• Clean Technology
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• v.11 no.4
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• pp.171-179
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• 2005

Biodiesel is synthesized by transesterification of vegetable or animal oils with alcohols. Since it has similar characteristic with diesel fuel, it can be used as a fuel by mixing with diesel fuel. Moreover, it is advantageous that biodiesel can reduce air pollution emitted from fuel combustion and is produced from sustainable energy, biomass. Recently, many researchers have investigated biodiesel synthesis using supercritical methanol since it is economical due to shorter reaction time and simple separation/purification process, compared with conventional alkali- or acid-catalyzed process. By the development of biodiesel production process from waste edible oil using supercritical methanol, it can be expected to utilize potential energy resources, reduce carbon dioxide emission, and improve environmental conditions.

• Bulletin of the Korean Chemical Society
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• v.30 no.2
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• pp.435-440
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• 2009

19 Aromatic ring and L-amino acid ester contained rupestonic acid amide derivatives 2a~2l, 3a~3g were synthesized and preliminarily evaluated in vitro against influenza virus $A_3$,B and herpes simplex virus type 1 (HSV-1), 2(HSV-2) by the national center for drug screening of China. The rusults showed that 2i possessed the highest inhibition against both influenza virus $A_3\;(TC_{50}\;=\;120.6\;{\mu}mol/L,\;IC_{50}=\;19.2\;{\mu}$mol/L, SI = 6.3) and B (T$C_{50}\;=\;120.6\;{\mu}mol/L,\;IC_{50}=\;29.9\;{\mu}$mol/L, SI = 4.0); 2g was more active against influenza $A_3$ virus at very low cytotoxicity ($TC_{50}\;>\;2092.1\;{\mu}mol/L,\;IC_{50}=\;143.7\;{\mu}mol/L,$ SI > 14.6) than the parent compound; Compounds 2b, 2c, 2f showed higher activities both against HSV-1 and HSV-2 than that of the parent compound, and 2f was the most potent inhibitor of HSV-1 ($TC_{50}\;=\;200.0\;{\mu}mol/L,\;IC_{50}\;=\;11.3\;{\mu}mol$/L, SI = 17.7 ) and HSV-2 ($TC_{50}\;=\;200.0\;{\mu}mol/L,\;IC_{50}\;=\;20.7\;{\mu}mol$/L , SI = 9.7).

• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1048-1056
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• 2018

Non-edible oil sources (i.e., Palm Acid Oil, waste animal fat) usually contain relatively high amount of free fatty acids (FFA) that make them inadequate for direct base catalyzed transesterification reaction. Enzymatic biodiesel synthesis can solve several problems posed by the alkaline-catalyzed transesterification, and has certain advantages over the chemical catalysis of transesterification, as it is less energy intensive, allows easy recovery of glycerol and the transesterification of glycerides with high free fatty acid contents. In this study, we synthesized biodiesel through enzymatic catalyzed process using high free fatty acid containing waste oil in biodiesel reactor (1 ton/day) and optimized the biodiesel production processes.

• Journal of Industrial Convergence
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• v.20 no.7
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• pp.131-137
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• 2022

In the study, we endeavored to assess the convergence effect of Silybum marianum-derived silymarin and epidemiologically-correlated alcohol intake on vascular contractility and to determine the mechanism involved. There were few reports addressing the question whether thin or thick filament modulation is included in ethanol and silymarin-induced regulation. We hypothesized that ethanol at a low concentration and silymarin play a role in agonist-dependent regulation of vascular contractility. Denuded arterial muscles of Sprague-Dawley male rats were suspended in organ baths and isometric tensions were transduced and recorded using isometric transducers and an automatic data acquisition system. Interestingly, both silymarin and ethanol didn't encourage silymarin alone-induced inhibition in agonists-induced contraction suggesting that endothelial nitric oxide synthesis might be involved in ethanol or silymarin-induced modulation of vascular contractility and additional pathways besides endothelial nitric oxide synthesis such as ROCK inactivation might be involved in the silymarin-induced modulation of vascular contractility.

• Macromolecular Research
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• v.8 no.1
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• pp.19-25
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• 2000

Aromatic diamine monomers containing allylic ester linkage, 1,5-bis(4-aminobenzoate)-1,2,3,4-tetrahydronaphthalene (4-DABTN) and 1,5-bis(3-amin obenzoate)-1,2,3,4-tetrahydronaphthalene (3-DABTN) were synthesized through the reaction of 1,5-dihydroxy-1,2,3,4-tetrahydronaphthalene and 4- or 3-nitrobenzoly chloride. By the reaction of these diamines with pyromellitic dianhydride (PMDA) or 4,4-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), poly(amic acid)s were obtained. The inherent viscosities of the poly(amic acid)s were between 0.55 and 1.31 dL/g. The poly(amic acid)s were converted to polyimides by chemical imidization. The thermogravimetric analysis (TGA) thermograms of these polyimides showed temperatures of 5% weight loss between 323 and 389$^{\circ}C$ in nitrogen atmosphere. The model compound ,1,5-bis (4-nitrobenzoate)-1,2,3,4-tetrahydronaphthalene (4-DNBTN), was decomposed to 4-nitrobenzoic acid and 5-(4-nitrobenzoate)-3,4-dihydronaphthalene upon addition of CF$_3$COOH.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1142-1146
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• 2004

The synthetic route and physical properties for three-ring derivatives, trans-2,3,2',3'-tetrafluoro-4-alkyl-4'-(4-alkyl-cyclohexyl)-biphenyl and 4-alkyl-cyclohexane carboxylic acid 2,3,2',3',4'-pentafluoro-biphenyl-4-yl ester are presented. They exhibit broad range nematic phases exceeding 30K and low viscosity of nematic liquid crystal mixtures containing these materials. Their viscosity is compared with that of homologues with a lateral isothiocyanate group and show large negative dielectric anisotropies. The threshold voltage $V_{th}$ was low enough to be operated at a driving voltage of 5V. Our novel LC compounds are suitable materials for the improvement of dielectric anisotropy of vertical align liquid crystal displays (VA-LDCs).

• YAKHAK HOEJI
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• v.50 no.5
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• pp.326-331
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• 2006

We designed and synthesized new benzylpiperidinyl ether derivatives as beta-amyloid aggregation inhibitors for the development of novel anti-Alzheimer's disease agents. As starting material, 4-hydroxypiperidine was used. For protection of the amine group in piperidine (2), di-tert-butyl dicarbonate was reacted with 4-hydroxypiperidine in the presence of triethylamine. For introduction of benzyl group, benzylbromide was treated with compound 2 in dioxane. After deprotection of Boc group on amine in compound 3, ester (5) was synthesized by addition of ethyl-4-chlorobutyrate. The alcohol 6 was synthesized by hydride reduction of 5 using $LiAlH_4$. To obtain final products (7-14), the alcohol 6 was condensed with each of substituted benzoic acids. To screen beta-amyloid aggregation inhibition of the products, thioflavinT assay was performed using $A{\beta}1-42\;at\;37^{\circ}C$ for 26 h incubation, in vitro. From the result of screening, compound 8, 9, 11 and 12 showed effective activity about $65{\sim}85\;{\mu}M\;as\;IC_{50}$ value. Among the prepared compounds, 4-[4-(benzyloxy)piperidino]butyl-4-chlorobenzoate (8) was the most effective inhibitor having $IC_{50}\;of\;65.4{\mu}M$.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.705-708
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• 2001

Enzymatic synthesis and purification of sugar esters using supercritical $CO_2$ were investigated. The observed yield of suagr ester produced by transesterification of methyl glucoside and oleic acid using a lipase(Novozym 435) was 67% at 24 hours of reaction in the supercritical $CO_2$. The solubility of the fatty acids in the supercritical $CO_2$ was measured to find the conditions of supercritical separation of the fatty acids from the reaction mixture. The solubility of capric and oleic acid was 5 ${\times}$ $10^{-4}$, 1.7 ${\times}$ $10^{-4}$ mol/mol $CO_2$, respectively, varying at $35{\sim}50^{\circ}C$ and 80${\sim}$120 atm.

• Applied Chemistry for Engineering
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• v.27 no.1
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• pp.50-55
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• 2016

Aromatic diamines containing hexafluoroisopropylidene and ester moiety were synthesized from 4,4'-hexafluoroisopropylidene diphenol and nitrobenzoyl chloride. The reaction of aromatic diamines with hexafluoroisopropylidene phthalicdianhydride (6FDA) or pyromellitic dianhydride (PMDA) gave four kinds of poly(amic acid)s. Their inherent viscosities ranged from 0.196 to 0.346 dL/g. Poly(amic acid)s were converted to polyimides by thermal imidization. The glass transition temperatures ($T_g$) of polyimides were between 241 and $289^{\circ}C$. The 5% weight loss temperatures were recorded in the range of $430{\sim}492^{\circ}C$. The tensile strength of polyimide films were measured as 29.84~64.38 MPa.

• Biomedical Science Letters
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• v.16 no.1
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• pp.25-32
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• 2010

Sprague-Dawley(SD) rats were orally administered with $N^G$-nitro-L-arginine methyl ester(L-NAME) which inhibits or blocks the production of nitric oxide from L-arginine in vascular endothelial cells and vessel tissue to statistically examine the effects of nitric oxide on some physiological changes such as blood pressure and heart rate, and to confirm the apoptosis induced by the suppressed nitric oxide activity in some related organs under light microscope. Systolic blood pressure significantly increased 28.5% by the chronic treatment of L-NAME for 8 weeks (P<0.001), no significant difference, however, was observed in heart rate between the control group and the L-NAME-treated group regardless of their age. Hematoxylin-eosin staining showed some histological alterations only in kidney among the examined organs; heart, liver, pancreas, and adrenal gland from the L-NAME-treated group. TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) test showed a strong positive reaction, representing that the chronic treatment of L-NAME facilitates apoptosis, in the cortex and medulla of kidney, but not any significance detectable in the other organs. These results conclude that chronic treatment of L-NAME significantly increases blood pressure, and that the followed inhibition of nitric oxide synthesis occurs a typical inducement of apoptosis in kidney.