Molten lithium carbonate—sodium carbonate—potassium carbonate eutectic: The reaction of ten main group acidic oxides and oxyanions

The reactions of ten main group acidic oxides and oxyanions with molten alkali metal carbonate eutectics have been studied by thermogravimetry. Products have been identified by IR and Raman spectroscopy and stoichiometries suggested for the several reactions as oxide is progressively incorporated. Ultimately the tetrahedral ortho-oxyanion was formed except with the less acidic oxides (As₂O₃, Sb₂O₃, SiO₂). Sulphite was partially oxidised by the carbon dioxide atmosphere to sulphate.     

Molten nitrate eutectics: The reaction of four lanthanide chlorides

The reactions of lanthanum(III), cerium(III), praseodymium(III) and europium(III) chlorides have been studied in the molten lithium nitrate-potassium nitrate and sodium nitrate-potassium nitrate eutectics. The ultimate reaction products have been shown to be oxides (La₂O₃, CeO₂, Pr₆O₁₁ and Eu₂O₃, respectively) which increased the rate of decomposition of the melts, while in three cases an intermediate oxide nitrate was formed (LaONO₃, PrONO₃ and EuONO₃). The temperatures and stoichiometries of the reactions have been established.     

Preparative isolation of (+)-beta-eudesmol fromAmyris balsamifera

Summary Optically pure (+)-beta-eudesmol is a possible starting material for the synthesis of several termite defense compounds. A two step procedure for the isolation of gram quantities of (+)-beta-eudesmol from commercially availableAmyris balsamifera oil (syn. West Indian sandalwood oil), containing 8% beta-eudesmol, was developed. Step one consisted of an efficient vacuum distillation of the total oil. Step two was a medium pressure LC separation with an AgNO₃ impregnated silica gel stationary phase. Several other separation procedures failed due to the presence of many closely related sesquiterpene alcohols (75% of the oil).     

Gas-liquid chromatographic study of monosubstituted benzaldehyde isomers

Monosubstituted benzaldehyde isomers have been studied quantitatively on nine stationary liquid phases of various physical and chemical characteristics and at different operating temperatures. Apiezon 1 + Bentone 34, dinonyl phthalate and di(2-ethylhexyl)sebacate are found to be selective for quantitative separation of the isomers studied.     

Investigations into beam monitors at the AEg ̄ IS experiment

Detailed diagnostic of antiproton beams at low energies is required for essentially all experiments at the Antiproton Decelerator (AD), but will be particularly important for the future Extra Low ENergy Antiproton ring (ELENA) and its keV beam lines to the different experiments. Many monitors have been successfully developed and operated at the AD, but in particular beam profile monitoring remains a challenge. A dedicated beam instrumentation and detector test stand has recently been setup at the AE \(\bar {g}\) IS experiment (Antimatter Experiment: Gravity, Interferometry, Spectroscopy). Located behind the actual experiment, it allows for parasitic use of the antiproton beam at different energies for testing and calibration. With the aim to explore and validate different candidate technologies for future low energy beam lines, as well as the downstream antihydrogen detector in AE \(\bar {g}\) IS, measurements have been carried out using Silicon strip and pixel detectors, a purpose-built secondary emission monitor and emulsions. Here, results from measurements and characterization of the different detector types with regard to their future use at the AD complex are presented.     

Separation of monosubstituted phenols by gas-liquid chromatography

The factors influencing the separation of monosubstituted phenols on silicone oil, poly(ethylene glycol) (1500), Apiezon L + Bentone 34, squalane, Versamide and diethylhexyl sebacate are discussed. Specific retention volumes, height equivalent to a theoretical plate and thermodynamic quantities are reported. Diethylhexyl sebacate and Versamide are selective for quantitative separation of all the isomers studied.     

A comparative study of the gas chromatographic behavior of liquid crystals and polyester stationary phases using paraffinic hydrocarbons as standards

Two new categories of stationary phase have been studied: liquid crystals and polyesters. The liquid crystals were p,p′-azoxyphenetol, p(n-hexyloxy)phenyl-p′-methoxy benzoate, and p-pentyloxy-p′-ethoxyazoxybenzene; and the polyester phases 1,4-butanediol succinate (LAC-860), ethylene glycol succinate (LAC-886), diethylene glycol succinate (LAC-738), diethylene glycol adipate (LAC-296), and neopentyl glycol adipate (LAC-769). Abnormal chromatographic behavior, has been observed: an increase in specific retention volumes and an improvement in the separation of normal, branched, and cycloparaffins, depending on their structures, at high temperatures within a specified range. This phenomenon is the opposite of the behavior of traditional stationary phases. From the chromatograms obtained, plots of log v against 1/T, and differential thermal analysis it is concluded that this abnormal behavior may be attributed to the penetration of solutes through the ordered structure of the mesophase and the rod-like molecules of the polyesters. Furthermore, the chromatographic behavior of some of the polyester (LAC-series) stationary phases in respect of temperature changes is similar to that of the nematic mesophases.