Gas chromatographic analysis for alpha-olefin sulfonate

The separation and determination of alkene sulfonate and hydroxyalkane sulfonate, and the carbon chain distribution of the lipophilic groups of long chain alpha-olefin sulfonates (C₁₄ to C₁₈) were studied by means of gas chromatography. Samples were hydrogenated initially, and converted to sulfonyl chlorides for gas chromatographic analysis. Using a glass column, 4 mm i.d. and 2.5 m long, packed with Silicon SE-30, 3% on 60 to 80 mesh Chromosorb WAW treated with hexamethyldisilazane, a 0.3 to 0.6 μl sample, as 10% carbon tetrachloride solution, was injected directly on the column, and alkane and monochloroalkane sulfonyl chloride were determined as alkyl chloride and alkyl dichloride, respectively. Minimization of further decomposition, improvement of peak separation and reproducibility were accomplished by this procedure. The method was applied to alpha-olefin sulfonates produced commercially from C₁₄ to C₁₈ alpha-olefins.     

Preparation of positive photoreactive polyimides and their characterization

Polyimide precursors were synthesized from a diamine and a diacid chloride that was derived from the reactant with promellitic dianhydride and o-nitrobenzyl alcohol. Their thermal properties were studied in nitrogen using dynamic thermogravimetry, and the photoreaction mechanism was investigated by ultraviolet and infrared spectrophotometry. The polyimide precursors were spin-coated onto silicon wafers, prebaked, and then exposed to UV light from a high pressure Hg–Xe lamp. When the films were dipped into 2% aqueous KOH after irradiation, the exposed area dissolved forming high resolution patterns. Relative sensitivities of the polymers were determined.     

Characterization of Particle Packing in an Injected Molded Green Body

The particle packing structure of alumina green bodies made by injection molding has been examined with the liquid immersion technique coupled with a polarized light microscope. In this method, the specimen is made transparent by an immersion liquid and is examined in the transmission mode. Fine particles of near-equiaxed alumina powder are found to be aligned, with their slightly elongated axis parallel to the flow direction of the molding process. The presence of very large alumina particles was also noted. Their concentraton was extremely low and can be detected only by the present method. The origins and significance of particle orientaton and large particles in ceramic processing are discussed.     

Diurnal variations in H2O2, O3, PAN, HNO3 and aldehyde concentrations and NO/NO2 ratios at Rishiri Island, Japan: potential influence from iodine chemistry

The presence of iodine chemistry, hypothesized due to the overprediction of HO(2) levels by a photochemical box model at Rishiri Island in June 2000, was quantitatively tested against the observed NO/NO(2) ratios and the net production rates of ozone. The observed NO/NO(2) ratios were reproduced reasonably well by considering the conversion of NO to NO(2) by IO, whose amount was calculated so as to reproduce the observed HO(2) levels. However, the net production rates of ozone were calculated to be negative when such high mixing ratios of IO were considered, which was inconsistent with the observed buildup of ozone during daytime. These results suggest that iodine chemistry may not be the sole mechanism for the reduced mixing ratios of HO(2), or that "hot spots" for iodine chemistry were present. Diurnal variations in the mixing ratios of HCHO, CH(3)CHO, peroxy acetyl nitrate (PAN) and HNO(3) observed during the study are presented along with the simulated ones. The box model simulations suggest that the effect of iodine chemistry on these concentrations is small and that important sources of CH(3)CHO and sinks of PAN are probably missing from our current understanding of the tropospheric chemistry mechanism.     

Effect of the introduction of tetrachloromethane into the feedstream for methane oxidation with oxygen and nitrous oxide on thermally stable strontium hydroxyapatites

Thermally stable strontium hydroxyapatite (SrHAp) was prepared with a variety of stoichiometries and employed as catalysts for the oxidation of methane with oxygen and nitrous oxide in the presence and absence of tetrachloromethane (TCM) as a gas‐phase additive. In contrast to the oxidation of methane on thermally unstable SrHAp, non‐selective oxidation to CO and CO₂ at 873 K proceeded with oxygen while the selectivity to CO increased with increasing time‐on‐stream in the presence of TCM and was higher than 90% at 6 h on‐stream, regardless of the Sr/P ratios in the catalysts. However, with nitrous oxide the selectivity to CO in the presence of TCM was strongly influenced by the Sr/P ratio with smaller values producing higher CO selectivity. In the presence of TCM, the catalyst consists of a complex mixture of the hydroxyapatite, the corresponding chlorapatite, phosphate, chloride and oxychloride, each of which contributes dissimilarly to the catalytic process. This revised version was published online in July 2006 with corrections to the Cover Date.     

Investigation of micro-phase separation of the additive,cyclotriphosphazene, in lubricant films of hard disk media

The micro-phase separation of the additive, cyclotriphosphazene (X-1P), in perfluoropolyether (PFPE) lubricant films on hard disk media was studied. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) indicated that the small spots appearing on the disk surface consisted predominantly of X-1P. Observation using an atomic force microscope (AFM) revealed the micro-phase separation process to be the sudden, continuous appearance of new spots some time after coating the film. Some spots grew over previous ones, while some spots dissolved. Finally, they stopped growing and the number of spots became saturated. The solubility of X-1P in the lubricant film increased in the order of ZDIAC, ZDOL2000, ZDOL4000 and Z03, and that in bulk lubricant increased in the order of Z03, ZDOL4000, ZDOL2000 and ZDIAC. The order of solubility of X-1P in the film did not correspond to that in the bulk.     

Synthesis of TiC<Subscript>x</Subscript> Powder via the Underwater Explosion of an Explosive

In this study, a novel approach to the explosive synthesis of titanium carbide (TiC) is discussed. Nonstoichiometric TiC_x powder was produced via the underwater explosion of a Ti powder encapsulated within a spherical explosive charge. The explosion process, bubble formation, and synthesis process were visualized using high-speed camera imaging. It was concluded that synthesis occurred within the detonation gas during the first expansion/contraction cycle of the bubble, which was accompanied by a strong emission of light. The recovered powders were studied using scanning electron microscopy and X-ray diffraction. Submicron particles were generated during the explosion. An increase in the carbon content of the starting powder resulted in an increase in the carbon content of the final product. No oxide byproducts were observed within the recovered powders.     

Enzyme electrode based on gold-plated polyester cloth

Summary Glucose oxidase is immobilized on gold-plated polyester cloth by entrapment method and coupled with an electron mediator, ferrocene derivative. Cyclic voltammogram depends on the existence of the substrate glucose and the flavo-enzyme was shown to donate electron(s) to the cloth electrode with mediation of the ferrocene derivative even in the immobilized state. The glucose-concentration dependence of the peak current was linear upto several tens of 35 mM, depending on the concentration of the mediator. Co-immobilization of polymer-anchored electron mediator is also studied.