Radiolysis of Trifluoroacetic Acid

1971 ◽  
Vol 49 (20) ◽  
pp. 3389-3393
Author(s):  
J. Betts ◽  
E. A. Cherniak
Keyword(s):  
Trifluoroacetic Acid ◽  
Product Formation ◽  
Gaseous Product ◽  
Gaseous Products

The gaseous products of the 60Co-γ radiolysis of liquid CF3COOH at 23 °C and solid CF3COOH at −196 °C have been identified and their G-values have been determined. The products and G-values are, for the radiolysis of liquid CF3COOH; CO2(7.1), CO(0.71), CF3H(0.27), C2F6(1.36), H2(0.031) and, for the radiolysis of solid CF3COOH; CO2(2.5), CF3H(0.30), C2F6(0.39). CO and H2 are not produced in the radiolysis of solid CF3COOH and CF4 and C2F4 are not produced in the radiolysis of solid and liquid CF3COOH. The mechanisms of gaseous product formation in the radiolysis of solid and liquid CF3COOH are compared.

Maximum heating rates for producing undistorted glassy carbon ware determined by wedge-shaped samples

1996 ◽  
Vol 11 (9) ◽  
pp. 2368-2375 ◽  
Author(s):  
Hossein Maleki ◽  
Lawrence R. Holland ◽  
Gwyn M. Jenkins ◽  
R. L. Zimmerman ◽  
Wally Porter
Keyword(s):  
Heating Rate ◽  
Treatment Process ◽  
Gaseous Product ◽  
Pyrolysis Mass Spectrometry ◽  
Heating Rates ◽  
Gaseous Products ◽  
Volatile Products ◽  
Solid Bodies ◽  
Polymeric Carbon ◽  
Maximum Heating

Polymeric carbon artifacts are particularly difficult to make in thick section. Heating rate, temperature, and sample thickness determine the outcome of carbonization of resin leading to a glassy polymeric carbon ware. Using wedge-shaped samples, we found the maximum thickness for various heating rates during gelling (300 K–360 K), curing (360 K–400 K), postcuring (400 K–500 K), and precarbonization (500 K–875 K). Excessive heating rate causes failure. In postcuring the critical heating rate varies inversely as the fifth power of thickness; in precarbonization this varies inversely as the third power of thickness. From thermogravimetric evidence we attribute such failure to low rates of diffusion of gaseous products of reactions occurring within the solid during pyrolysis. Mass spectrometry shows the main gaseous product is water vapor; some carboniferous gases are also evolved during precarbonization. We discuss a diffusion model applicable to any heat-treatment process in which volatile products are removed from solid bodies.

scholarly journals Py–FTIR–GC/MS Analysis of Volatile Products of Automobile Shredder Residue Pyrolysis

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2734
Author(s):  
Bin Yang ◽  
Ming Chen
Keyword(s):  
Alternative Energy ◽  
Oil And Gas ◽  
Gaseous Product ◽  
Steam Gasification ◽  
Pyrolysis Oil ◽  
Shredder Residue ◽  
Gaseous Products ◽  
Automobile Shredder Residue ◽  
Ms Analysis ◽  
Volatile Products

Automobile shredder residue (ASR) pyrolysis produces solid, liquid, and gaseous products, particularly pyrolysis oil and gas, which could be used as renewable alternative energy resources. Due to the primary pyrolysis reaction not being complete, the yield of gaseous product is low. The pyrolysis tar comprises chemically unstable volatiles before condensing into liquid. Understanding the characteristics of volatile products will aid the design and improvement of subsequent processes. In order to accurately analyze the chemical characteristics and yields of volatile products of ASR primary pyrolysis, TG–FTIR–GC/MS analysis technology was used. According to the analysis results of the Gram–Schmidt profiles, the 3D stack plots, and GC/MS chromatograms of MixASR, ASR, and its main components, the major pyrolytic products of ASR included alkanes, olefins, and alcohols, and both had dense and indistinguishable weak peaks in the wavenumber range of 1900–1400 cm−1. Many of these products have unstable or weaker chemical bonds, such as =CH–, =CH2, –C=C–, and –C=CH2. Hence, more syngas with higher heating values can be obtained with further catalytic pyrolysis gasification, steam gasification, or higher temperature pyrolysis.

The pyrolysis of acetylene at temperatures from 500 to 1000 °C

1964 ◽  
Vol 280 (1380) ◽  
pp. 139-152 ◽  
Keyword(s):  
Triplet State ◽  
Underlying Mechanism ◽  
Gaseous Product ◽  
Polymer Chains ◽  
Order Kinetic ◽  
Initial Product ◽  
Ambient Temperatures ◽  
Temperature Range ◽  
Gaseous Products ◽  
Chain Character

Several features of the pyrolysis of acetylene in the temperature range 500 to 1000 °C suggest that the underlying mechanism is the same as that in operation at both lower and higher temperatures. Thus the rate of consumption of acetylene obeys a second-order kinetic law and is little affected by additions of the gaseous products; the observed velocity constants agree closely with those expected if a single mechanism were in operation over the whole temperature range 350 to 2500 °C. The analytical results show conclusively that the sole initial product of the reaction is vinylacetylene. Diacetylene appears to be formed by heterogeneous decomposition of vinylacetylene and this reaction can occur at ambient temperatures in the presence of carbonaceous deposits. Methylacetylene and benzene probably arise from the further reaction of C 6 species which are formed during the building-up of polymer chains. Methane is the predominant final gaseous product of the reaction at the temperatures investigated. A mechanism is proposed which accounts for both the chain character of the reaction and the apparent existence of equilibria. It appears that acetylene is first converted to the triplet state by a surface reaction. This initial stage is then followed either by the production of C 4 and subsequent species in the triplet state by a series of step-wise reactions involving further acetylene or by the regeneration of stable species as a result of reaction, at a surface, of the corresponding excited species.

Kinetics of Gaseous Product Formation in the Surface Treatment of Polypropylene with Nitrogen–Oxygen Plasmas

2004 ◽  
Vol 38 (3) ◽  
pp. 200-202 ◽  
Author(s):  
E. V. Kuvaldina ◽  
D. A. Shutov ◽  
V. V. Rybkin ◽  
S. A. Smirnov
Keyword(s):  
Surface Treatment ◽  
Product Formation ◽  
Gaseous Product ◽  
Kinetics Of

scholarly journals Modelling, computation and analysis on combustion of explosives

2021 ◽  
pp. 1-31
Author(s):  
S. SAID ◽  
F. T. SMITH ◽  
J. P. CURTIS
Keyword(s):  
Mathematical Modelling ◽  
Close Agreement ◽  
Reaction Diffusion ◽  
Diffusion Problem ◽  
Gaseous Product ◽  
Single Step ◽  
Asymptotic Approach ◽  
Arrhenius Model ◽  
Gaseous Products ◽  
Asymptotic Problem

When an explosive burns, gaseous products are formed as a result. The interaction of the burning solid and gas is not well understood. More specifically, the process of the gaseous product heating the explosive is yet to be explored in detail. The present work sets out to fill some of that gap using mathematical modelling: this aims to track the temperature profile in the explosive. The work begins by modelling single-step reactions using a simple Arrhenius model. The model is then extended to include three-step reaction. An alternative asymptotic approach is also employed. There is close agreement between results from the full reaction-diffusion problem and the asymptotic problem.

Kinetics of Gaseous Product Formation in the Coke Combustion of a Fluidized Catalytic Cracking Catalyst

1999 ◽  
Vol 38 (9) ◽  
pp. 3255-3260 ◽  
Author(s):  
José M. Arandes ◽  
Iñaki Abajo ◽  
Inmaculada Fernández ◽  
Danilo López ◽  
Javier Bilbao
Keyword(s):  
Catalytic Cracking ◽  
Product Formation ◽  
Gaseous Product ◽  
Fluidized Catalytic Cracking ◽  
Coke Combustion ◽  
Kinetics Of

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.

scholarly journals Study on combustion and emission characteristics of chars from low-temperature and fast pyrolysis of coals with TG-MS

2019 ◽  
Vol 25 (4) ◽  
pp. 522-528 ◽  
Author(s):  
Lei Liu ◽  
Zhiqiang Gong ◽  
Zhenbo Wang ◽  
Haoteng Zhang
Keyword(s):  
Low Temperature ◽  
Fast Pyrolysis ◽  
Horizontal Tube ◽  
Gaseous Product ◽  
Low Rank ◽  
Pollutant Emission ◽  
Combustion Characteristic ◽  
Emission Characteristics ◽  
Gaseous Products ◽  
Good Agreement

To achieve the clean and efficient utilization of low-rank coal, the combustion and pollutant emission characteristics of chars from low-temperature and fast pyrolysis in a horizontal tube furnace were investigated in a TG-MS analyzer. According to the results, the combustion characteristic of chars was poorer than its parent coals. The temperature range of gaseous product release had a good agreement with that of TGA weight loss. Gaseous products of samples with high content of volatile were released earlier. The NO and NO<sub>2</sub> emissions of chars were lower than their parent coals. Coals of high rank (anthracite and sub-bituminous) released more NO and NO<sub>2</sub> than low rank coals of lignite, so were chars from coals of different ranks. SO<sub>2</sub> emissions of char samples were lower than parent coals and did not show obvious relationship with coal ranks.

TG-FTIR Analysis of Wood Based Bio-Oil

2011 ◽  
Vol 347-353 ◽  
pp. 2661-2665
Author(s):  
Jin Xing Peng ◽  
Bei Bei Yan ◽  
Guan Yi Chen ◽  
Xin Li Zhu ◽  
Chao Wang
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fast Pyrolysis ◽  
Combustion Process ◽  
Gaseous Product ◽  
Combustion Mechanism ◽  
Ftir Analysis ◽  
Gaseous Products ◽  
Second Stage ◽  
Bio Oil

The combustion mechanism of bio-oil derived from wood fast pyrolysis was investigated by thermogravimetric analysis coupled with Fourier transform infrared spectroscopy (TG–FTIR) in flowing air. The results show that the combustion process of bio-oil consists of two main consecutive stages at a low heating rate. The combustion reaction becomes more and more intense from the first to the second stage. The release of volatiles occurs mainly at 80～200 °C and 350～500°C, and the gaseous products in each stage are different. The main products in the first stage are H2O with a few low molecule weight compounds, such as methanol, formic acid, etc. In the second stage, some new volatiles such as CO2, CO and CH4, etc. are present. Among the above volatiles, CO2 is the dominant gaseous product in the whole combustion process. The concentrations of CO2 and CO keep increasing, and reach the maximum at about 450 °C. Over 570°C, there are few products released at the end of the combustion process.

Pyrolysis Kinetics and Emission Characteristics of Waste Disposable Paper Cups Using the Thermogravimetric-FTIR Technique

2017 ◽  
Vol 42 (2) ◽  
pp. 126-135 ◽  
Author(s):  
Daiwang Song ◽  
Jing Wang ◽  
Yushan Zhang ◽  
Yuhui Ma
Keyword(s):  
Weight Loss ◽  
Gaseous Product ◽  
Pyrolysis Kinetics ◽  
Cellulose Fibres ◽  
Gaseous Products ◽  
Highest Weight ◽  
Master Plots ◽  
Infrared Spectrometer ◽  
Fwo Method ◽  
Paper Cups

The pyrolysis of waste disposable paper cups (WDPCs) was investigated using a thermogravimetric analyser coupled with a Fourier transform infrared spectrometer. The activation energies of the pyrolysis reactions were obtained by the Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) methods respectively. The kinetic model was determined by the master plots method. Thermogravimetric results showed that the highest weight loss rate occurred from 345 to 365 °C as the heating rate was increased from 10 to 30 °C min−1, indicating the pyrolysis of cellulosic material in the WDPC. The weight loss between 400 and 500 °C can be attributed to the decomposition of polyethylene. By analysing the FTIR spectra, it was found that the absorbance of all the evolved gaseous products had peaks at 360 °C due to the decomposition of cellulose fibres and the cracking of polyethylene at 485 °C led to the emergence of a second hydrocarbon peak. Ketones were the most abundant condensable organic products and CO2 was the dominating gaseous product, which can also be produced via secondary cracking of the small molecule organics above 400 °C. Kinetic analysis revealed that the average activation energy of the pyrolysis of the WDPC was 153.75 kJ mol−1 from the FWO method and 151.43 kJ mol−1 from the KAS method. The reaction mechanism can be described by the R3 model.

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