By thermal oxidation

THERMAL OXIDATION OF CHLORINATED HYDROCARBONS IN AIR.a OVER STEEL [1894] 

Small quantities of phosgene were noted when the vapours of many chlorinated 

It is generally believed that cigarette smoking in atmospheres contaminated with 

Thermal oxidation of trichloromethane, CHCI3, in the presence of air results in the formation of peroxide intermediates which ultimately decompose to give phosgene [356]  

The decomposition of CHCI3 to COClj has been noted as a result of exposure to a gas flame [1529]. Trichloromethane oxidation is also considered to be responsible for the generation of phosgene following the addition of trichloroethanoic acid in flame photometric procedures [1219]  

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The polymer is exposed to an extensive heat history in this process. Early work on transesterification technology was troubled by thermal—oxidative limitations of the polymer, especially in the presence of the catalyst. More recent work on catalyst systems, more reactive carbonates, and modified processes have improved the process to the point where color and decomposition can be suppressed. One of the key requirements for the transesterification process is the use of clean starting materials. Methods for purification of both BPA and diphenyl carbonate have been developed. 

The reaction presented above is utilized to leach lead sulfate obtained by thermal oxidation of a mixture of sulfide minerals. The rate of dissolution chemically with a reagent in an... 

Many liquid-phase reactions are carried out in a solvent. If this is the case, then the solvent, in the first instance, should be assumed to be separated and recycled in arrangements similar to that in Figure 13.5. In some cases, the solvent will be contaminated with byproducts of reaction that will need to be separated and disposed of (e.g. by thermal oxidation). In this case, it might be... 

In summary, condensation and absorption are usually the simplest methods of VOC recovery. Recovery methods can be used in combination effectively (but at a cost). Adsorption is usually the only method capable of recovery to achieve very low concentrations of VOC. If the gas stream contains a mixture of VOCs, then the recovered liquid might not be suitable for reuse and will need to be separated by distillation or destroyed by thermal oxidation. 

Lorenz, K., Preston, C.M., Kandeler, E. 2006. Soil organic matter in urban soils Estimation of elemental carbon by thermal oxidation and characterization of organic matter by solid-state 13C NMR spectroscopy. Geoderma, 130, 312-323. 

The conversion of PS to SiOz by thermal oxidation was reported in 1971 by Watanabe and Sakai [Wa7]. Arita in 1978 [Ar3] and Unagami in 1980 [Uni] performed thermal oxidation experiments on PS, which a few years later led to an sil-icon-on-insulator (SOI) technology based on oxidized PS [Hoi, Iml]. Another approach to manufacturing SOI structures was developed in 1986 by Lin and coworkers [Lil], by growing a Si molecular beam epitaxy (MBE) film on PS and subsequent oxidation. However, a major drawback of PS-based SOI technologies is the need for windows in the Si film to carry out the oxidation of the underlying PS. 

Apart from titanium oxide, two other carbon-modified semiconductors were studied in water photoelectrolysis due to their low band gap energy, namely iron (Fe203) and tungsten oxide (W03) [70,90]. Carbon-modified iron oxide demonstrated promising photoconversion efficiency, 4 % and 7 % for modified oxides synthesized in oven and by thermal oxidation respectively [90]. Also, carbon-modified tungsten oxide (C-W03) photocatalysts exhibited a 2 % photoconversion efficiency [70],... 

Polycrystalline oxide materials, both undoped and doped, have been extensively examined for use as photoanodes. Ti02 electrodes have been prepared by thermal oxidation of a Ti plate in an electric furnace in air at 300-800°C (15-60 min) and in a flame at 1300°C (20 min) [27-30]. XRD analysis of thermally oxidized samples indicates the formation of metallic sub-oxide interstitial compounds, i.e. TiOo+x (x < 0.33) or Ti20i y (0 < y < 0.33) and Ti30 together with rutile Ti02 [27]. The characteristic reflection of metallic titanium decreases in intensity after prolonged oxidation (60 min) at 800° C indicating the presence of a fairly thick oxide layer (10-15 pm). Oxidation at 900°C leads to poor adhesion of the oxide film... 

Lindquist SE, Lindgren A, Ning ZY (1985) On the origin of the bandshifts in the action spectra of polyciystalline TiOa electrode prepared by thermal oxidation of titanium. J Electochem Soc 132 623-631... 

To accomplish the thermal desorption, contaminated media are heated, generally between 300 and 1000°F, thus driving off the water, volatile contaminants, and some semivolatile contaminants from the contaminated media and into the off-gas stream. The removed contaminants are then treated by thermal oxidation in an afterburner, condensed in a single- or multiple-stage condenser, or captured by carbon adsorption beds. 

ZnO Zn is a typical example of a self-activated phosphor. In the case of zinc oxide, it is an excess of zinc which enables the phosphor to luminesce. The production is carried out by thermal oxidation of crystallized zinc sulfide in air at ca. 400 °C. The green luminescence, with a broad maximum at 505 nm, has a very short decay time of 10-6 s. As a phosphor for cathode-ray tubes, ZnO.Zn is classified in the TEPAC list as P 24 and in the WTDS system as GE. 

P. Gimmel, K.D. Schierbaum, W. Gopel, H.H. van den Vlekkert and N.F. de Rooij, Microstructured solid-state ion-sensitive membranes by thermal oxidation of Ta, Sens. Actuators B Chern., 1(1-6) (1990) 345-349. 

Oxide layers of various thickness (260, 182, 98, 62, 43, or 20 A) were prepared on the Si wafers. At the beginning we prepared an oxide layer thicker than 200 A by thermal oxidation, and then evaluated the thickness (260 A). Following that, the 260-A thick layer was etched down to each thickness using a 1.6%-HF aqueous solution. Each thickness was evaluated with an ellipsometer. Using Auger electron spectroscopy, we determined the thickness of the native oxide layer on the Si wafer to be 11 A. 

Xie et al. [20] reported the fabrication chip for pumps and an electrospray nozzle. The process used to fabricate the electrochemical pump chips with electrospray nozzle is shown in Fig. 2.11. A 1.5 xm layer of Si02 was grown on the surface of a 4 inch silicon wafer by thermal oxidation. The front side oxide layer was patterned and removed with buffered FIF. XeF2 gaseous etching was used to roughen the silicon surface in order to promote the adhesion between subsequent layers and the substrate. The first 4.5 p,m parylene layer was deposited. 

Controlled burning of carbon does not regenerate all catalysts. Catalysts can be deactivated by particle growth, compound formation, tramp metal deposition, crystal-phase changes, and adsorption of catalyst poisons that cannot be reversed by thermal oxidative treatment. 

After the failure criterion has been defined, the various processes that could cause this failure must be analyzed. For example, an increase in modulus could occur by thermal oxidation, increased postcure crosslinking, or the loss of plasticizer. Whatever the mechanism, each possible process needs to be identified and its rate characterized separately. Only then can interactions between different mechanisms be considered for life prediction. 

Furthermore, the chemical structure of networks are changed by thermal oxidation reactions 17,23,24F These are rather important for epoxy networks with aliphatic amines since they usually take place in the presence of air at T 130 °C. In aromatic amine-based polymers this kind of reaction becomes important at T > 220° 240 °C 17-23>. The only exception are polymers with a large excess of epoxy groups in the initial mixture. For example, the polymer with P = 0.4 23) starts loosing its weight at 160 °C17 23,24). All polymers considered in this paper are prepared from mixtures with 0.6 P 1.6. Cure and post-cure treatment temperatures are below 190 °C. This means we may not consider thermal oxidation processes in our structural analysis of the networks. 

X-ray diffraction analysis indicates that oligomers are amorphous systems with the interchain dis-tance equal d 8.64 A. Thermogravimetric studies show that by thermal oxidative stability oligo-mers are behind polyorganocyclotetrasiloxanes only. 

P. H. KECK (Sylvania) What variation could one expect in the thickness of an oxide layer formed on germanium or silicon by thermal oxidation ... 

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