Kaoru Masuda

Chromatographic characterization of preasphaltenes in liquefied products from Victorian brown coal

Gel permeation chromatography was applied to the measurement of molecular weight distribution of the preasphaltenes in liquefied products from Victorian brown coal. When polar solvents such as N-methyl-2-pyrrolidone were used as elution solvents, two major peaks were separately observed at different retention times, reflecting the polarity of their components. By applying a new calibration method to the polar and non-polar components in the preasphaltenes, using a novolak phenol resin and polystyrenes respectively, the molecular weights of both components were estimated to be distributed around 103. According to the present evaluation, a high liquefaction temperature was found to be effective in reducing the polar components in the preasphaltenes.

High-temperature n.m.r. analysis of aromatic units in asphaltenes and preasphaltenes derived from Victorian brown coal

Average aromatic structures of asphaltenes and preasphaltenes in liquefied products of Victorian brown coal were investigated using high-temperature n.m.r. analysis. By applying gated decoupling and the DEPT pulse sequence, aromatic carbons in the samples were fractionated into protonated and quaternary carbons, the latter of which were further fractionated into outer and inner quaternary carbons. By comparing the numbers of fractionated aromatic carbons with those of model aromatic compounds, the differences in the aromatic structures of the asphaltenes and preasphaltenes are discussed.

Fused state/sup 13/C-NMR study on liquid crystalline polyacutylene derivatives - magnetically forced alignment and orientational behavior

Summary form only given. Magnetically forced alignments and orientational behaviors of a series of side-chain liquid crystalline polymers, poly(mono-substituted acetylenes), as well as a liquid crystalline mononux, have been investigated through the fused-state/sup 13/C NMR measurements with proton dipolar decoupling. Upon a phase transition from isotropic to nematic or smectic phase, aromatic carbon signals notably shifted to the lower magnetic field, whereas aliphatic carbon signals slightly shifted to the higher magnetic field. This indicates that in the nematic or smectic phase, the side chain liquid crystal group is preferentially aligned along the direction of magnetic field. Analyses of chemical shift tensors are also carried out to evaluate an order parameter and shieldbig anisotropy in liquid crystalline phase, As a result, we have demonstrated that the liquid crystalline conjugated polymers are uniaxially aligned due to the magnetically forced alignment of the liquid crystalline side-chain, giving rise to a mono-domain structure.

Solvent de-ashing from heavy product of brown coal liquefaction using toluene 1. Solubility of heavy products and settling velocity of ash

The Brown Coal Liquefaction (BCL) process is a two-stage liquefaction (hydrogenation) process developed for Victorian brown coal in Australia. In the BCL process, the heavy product (vacuum residue) derived from the coal in the primary hydrogenation, which is named CLB (coal liquid bottom, boiling point > 420°C), is treated in a solvent (CLB/solvent ratio, 18–14, wt./wt.) under high temperature (200–290°C) and high pressure (4–5 MPa) to remove the ash and heavy preasphaltenes. This solvent de-ashing process uses toluene or coal-derived naphtha as a de-ashing solvent. After dissolving the CLB into the solvent, insoluble solid particles which consist of the ash and heavy preasphaltenes are settled in a settler by gravity and separated from the solution as an ash-concentrated slurry. The ash-concentrated slurry and the de-ashed solution are withdrawn from the settler as an underflow and overflow, respectively. The de-ashing solvent is recovered from both the overflow and underflow by distillation, and reused in the de-ashing process. The de-ashed heavy product recovered from the solution by eliminating the solvent is further hydrogenated in the secondary hydrogenation. n nThis paper discusses the solubility of the CLB into toluene and settling velocity of the ash under the de-ashing conditions. The extraction experiments made clear that toluene dissolved ∼ 60 wt.% of preasphaltenes (benzene insoluble-pyridine solubles) in the CLB under the following conditions, temperature 100–300°C and CLB/toluene ratio (wt./wt.) of 13 or less. This solubility of CLB (ϵCLB) under the de-ashing conditions is expressed as ϵCLB = CBS + 0.6CBIorg, where CBS and CBIorg are the contents of benzene solubles and organic benzene insolubles, respectively, and organic CLB (ash-free CLB) = CBS + CBIorg. The de-ashing experiments confirmed that the insolubles including ash formed a boundary of concentration during the settling period, and the de-ashing efficiency was represented by the settling velocity of the boundary (V), V is expressed as V = ACLB(CSA/2.5)−0.91(T/573)9.5. Where, ACLB, CSAand T are parameters expressing the properties of organic CLB, ash content in the feed slurry (wt.%) and temperature (K), respectively. The ACLB is also expressed by using the analytical results of the organic insolubles in the CLB under the de-ashing conditions. The ash content of the de-ashed heavy product recovered from the upper zone of the boundary is less than 3000 ppm, which is low enough to feed as a mixture with two times of the middle distillate to the secondary hydrogenation over Niue5f8Mo catalyst with fixed bed reactors.

Orientation analysis of polyacetylene with liquid crystalline side chains

Abstract Polyacetylene substituted by liquid crystalline side chains and its monomer were characterized by 13 C NMR spectroscopy in order to investigate their orientation and dynamics in the liquid crystalline state. Anisotropic chemical shifts of phenylene carbons, acetylene carbons and ethylene carbons were analysed. In both the monomer and the polymer, phenylene carbons showed downfield chemical shifts indicating their orientation to the magnetic field. On the other hand, by comparing observed chemical shifts and theoretical ones, acetylene carbons in the monomer were found to move freely in the liquid crystalline state. For the polymer, the dynamics of ethylene carbons (polyacetylene backbones) was interpreted in terms of a swing model, while that of side-chain phenylene carbons was explained as a swing model synchronized with the main chain accompanied by rotation around the director. These results directly reveal the scheme of the alignment of the main chain induced by the side chain orientation, and also suggest that the polymer structure is constructed by head-to-head or tail-to-tail type connection of monomers.

Preparation of high aspect ratio 70 nm patterns by supercritical drying technique in proximity x-ray lithography

Supercritical drying (sc-drying) was applied for the photoresist (resist) patterns replicated by proximity x-ray lithography. By that technique, 70 nm L/S patterns with the aspect ratio of 5 were successfully obtained without pattern collapse for both solvent and aqueous development resists by ZEP and UV6, respectively. The procedure was that a puddle developed 8 inch wafer was rinsed 3 times successively without spin drying by changing rinse liquids, and the wafer wet with the 3rd rinse solution which is soluble in supercritical CO2 was transferred to a sc-drying chamber. The sc-drying process was performed with a condition of 8 MPa and 55 degrees C for about 15 min. The process uniformity within a wafer was examined by measuring the pattern width of 100 nm L/S with the resist UVII-HS and it was quite satisfactory. The feasibility study of dry etching with the sc-dried resist was performed. No noticeable change was found in etching ratio between with/without sc-dried resist. The composition change of resist was also investigated by thermal desorption spectroscopy (TDS) and by molecular weight dispersion measurement, and no change was found after sc-drying. The sc-drying technique has high potential to be accepted in semiconductor device manufacturing process.

Reduction of Hydrocarbon Impurities in 200 L/H Helium Liquefier-Refrigerator System

A cryogenic system with the capacity of 200 l/h or 500 W at 4.4 K has been operated to develop the superconducting conductors and coils for the LHD. The system has contributed in various superconducting technologies along with the dc 75kA power supply and 10 MN mechanical testing machine, and completed the basic R&D works of the LHD. While operating the cryogenic system, impurity densities of hydrocarbon gases in circulating helium gas became much larger than expected for this cryogenic system. The densities of some impurity gases were carefully monitored in reference to the operational conditions of the circulating compressor by using gas chromatography. Impurity gas densities of oxygen, nitrogen and ethane increased observably, when the output capacity of the compressor was reduced. In a two-stage oil injected compression system with a variable stroke mechanism for a first stage, a reduction in the capacity of the first stage leads to a larger compression ratio for the second stage, and the temperature of the injected oil increases. The production of the impurities in the helium might be caused by cracking a part of the injected oil in the compressor. The compressor, therefore, was reconstructed such that sufficient injection oil is supplied and the compression ratio division becomes even. It was confirmed that the impurities are not produced after modification.