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.

scholarly journals The homogeneous unimolecular decomposition of gaseous alkyl nitrites - IV—The decomposition of Iso -propyl nitrite

1935 ◽  
Vol 151 (874) ◽  
pp. 685-693 ◽  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Pressure Change ◽  
Methyl Ethyl ◽  
Unimolecular Decomposition ◽  
Decomposition Rates ◽  
Straight Chain ◽  
Alkyl Nitrites ◽  
Branched Chain ◽  
Reaction Vessels

It has already been shown that the first three straight chain members of the nitrite homologous series, i. e ., methyl, ethyl, and n -propyl nitrites, have exhibited in their thermal decomposition the characteristics pertaining to homogeneous unimolecular reactions. This paper deals with the investigation carried out on iso -propyl nitrite decomposition. This member of the series is particularly interesting as it allows comparison to be made between a straight-chain and a branched-chain isomer. The effect of these chemical configurations on the activation energy and the decomposition rates can be very effectively studies as no complications enter into the reactions to confuse measurements. Experimental Reaction velocities were measured as before by observing the rate of pressure change in a system at constant volume. The reaction vessels were Pyrex glass bulbs with a capacity of about 125 cc. The apparatus was similar to that used in previous experiments. The connecting tubing was heated to 105° C to prevent any of the products of the reaction condensing out. Control and measurement of the temperature was carried out as before. The temperature could be maintained constant to within 0·25° C.

scholarly journals TEMPERATURE CHARACTERISTICS FOR THE METABOLISM OF CHLORELLA

1934 ◽  
Vol 18 (2) ◽  
pp. 209-213 ◽  
Author(s):  
C. S. French
Keyword(s):  
Hydrogen Peroxide ◽  
Low Temperatures ◽  
Temperature Characteristics ◽  
First Order

The decomposition of hydrogen peroxide by intact Chlorella cells follows a first order course at very low temperatures, but at higher temperatures gives falling first order constants. Between 0.6° and 20°C. the value of µ is 10,500 calories.

The thermal decomposition of cyclobutane-1,2-dione

1985 ◽  
Vol 63 (11) ◽  
pp. 2945-2948 ◽  
Author(s):  
J.-R. Cao ◽  
R. A. Back
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Vapor Pressure ◽  
Gas Phase ◽  
Rate Constant ◽  
Surface Reaction ◽  
Order Rate Constant ◽  
Reaction Vessel ◽  
Arrhenius Parameters ◽  
First Order

The thermal decomposition of cyclobutane-1,2-dione has been studied in the gas phase at temperatures from 120 to 250 °C and pressures from 0.2 to 1.5 Torr. Products were C2H4 + 2CO, apparently formed in a simple unimolecular process. The first-order rate constant was strongly pressure dependent, and values of k∞ were obtained by extrapolation of plots of 1/k vs. 1/p to1/p = 0. Experiments in a packed reaction vessel showed that the reaction was enhanced by surface at the lower temperatures. Arrhenius parameters for k∞, corrected for surface reaction, were log A (s−1) = 15.07(±0.3) and E = 39.3(±2) kcal/mol. This activation energy seems too low for a biradical mechanism, and it is suggested that the decomposition is probably a concerted process. The vapor pressure of solid cyclobutane-1,2-dione was measured at temperatures from 22 to 62 °C and a heat of sublimation of 13.1 kcal/mol was estimated.

The thermal decomposition of nitrous oxide I. Secondary catalytic and surface effects

1955 ◽  
Vol 231 (1185) ◽  
pp. 162-178 ◽  
Keyword(s):  
Nitric Oxide ◽  
Thermal Decomposition ◽  
Nitrous Oxide ◽  
Surface Reaction ◽  
Order Rate Constant ◽  
Side Reactions ◽  
Chain Reactions ◽  
First Order ◽  
Reaction Vessels ◽  
Decomposition Of Nitrous Oxide

In the region of pressure 0 to 500 mrn approximately to the equation the thermal decomposition of nitrous oxide conforms approximately to the equation k = an /1 + a'n + bn , where k is the form al first-order rate constant, — (1/n) d n /d t , n the initial concentration and a, a' and b are nearly constant. Above about 100 m m this expression approximates to k = A + bn , which holds up to several atmospheres. Fresh and more detailed experiments have once again disproved the suggestion that the first term in these expressions is due to a surface reaction. (In certain states of reaction vessels, made of a particular brand of silica, a surface reaction may appear but is immediately recognizable by special criteria, and can be eliminated.) Detailed study of the formation of nitric oxide in the course of the decomposition, and of the effect of inert gas upon this process, shows that side reactions involving oxygen atoms, chain reactions and catalysis by nitric oxide play only minor parts in determining the shape of the k-n curve. The form of this curve, which is an inherent character of the reaction N 2 O = N 2 + O, raises theoretical questions of considerable interest.

THE THERMAL DECOMPOSITION OF HYDROGEN PEROXIDE VAPOUR

1945 ◽  
Vol 23b (5) ◽  
pp. 167-182 ◽  
Author(s):  
Bruce E. Baker ◽  
C. Ouellet
Keyword(s):  
Hydrogen Peroxide ◽  
Temperature Coefficient ◽  
Pure Hydrogen ◽  
First Order ◽  
Soda Glass ◽  
Manometric Method ◽  
Apparent Activation Energies ◽  
Reaction Vessels ◽  
First Time ◽  
Kinetics Of

The kinetics of the decomposition of hydrogen peroxide in the vapour state have been studied by a manometric method, with pure hydrogen peroxide at a concentration of about 99.5%. The temperature coefficient of the reaction has been measured for the first time. The pressures ranged from 1 to 2 cm. of mercury and the temperatures from 70° to 200 °C. Pyrex reaction vessels of various sizes and shapes, and also a fused Pyrex and a soda-glass vessel, were used. The reaction was purely heterogeneous, of the first order up to 140 °C. but more complicated at higher temperatures. Identical vessels yielded consistent results. The rates were not affected by air, carbon dioxide, or water vapour, but they varied greatly with the size and shape of the vessel. The reaction was very slow on fused Pyrex and very rapid on soda-glass. In one vessel, the temperature coefficient became negligible above 120 °C. No explosion was detected up to 335 °C. at a pressure of 18 cm. of mercury. The apparent activation energies in various vessels ranged from 13.5 to 18.5 kcal. per mole. A tentative reaction mechanism is suggested.

The thermal decomposition of ammonium perchlorate at low temperatures

1960 ◽  
Vol 254 (1279) ◽  
pp. 455-469 ◽  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Kinetic Equation ◽  
Ammonium Perchlorate ◽  
Low Temperatures ◽  
Cold Working ◽  
Experimental Results ◽  
Detailed Model

The thermal decomposition of ammonium perchlorate shows several unusual characteristics. The most striking of these is that at low temperatures it decomposes only to the extent of about 20 to 30 %, leaving a residue which is chemically identical with the original salt. The experimental results for the rate of decomposition of whole crystals, powder and pellets are shown to be well fitted by a kinetic equation which is in accord with a detailed model for the decomposing salt. It is possible to account in terms of this model (which involves the decomposition of intergranular material only) for the observed dependence of the activation energy on the extent of cold-working to which the solid is subjected.

FREE RADICALS BY MASS SPECTROMETRY: XXXV. THE HEAT OF FORMATION OF ALLYL RADICAL FROM BIALLYL PYROLYSIS

1966 ◽  
Vol 44 (18) ◽  
pp. 2211-2217 ◽  
Author(s):  
J. B. Homer ◽  
F. P. Lossing
Keyword(s):  
Mass Spectrometry ◽  
Activation Energy ◽  
Thermal Decomposition ◽  
Total Pressure ◽  
Heat Of Formation ◽  
Kcal Mole ◽  
Allyl Radical ◽  
First Order ◽  
Secondary Reactions ◽  
Gas Pressures

The thermal decomposition of biallyl has been investigated from 977 – 1 070 °K at helium carrier gas pressures of 10–50 Torr. Under these conditions the rate of central C—C bond fission to give two allyl radicals can be measured without interference from secondary reactions. The reaction at the pressures employed is first order with respect to biallyl, but between first and second order in the total pressure. The temperature dependence of the rate constants, extrapolated to infinite pressure, and corrected to 298 °K, gives an activation energy of 45.7 kcal/mole for the reaction, corresponding to ΔHf(allyl) = 33.0 kcal/mole.

Reactions with half-lives of several years

1964 ◽  
Vol 17 (4) ◽  
pp. 406 ◽  
Author(s):  
GA Bottomley ◽  
GL Nyberg
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Gas Phase ◽  
Virial Coefficient ◽  
Energy Equation ◽  
Second Virial Coefficient ◽  
First Order ◽  
First Order Kinetics ◽  
Reciprocal Temperature ◽  
Temperature Activation

The gas-phase thermal decomposition of dimethyldiazirine, (CH3)2CN2, at very slow rates has been investigated using precision gas-volumetric techniques previously applied to second virial coefficient studies. At 50-70� the first-order kinetics correspond to half-lives about 0.3-3.0 years. The present results, together with data obtained by other workers using conventional apparatus at 124-174�, fit a single log rate-reciprocal temperature activation energy equation.

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.

The Pyrolysis Behavior of Alkali Lignin Oxygenized by Hydrogen Peroxide in Ionic Liquid 1-Butyl-3-Methylimidazolium Chloride ([BMIm]Cl)

2014 ◽  
Vol 598 ◽  
pp. 86-89
Author(s):  
Zhong Lian Yang ◽  
Ming Qiang Chen ◽  
Zhong Yi Luan ◽  
Wen Tao Zhang
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Ionic Liquid ◽  
Black Liquor ◽  
Mixed Solution ◽  
Alkali Lignin ◽  
Pyrolysis Reaction ◽  
First Order ◽  
Pyrolysis Behavior

In order to make better use of lignin, a mixed solution with isopyknic hydrogen peroxide 30% aqueous solution and an ionic liquid 1-butyl-3-methylimidazolium chloride ([BMIm]Cl) was used to oxygenize alkali lignin from black liquor. The pyrolysis behavior of the treated alkali lignin (Regenerated ALG) was investigated via TGA. The kinetic controlling temperature range of the Regenerated ALG pyrolysis is between 533K and 649K approved by TG/DTG/DTA data, and the dominated pyrolysis is occurred below 574.7K, which was calculated from a kinetics model using Coats-Redfern method with a first order pyrolysis reaction. The activation energy of the Regenerated ALG also reached up to 105.675kJ/mol, which is 2.2 times greater than the non-treated one.

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