• Title/Summary/Keyword: alcohols

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Metal-Free Oxidation of Alcohols to Their Corresponding Carbonyl Compounds Using NH4NO3/Silica Sulfuric Acid

  • Zarei, Amin
    • Bulletin of the Korean Chemical Society
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    • v.33 no.7
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    • pp.2149-2155
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    • 2012
  • A metal-free and efficient procedure for the oxidation of alcohols into the corresponding carbonyl compounds has been described using ammonium nitrate in the presence of silica sulfuric acid under mild and heterogeneous conditions. The use of non-toxic and inexpensive materials, simple and clean work-up, short reaction times and good yields of the products are among the advantages of this method.

A Convenient Synthesis of Optically Active Unhindered Aliphatic Alcohols with High Optical Purity from Non-Racemic β-Hydroxy Sulfides

  • Cho, Byung-Tae;Kim, Dong-Jun
    • Bulletin of the Korean Chemical Society
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    • v.25 no.9
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    • pp.1385-1391
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    • 2004
  • A general route for the synthesis of optically active unhindered aliphatic alcohols, where the steric demands between two alkyl groups adjacent to the carbinol are similar, with high enantiomeric purity has been developed by sulfoxifation of chiral ${\beta}$-hydroxy sulfides, followed by alkylation and desulfurization.

Convenient Procedure for the Reduction of Carboxylic Acids via Acyloxyborohydrides

  • Cho, Byung-Tae;Yoon, Nung-Min
    • Bulletin of the Korean Chemical Society
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    • v.3 no.4
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    • pp.149-152
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    • 1982
  • A new convenient method for the reduction of carboxylic acids to the corresponding alcohols via acyloxyborohydrides was explored. Acyloxyborohydrides, prepared from the reaction of various carboxylic acids and sodium borohydride, underwent reduction to the corresponding alcohols readily by the addition of dimethyl sulfate or Lewis acids, such as boron trifluoride etherate and triphenyl borate, presumably through acyloxyboranes. By utilizing this procedure, aliphatic and aromatic acids are rapidly and quantitatively reduced to the corresponding alcohols in terahydrofuran either at room temperature (or at $65^{\circ}$). This procedure provides selective reduction of carboxylic acids in the presence of halogen, nitro, and heterocyclic rings such as furan and thiophene.

Dynamics and Transport of Molecules Studied by Transient Grating Method : Methyl Red in Solution

  • 김선희;김성규
    • Bulletin of the Korean Chemical Society
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    • v.17 no.4
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    • pp.365-373
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    • 1996
  • Time profile of the transient grating signal induced by a nanosecond pulsed laser excitation of methyl red is investigated in alcohols and toluene at several solvent temperatures. The signal decays biexponentially with well-separated time constants; the faster decay is identified as due to thermal diffusion of the solvents and the slower one as mainly due to translational diffusion of the solute. The measured translational diffusion constants of methyl red in toluene are close to a hydrodynamic prediction with a slip boundary condition while those in alcohols are larger by 30% and increase slightly with the size of alcohols. We compare the results with modified hydrodynamic models.

Synthesis of solid enantioselective macromer of trimesic acid for the enantiomeric separation of chiral alcohols

  • Ingole, Pravin G.;Bajaj, Hari C.;Singh, Kripal
    • Advances in materials Research
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    • v.2 no.1
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    • pp.51-64
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    • 2013
  • Enantioselective macromer of trimesic acid was prepared using S(-) menthol with trimesoyl chloride on polyimide (PI) ultrafiltration membrane. The chemical composition of macromer as well as polyimide ultrafiltration membrane was determined by ATR-FTIR Spectroscopy. The optical resolution of chiral alcohols was performed in pressure driven process. The effect of monomer solutions concentration, effect of air-drying time of S(-) menthol solution, effect of reaction time, effect of operating pressure, effect of feed concentration of racemate on the performance of macromer was studied. The synthesised material exhibits separation of chiral alcohols (menthol ~23% and sobrelol ~21%).

The Effects of Enhancers on Transdermal Absorption of Ketoprofen Packs (케토프로펜 팩제제에서 경피흡수에 미치는 투과촉진제의 영향)

  • Cho, Su-Jin;You, Do-Ra;Kim, Kil-Soo
    • Journal of Pharmaceutical Investigation
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    • v.31 no.2
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    • pp.107-112
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    • 2001
  • In order to reduce the systemic side effects and gastrointestinal irritation after its oral adminitration, ketoprofen was formulated as water-soluble packs. The effects of fatty acids and fatty alcohols on the penetration of ketoprofen through excised rat skins were evaluated. The role of stratum corneum as a protective barrier was also investigated. Fatty acids and fatty alcohols were generally effective in promoting ketoprofen penetration. The flux of ketoprofen through rat skin was maximized when oleic acid or lauryl alcohol was used as an enhancer. As the concentration of fatty acids and fatty alcohols varied from 0% to 10%, the amounts of ketoprofen penetrated were in direct proportion to that of fatty acids but those had no relationship with that of fatty alcohols. The penetration of ketoprofen through stripped skin was enhanced compared to normal skin irrespective of enhancer type, which indicated that the action site of enhancers would be stratum corneum.

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Electrochemical Oxidations of Alcohols on Platinum/Carbon Nanotube Composites

  • Kim, Jungsoo;Nam, Dae-Geun;Oh, Weontae
    • Transactions on Electrical and Electronic Materials
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    • v.14 no.3
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    • pp.125-129
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    • 2013
  • Composites of platinum and multiwalled carbon nanotubes (MWNTs) were prepared in various reduction conditions and characterized using cyclic voltammetry. The MWNTs were functionalized with carboxylic acid and/or hydroxyl groups in acidic solutions prior to the formation of MWNT-Pt composites. Platinum nanoparticles were deposited onto the chemically-oxidized MWNTs in 1-propanol and 1,3-propanediol. The reduction of Pt precursors in other solutions could induce differences in their morphologies in composite thin films. The morphologies of MWNTs with Pt deposited were dependent on the reduction solutions, and the electrocatalytic activities on alcohols changed accordingly. The electrochemical activities of the as-prepared MWNT-Pt thin films on common alcohols such as methanol and ethanol were investigated.

Allyl Alcohol Found in Heated Garlic is a Potent Selective Inhibitor of Yeasts

  • Lee Se-Hi;Woo Yong-Ho;Kyung Kyu-Hang
    • Journal of Microbiology and Biotechnology
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    • v.16 no.8
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    • pp.1236-1239
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    • 2006
  • Allyl alcohol (2-propen-l-ol), found in considerable amounts in heated garlic, was able to discriminate yeasts from bacteria and was approximately three orders of magnitude more inhibitory towards yeasts than bacteria. The average minimum inhibitory concentration (MIC) of allyl alcohol for bacteria and yeasts was 5.0% and 0.0056%, respectively. The unsaturated primary alcohols, including allyl alcohol and 2-buten-l-ol, seemed to work differently from all the other saturated alcohols and unsaturated secondary alcohols in inhibiting various yeasts. An alcohol dehydrogenase-negative (ADH$^-$) strain of Saccharomyces cerevisiae was as resistant to allyl alcohol as various bacteria, exhibiting an MIC of 5.0%. The unsaturated primary alcohols were apparently oxidized into the corresponding unsaturated aldehydes before they inhibited the yeasts.

Studies on the Adsorption of Erythrosine in the Suspension of Antibiotics (항생물질 현탁액중에서 Erythrosine의 흡수에 관한 연구)

  • 백우현;송영준;김정우;김종갑
    • YAKHAK HOEJI
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    • v.23 no.3_4
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    • pp.133-140
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    • 1979
  • The adsorption of erythrosine in the aliphatic alcohols by antibiotics such as ampicillin anhydrous, ampicillin trihydrate, amoxicillin trihydrate, cephalexin monohydrate was studied. The adsorption isotherms were all described with Freudlich equation. From the various experimerts, it was found that the adsorption of erythrosine by antibiotics in the aliphatic alcohols was affected by the solubility of adsorbents. The adsoption in the mixture of aliphatic alcohols and water is related with the dielectric constant of mixed solvents. According to increase in the pH values of aqueous solution, the adsorption of erythrosine for antibiotics is decreased, but increased in the mixture of aliphatic alcohols and water. The adsorption of erythrosine in the suspension of antibiotics showed a correlation with the temperature. Colloidal silica which is used as stabilizer had a favorable effect on the adsorption of erythrosine in the suspension of antibiotics.

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Effect of Sugar Alcohol on Wheat Starch Gelatinization and Retrogradation (당알콜이 밀전분이 호화 및 노화에 미치는 영향)

  • 김혁일;신인영;김창순
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.28 no.6
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    • pp.1251-1255
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    • 1999
  • The sugar alcohols are useful alternatives to sucrose in confections because they provide desirable taste but lessen the potential risks for dental caries. The effects of sugar alcohol and their interaction on starch pasting properties were determined by the viscoamylograph with the concentration of 30%, 20%, 10% sugar alcohol in 1% CMC. The disaccharides, lactitol, maltitol, and isomalt, delayed pasting more than did monosaccharides, sorbitol and xylitol. With regard to the solubility in water, sorbitol and xylitol are more soluble than sucrose, maltitol and lactitol are almost equal and isomalt is less soluble than sucrose. Sorbitol and xylitol were highest on gelatinization. But their retrogradation occurred faster than other sugar alcohols. Lactitol and maltitol decreased gel strength more than did sucrose and other sugar alcohols.

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