Chemistry in high temperature

Symposium Chemistry in high temperature aqueous solutions. J. Solution Chem. 21(8), 711-932 (1992). 

Inghram, M.G., Drowart, J. (1960) Mass spectrometry applied to high temperature chemistry. In High Temperature Technology. New York McGraw-Hill Book Company, pp. 219-240. Organized by the Stanford Research Institute. 

D. D. Macdonald, S. Hettiarachchi, S. J. Lenhart, in Proc. 1987 Symposium on Chemistry in High Temperature Water, EPRI Report NP-6005, Brigham Young University, Provo, Utah, 1990. 

Compared with ferritic carbon and low-alloy steels, relatively little information is available in the literature concerning stainless steels or nickel-base alloys. From the preceding section concerning low-alloy steels in high temperature aqueous environments, where environmental effects depend critically on water chemistry and dissolution and repassivation kinetics when protective oxide films are ruptured, it can be anticipated that this factor would be of even more importance for more highly alloyed corrosion-resistant materials. 

The chemistry of polysulfide dianions is closely related to that of the radical-monoanions S since both types of anions are in equilibrium with each other in solution and in high-temperature melts, e.g. ... 

The versatile IR method may be extended to extremes of both temperature and pressure as a probe of adsorption and reaction processes on surfaces. The extension of IR spectroscopy to the study of weakly-bound surface species at low temperatures opens up the possibility of stabilization of transient surface species which are Involved in surface chemistry at high temperatures. 

Polythermal reaction models (Section 14.1), however, are commonly applied to closed systems, as in studies of groundwater geothermometry (Chapter 23), and interpretations of laboratory experiments. In hydrothermal experiments, for example, researchers sample and analyze fluids from runs conducted at high temperature, but can determine pH only at room temperature (Fig. 2.2). To reconstruct the original pH (e.g., Reed and Spycher, 1984), assuming that gas did not escape from the fluid before it was analyzed, an experimentalist can calculate the equilibrium state at room temperature and follow a polythermal path to estimate the fluid chemistry at high temperature. 

Solid state NMR has been used to study polymers of various classes over the past several years. In particular, the technique has been used to study curing reactions in epoxies (12). polyimides (1), and acetylenic terminated sulfones (13). The ability to observe the evolution of the carbons of the reacting species has been clearly shown to provide valuable information which has been difficult or impossible to obtain with other techniques. The use of 13C solid state NMR techniques is essential for the understanding of curing reactions in high temperature polymers in order to be able to correlate the reaction chemistry with the structural and resulting physical properties. 

His research interests are generally in high-temperature and solid-state chemistry of materials, including electrochemical devices (e.g., chemical sensors and fuel cells) and the chemical stability of materials (e.g., high-temperature oxidation). Dr. Fergus is an active member of the Electrochemical Society, the Metals, Minerals and Materials Society, the American Ceramics Society, the Materials Research Society, and the American Society for Engineering Education. 

The 1980s saw major developments in secondary synthesis and modification chemistry of zeolites. SUicon-enriched frameworks of over a dozen zeolites were described using methods of (i) thermochemical modification (prolonged steaming) with or without subsequent acid extraction, (ii) mild aqueous ammonium fluorosilicate chemistry, (iii) high-temperature treatment with silicon tetrachloride and (iv) low-temperature treatment with fluorine gas. Similarly, framework metal substitution using mild aqueous ammonium fluorometaUate chemistry was reported to incorporate iron, titanium, chromium and tin into zeolite frameworks by secondary synthesis techniques. 

By far the most widespread use of NMR in an on-line production environment is the utilization of downhole exploration tools by petroleum service companies such as Schlumberger, Halliburton, and Baker Hughes. Articles on these unilateral NMR systems are found in the patent databases, " academic literature, and on-line resources provided by the exploration companies. The references provided here are just a few examples in a very prolific field. The technique is applied in high-temperature and pressure situations and currently is used down to a depth of about 10 km (6 miles) to produce a picture of water/oil content in the adjacent rock formations as well as to derive permeability, diffusivity, and hydrocarbon chemistry information. Mobile unilateral NMR systems such as the NMR-MOUSE are also being developed in order to take benchtop NMR systems into the field to perform analysis of geological core samples at the drill site. NMR analyzers are also being developed to determine the bitumen content and properties in tar sand production and processing. " " ... 

John L. Margrave, a member of the National Academy of Sciences, graduated from the University of Kansas with a B.S. in engineering physics and a Ph.D. in physical chemistry. Dr. Margrave is currently the chief scientific officer at the Houston Advanced Research Center and the E.D. Butcher Professor of Chemistry at Rice University. His expertise is in high-temperature chemistry, materials science, environmental chemistry, and nanoscience technology. His research interests include various areas of physical/inorganic... 

Cairns, E. and Steunenberg, R., "High Temperature Batteries", in "Progress in High Temperature Physics and Chemistry",... 

As shown, peroxy radical chemistry plays a substantial role in low-temperature combustion as opposed to the alkoxy radical chemistry of high-temperature combustion. Thus, the peroxy radicals constitute an important class of reactive intermediates with significant implications for low temperature combustion and atmospheric reactions. 

Fei YW, Wang YB (2000) In High-temperature and high-pressure crystal chemistry, reviews in mineralogy and geochemistry, voi 41, pp 521-557... 

Sleight, A.W., High-Temperature Superconductivity in Oxides, in Chemistry of High-Temperature Superconductors, (Nelson, Whittingham, George, eds.) p. 2, Amer. Chem. Soc., Wash. D.C. (1987). 

Until recently, most of the physicochemical data on molten oxides have been directly obtained from the industrial slags and glasses. These are mainly based on highly complex polycomponent systems and hence not usually amenable to basic interpretation. In the last two decades, however, the increasing interest in high temperature chemistry and the advances in... 

A broader definition than that confined to solutions is demanded in some fields of chemistry (e.g., in high temperature reactions of acids, bases, and salts). In the foimation of metallulgical slags, at furnace tempeiatuies, calcium oxide is used as base and silicon oxide and aluminum oxide as acids calcium aluminosilicate is produced as a fused salt. Sodium carbonate and silicon oxide when fused react to form the salt sodium silicate with the evolution of carbon dioxide. In this sense ... 

Today our knowledge of the specific heat and dissociation of gases at high temperatures has made extraordinary progress, primarily through the work of American scientists. However, even now, in order to solve a number of problems in high-temperature chemistry, analysis is needed of experimental data on phenomena of combustion, explosion and detonation. 

We have used data available in the literature on detonation velocity to solve several problems in high-temperature chemistry (the calculations were carried out in collaboration with a post-graduate student, S. B. Ratner). 

Rosner, D. E. In High Temperature Lamp Chemistry Electrochemical Society Pennington, NJ, 1988 pp 88-84, 111-138. 

The intensive development of the chemistry of homo- and heterometallic alkoxides of copper started more than 10 years ago in connection with the prospects of their application in the preparation of materials and initially in high temperature superconductors. In the search for the appropriate precursors in sol-gel and MOCVD techniques, attention was focused on the alkoxides of copper (I) and the fluorinated alkoxides of copper (II) — oligomeric derivatives soluble in non-polar solvents and existing not only in condensed but also in the gas phase. The derivatives of copper (II) and aliphatic alcohols, even rather branched or functional ones (such as alkoxyalkoxides) turned out to be polymeric substances uninteresting for further application. 

Under argon bubbling, the degradation is faster than under air or oxygen no PCP is detected after 50-min sonication. From these experiments, it was postulated that C02 is transformed to CO as observed in high-temperature chemistry because of the high temperature inside the cavitation bubble. 

The heavier alkaline earths - from Ca downwards in Group 2 -have little covalent chemistry and are almost invariably found (except in high-temperature gaseous species) as M2+ ions. However, the chemistry of Be is almost entirely covalent with Mg being intermediate. Table 6.3 lists the principal types of covalent bonding situations for Be and Mg. 

---