The thermal decomposition of benzoic acid

1970 ◽  
Vol 48 (24) ◽  
pp. 3797-3801 ◽  
Author(s):  
Keith Winter ◽  
Donald Barton
Keyword(s):  
Thermal Decomposition ◽  
Benzoic Acid ◽  
Pressure Range ◽  
Initial Rate ◽  
Material Balance ◽  
Reaction Vessel ◽  
Radical Processes

The thermal decomposition of benzoic acid has been studied in a Pyrex reaction vessel at 475, 486, and 499 °C over the pressure range 5 to 40 Torr. The main products, CO2 and C6H6, were accompanied by smaller quantities of CO, H2, and biphenyl. The percentage of conversion varied from less than 1% for initial rate experiments to over 90 % in attempts to obtain a material balance. Moderately reproducible initial rates of formation of CO2 were obtained after the vessel had been conditioned by pyrolysis of benzoic acid. The order for the initial rate of formation of CO2, 1.20 ± 0.03 at 475 °C and 1.28 ± 0.04 at 499 °C, is discussed in terms of a combination of first and three-halves order reactions. Formation of both C6H5D and C6H6 in the presence of C6D5CD3 is accepted tentatively as evidence of formation of benzene by both molecular and radical processes.

The pyrolysis of monosilane

1966 ◽  
Vol 293 (1435) ◽  
pp. 543-561 ◽  
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Study ◽  
Pressure Range ◽  
Initial Pressure ◽  
Product Formation ◽  
Reaction Vessel ◽  
Silicon Hydride ◽  
Temperature Range ◽  
Gaseous Products ◽  
Kinetic Features

A detailed analytical and kinetic study of the thermal decomposition of monosilane in the temperature range 375 to 430 °C and the initial pressure range 35 to 230 mmHg has been conducted. The gaseous products in the very early stages of the reaction are hydrogen, disilane and trisilane. In addition, later in the reaction a solid silicon hydride is formed, its composition varying as the reaction progresses. The kinetic features of product formation during the first 3 % of decomposition have been studied in detail, while those relating to higher extents of decomposition have been investigated less fully. The reaction is accelerated by the addition of certain foreign gases, but is unaffected by packing of the reaction vessel. A tentative mechanism involving the species silene, SiH 2 , is proposed.

Mercury-photosensitized decomposition of dimethyl ether. Part I. Mechanism

1967 ◽  
Vol 45 (22) ◽  
pp. 2763-2766 ◽  
Author(s):  
L. F Loucks ◽  
K. J Laidler
Keyword(s):  
Mass Balance ◽  
Dimethyl Ether ◽  
Pressure Range ◽  
Reaction Vessel ◽  
No Decomposition ◽  
Methyl Radical ◽  
Reaction Conditions ◽  
Products Of Reaction

The mercury-photosensitized decomposition of dimethyl ether was investigated from 200 to 300 °C and over the pressure range 3 to 600 mm Hg. Measurements were made of the initial rates of formation of the products of reaction, which are CO, H2, C2H6, CH4, CH3OC2H5, and CH3OCH2CH2OCH3. It is concluded that the primary step involves a C—H split; there is no evidence for a primary C—O split. Over the range 200 to 300 °C the methoxymethyl radical, CH3OCH2, decomposed to give formaldehyde and a methyl radical, whereas at 30 °C no decomposition of the CH3OCH2 radical was detected. The mass balance is consistent with the mechanism proposed. The homogeneity of the reaction conditions was examined by varying the concentration of mercury in the reaction vessel.

scholarly journals The Evolving E-cigarette: Comparative Chemical Analyses of E-cigarette Vapor and Cigarette Smoke

2020 ◽  
Vol 2 ◽  
Author(s):  
Anthony Cunningham ◽  
Kevin McAdam ◽  
Jesse Thissen ◽  
Helena Digard
Keyword(s):  
Thermal Decomposition ◽  
Thermal Degradation ◽  
Benzoic Acid ◽  
Cigarette Smoke ◽  
Iron Alloy ◽  
Decomposition Products ◽  
Nickel Iron ◽  
Degradation Reactions ◽  
Nickel Iron Alloy ◽  
The Impact

Background: E-cigarette designs, materials, and ingredients are continually evolving, with cotton wicks and diverse coil materials emerging as the popular components of atomisers. Another recent development is the use of nicotine salts in e-liquids to replicate the form of nicotine found in cigarette smoke, which may help cigarette smokers to transition to e-cigarettes. However, scientific understanding of the impact of such innovations on e-cigarette aerosol chemistry is limited.Methods: To address these knowledge gaps, we have conducted a comparative study analyzing relevant toxicant emissions from five e-cigarettes varying in wick, atomiser coil, and benzoic acid content and two tobacco cigarettes, quantifying 97 aerosol constituents and 84 smoke compounds, respectively. Our focus was the potential for benzoic acid in e-liquids and cotton wicks to form aerosol toxicants through thermal degradation reactions, and the potential for nickel–iron alloy coils to catalyze degradation of aerosol formers. In addition, we analyzed e-cigarette emissions for 19 flavor compounds, thermal decomposition products, and e-liquid contaminants that the FDA has recently proposed adding to the established list of Harmful and Potentially Harmful Constituents (HPHCs) in tobacco products.Results: Analyses for benzene and phenol showed no evidence of the thermal decomposition of benzoic acid in the e-cigarettes tested. Measurements of cotton decomposition products, such as carbonyls, hydrocarbons, aromatics, and PAHs, further indicated that cotton wicks can be used without thermal degradation in suitable e-cigarette designs. No evidence was found for enhanced thermal decomposition of propylene glycol or glycerol by the nickel–iron coil. Sixteen of the 19 FDA-proposed compounds were not detected in the e-cigarettes. Comparing toxicant emissions from e-cigarettes and tobacco cigarettes showed that levels of the nine WHO TobReg priority cigarette smoke toxicants were more than 99% lower in the aerosols from each of five e-cigarettes as compared with the commercial and reference cigarettes.Conclusions: Despite continuing evolution in design, components and ingredients, e-cigarettes continue to offer significantly lower toxicant exposure alternatives to cigarette smoking.

THE KINETICS OF THE THERMAL DECOMPOSITIONS OF THE LOWER PARAFFINS: V. THE NITRIC OXIDE INHIBITED DECOMPOSITION OF n-BUTANE

1940 ◽  
Vol 18b (1) ◽  
pp. 1-11 ◽  
Author(s):  
E. W. R. Steacie ◽  
H. O. Folkins
Keyword(s):  
Nitric Oxide ◽  
Thermal Decomposition ◽  
Free Radical ◽  
High Pressures ◽  
Free Radical Processes ◽  
Temperature Range ◽  
Radical Recombination ◽  
Radical Processes ◽  
Kinetics Of ◽  
Good Agreement

A detailed investigation of the inhibition by nitric oxide of the thermal decomposition of n-butane has been carried out over the temperature range 500° to 550 °C.In all cases it was found that inhibition decreased with increasing butane concentration. This suggests that radical recombination occurs in the normal decomposition by ternary collisions with butane molecules acting as third bodies.The activation energies of the normal and inhibited reactions have been determined. For high pressures the two values are in good agreement, viz., 58,200 and 57,200 cal. per mole respectively. The products of the inhibited reaction were also found to be the same as those of the normal reaction.It is concluded that free radical processes predominate, involving comparatively short chains.

Using a Concentrating Solar Reactor to Produce Hydrogen and Carbon Black via Thermal Decomposition of Natural Gas: Feasibility and Economics

2003 ◽  
Vol 125 (2) ◽  
pp. 159-164 ◽  
Author(s):  
Pamela L. Spath ◽  
Wade A. Amos
Keyword(s):  
Thermal Decomposition ◽  
Energy Balance ◽  
Natural Gas ◽  
Carbon Black ◽  
Material Balance ◽  
Cost Effective ◽  
Economic Feasibility ◽  
Solar Reactor ◽  
Effective Manner ◽  
Field Area

Producing hydrogen in a cost-effective manner while minimizing environmental impacts is a big challenge. Hydrogen can be generated with carbon as a by-product from thermal decomposition of natural gas. A system using a solar reactor to produce hydrogen on-site for fueling stations was examined for its technical and economic feasibility. Integrated energy and material balance calculations were made to determine the amount of hydrogen that could be produced from a given reactor size and heliostat field area. Hourly solar data were applied to the model to properly estimate real storage requirements. This paper gives the results of the study including the greenhouse gas emissions and energy balance.

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.

Cool flames in the combustion of toluene and ethylbenzene

1956 ◽  
Vol 238 (1213) ◽  
pp. 143-153 ◽  
Keyword(s):  
Hydrogen Peroxide ◽  
Light Intensity ◽  
Benzoic Acid ◽  
Aromatic Compounds ◽  
Flow System ◽  
Reaction Vessel ◽  
Static System ◽  
Cool Flame ◽  
Cool Flames ◽  
Blue Flame

The oxidation of toluene and ethylbenzene has been studied in a static system using a spherical reaction vessel (700 ml.) over the temperature range 300 to 500°C, and at total pressures up to 600 mm. Cool flames were observed in the oxidation of both hydrocarbons, but only the reaction of ethylbenzene gave rise to a ‘blue’ flame at higher temperatures. With neither hydrocarbon did periodicity in light intensity, or pressure pulses, occur. The ignition diagrams for 4 to 1 fuel + oxygen mixtures have been mapped out. With ethyl­benzene, the cool flame was maintained in a flow system, its spectrum was photographed and shown to be similar to that of fluorescent formaldehyde. The products of the reaction con­tained acetophenone, benzaldehyde and benzoic acid, phenol, quinol, hydrogen peroxide and methoxyhydroperoxide. The results have been compared with corresponding data for the oxidation of paraffin hydrocarbons, and it is concluded that, with both aromatic compounds, the processes allowing the possibility of cool-flame formation are themselves secondary in nature.

scholarly journals The Kinetics of the decomposition of chloral and its catalysis by iodine

1934 ◽  
Vol 146 (857) ◽  
pp. 334-344 ◽  
Keyword(s):  
Thermal Decomposition ◽  
High Temperature ◽  
Organic Compounds ◽  
Reaction Vessel ◽  
Reaction Products ◽  
Considerable Difficulty ◽  
Gaseous Reaction ◽  
High Boiling Point ◽  
Kinetics Of ◽  
Mercury Manometer

The introduction of chlorine atoms into organic compounds causes marked changes in properties which can often be explained in terms of a displacement of electrons under the influence of the substituent. It is an interesting question how far these influences will show themselves in the kinetic behaviour of the substituted molecules. Accordingly the thermal decomposition of chloral and its catalysis by iodine have been studied. The decomposition is a homogeneous gaseous reaction which can be compared with the decomposition of acetaldehyde and propionic aldehyde. Apparatus The apparatus was of the usual type, with a silica reaction vessel heated in an electric furnace. A tube led to a capillary mercury manometer outside the furnace, and the course of the reaction was followed by observing the rate of pressure increase. In view of the relatively high boiling point of chloral it was necessary to keep all the connecting tubes heated to 80°-90° C. Considerable difficulty was experienced with the lubricants for the stop-cocks operating at this temperature. A special high temperature vapourless grease was used, but even this showed a tendency to run and foul the connecting tubes. The reaction products also tended to foul the apparatus so that frequent cleaning of the whole, including the manometer and the mercury pump, was required.

The thermal decomposition of RDX at temperatures below the melting point. I. Comments on the mechanism

1970 ◽  
Vol 23 (4) ◽  
pp. 737 ◽  
Author(s):  
JJ Batten ◽  
DC Murdie
Keyword(s):  
Thermal Decomposition ◽  
Melting Point ◽  
Liquid Phase ◽  
Condensed Phase ◽  
Initial Rate ◽  
Decomposition Products ◽  
Sample Geometry

Two mechanisms have recently been proposed to explain the behaviour of the initial rate of decomposition of RDX, with change in sample geometry. These are (i)that the decomposition proceeds by concurrent gas and liquid phase reactions, and (ii) that gaseous decomposition products influence the rate of decomposition of undecomposed RDX in the condensed phase. In this paper it is concluded that mechanism (ii) is the more probable when the reaction is carried out in the presence of nitrogen.

Sign in / Sign up

Export Citation Format

Share Document