Kinetics and Mechanisms of the Thermal Decomposition of Copper(II) Hydroxide: A Consecutive Process Comprising Induction Period, Surface Reaction, and Phase Boundary-Controlled Reaction

2018 ◽  
Vol 122 (24) ◽  
pp. 12869-12879 ◽  
Author(s):  
Masahiro Fukuda ◽  
Nobuyoshi Koga
Keyword(s):  
Thermal Decomposition ◽  
Phase Boundary ◽  
Induction Period ◽  
Surface Reaction

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.

scholarly journals Phase boundary potentials of absorbed films on metals.—Part I.—On the behaviour of oxygen on gold

1933 ◽  
Vol 140 (842) ◽  
pp. 484-489 ◽  
Keyword(s):  
Phase Boundary ◽  
Metal Surfaces ◽  
Short Range ◽  
Surface Reaction ◽  
High Pressures ◽  
Surface Absorption ◽  
Radioactive Materials ◽  
Interfacial Potential ◽  
Gas Potential ◽  
Α Particles

Whilst changes in interfacial potential differences owing to surface absorption can be measured both by thermionic and by photoelectric methods, these are not generally applicable to systems containing gases at relatively high pressures. That changes in metal gas potential differences occur when adsorption or surface reaction occurs was first demonstrated by Volta in measurements of contact potentials by a condenser method. His principle, with various modifications, has been employed by numerous subsequent workers, notably Fabroni, De la Rive, Pellat, Hughes, Henning, and especially Dubois. Ionization of the gap between two surfaces by means of the emission from radioactive materials was first employed by McLennan and Burton, and by Lord Blythswood and Allen, but their results are discordant, the cause indubitably lying, as Greimacher pointed out, in their use of radium salts. Reliable measurements of interfacial potential differences at liquid-gas interfaces were obtained by Guyot, Frumkin, Rideal and Schulman, when the relatively short range α-particles emitted by polonium were used as the source of ionization. This method has been extended to the examination of metal surfaces by Andauer and by Joffé and Lukirsky. On examination of the results obtained either by the various modifications of Volta’s method, or by that of Guyot for changes in the metal-gas potential differences as a result of oxidation of the surface, one is impressed by the smallness of the changes recorded. Andauer observed changes in the order of 0·1 volts when metal surfaces are reduced and oxidized, whilst the more recent publications of Dubois include the following values :—

scholarly journals Solid-Phase Thermal Decomposition of 2,4-Dinitroimidazole (2,4-DNI)

1995 ◽  
Vol 418 ◽  
Author(s):  
Leanna Minier ◽  
Richard Behrens ◽  
Suryanarayana Bulusu
Keyword(s):  
Thermal Decomposition ◽  
Induction Period ◽  
Solid Phase ◽  
Low Molecular Weight ◽  
Ftir Analysis ◽  
Pyrolysis Products ◽  
Gaseous Products ◽  
Elemental Formula ◽  
Gas Formation ◽  
Primary Products

AbstractThe solid-phase thermal decomposition of the insensitive energetic aromatic heterocycle 2,4- dinitroimidazole (2,4-DNI: mp 265–274°C) is studied utilizing simultaneous thermogravimetric modulated beam mass spectrometry (STMBMS) between 200° and 247°C. The pyrolysis products have been identified using perdeuterated and N-labeled isotopomers. The products consist of low molecular-weight gases and a thermally stable solid residue. The major gaseous products are NO, CO2, CO, N2, HNCO and H2O. Minor gaseous products are HCN, C2N2, NO2, C3H4N2, C3H3N3O and NH3. The elemental formula of the residue is C2HN2O and FTIR analysis suggests that it is polyurea- and polycarbamate-like in nature. The rates of formation of the gaseous products and their respective quantities have been determined for a typical isothermal decomposition experiment at 235°C. The temporal behaviors of the gas formation rates indicate that the overall decomposition is characterized by a sequence of four events; 1) an early decomposition period induced by impurities and H2O, 2) an induction period where CO2 and NO are the primary products formed at relatively constant rates, 3) an autoacceleratory period that peaks when the sample is depleted and 4) a final period in which the residue decomposes. Arrhenius parameters for the induction period are Ea = 46.9 ± 0.7 kcal/mol and Log(A) = 16.3 ± 0.3. Decomposition pathways that are consistent with the data are presented.

The thermal decomposition of lithium aluminium hydride

1952 ◽  
Vol 211 (1106) ◽  
pp. 335-351 ◽  
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Thermal Decomposition ◽  
Surface Reaction ◽  
Interface Reaction ◽  
Initial Reaction ◽  
Positive Temperature ◽  
Initial Surface ◽  
Lithium Aluminium Hydride ◽  
Lithium Aluminium

Lithium aluminium hydride on heating decomposes in three stages: ( a ) an initial surface reaction during the induction period, followed by ( b ) an interface reaction giving an S-shaped pressure against time curve, corresponding to LiAlH 4 → LiAlH 2 + H 2 , and ( c ) a slow process during which a third hydrogen atom is liberated. The initial reaction is rapid at first and then slows down to a constant rate. It occurs to the extent of about 0⋅7% of the total decomposition and penetrates the surface to a depth of several molecular layers. Its activation energy is 22 kcal. The interface reaction obeys a cube-root plot and has an activa­tion energy of 25 kcal. The electrical conductivity of LiAlH 4 has a positive temperature coefficient with an activation energy of 16 kcal. During the thermal decomposition there is a maximum on the electrical conductivity curve, occurring early in the initial surface reaction. The conductivity at the maximum is ten times greater than the extrapolated from the natural conductivity. It is concluded that conductivity arising during the thermal decomposition is, in the main, due to defects produced during the initial surface reaction; also, that the formation of nuclei is a two-stage process consisting ( a ) of the aggregation of defects at lattice discontinuities followed by ( b ) the collapse of the defect aggregate to give nuclei at which a normal interface reaction proceeds.

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 .

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