• Journal of Photoscience
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• v.10 no.2
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• pp.181-184
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• 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
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• v.18 no.11
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• pp.1192-1195
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• 1997

A divergent approach to 2-(hydroxymethyl)pyrrolidine-3,4-diols has been studied with 1,4-dideoxy-1,4-imino-D-arabinitol (D-AB1), a potent glycosidase inhibitor. D-AB1 was efficiently synthesized from 2,3-epoxyalcohol 6a in overall 11% yield.

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

• Bulletin of the Korean Chemical Society
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• v.17 no.4
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• pp.362-365
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• 1996

Carbonyl compounds 1, alkyl- and arylaldehydes and alkyl, aryl, benzylic, and cyclic ketones were converted to the corresponding 1,3-dioxolanes 2 and 1,3-dioxanes 4 with ethylene glycol and 2,2-dimethyl-1,3-propanediol in the presence of 1-3 mol% of 1-(p-substituted)benzyl-1,1-dimethyl-2-(p-substituted)-benzoyl hydrazinium hexafluoroantimonates 3 in high yields.

• Macromolecular Research
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• v.12 no.4
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• pp.359-366
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• 2004

The polysaccharide, (1\longrightarrow5)-$\alpha$-D-ribofuranan, was synthesized by a cationic ring-opening polymerization of 1,4-anhydro-2,3-di-O-benzyl-$\alpha$-D-ribopyranose with the aid of boron trifluoride etherate and subsequent debenzylation. This polysaccharide catalyzed the hydrolysis of ethyl p-nitrophenyl phosphate, uridylyl(3'\longrightarrow5')uridine ammonium salt, and 4-tert-butylcatechol cyclic phosphate N-methyl pyridinium. The polymer also catalyzed the cleavage of nucleic acids (DNA and RNA). The hydrolysis of ethyl p-nitrophenyl phosphate in the presence of the polymer was accelerated by 1.5 ${\times}$ 10$^3$ times relative to the uncatalyzed reaction. The catalytic activity was attributable to the vic-cis-diols of the riboses being located inside the active center that is formed by polymer chain folding; these diols form hydrogen bonds with two phosphoryl oxygen atoms of the phosphates so as to activate the phosphorus atoms to be attacked by nucleophile ($H_2O$).

• Journal of the Korean Chemical Society
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• v.37 no.2
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• pp.244-248
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• 1993

Nitroalcohols were prepared by a substitution reaction from the corresponding bromoalcohols. The second nitro group was introduced via different methods depending on the carbon chain length. 3,3-Dinitro-1-propanol was obtained by an intramolecular varient of the alkaline nitration method. Whereas 5,5-dinitro-1-pentanol was given by the catalytic oxidative nitration. 3,3-Dinitro-1-propanol and 5,5-dinitro-1-pentanol were converted to 3,3-dinitro-1,6-hexanediol and 4,4-dinitro-1,8-octanediol via Michael reaction with acrolein followed by the reduction of the resulting aldehydes. Acetyl group was a good protecting group for the substitution reaction while THP was for the catalytic oxidative nitration.

• Journal of the Korean Society of Tobacco Science
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• v.24 no.2
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• pp.75-81
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• 2002

This study was performed to investigate the influence of curing conditions on the composition of essential oil during curing process of burley tobacco leaves. The curing conditions were the primed curing in vinyl house (house-curing), air-curing barn (air-curing) and stalk-curing in conventional curing house (stalk-curing). Total 90 compounds are identified from the steam volatile oils of harvest and cured tobacco leaves by GC and GC-MS, respectively. The major components were neophytadiene, hexadecanoic acid, 3,8,13-duvatriene-1,5-diols, oxide-9-methylene-3,13-duvadienols, solanone, megastigma-4,6,8-trien-3-ones, phenylacetaldehyde, $\beta$-phenylethyl alcohol, indole, dihydroactinidiolide and phytol. The amount of alcoholic compounds was decreased more than approximately 50% in cured leaves without regard to the curing conditions. $\beta$-Phenylethyl alcohol and 3,8,13-duvatriene-1,5-diols were decreased more in air curing and stalk curing than in house curing. The amounts of phenylacetaldehyde, solanone, $\beta$-damascone, $\beta$ -damascenone, oxysolanone and megastigma-4,6,8-trien-3-ones as ketonic compounds, dihydroactinidiolide and indole as miscellaneous compounds in air-cured and stalk-cured tobacco leaves were 2 times higher than those in house-cured leaves, while esteric and acidic compounds were not changed largely in content by curing conditions.

• Bulletin of the Korean Chemical Society
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• v.8 no.6
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• pp.466-470
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• 1987

Di-2-pyridyl thionocarbonate, prepared from thiophosgene and 2-hydroxypyridine in the presence of triethylamine in dichloromethane, was found to be very effective for dehydration, dehydrosulfurization, and thiocarbonyl transfer reactions. Di-2-pyridyl thionocarbonate was successfully for the esterification of carboxylic acids, dehydration of aldoximes into nitriles, preparation of isothiocyanates from amines, and preparation of cyclic thionocarbonates from 1,2- and 1,3-diols.

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

• Polymer(Korea)
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• v.35 no.6
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• pp.526-530
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• 2011

Furan-2,5-dicarboxylic acid (FDCA) was synthesized by $KMnO_4$ oxidation of 2,5-dihydroxymethylfuran(DHMF) derived from biomass. Polyesters were synthesized by esterification and polycondensation of FDCA with various diols(ethane-1,2-diol, propane-1,3-diol, butane-1,4-diol, hexane-1,6-diol, decane-1,10-diol). The composition of polyesters was characterized by using $^1H$ NMR. Thermal properties of the polyesters were characterized by DSC and TGA. Intrinsic viscosities(IV) of the polyesters were measured to be 0.78~1.2 dL/g comparable with IV of commercial poly(ethylene terephthalate)(PET). As the chain lengths of diols increased, Young's modulus and strength decreased and elongation-to-break generally increased. Young's modulus and strength of the polyesters were measured to be 3551 MPa and 103 MPa, respectively, comparable with commercial PET.