• 제목/요약/키워드: Organosoluble

검색결과 9건 처리시간 0.018초

Characterization of by-products from organosolv pretreatments of yellow poplar wood (Liriodendron tulipifera) in the presence of acid and alkali catalysts

  • 곽기섭;구본욱;박나현;정한섭;최준원;여환명;최인규
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2009년도 추계학술대회 논문집
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    • pp.520-520
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    • 2009
  • Organic by-products derived from cellulose and lignin during organosolv pretreatments of yellow poplar wood (Liriodendron tulipifera) in the presence of $H_2SO_4$ and NaOH as catalysts, respectively, were subjected to various analyses to elucidate their effects on further performance of biological ethanol fermentation and provide preliminary data for the structure and utilization of organosolv lignin. Monomeric sugars amounted to ca. 2.2-7.7% in the organosoluble fraction of the organosolv pretreatment with $H_2SO_4$, while significantly low amount of sugars (0.2-0.3%) were determined in that of the organosolv pretreatment with NaOH. In case of addition of $H_2SO_4$ during organosolv pretreatment of biomass, a fermentation of the organosoluble fraction could be considered as an essential process to increase an efficiency of biomass utilization as well as yield of bioethanol. Precipitates, insoluble by-products in the solvent mixture, were also cficiency oed by diverse analytical methods and revealed that these were typically composed of a lignin moiety regardless of catalyst. According to the results of nuclear magnetic resonance (NMR), Fourier Tcinsform Infrared Spectroscopy (FT-IR) and Gel permeation chromatograp r (GPC), the main components of precipitates seem to be lignin polymers. However, their structures could be slightly modified during pretreatment and mixed with some carbohydrates by chemical bonds and/or physical associations.

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Rapid Formation of Optically Active and Organosoluble Polyamides Containing L-Alaninephthalimide Side Chain via Microwave Irradiation

  • Mallakpour, Shadpour;Rafiee, Zahra
    • Macromolecular Research
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    • 제17권11호
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    • pp.901-906
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    • 2009
  • Several aromatic optically active polyamides (PA)s were synthesized from 5-(2-phthalimidiylpropanoylamino)isophthalic acid with various aromatic diamines via direct polycondensation with triphenyl phosphite and pyridine in the presence of calcium chloride and N-methyl-2-pyrrolidone under microwave irradiation and conventional heating conditions. Under the optimized conditions, the reaction mixture was irradiated for 2 min. with a 100% irradiation power (900 W). The resulting polymers were obtained in high yield and moderate inherent viscosity ranging from 0.35 to 0.60 dL/g. All synthesized polymers showed excellent solubility in amide-type solvents. Thermogravimetric analysis revealed a 10% weight loss temperature and char yield at $600^{\circ}C$ in a nitrogen atmosphere of > $350^{\circ}C$ and > 58%, respectively, which suggests that the resulting PAs have good thermal stability.

새로운 Hyperbranchedpolyimidesandpolyamides: 합성, 말단기 변형, 경화 연구, 그리고 물리적 성질 (New Hyperbranched Polyimides and Polyamides: Synthesis, Chain-End Functionalizations, Curing Studies, and Some Physical Properties)

  • Baek, Jong-Beom;Chris B. Lyon;Tan, Loon-Seng
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 2003년도 추계학술발표대회 논문집
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    • pp.1-2
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    • 2003
  • While aromatic polyimides and polyamides have found widespread use as high performance polymers, the present work addressed the need for organosoluble materials through the use of a hyperbranching scheme. The $AB_2$ monomers were prepared. The $AB_2$ monomers were then polymerized via aromatic fluoride-displacement and Yamazaki reactions to afford the corresponding hydroxyl-terminated hyperbranched polyimides (HT-PAEKI) and amine-terminated hyperbranched polyamides, respectively. HT-FAEKI was then functionalized with allyl and propargyl bromides as well as epichlorohydrin to afford allyl-terminated AT-PAEKI, propargyl-terminated PT-PAEKI, and epoxy (glycidyl)-terminated ET-PAEKI, in that order. All hyperbranched poly(ether-ketone-imide)s were soluble in common organic solvents. AT-PAEKI was blended with a bisphenol-A-based bismaleimide (BFA-BMI) in various weight ratios. Thermal, rheological, and mechanical properties of these blend systems were evaluated. Two characteristic hyperbranched polyamides, which the one has para-electron donating groups to the surface amine groups and the other has para-electron withdrawing groups to the surface amine groups, were selected to compare BMI curing behaviors. The electron rich polymer displayed ordinary Michael addition type exothermic reaction, while electron deficient polymer did display unusual curing behaviors. Based on analytical data, the later system provided the strong evidences to support room temperature curing of BMI by reactive intermediates instead of reactive primary amine groups on the macromolecule surface.

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Optically Active and Organosoluble Poly(amide-imide)s Derived from N,N'-(Pyromellitoyl)bis-L-histidine and Various Diamines: Synthesis and Characterization

  • Faghihi, Khalil;Shabanian, Meisam;Hajibeygi, Mohsen
    • Macromolecular Research
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    • 제17권11호
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    • pp.912-918
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    • 2009
  • An optically active diacid containing the L-histidine moiety was prepared by reacting pyromellitic dianhydride (1,2,4,5-benzenetetracarboxylic acid 1,2,4,5-dianhydride) 1 with L-histidine 2 in acetic acid, and was polymerized with several aromatic diamines 5a-g to obtain a new series of optically active poly(amide-imide)s (PAIs) using two different methods, such as direct polycondensation in a medium consisting of N-methyl-2-pyrrolidone (NMP)/triphenyl phosphite (TPP)/calcium chloride ($CaCl_2$)/pyridine (Py) and direct polycondensation in a tosyl chloride (TsCl)/pyridine (Py)/N,N-dimethylformamide (DMF) system as a condensation agent. The resulting new polymers 6a-g with inherent viscosity was obtained in good yield. The polymers were readily soluble in polar organic solvents, such as N,N-dimethyacetamide (DMAc), N,N-dimethyformamide (DMF), and dimethyl sulfoxide (DMSO). The obtained polymers were characterized by FTIR, specific rotation, elemental analysis as well as $^1$H-NMR spectroscopy and gel permeation chromatography (GPC). The thermal stability of the resulting PAIs was evaluated with thermogravimetric analysis techniques under a nitrogen atmosphere.

목련(Magnolia kobus DC. var. borealis Sarg.) 추출성분의 항균성에 관한 연구 (Studies on the Antimicrobial Activities of the Extractives from Magnolia (Magnolia kobus DC. var. borealis Sarg.))

  • 김윤근
    • Journal of the Korean Wood Science and Technology
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    • 제27권1호
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    • pp.105-114
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    • 1999
  • 목련 각 부위의 에탄올추출물과 분별물 및 잎 부위에서 단리한 리그난류의 항균활성 검정 결과, 포자발육저해의 성분은 각 부위에 걸쳐서 특히 석유에테르 가용부, 에테르 가용부에 집중되어 있었다. 여기서 효과를 갖는 리그난은 (-)syringaresinol(X III), medioresinol(VI), phillygenin(VIII), kobusinol A(X)이었는데, 이들은 모두 구조적으로는 guaiacyl 및 syringyl의 골격을 갖는 페놀성 수산기의 특징을 보여 주었다. 추출물 및 분별물의 항미생물 활성은 석유에테르 가용부에서 가장 강한 억제효과가 있었다. 공시균에 대한 리그난류의 성장저해 효과는 그다지 현저하지는 않았지만, 이들 리그난류를 함유하는 추출물 및 각 분별물은 리그난과의 상승효과를 보였다.

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The Alignment of Liquid Crystals on the Film Surfaces of Soluble Aromatic Polyimides Bearing t-Butylphenyl and Trimethylsilylphenyl Side Groups

  • Hahm, Suk-Gyu;Jin, Kyeong-Sik;Park, Sam-Dae;Ree, Moon-Hor;Kim, Hyung-Sun;Kwon, Soon-Ki;Kim, Yun-Hi
    • Macromolecular Research
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    • 제17권12호
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    • pp.976-986
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    • 2009
  • With the study goal of firstly elucidating the anisotropic interactions between oriented polymer chain segments and liquid crystal (LC) molecules, and secondly of determining the contributions of the chemical components of the polymer segments to the film surface topography, LC alignment, pretilt, and anchoring energy, we synthesized three dianhydrides, 1,4-bis(4'-t-butylphenyl)pyromellitic dianhydride (BBPD), 1,4-bis(4'-trimethylsilylphenyl)pyromellitic dianhydride(BTPD), and 2,2'-bis(4"-tert-butylphenyl)-4,4',5,5'-biphenyltetracarboxylic dianhydride (BBBPAn), and a series of their organosoluble polyirnides, BBPD-ODA, BBPD-MDA, BBPD-FDA, BTPD-FDA, and BBBPAn-FDA, which contain the diamines 4,4'-oxydianiline (ODA), 4,4'-methylenediamine (MDA), and 4,4'-(hexafluoroisopropylidene)dianiline (FDA). All the polyimides were determined to be positive birefringent polymers, regardless of the chemical components. Although all the rubbed polyimide films exhibited microgrooves which were created by rubbing process, the film surface topography varied depending on the polyimides. In all the rubbed films, the polymer chains were unidirectionally oriented along the rubbing direction. However, the degree of in-plane birefringence in the rubbed film varied depending on the polyimides. The rubbing-aligned polymer chains in the polyimide films effectively induced the alignment of nematic LCs along their orientation directors by anisotropic interactions between the preferentially oriented polymer chain segments and the LCs. The azimuthal and polar anchoring energies of the LCs ranged from $0.45{\times}10^{-4}\;-\;1.37{\times}10^{-4}\;J/m^2$ and from $0.86{\times}10^{-5}\;-\;4.26{\times}10^{-5}\;J/m^2$, respectively, depending on the polyimides. The pretilt angles of the LCs were in the range $0.10-0.62^{\circ}$. In summary, the soluble aromatic polyimides reported here are promising LC alignment layer candidates for the production of advanced LC display devices.

떡갈나무 추출물의 항균활성 및 항산화활성 (Antimicrobial Activity and Antioxidative Activity in the Extractives of Quercus dentata Thunberg)

  • 김민영;김윤근;김태홍;조종수;양재경
    • Journal of the Korean Wood Science and Technology
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    • 제28권3호
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    • pp.42-51
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    • 2000
  • 떡갈나무의 부위별 추출물에 대한 항균활성 및 항산화활성을 시험하였다. 항균활성은 paper disk법과 bioautography법으로 시험하였다. 잎으로부터 추출된 ethyl acetate 가용부는 Klebsiella pneumoniae균에 대해서 가장 강한 항균력을 나타냈다. 수피로부터 추출된 ethyl acetate 가용부는 Bacillus subtilis, Klebsiella pneumoniae균에 대해 항균효과가 우수하였다. 목절부의 에탄올 추출물은 Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumoniae 및 Vibrio parahaemolyticus균에 대해서 저해효과가 가장 높게 나타났다. 떡갈나무 에탄올 추출물의 항균활성은 잎, 수피, 목질부의 순으로 높게 나타났다. Bioautography법에 의한 항균활성은 목질부 에탄올 추출물에 있어서 Rf치 0.41~0.63 영역의 물질이 가장 강한 저해를 나타냈다. 떡갈나무의 부위별 추출물에 대한 항산화활성 시험 결과, 잎 추출물에서는 petroleum ether 가용부가 매우 낮은 항산화활성을 나타냈으나, ethyl acetate 불용부에서는 높은 항산화활성을 나타냈다. 수피와 목질부의 추출물에 있어서. petroleum ether 가용부를 제외한 나머지 분획물의 항산화활성은 BHT의 항산화 성보다 약 2배 정도 높은 수치를 보였다.

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In vivo 시험에 의한 잉어체내 $^{14}C-endosulfan$의 대사 (In vivo Metabolism of Endosulfan in Carp (Cyprinus carpio))

  • 이강봉;심재한;서용택
    • Applied Biological Chemistry
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    • 제37권3호
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    • pp.203-209
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    • 1994
  • $^{14}C-{\alpha}-endosulfan$(100 nM, $41\;{\mu}g$)을 공시어의 각 조직(간, 신장, 소화관) 추출액에 처리하여 대사물질의 생성과 이에 미치는 cofactor의 영향을 시험관내 반응으로 비교한 결과, 105,000 g soluble fraction에서 phase I system에 해당되는 cofactor의 첨가시 공시어의 간 조직에서 가장 높은 대사물질 생성율을 보였고 phase II system에서는 NADPH를 cofactor로 첨가하였을 때 간과 신장조직에서 높은 대사물질 생성율을 보였다. 하지만 소화관 조직에서는 GSH 단독처리나 GSH+NADPH의 혼합처리시 높은 대사물질 생성율을 보였다. 또한 microsomal fraction에서는 phase I system에 해당되는 cofactor의 첨가시 공시어의 소화관 조직에서, phase II system의 경우 NADPH 단독처리나 NADPH+GSH 혼합처리시 대사물질의 생성이 가장 많았다. 이러한 결과로 보아 공시어의 간과 신장에서는 MFO에 의한 대사작용이, 소화관에서는 GST에 의한 대사작용이 활발하다고 할 수 있었다. 공시어의 각 조직에서 높은 생성율을 보인 대사물질은 EA(endosulfan alcohol), EE(endosulfan ether), EHE(endosulfan hydroxyether)이었으며 in vivo 시험에서와 마찬가지로 endosulfan sulfate는 검출되지 않았다. 이 실험에서 ${\alpha}-endosulfan$은 잉어체내에서 ${\beta}-endosulfan$으로 이성화되었다가 EA로 가수분해되거나 직접 EA로 가수분해되어 다시 EE나 EHE로 산화되며 EHE는 EL(endosulfan lactone)로 산화되는 것으로 제안할 수 있었다.

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