termination step becomes C 2 H 5 + HNO → C 2 H 6 + NO. The mechanism is shown to account for the fact that propylene and other inhibitors give rise to the same limiting rate.

scholarly journals Effect of Nano-Magnesium Hydride on the Thermal Decomposition Behaviors of RDX

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Miao Yao ◽  
Liping Chen ◽  
Guoning Rao ◽  
Jianxin Zou ◽  
Xiaoqin Zeng ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Thermal Decomposition ◽  
Apparent Activation Energy ◽  
Frequency Factor ◽  
High Heat ◽  
Magnesium Hydride ◽  
Probable Mechanism ◽  
Kinetic Properties ◽  
Calculation Results

In order to improve the detonation performance of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) explosive, addictives with high heat values were used, and magnesium hydride (MgH2) is one of the candidates. However, it is important to see whether MgH2is a safe addictive. In this paper, the thermal and kinetic properties of RDX and mixture of RDX/MgH2were investigated by differential scanning calorimeter (DSC) and accelerating rate calorimeter (ARC), respectively. The apparent activation energy (E) and frequency factor (A) of thermal explosion were calculated based on the data of DSC experiments using the Kissinger and Ozawa approaches. The results show that the addition of MgH2decreases bothEandAof RDX, which means that the mixture of RDX/MgH2has a lower thermal stability than RDX, and the calculation results obtained from the ARC experiments data support this too. Besides, the most probable mechanism functions about the decomposition of RDX and RDX/MgH2were given in this paper which confirmed the change of the decomposition mechanism.

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