PYROLYSIS STUDIES: X. RATES OF THE THERMAL DECOMPOSITION OF ortho-SUBSTITUTED ETHYL BENZOATES IN THE GAS PHASE

1964 ◽  
Vol 42 (2) ◽  
pp. 294-297 ◽  
Author(s):  
Grant Gill Smith ◽  
David F. Brown
Keyword(s):  
Thermal Decomposition ◽  
Benzoic Acid ◽  
Gas Phase ◽  
Steric Effects ◽  
First Approximation ◽  
Chromatographic Measurement

Eight ortho-substituted ethyl benzoates (with substituents varying from o-NH2 to o-NO2) have been partially pyrolyzed to ethylene and the corresponding benzoic acid. By gas chromatographic measurement of the amount of ethylene produced, the relative rates of the thermal decomposition of the various ethers have been determined. There are minor steric effects (primary or secondary) in the reaction and direct field influences are negligible. The varying reactivity, therefore, is attributed to changes in polar effects of the substituent. This reaction appears to be a useful method of determining, quantitatively, to a good first approximation, polar effects of ortho substituents.

Synthesis of Sic Fine Particles by Gas-Phase Reaction Under Short-Time Microgravity

1992 ◽  
Vol 286 ◽  
Author(s):  
Takeshi Okutani ◽  
Yoshinori Nakata ◽  
Masaakt Suzuki ◽  
Yves Maniette ◽  
Nobuyoshi Goto ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Heat Source ◽  
Size Distribution ◽  
Gas Phase ◽  
Fine Particles ◽  
Rapid Heating ◽  
Exothermic Reaction ◽  
Phase Reaction ◽  
Gas Phase Reaction ◽  
Short Time

ABSTRACTSiC fine particles were synthesized by the gas-phase thermal decomposition of tetramethylsilane (Si(CH3)4) in hydrogen under microgravity of 10−4G for 10 sec. Rapid heating to the temperature over 800°C which is required for thermal decomposition of Si(CH3)4) under short-time microgravity was attained using a chemical oven where the heat of exothermic reaction of combustion synthesis of Ti-A1-4B composites was used as the heat source. Monodisperse and spherical SiC fine particles were synthesized under microgravity, whereas aggregates of SiC fine particles were synthesized under 1 G gravity. The SiC particles synthesized under microgravity (150-200 nm) were bigger in size and narrower in size distribution than those under 1 G gravity (100-150 nm).

Thermal decomposition of benzoyl azide and diazoacetone in the gas phase

1988 ◽  
Vol 37 (8) ◽  
pp. 1541-1544
Author(s):  
V. G. Prokudin ◽  
A. M. Sipyagin ◽  
V. G. Kartsev ◽  
S. A. Vozchikova
Keyword(s):  
Thermal Decomposition ◽  
Gas Phase

COMPARATIVE ANALYSIS OF THE CONTENT OF TOXIC SUBSTANCES IN THE GAS PHASE OF AEROSOL OF CIGARETTES AND HEATED TOBACCO STICKS FOR ELECTRIC TOBACCO HEATING SYSTEMS

2020 ◽  
Author(s):  
С.Н. МЕДВЕДЕВА ◽  
Т.А. ПЕРЕЖОГИНА ◽  
Е.В. ГНУЧИХ
Keyword(s):  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Comparative Analysis ◽  
Gas Phase ◽  
Control Sample ◽  
Toxic Substances ◽  
Heating Systems

Представлены результаты анализа содержания монооксида углерода, бензола, 1,3-бутадиена в газовой фазе аэрозоля (ГФА) образцов нагреваемых табачных палочек (стики) для электрических систем нагревания табака, пяти марок коммерческих сигарет, контрольной сигареты 3R4F с помощью тестирования на курительной машине в стандартном режиме прокуривания ISO и интенсивном ISO Intense. Установлено значительное снижение содержания монооксида углерода, бензола и 1,3-бутадиена в аэрозоле образцов стиков по режиму ISO Intense и ISO. Количество образующегося монооксида углерода в ГФА образцов стиков составляет 2% от его содержания в ГФА образца контрольных сигарет 3R4F, что подтверждает отсутствие процессов термического разложения (пиролиза) табака. Определено, что в ГФА образцов стиков содержится значительно меньше вредных и потенциально опасных соединений. Установлено снижение содержания бензола и 1,3-бутадиена более чем на 99% по сравнению с контрольным образцом 3R4F и пятью образцами популярных в России марок сигарет. The results of the analysis of the content of carbon monoxide, benzene, 1,3-butadiene in the aerosol gas phase (AGPh) of heated tobacco sticks for electric tobacco heating systems, five brands of commercial cigarettes, 3R4F control cigarette using testing on a Smoking machine in standard ISO smoking mode and ISO Intense are presented. A significant decrease in the content of carbon monoxide, benzene and 1,3-butadiene in stick aerosols according to the ISO Intense and ISO modes was found. The amount of carbon monoxide produced in the effluent AGPh is 2% of its content in the AGPh of 3R4F control cigarettes, which confirms the absence of thermal decomposition (pyrolysis) of tobacco. It was determined that the AGPh of verses contains significantly fewer harmful and potentially dangerous compounds. A decrease in the content of benzene and 1,3-butadiene was found by more than 99% compared to the control sample of 3R4F cigarettes and five brands of cigarettes popular in Russia.

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.

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