• Korean Chemical Engineering Research
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• 제56권1호
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• pp.61-65
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• 2018

본 연구는 해양 갑각류의 껍질의 주요 구성성분인 키틴/키토산의 단량체인 glucosamine을 고체 산 촉매를 이용하여 화학중간체인 levulinic acid와 5-hydroxymethyl furfural (5-HMF)을 생산하기 위한 전환 반응을 수행하였다. 반응 결과, glucosamine 50 g/L, 반응온도 $180^{\circ}C$, 촉매량 5%, 그리고 반응시간 60분의 조건에서 약 36.86%의 levulinic acid를 얻을 수 있었다. 반면에 5-HMF는 약 0.91%의 낮은 수율로 전환되었다.

• 한국식생활문화학회지
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• 제11권3호
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• pp.385-392
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• 1996

The soluble solid of red pepper was extracted by water in order to investigate changes of soluble solid content by different extraction temperature $(4{\sim}90^{\circ}C)$ and time $(1/2{\sim}3\;hrs)$, and the contents of carotenoid, capsaicinoids, free sugar, organic acid, free amino acid in soluble solid were measured. Most of soluble solid in red pepper was extracted within the first 2 hrs and $93{\sim}98%$ of total soluble solid was extracted during the first 30 min. The contents of carotenoid increased by increasing extraction time and temperature, but decreased by increasing extraction time at $60^{\circ}C$ and $90^{\circ}C$. ${\beta}$-carotene content was sharply decreased after 2 hrs at $90^{\circ}C$. The content of capsaicinoid was sharply increased between 1 hr and 2 hr. Fructose and glucose in red pepper were extracted in the range of $83.8%{\sim}96.4%$ and the contents of free sugar gradually increased by increasing extraction time and temperature. The content of organic acid was gradually increased by increasing extraction time and temperature and the greatest amount of organic acid was extracted during the first 30 min of extraction time. The content of free amino acid was decreased by increasing extraction temperature.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.347-347
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• 2006

Polymers containing poly(vinyl phosphonic) acid segments are promising candidates to be used as proton conducting membranes. Solid state NMR spectroscopy represents an ideal probe of proton motion on the molecular level, because it allows us to selectively detect the nuclei of interest. In this paper, we apply solid state NMR methods to poly(vinyl phosphonic) acid in order to demonstrate that the proton conduction of poly(vinyl phosphonic acid) results from P-OH proton through hydrogen bonding and that the condensation of phosphonic acid leads to decrease in proton conductivity. $^{1}H\;and\;^{31}P$ solid state NMR experiments are supported by quantum chemical computation of NMR parameters.

• 한국세라믹학회지
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• 제29권5호
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• pp.396-402
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• 1992

Carbon solid was prepared from dormant mesophase pitch (DMPP) without using a binder and its properties were characterized. DMPP powder was stabilized with air or nitric acid in pretreatment stage so that it might not soften in later heat ttreatment stage. Optimum sintering properties were obtained from carbon powder with 2.36∼2.38 of C/H atomic ratio and 1.27∼1.40 of C/O atomic ration in air stabilization. In nitric acid stabilization, optimum sintering properties were obtained when 20∼40 vol.% of nitric acid solution was used. Compressive strength increased up to 1200$^{\circ}C$ of heat treatment temperature, and the highest compressive strength and bulk density of carbon solid from DMPP were 3000 kgf/㎤, respectively. The optical properties of carbon solid obtained was fine mosaic structure. Carbon solid after graphitization showed the properties of hard carbon due to stabilization and its shore hardness was 120.

• Bulletin of the Korean Chemical Society
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• 제25권12호
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• pp.1929-1931
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• 2004

• Journal of the Korean Wood Science and Technology
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• 제41권1호
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• pp.1-11
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• 2013

본 연구에서는 은수원사시나무의 산 당화공정에서 생성되는 고형 부산물의 화학적, 구조적 특성을 관찰하였다. 산 가수분해는 황산과 염산을 사용하였고, 1차 가수분해농도를 72%, 36%, 18%로 변화를 주었고, 2차 가수분해에서 4%로 동일하게 희석하였다. 가수분해 후 액상 가수분해액과 고형 부산물을 각각 분리하였고 고형 부산물을 각각 RS72, RS36, RS18, RC36, RC18이라고 하였다. 황산의 농도가 높아짐에 따라 생성된 고형부산물은 감소(71.2~21.4%)하였지만, 염산의 농도는 고형 부산물의 생성량(65.0~67.0%)에 큰 영향을 주지 않았다. 또한 RS36과 RS18은 고형 부산물 질량 대비 23.6%, RC36과 RC18은 각각 25.6%, 27.3%가 리그닌으로 이루어져 있었다. 고형 부산물의 열분해산물 분석 결과 Levoglucosan, Furfural 등 탄수화물 유래 물질과 리그닌 유래 물질인 Guaiacol, Syringol 등이 검출되었지만 RS72에서는 리그닌 유래 물질만이 검출되었다. 또한 열중량분석결과 고형 부산물 내 리그닌 함량이 높아질수록 다량의 탄이 생성되고 최대 중량 감소율이 감소하여 염산에 비해 황산이, 또한 산의 농도가 높을수록 화학적으로 축합된 구조를 형성하는 것을 확인하였다.

• Journal of Pharmaceutical Investigation
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• 제31권3호
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• pp.167-172
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• 2001

All-trans retinoic acid (ATRA), vitamin A acid, has been shown to exert anticancer activity in a number of types of cancers, particularly in acute promyelocytic leukaemia (APL). Due to its highly variable bioavailability and induction of its own metabolism after oral treatment, development of parenteral dosage forms are required. However, its poor aqueous solubility and chemical unstability give major drawbacks in parenteral administration. This study was undertaken to investigate a possibility to develop a parenteral formulation of ATRA by employing solid lipid nanoparticle (SLN) as a carrier. By optimizing the production parameters and the composition of SLNs, SLNs with desired mean particle size (<100 nm) as a parenteral dosage form could be produced from trimyristin (as solid lipid), Egg phosphatidylcholine and Tween 80 (as SLN stabilizer). The mean particle size of SLN formulation of ATRA was not changed during storage, suggesting its physical stability. Thermal analysis confirmed that the inner lipid core of SLNs exist at solid state. The mean particle size of ATRA-loaded SLNs was not significantly changed by the lyophilization process. ATRA could be efficiently loaded in SLNs, while maintaining its anticancer activity against HL-60, a well-known APL cell line. Furthermore, by lyophilization, ATRA loaded in SLN could be retained chemically stable during storage. Taken together, our present study demonstrates that physically and chemically stable ATRA formulation adequate for parenteral administration could be obtained by employing SLN technology.

• Korean Chemical Engineering Research
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• 제53권4호
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• pp.478-481
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• 2015

본 연구는 거대 녹조류인 창자파래(Enteromorpha intestinalis)를 대상으로 고체 산촉매를 사용하여 환원당을 생산하고자 하였다. 가수분해 반응은 고액비, 촉매량, 반응온도와 반응시간을 대상으로 최적화하였다. 결과적으로 액/고비 7.5, 반응온도 $140^{\circ}C$, 촉매량 15%, 그리고 반응시간 2 hr에서 7.74 g/L의 환원당을 얻었다. 반면에 단지 0.13 g/L의 5-HMF만이 생성되었다. 이로부터 고체 산촉매를 이용한 해양 바이오매스 자원의 가능성을 확인하였다.

• Macromolecular Research
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• 제13권3호
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• pp.253-256
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• 2005

We prepared amino acid-derived diacetylene monomers using solid-phase organic synthesis. The solid-phase synthetic method allowed for the rapid and efficient preparation of functional diacetylenes. Amino acids having hydrophobic sidechains such as alanine, leucine, and phenylalanine, as well as hydrophilic sidechains such as aspartic acid and lysine, were successfully coupled to the diacetylene lipid. The diacetylene monomers prepared in this way were subjected to routine procedures for the generation of polydiacetylene vesicles. Depending on the nature of the side-chains, pink to blue colored polydiacetylenes were generated.

• Archives of Pharmacal Research
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• 제28권7호
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• pp.756-760
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• 2005

Polyene macrolide amphotericin B (AmB) is the drug of choice for the treatment of disseminated fungal infections. However, because of its pronounced side effects, the drug has limited applicability. There are few interesting reports, which state that co-administration of the drug with homo-peptide of polyaspartic acid reduces the side effects of the drug. In our present study, an approach has been made to systematically synthesize low molecular weight heteropeptides consisting of L-aspartic acid and its derivative. It was hypothesized that such heteropeptides will reduce the toxic side effects of the drug by facile hydrophobic binding between the polymer and the drug. We have employed the strategy of solid phase peptide synthesis (SPPS) to synthesize low molecular weight hetero-peptides by using L-aspartic acid and benzyl-L-aspartic acid to induce the hydrophobic binding between the peptide and the drug. In future, the proposed methodology can be employed to tailor other polypeptides substituted with benzyl groups to reduce the nephrotoxicity of AmB.