Thermal Decomposition Products

Board (United Kingdom) System for Coal (Chapter 2) 

Group Class (% dmmO Coke Type Description 

Coal Limits Mean Limits Mean Limits Mean Limits Mean 

Source Selvig, W.A. and Ode, W.A., Bulletin No. 571, United States Bureau of Mines, Department of the Interior, 

The assays are conducted at 500°C or 600°C (930°F or lllO F), even though they tend at these temperatures to underestimate gas volumes and to show maximum tar plus light oil yields, and both are sufficiently precise to yield mass balances of 100 0.3%. The Gray-King assay can also be carried out at 900°C (1650°F) to provide information about the quality of the solid residue. 

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Prolonged exposure to thermal decomposition products causes so-called polymer fume fever, a temporary influenza-like condition. It may be contracted by smoking tobacco that has been contaminated with the polymer. It occurs several hours after exposure and passes within 36—48 hours the temporary effects are not cumulative. 

Another example of a cycHc product is the formation of cyclopentanone [120-92-3] as a thermal decomposition product in nylon-6,6 (81,82). The following mechanism (eqs. 8 and 9) accounts not only for the formation of the cycloketone but also for the increase in amine ends, the decrease in acid ends, and the evolution of CO2 that is observed in the thermal decomposition of nylon-6,6 (82). 

Polyurethanes. These polymers can be considered safe for human use. However, exposure to dust, generated in finishing operations, should be avoided. Ventilation, dust masks, and eye protection are recommended in foam fabrication operations. Polyurethane or polyisocyanurate dust may present an explosion risk under certain conditions. Airborne concentrations of 25—30 g/m are required before an explosion occurs. Inhalation of thermal decomposition products of polyurethanes should be avoided because carbon monoxide and hydrogen cyanide are among the many products present. 

Table 4. Thermal Decomposition Products of Vinyl Alcohol—Vinyl Acetate Copolymers, %...

Sodium Chlorite. The standard enthalpy, Gibbs free energy of formation, and standard entropy for aqueous chlorite ions ate AH° = —66.5 kJ/mol ( — 15.9 kcal/mol), AG = 17.2 kJ/mol (4.1 kcal/mol), and S° = 0.1883 kJ/(molK) (0.045 kcal/(molK)), respectively (107). The thermal decomposition products of NaClO, in the 175—200°C temperature range ate sodium chlorate and sodium chloride (102,109) ... 

Hypalon raw polymer compounds or cured product may be disposed of in an approved landfill. Incineration is not recommended because of the evolution of toxic gases. Additional information is available from Du Pont concerning these and other potential health hazards when handling Hypalon compounds, finished products, thermal decomposition products, or waste disposal (43). 

The partially reduced form of niobium accounts for the color change of samples that underwent thermal treatment in vacuum or inert atmospheres. Whereas the thermal treatment of the mixture in air leads to the simultaneous oxidation of Nb4+ by oxygen, this is actually equivalent to the replacement of fluorine ions by oxygen ions in the complex structure of oxyfluoroniobate. Extended thermal treatment of systems containing LiNbOF4 and LiF yields a mixture of LiF and LiNbOs as the final thermal decomposition product. 

Analytical procedures sensitive to 2 ppm for styrene and 0.05 ppm or less for other items were used for examining the extracts. Even under these exaggerated exposure conditions no detectable levels of the monomers, of the polymer, or of other potential residuals were observed. The materials are truly non-food-additive by the FDA definitions. Hydrogen cyanide was included in the list of substances for analysis since it can be present at low levels in commercial acrylonitrile monomer, and it has been reported as a thermal decomposition product of acrylonitrile polymers. As shown here, it is not detectable in extracts by tests sensitive to... 

The transmittance readings should be taken within 5 to 10 minutes after red color development. The developed red color is stable on standing up to at least 2 hours when working with crystalline dihydrotriazole only however, when phenyl azide is used, as it must be in an actual analysis for Compound 118, some of its nonvolatile thermal decomposition products develop colors on standing. 

Koebel, M. and Elsener, M. (1995) Determination of Urea and its Thermal Decomposition Products by High-Performance Liquid Chromatography, J. Chromatogr., 689, 164. 

Reichle, W. T. Preparation, Properties, and Thermal Decomposition Products of Organoazides of Silicon, Germanium, Tin, Lead, Phosphorus, and Sulfur. Inorg. Chem. 3, 402 (1964). 

It has been suggested however that isotacticity derives from polymerization occurring on colloidal particles formed by thermal decomposition of the catalysts. As stated previously, in the presence of the monomer even the allyl compounds are stable at 65°C and none of the thermal decomposition products (black to yellow solids) could be detected. As a check on these results a polymerization of propylene was carried out with Zr (benzyl) 4 in toluene at 0°C in a sealed tube. The reaction was very slow and analytical quantities of polymer could be obtained only after 312 hr. NMR analysis showed peaks assignable to isotactic sequences, and these were much stronger than the peaks assignable to syndiotactic diads. It was concluded... 

Crane CR, Sanders DC, Endecott BR, et al. 1986. Inhalation toxicology VI. Evaluation of the relative toxicity of thermal decomposition products from nine aircraft panel materials. Washington, DC Federal Aviation Administration, Office of Aviation Medicine. DOT/FAA/AM-86/3. 

Kennah, H.E. Stock, M.F. Alarie, Y.C. "Toxicity of Thermal Decomposition Products from Composites, J. Fire Sciences 1987, 5(1), 3-16. 

Anderson, R.C. Alarie, Y. "Acute Lethal Effects of Polyvinyl-chloride Thermal Decomposition Products in Normal and Cannulated Mice, Abstracts... 

Producing Thermal Decomposition Products from Materials in an Air Stream and Their Toxicological Testing Part 1. Test Method 53436. Deutsches Institut fur Normung, Berlin, 1981. 

The gaseous thermal decomposition product is given as the last product in each of these chemical equations. 

Thermal decomposition of hydrazine, 13 566-567 of limestone, 15 32 of maleic anhydride, 15 490 Thermal decomposition products, exposure to, 18 304... 

An example of the effect of source temperature is seen for TiF40xH 110), for which, at 180°C, the highest m/e corresponds to TiFsOX (i.e., P—HF), whereas at 240°C the thermal decomposition product, TiF20X2, is observed. Compound Cu(NOs)2 shows a parent ion 111, 112) [unlike Sn(NOs)4 (79)], but thermal decomposition occurs even at source temperatures of 100°C resulting in much of the N02 and NO observed. As samples are volatilized from the probe at temperatures of up to 350°C, serious thermal decomposition or polymerization may result 8,113-116). Even with the source at a low temperature, there is still the very hot region in the vicinity of the filament that can cause pyrolysis. 

Exposure of three firefighters to unknown but very high vapor concentrations was characterized by disorientation, headache, nausea, and irritation of the eyes and throat. Two of the three became comatose one had convulsive seizures, and the other had respiratory arrest from which he was resuscitated. Recovery was slow but complete. Some effects may have been due to the inhalation of thermal decomposition products. 

Ishikawa, T. Cai,W.Y. Kandori, K. (1992) Characterization of the thermal decomposition products of 8-FeOOH by Eourier-trans-form infrared spectroscopy and N2 adsorption. J. Chem. Soc. Faraday Trans. I. 88 1173-1177... 

Reaction of (159) with other carbonyl compounds was monitored by H NMR spectroscopy <90JHC1993>. Acetophenone and benzophenone in CDCI3 at 60 °C gave within 2 h a small amount of (179) analogues but mainly thermal decomposition products of the latter. Benzaldehyde reacts at room temperature but the resulting analogue (179) decomposes completely. 

Next, the thermal properties of the dye must be such that absorption of the laser energy will result in dye diffusion but not in decomposition. The melting temperature Tm, the latent heat of fusion, AH, and the specific heat for these dyes were determined by differential scanning calorimetry using a DuPont 990 Thermal Analyzer. The data are given in Table II. No thermal decomposition products for these dyes were detected upon heating to 600 °C for 20 msec. 

Diphenylamine is only slowly converted even at higher temperatures (50% water 50% t-butanol, O.IM KOH, 50 °C) and there it yields thermal decomposition products, that possibly originate from tetraphenylhydrazine . ... 

J. Bozi, Z. Czeg ny, and M. Blazs6, Conversion of the volatile thermal decomposition products of polyamide-6,6 and ABS over Y zeolites, Thermochim. Acta, 472(l-2) 84-94, June 2008. 

Burning characteristics and thermal decomposition products of some synthetic cellular materials 2 B356-B357... 

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