Coal liquefaction by in-situ hydrogen generation.: 2. Zinc-water model compound reactions

Model compound studies were carried out to elucidate the reaction mechanisms taking place during the liquefaction of coal with the hydrogen produced from the reaction of zinc and water. In compounds of the type Ph-(CH₂)_n-Ph the splitting of the aliphatic bridge was easier with higher n values. Ether type compounds such as diphenylether were unreactive although the C-O bond in dibenzylether was easily cleaved. Condensed ring aromatic compounds gave low conversion with hydrogenation being facilitated by an increase in ring number. Phenolic compounds such as phenol did not react well, but the reactivity increased with increase in aromatic ring size. The cleavage of the aliphatic bridge was accelerated by the OH group, for example, in the case of 4-hydroxydiphenylmethane bond scission was about 15 times higher than that of diphenylmethane. Heterocyclic compounds were unreactive.     

Reactions of phenols with tung oil

As regards the aromatic ring substitution reactions of various kinds of phenols with tung oil under acidic conditions, an investigation was made on the influences of the kinds and substitution positions of alkyl groups of the phenlos on the reaction. Alkyl phenols increased in reactivity in the order of ortho, meta, and para in the position of alkyl substitution. This can be attributed to the preferential para addition of tung oil to the phenol nucleus as reported in the previous paper. The larger alkyl group gave increased reactivities in the reactions of alkyl phenols with tung oil. This has something to do with compatibilities between phenols and tung oil (differences in solubility parameter between phenols and tung oil).     

In Situ Observation of Zirconia Particles at 1200°C by High-Resolution Electron Microscopy

Zirconia (ZrO₂) particles (average diameter, 30 nm) were observed in an in situ heating experiment up to 1200°C using a 400-kV high-resolution electron microscope. Thermal vibration of atoms on a (001) surface plane was observed at 1100°C. At 1200°C, grain growth and sintering phenomena were recorded on a videotape, showing (100) lattice planes migrating on a surface of a particle. Direct observation of the sintering process on a lattice level was accomplished for the first time.     

Colorimetric microdetermination of sulphites in foods by use of the modified rankine apparatus. IV.

Summary Detection and determination of traces of sulphites in foods was attempted by use of the modified Rankine apparatus and pararosaniline colorimetry. Replacement of alkaline titration reported previously by pararosaniline colorimetry lowered the absolute detection limit from 30 g (titration method) to 2 g. In view of clean analysis, in the color developing system, 0.1 N-sodium hydroxide was used in place of mercuric chloride solution commonly used as an absorbant of sulphites. In order to prevent oxidative decomposition of sulphites during operation, nitrogen gas was used as carrier instead of air. Dimedone and sodium azide were used for the elimination of aldehydes and nitrites, respecitvely, in the sample, which will disturb the color development of sulphites with pararosaniline-formaldehyde reagents. With this improved method, it was possible to determine the residual sulphites in frozen peeled shrimps, sugared beans and other foods with low sulphite contents accurately.

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Colorimetrische Mikrobestimmung von Sulfiten in Lebensmitteln bei Anwendung der modifizierten IV. Rankine Apparatur

Zusammenfassung Geringe Sulfitmengen in Lebensmitteln (geschälte Garnelen, gezuckerte Bohnen) können colorimetrisch bestimmt werden. Die neuentwickelte Methode beruht auf einer Kombination von colorimetrischer Bestimmung mittels p-Rosanilin und der Bestimmungsmethode nach Rankine. Auf diese Weise lassen sich Gehalte von 2 g noch genau bestimmen. Bei der Farbentwicklung wurde das giftige Quecksilbertetrachlorid durch 0.1 n-NaOH ersetzt, anstelle von Luft Stickstoff als Trägergas verwendet und somit eine Oxydation des Sulfits während der Bestimmung vermieden. Da Nitrit und Aldehyde die Farbentwicklung stören, wurde ihr Einfluß durch Dimedon und Natriumazid ausgeschaltet.

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Studies on the Analyses of Sulphites in Foods (IV)     

Establishment of a modified rankine method for the separate determination of free and combined sulphites in foods. III

Summary Considerable improvements were made to the original Rankine method. Replacement of aspiration with an injection system contributed a great deal to the simplification of procedure, being accompanied with an increase in reproducibility. Air (flow rate 1.01/min) was used for injection because the use of inert gas gave little increase in recovery rate.Sodium bisulphite (free sulphite) and three kinds of combined sulphite compound (bisulphite adducts of acetaldehyde, pyruvic acid and D-mannose) were used to find the most suitable conditions for the separate determination of free and combine sulphites.Free sulphite was expelled from the sample by bubbling at 0 °C for 30 min. It was confirmed that no combined sulphite was dissociated under these conditions. The phosphoric acid concentration had an important role in the liberation of sulphite. When 25% phosphoric acid was used, more than 99% of free sulphite was expelled by cold bubbling and more than 99% of combined sulphite was recovered by heating afterwards for 10 min.The scope of the modified Rankine method was also extended to the determination of sulphite in concentrated orange juice.

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Verwendung der modifizierten Rankine-Methode zur getrennten Bestimmung von Sulfiten in Lebensmitteln. III

Zusammenfassung Die Rankine-Methode wurde bedeutend verbessert. Ein Umtausch der Aspiration mit Blasensystem trug beträchtlich zur Vereinfachung des Bestimmungsverfahrens bei, und die Reproduzierbarkeit wurde verbessert. Luft (Fließrate 1,01/min) wurde als Blasengas benutzt, da der Gebrauch von Inertgas für die Wiederfindungsrate unbedeutend ist.Natriumhydrogensulfit (freies Sulfit) und drei Arten gebundener Sulfite (Acetaldehydhydrogensulfit, Pyruvathydrogensulfit undd-Mannosehydrogensulfit) dienten dazu, die geeignetsten Bedingungen für die getrennte Bestimmung der freien und gebundenen Sulfite zu ermitteln.Freies Sulfit wurde bei 0 °C durch 30 min Durchblasen vertrieben. Hierbei ging kein gebundenes Sulîit verloren. Die Phosphorsäurekonzentration war wichtig für die Freisetzung des Sulfites. Wenn man 25%ige Phosphorsäure verwendet, werden > 99% freien Sulfites beim Durchblasen in der Kälte vertrieben, während > 99% gebundenen Sulfites durch nachheriges 10 min langes Erhitzen wiedergewonnen werden.Die modifizierte Rankine-Methode wurde weiterhin für konzentrierte Säfte verwendet.

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Studies on the Analyses of Sulphites in Foods (III)     

Correlation of reactivity to hydrogenation and chemical structure of lignites

Three North Dakota lignites with almost the same percentage carbon have been used to determine the relation between chemical structure and reactivity to hydrogenation. Average structural indices of the lignites were estimated using the pyridine-soluble products after alcohol-alkali treatment, the structural indices obtained at various reaction times being extrapolated to zero reaction time. Hydrogenation was influenced by the average structure, with the lignite having higher aromaticity, higher molecular weight of the pyridine extract from the alcohol-alkali reaction product, larger aromatic ring size and lower content of aliphatic structure, showing a smaller degree of conversion.     

Determination and confirmation of five phenolic antioxidants in foods by LC/MS and GC/MS

Identification and determination of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), nordihydroguaiaretic acid (NDGA), propyl gallate (PG) and tert-butylhydroquinone (TBHQ) by means of LC/MS and GC/MS were examined. These five phenolic antioxidants were detected as their pseudo-molecular ions [M-H]- by LC/MS using a Shim-pack FC-ODS column with drying gas. Moreover, BHA, BHT and TBHQ were detected based on their mass fragment ions by GC/MS. Decomposition of TBHQ, NDGA and PG during analysis could be prevented by the addition of L-ascorbic acid (AsA) to the extraction solvent. All five antioxidants were extracted from nikuman, olive oils, peanut butter, pasta sauce and chewing gum with a mixture of acetonitrile-2-propanol-ethanol (2:1:1) containing 0.1% AsA (AsA mixture), which had been cooled in a freezer and filtered. One part filtrate and 5 parts water were mixed and placed on a Mega-Bond Elut C18 cartridge, except in the case of chewing gum. Lipids in foods were removed on a C18 cartridge by washing with 5 mL of 5% acetic acid, and antioxidants were eluted with 5 mL of AsA mixture. The antioxidants spiked into nikuman, olive oil, peanut butter, pasta sauce and chewing gum were successfully identified and their concentrations determined by LC/MS, and GC/MS with good recoveries.     

Tan δ of ethylene-propylene rubber in cryogenic temperature region–effects of additives and sample thickness

The authors have been developing extruded polymer insulated superconducting power cables. Dielectric loss in electrical insulation cannot be ignored in superconducting cables since conductor loss in the cables is minimal. Studies so far show that ethylene-propylene rubber (EPR) is suitable as an electrical insulating material in the extruded polymer insulated superconducting cable design because it demonstrates excellent mechanical and relatively good electrical qualities at a cryogenic temperature. Widely used EPR includes some kinds of additives; however, their effect on tan δ of EPR at cryogenic temperature remains unknown. The effect of additives such as crosslinking agent and fillers on tan δ of EPR was examined at temperatures of between 4.2 K and 300 K. Thickness dependence of tan δ was also measured using EPR films of different thickness and an extruded EPR insulated cable sample. The results show that additives increase tan δ of relatively thin films of EPR even in the cryogenic temperature region; however, they do not have an intolerable dielectric loss in comparison with conductor loss and heat inflow of the superconducting cable. The remedy to tan δ increase due to the polymer contraction relative to shielding wires has been established.     

Theoretical concentration of solar radiation by central receiver systems

Solar concentrations by central receiver systems have been calculated theoretically for various values of obliquity of the incident radiation, assuming that plane heliostat-mirrors, sufficiently small in dimension, cover a circular field without clearance. Through this calculation, the performance characteristics of this system such as the availability of the radiant energy incident on the heliostat-field, the distribution of interruption by an adjacent mirror, the optimum rim-angle for the mean area- and the mean volume-concentration and the attainable temperature were revealed. The study was extended towards the practical problem of decreasing the number of heliostats by increasing the dimensions of heliostat-mirrors, and the effect of increasing mirror-dimensions was argued for both plane and curved mirrors.