Kent J. Eisentraut

Thermogravimetric studies of metal β-diketonates☆

Abstract Thermogravimetric analysis (TGA) is applied to the rapid determination of the relative volatilities of various metal β-diketonate chelates. Differences are seen in the volatility of a series of thermally stable tris (2,2,6,6-tetramethyl-3,5-heptanedionato) rare earth chelates. The trend in volatility of the rare earth chelates is related to the size of the trivalent rare earth ion and is independent of chelate mass. The order of increasing volatility as seen from the thermograms of the volatile rare earth chelates parallels the order of increasing ease of elution of these chelates from non-polar gas chromatographic liquid partioning phases. Some of the chelates are considerably more volatile than alkane hydrocarbons of considerably lower carbon number. Volatilities of metal β-diketonates of Cr(III), Fe(III), Rh(III), Al(III), Na(I), Zr(IV), Sc(III), Y(III), and the trivalent lanthanides are compared. Differences in the volatilities of metal chelates, arising from substitution in the chelate ligand, are illustrated for metal chelate derivatives of various β-diketone ligands.

Determination of Wear Metals in Aircraft Lubricating Oils by Atomic Absorption Spectrophotometry Using a Graphite Furnace Atomizer

Atomic absorption spectrophotometry equipped with a graphite furnace atomizer has proven to be a very effective technique for determining iron, copper, aluminum, magnesium, and other critical wear metals in lubricating oils. Oil samples are diluted 1:4 with kerosene, and 0.5–20 μL can be analyzed by direct injection into the furnace. Analytical conditions have been established for 10 wear metals. Working curves, times, and temperatures for drying, ashing, and atomizing cycles have been determined. Precision of analysis was determined for standards (dissolved) and samples containing metallic particles (undissolved). The RSDs for 10 runs of 3 ppm Fe, 1 ppm Cu, and 1 ppm Al were 10.0, 4.0, and 3.9 percent, respectively. Metal powders of Fe, Cu, and Al having maximum sizes of 5, 10, and 20–30 μm were analyzed and precisions determined. Comparative analytical results were obtained for Fe particles of 1, 3, 5, 8, 10, 12, and 20–30 μm with the use of various spectrometric techniques. The graphite furnace was shown to be superior to ICP, DCP, flame AA, and rotating disk AES. In the analysis of used oil samples, the graphite furnace gave better precision and analyzability for Fe and Cu than the other instruments considered.

A new general synthesis route to 1,1,1-trihalopolyfluoroalkanes

Abstract 1,1,1-Trichloro- and tribromo polyfluoroalkanes have been synthesized from perfluoroalkyl iodides and anhydrous aluminum chloride and bromide respectively. The reaction is also applicable to perfluoroalkylether iodides, though varying amounts of by-products are formed depending on the structure of the starting iodide.

Chemical Nature of Wear Debris

Depending upon the mechanism of wear occurring within aircraft gas-turbine engines, different types of wear debris are expected to be produced in lubricating oils. A procedure was developed to identify the chemical nature of these wear species. The procedure involves filtration and solvent extraction techniques, followed by spectrometric analysis to separate and quantify the different chemical forms of the wear metal debris. The chemical form of some of the most critical wear species are identified as metallic, oxide, and metallo-organic species. The development and application of the procedure to identify and quantify the wear debris of Cu, Fe, and Mg in aircraft lubricating oils are discussed. Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in San Diego, California, October 22–24, 1984

Fluoro-ketones. VIII: Synthesis of some fluoroquinoxaline compounds from fluoroketones

Abstract The reaction between a perfluoroalkylether α,β-diketone or perfluoroalkyletherketoester and o-phenylenediamine yielding quinoxaline compounds was studied in detail. The various intermediate compounds leading to the formation of the quinoxalines were examined by NMR, MS, GC/MS and IR. 2,3-Perfluoroalkylether substituted quinoxaline is the major product of the reaction. In addition however, the formation of a minor product 3-perfluoro-alkylether-2(1H)-quinoxalinone, indicates an alternate reaction path.