• Bulletin of the Korean Chemical Society
• /
• v.18 no.3
• /
• pp.263-264
• /
• 1997

• Journal of Photoscience
• /
• v.10 no.2
• /
• pp.181-184
• /
• 2003

Photochemical reactions of some organic molecules on titanium dioxide were investigated in methanol. A methanolic solution of trans-cinnamic acid and titanium dioxide was irradiated with 300 nm UV lamps for 24 h to afford methyl cinnamate. In the case of trans-cinnamamide, the major product was found to be 3-phenylpropionamide, i.e., a saturation product of ethylenic double bond. However, irradiation of urocanic acid, caffeic acid, ethyl cinnamate, trans-chalcone, trans-cinnamonitrile, trans-stilbene or trans, trans-1,4-diphenyl-1,3-butadiene on titanium dioxide under the same conditions did not give any noticeable products. Meanwhile, when irradiated some aromatic aldehydes, such as trans-cinnamaldehyde, l-naphthaldehyde, and 2-naphthaldehyde in methanol, vicinal diols and alcohols derived from the diols were produced. On the other hand, irradiation of 9-anthraldehyde and titanium dioxide in methanol afforded only alcohols, in which diol was not observed.

• Bulletin of the Korean Chemical Society
• /
• v.26 no.9
• /
• pp.1434-1436
• /
• 2005

• Bulletin of the Korean Chemical Society
• /
• v.11 no.1
• /
• pp.45-49
• /
• 1990

${\alpha},{\omega}$-Diols react with secondary amines in the presence of a catalytic amount of ruthenium catalyst at $180^{\circ}C$ to give diamino compounds in good to excellent yields. The yield of diamino compound was affected by the molar ratio of ${\alpha},{\omega}$-diol to secondary amine. The reaction is affected by the nature of the phosphorus ligands employed and the effectiveness of the added ligand is completely different depending on the chain length of the ${\alpha},{\omega}$-diol. The reaction between ethylene glycol and primary amine in the presence of a catalytic amount of ruthenium catalyst gave 1,4-disubstituted piperazine.

• Bulletin of the Korean Chemical Society
• /
• v.19 no.6
• /
• pp.680-685
• /
• 1998

Two kinds of new aliphatic diols were synthesized by the ring-opening reaction of lactide and glycolide with 1,4-butanediol, a difunctional initiator, in the presence of stannous octoate. The resulting aliphatic diols were melt-polymerized with D-tartaric acid at 150 ℃ to produce new crosslinkable polyesters. They were reacted with hexamethylene diisocyanate in THF at 65 ℃ in a teflon mold for 24 h to prepare sequentially ordered crosslinked polyesters (BD/LT/GL/D-tartarate). Degradation of the prepared yellow crosslinked films was carried out in a buffer solution in order to examine the effect of time, pH, temperature and crosslinking degree on their degradation rate and mechanism. The rate of degradation increased with an increase in pH and temperature, but it decreased with increasing degree of crosslinkage incorporated into the crosslinked polyesters. We also found that the crosslinked polymers were converted into the acidic compounds such as lactic, glycolic, and D-tartaric acids during the degradation.

• Bulletin of the Korean Chemical Society
• /
• v.6 no.6
• /
• pp.378-378
• /
• 1985

• Proceedings of the PSK Conference
• /
• 2002.04a
• /
• pp.182.2-182.2
• /
• 2002

• Proceedings of the PSK Conference
• /
• 2002.04a
• /
• pp.184.1-184.1
• /
• 2002

• Fibers and Polymers
• /
• v.2 no.3
• /
• pp.122-128
• /
• 2001

UV-curable polyurethane acrylate prepolymers were prepared from diisocyanates [isophorone diisocyanate (IPDI), 2,4-toluene diisocyanate (TDI), or 4,4'-dicyclohexylmethane diisocyanate (H$_{12}$MDI)], diols [ethylene glycol (EG), 1,4-butane diol (BD), or 1,6-hexane diol (HD)], polypropylene glycol as a polyol. UY-curable mixtures were formulated from the prepolymer (90 wt%), reactive diluent monomer trimethylol propane triacrylate (10 wt%). and photoinitiator 1-hydroxycy-clohexyl ketone (3 wt% based on prepolymer/diluent). The effects of different diisocyanates/low molecular weigh dial on the dynamic mechanical thermal properties and elastic recovery of UV-cured polyurethane acrylate films were examined. The tensile storage modulus increased a little in the order of EG > BD > HD at the same diisocyanate. Two loss modulus peaks for all samples are observed owing to the glads transition of softs segments ($T_gh$) and the glass transition temperature of hard segments ($T_gh$). For the same diisocyanate, $T_gh$, decreased, however, $T_gh$ increased, in the order of HD > BD > EG. The elastic recovery also increased in the order of HD > BD > EG at the same diisocyanate. In case of same diols, $T_gh$ increased in the order of $H_12$MDl > TDI > IPDI significantly. The ultimate elongation and elastic recovery increased in the order of TDI > IPDI > $H_12$MDl at the same diol.l.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.41 no.6
• /
• pp.692-697
• /
• 1996

This experiment was conducted to determine the influences of growth stage, stalk position and growth environment on duvatrienediols(DVT-diols) and cis-abienol production in Nicotiana tabacum L. The leaves of plants at transplanting stage contained very small amount of duvatrienediols and cis-abienol. Comparing leaves on different stalk position at flowering stage, upper and middle leaves contained more DVT-diols and cis-abienol than lower leaves. Plants grown under controlled environmental room at 3$0^{\circ}C$ contained more DVT-diols and cis-abienols than room at 18$^{\circ}C$, $25^{\circ}C$ and glass room. Tobacco plant grown under field condition produced lower levels of duvatrienediols and cis-abienol contents than glass room-grown plants. The amounts of duvatrienediols and cis-abienol of tobacco leaves significantly decreased after rain under field conditions.