Oils with a high DAG (1,3-DAG) content have attracted considerable attention as a healthful food oil component. In this study, we report on the synthesis of 1,3-DAG from a mixture of FA, constituted largely of oleic and linoleic acids, using an immobilized 1,3-regioselective lipase from Rhizomucor miehei in a solvent-free system. The kinetics of 1,3-DAG production from FA and glycerol were investigated on the basis of a simplified model, taking into consideration the acyl migration reaction, the removal of water, and glycerol dissolution in the oil phase in addition to the esterification reactions. Both the yield of 1,3-DAG and the purity of DAG were evaluated under a variety of experimental conditions, including reaction temperature, pressure, and amount of enzyme present. When either the reaction temperature or the amount of enzyme used was increased, the 1,3-DAG production rate increased, but yield remained relatively constant. The 1,3-DAG yield as well as the purity of DAG gradually decreased because of the enhancement of acyl migration at later stages of the reaction after the 1,3-DAG concentration reached a maximum. Vacuum was important for attaining high yields of 1,3-DAG. Under conditions of a high vacuum (1 mm Hg) at 50°C, 1.09 M 1,3-DAG was produced from 1.29 M glycerol and 2.59 M FA in an 84% yield and in 90% purity.Rate constants k 1 = 7.50 × 10 −4 (L/mol/s) k 3 = 2.91 × 10 −4 (L/mol/s) k 5 = 7.85 × 10 −6 (1/s) k 7 = 1.84 × 10 −3 (L/mol/s) k 9 = 3.59 × 10 −4 (1/s) k 10 = 1.20 × 10 −2 (1/s)

Five-membered metallacyclic alkynes that have no substituents adjacent to the triple bond have been synthesized, isolated, and structurally characterized. Zirconocene dichlorides, Cp'2ZrCl2 (Cp' = C5H5, C5H4-t-Bu), reacted with 1,4-dichlorobut-2-yne in the presence of magnesium to give 1-zirconacyclopent-3-yne compounds (5 (a) Cp' = C5H5, (b) Cp' = C5H4-t-Bu) that have a -CH2CCCH2- moiety in good yields. They are stable enough to be isolated in a pure form, despite the absence of substituents. 5a reacted with an equimolar amount of Cp2Zr(but-1-ene)(PMe3) to produce a bimetallic complex in which the zirconacyclopentyne coordinates to the other zirconocene moiety as an alkyne.

We investigated the electrochemical lithium ion (Li(+)) insertion/desertion behavior on highly pure and bundled single- and double-walled carbon nanotubes (SWNTs and DWNTs) using an in situ Raman technique. In general, two storage sites could host Li(+) in SWNT and DWNT bundles when varying an external potential: a) the outer surface sites, and b) the interstitial spaces within the bundles. The most sensitive changes in the tangential mode (TM) of the Raman spectra upon doping with Li(+) can be divided into two regions. The first region was found from 2.8 to 1.0 V (the coverage of Li(+) on the outer surface of a bundled nanotube) and was characterized by the loss of resonant conditions via partial charge transfer, where the G(+) line of the SWNT and the TM of the outer tube of DWNTs experienced a highly depressed intensity, but remained almost constant in frequency. The appearance of a Breit-Wigner-Fano (BWF) profile provided strong evidence of metallic inner tubes within DWNTs. The second region was observed when the applied potentials ranged from 0.9 to 0 V and was characterized by Li(+) diffusion into the interstitial sites of the bundled nanotube material. This phenomenon invoked a large downshift of the G(-) band in SWNTs, and a small downshift of the TM of the inner tube of DWNTs caused by expansion of the C--C bonds due to the charge transferred to the nanotubes, and the disappearance of the BWF profile through the screening effect of the interstitial Li(+) layers.

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