Transesterification of vegetable oil to biodiesel fuel using acid catalysts in the presence of dimethyl ether

The immiscibility of methanol and vegetable oil leads to a mass-transfer resistance in the transesterification of vegetable oil. To overcome this problem, dimethyl ether (DME) was used as an environmentally friendly cosolvent to produce a homogeneous solution. Methylesterifications of corn oil in both the presence and the absence of DME were performed using p-toluenesulfonic acid (PTSA), benzenesulfonic acid and sulfuric acid. PTSA showed highest catalytic activity. The yield of FAME reached 97.1% when 4 wt% of PTSA based on the oil weight was used at 80 °C with a reaction time of 2 h in the presence of DME. The obtained biodiesel was composed of methyl palmitate (9.1 wt%), methyl oleate (33.9 wt%), methyl linoleate (53.5 wt%), methyl linolenate (3.0 wt%) and methyl arachidate (0.5 wt%), and it was similar to the biodiesel compositions from corn oil as reported. The effects of concentrations of FFA and water on FAME yields were also investigated. All results suggested that the reaction rate was greatly improved by the addition of DME to the reaction system.     

利用同步辐射进行氟塑料的表面改性与微器件制造研究

It is well-known that fluorinated polymers are very unique polymer materials because of their distinguished properties, such as high electrical resistivities, chemical and thermal stabilities, bio-compatibilities, etc. However,polytetrafluoroethylene (PTFE) is degraded by ionizing radiation with a low dose through main chain scission, and the mechanical properties are seriously deteriorated. In early 1990's, it was found that irradiation for PTFE at elevating temperature enhances recombination of radicals induced by ionizing radiation. Thus, crosslinked PTFE had been obtained[1,2]. The crosslinked PTFE shows remarkable improvements for the radiation durability and mechanical properties, etc.We have performed micro-fabrication by means of synchrotron radiation (SR) for various kinds of PTFEs including crosslinked PTFEs. The direct photo--etching technique using SR is known as TIEGA() technology,which has been developed by Sumitomo Heavy Industries, Ltd. The technology was applied for the micro-fabrication of fluorinated polymers. It has been found that etching rates obtained for crosslinked PTFEs were much larger than those of the non-crosslinked. The fact is strange from the viewpoint of radiation durability of crosslinked PTFEs. Hence, the results are not described by simple consideration such as the G-values of main chain scission. We have proposed that the etching rates should be controlled by the complex mechanism through at least two different steps as polymer decomposition and fragment desorption mechanisms.On the other hand, we have found that abnormal reactions were induced at the surface region under the SR etching for the various kinds of fluorinated polymers. Through the measurements using differential scanning calorimetory (DSC) and solid state 19F-NMR, we have confirmed crosslinking reactions for the polymers even in solid states. This reaction should be induced by the very high density radicals formation and their recombination in very localized area of the polymers under the SR etching processes.     

Evaluation of effects of hydroquinone on pigmentation by spectroscopy image analysis

Generally, depigmentation efficacy is evaluated by analyzing the L* value of skin to which the objective agent has been applied. However, in this method, slight inflammation and blood circulation affect the brightness, and then disturb the evaluation. So novel method that is able to quantitate melanin coloration accurately has been required. In this report, we modified the image-processing method that was devised by Takiwaki et al . Our method can evaluate pigmentation degree and area quantitatively. Using this method, we evaluated the availability of hydroquinone agent, which has high whitening effectiveness clinically; in addition, we examined the validity of this method.     

Regional trend and tissue distribution of brominated flame retardants and persistent organochlorines in raccoon dogs (Nyctereutes procyonoides) from Japan

The present study investigated concentrations and patterns of brominated flame retardants, such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs), and persistent organochlorines (OCs) in liver and adipose tissues of raccoon dogs (RD: Nyctereutes procyonoides) collected from two metropolises and a local prefecture in Japan during 2001-2006. Relatively high concentrations of PBDEs were found in RD livers, while HBCD levels were the lowest among the measured organohalogen compounds. Among PBDE congeners, BDE 209 was predominant in RDs from all the regions, indicating that pollution derived from the technical decaBDE product is extensive across Japan. On the other hand, concentrations of tetra- to nona-BDE congeners in RDs from a metropolis were significantly higher than those from the other two regions, implying that there were regional differences in the past usage of the technical tetraBDE and octaBDE products. Such a regional difference was also observed for HBCD levels. Lipid-normalized concentration ratios of liver to adipose tissue (L/A ratio) for tri to hepta-BDE congeners were lower than 1.0 in the investigated eight RDs, suggesting lipid-dependent accumulation. However, the LA ratios of BDE 209 exceeded 1.0 in all the specimens, suggesting hepatic retention of this compound. In addition, lipid-dependent accumulation of a-HBCD was observed, but the L/A ratios of gamma-HBCD were greater than 1.0 in some specimens. These results indicate that Japanese RDs have been recently exposed to BDE 209 and gamma-HBCD and accumulated both these compounds preferentially in blood-rich organs, probably due to their binding to proteins and/or rapid biotransformation, as reported in experimental rodents.     

Biochemistry and regulation of a novel Escherichia coli K-12 porin protein, OmpG, which produces unusually large channels

A novel porin, OmpG, is produced in response to a chromosomal mutation termed cog-192. Molecular characterization of cog-192 revealed that it is a large chromosomal deletion extending from the 3' end of pspA through to the 5' end of an open reading frame located immediately upstream of ompG. As a result of this 13.1-kb deletion, the expression of ompG was placed under the control of the pspA promoter. Characterization of OmpG revealed that it is quite different from other porins. Proteoliposome swelling assays showed that OmpG channels were much larger than those of the OmpF and OmpC porins, with an estimated limited diameter of about 2 nm. The channel lacked any obvious solute specificity. The folding model of OmpG suggests that it is the first 16-stranded beta-barrel porin that lacks the large external loop, L3, which constricts the channels of other nonspecific and specific porins. Consistent with the folding model, circular dichroism showed that OmpG contains largely a beta-sheet structure. In contrast to other Escherichia coli porins, there is no evidence that OmpG exists as stable oligomers. Although ompG DNA was present in all E. coli strains examined so far, its expression under laboratory conditions was seen only due to rare chromosomal mutations. Curiously, OmpG was constitutively expressed, albeit at low levels, in Salmonella, Shigella, and Pseudomonas species.     

Photocatalytic behavior of TiO2 nanoparticles supported on porous aluminosilicate surface modified by cationic surfactant

In order to utilize the photocatalytic function of TiO₂ nanoparticles in materials manufactured from organic polymeric compounds, such as paper, resins, and textiles, TiO₂ nanoparticles supported on aluminosilicate, which contained 1, 5, and 10 wt% of TiO₂ were prepared by mixing commercial TiO₂ nanoparticles and porous aluminosilicate at pH 7 in a cationic surfactant aqueous solution. Most of the supported TiO₂ nanoparticles on the aluminosilicate surface were observed by TEM–EDS (energy depressive X-ray spectroscopy) analysis. TiO₂ nanoparticles supported on aluminosilicate reduced the formaldehyde concentration from 20 to 0 ppm after UV irradiation for 20 h; the reduction of formaldehyde concentration under UV irradiation was obviously different from that in the dark. Moreover, a paper mixed with 20 wt% of TiO₂ nanoparticles supported on aluminosilicate bleached the stains colored with cigarette tar after UV irradiation for 6 h. However, the paper maintained its initial tensile strength even after UV irradiation for 1 year; in contrast, the paper mixed with a simple dry mixture of TiO₂ powder and aluminosilicate lost approximately half of its initial tensile strength after a year. TiO₂ nanoparticles supported on aluminosilicate could exhibit photocatalytic activity without decomposing the organic polymeric compounds.     

Acyclic and incompletely cyclized triterpene alcohols in the seed oils of theaceae and Gramineae

The triterpene alcohol constituents of the non-saponifiable lipids of two Theaceae seed oils, sasanqua and camellia oils, and two Gramineae seed oils, wheat germ and rice bran oils, were investigated. This led to the isolation and characterization of one acyclic and eight incompletely cyclized triterpene alcohols. They are camelliol A, camelliol B, camelliol C, achilleol A, helianol, isohelianol, sasanquol, graminol A [(13R, 14R)-3,4-seco-25(10→9)abeo-8α,9β,10α-podioda-4,17,21-trien-3-ol], and (2Z,6Z,10Z,14E,18E)-farnesylfarnesol. Two other compounds isolated were characterized as (2Z,6Z,10E,14E)-geranylfarnesol, a sesterterpene alcohol, and phytol, a diterpene alcohol. Graminol A and (2Z,6Z,10E,14E)-geranylfarnesol are considered to be new natural products. Based on a paper presented at the symposium, “Chemistry, Biochemistry, and Function of Sterols,” AOCS Annual Meeting & Expo, Orlando, FL, May 1999.