THE THERMAL DECOMPOSITION OF OZONE. III. THE TEMPERATURE COEFFICIENT OF REACTION RATE

1927 ◽  
Vol 49 (7) ◽  
pp. 1650-1664 ◽  
Author(s):  
Oliver R. Wulf ◽  
Richard C. Tolman
Keyword(s):  
Thermal Decomposition ◽  
Temperature Coefficient ◽  
Reaction Rate

Thermal Decomposition Kinetics of Glyphosate (GP) and its Metabolite Aminomethylphosphonic Acid (AMPA)

2019 ◽  
Author(s):  
Milad Narimani ◽  
Gabriel da Silva
Keyword(s):  
Thermal Decomposition ◽  
Reaction Rate ◽  
Decomposition Kinetics ◽  
Rate Theory ◽  
Thermal Decomposition Mechanism ◽  
Treatment Processes ◽  
Aminomethylphosphonic Acid ◽  
Reaction Rate Theory ◽  
Decomposition Chemistry ◽  
Kinetics Of

Glyphosate (GP) is a widely used herbicide worldwide, yet accumulation of GP and its main byproduct, aminomethylphosphonic acid (AMPA), in soil and water has raised concerns about its potential effects to human health. Thermal treatment processes are one option for decontaminating material containing GP and AMPA, yet the thermal decomposition chemistry of these compounds remains poorly understood. Here, we have revealed the thermal decomposition mechanism of GP and AMPA by applying computational chemistry and reaction rate theory methods. <br>

Mechanism of Rubber Vulcanization with Sulfur

1938 ◽  
Vol 11 (1) ◽  
pp. 107-130
Author(s):  
W. K. Lewis ◽  
Lombard Squires ◽  
Robert D. Nutting
Keyword(s):  
Natural Rubber ◽  
Temperature Coefficient ◽  
Chemical Reactions ◽  
Chemical Reaction ◽  
Reaction Rate ◽  
Complex Behavior ◽  
Double Bonds ◽  
Irreversible Reaction ◽  
Sulfur Addition

Abstract THAT vulcanization of rubber with sulfur always involves a chemical reaction consisting in the addition of sulfur to the double bonds of the rubber molecule has been conclusively established (18, 28). The facts indicate that this addition of sulfur to rubber is an irreversible reaction (31). The temperature coefficient of the reaction is high, increasing about 2.65 fold per 10° C. at ordinary curing temperatures (31). Furthermore, the reaction is apparently exothermic (4, 24). It is noteworthy that catalysts are apparently necessary, since synthetic rubbers prepared from pure materials add sulfur slowly, if at all. The proteins and perhaps the resins in natural rubber undoubtedly serve as accelerators. The curves for combined sulfur vs. time of cure for typical mixes are shown in Figures 1 and 2. Figure 1 is taken from the data of Kratz and Flower (16); the composition and temperature of cure for this mix are shown in Cranor's Table I (9). Figure 2, curve 1, is from Table I of Eaton and Day (10), and curve 2 from data obtained in this laboratory (27, Table I). Superficial inspection of these curves shows extraordinary divergence of type. Figure 1 is a typical fadeaway curve, characteristic of most chemical reactions, where the reaction rate decreases with decreasing concentration of the reacting materials. Curve 1, Figure 2, is an entirely different type, where the rate of sulfur addition is constant until nearly 70 per cent of the initial sulfur has reacted. Curve 2, Figure 2, shows even more complex behavior. Again the rate is constant in the initial portions of the cure. However, following this period, the rate increases markedly but later falls off, approaching zero, to give an S-shaped eurve.

Cavitation-induced Reactions in Pure Substituted Benzenes

1972 ◽  
Vol 50 (11) ◽  
pp. 1743-1750 ◽  
Author(s):  
G. K. Diedrich ◽  
P. Kruus ◽  
L. M. Rachlis
Keyword(s):  
Thermal Decomposition ◽  
Low Temperature ◽  
Bond Dissociation Energy ◽  
Dissociation Energy ◽  
Cavitation Bubble ◽  
Reaction Rate ◽  
Substituted Benzenes ◽  
Thermal Reactions ◽  
Initiation Reaction ◽  
Low Temperature Pyrolysis

The formation of polymers has been observed on exposure of pure substituted benzenes to ultrasound intense enough to cause cavitation. The products have some of the characteristics of the char obtained from low temperature pyrolysis of hydrocarbons. They are difficult to dissolve, melt above 300 °C, and give a large broad e.p.r. signal. A crude correlation between bond dissociation energy and the reaction rate suggests that the initiation reaction is a thermal decomposition in a cavitation bubble. The phenomenon is compared to radiolysis and thermal reactions.

Thermal Decomposition and Isomerization of Furfural and 2-Pyrone: A Theoretical Kinetic Study

2020 ◽  
Author(s):  
Saddam Al-Hammadi ◽  
Gabriel da Silva
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Study ◽  
Gas Phase ◽  
Quantum Chemical ◽  
Reaction Rate ◽  
Rate Theory ◽  
Reaction Rate Theory ◽  
Reaction Channels

We have studied the decomposition and isomerization of furfural in the gas-phase using quantum chemical and statistical reaction rate theory techniques. This work uncovers a variety of new reaction channels...

scholarly journals On the thermal decomposition of methyl nitrite

1937 ◽  
Vol 158 (895) ◽  
pp. 495-498 ◽  
Keyword(s):  
Thermal Decomposition ◽  
Temperature Coefficient ◽  
Decomposition Process ◽  
Methyl Nitrite ◽  
First Order ◽  
Alkyl Nitrites

Steacie and Shaw have made a study of the thermal decomposition of a series of alkyl nitrites at temperatures between 170° and 240°. Their results are contained in the series of papers to which reference is made; but of these only the first is at present significant, for in it they consider the decomposition of methyl nitrite, and give their reasons for the conclusions which they arrive at regarding the nature of the decomposition process, which they assume to be common to the whole series. Their results led them to the conclusion that the decomposition process proceeds in accordance with the equation, 2CH 3 NO 2 = CH 2 O + CH 4 O + 2NO, (1) the process being of the first order. Assuming that this was so, the critical increment calculated from the temperature coefficient was found to be 36⋅4 kcals. If the decomposition process really does take place in accordance with the equation written above, the conclusion that the process is uni-molecular is confusing rather than helpful. It appeared possible that a study of the problem by methods more detailed than that applied by Steacie and Shaw might throw further light upon it, and with that object in view the present work was undertaken.

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