• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1998년도 가을 학술발표회논문집
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• pp.5-8
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• 1998

폴리에스테르 공중합체의 합성에 이용될 수 있는 에스테르 교환 반응은 alcoholysis, acidolysis 및 transesterification 반응들에 의해 복합적으로 진행되며 이 때 각각의 반응 속도를 비교하여 보면 어느 한 쪽 분자쇄의 말단 알코올기가 다른 쪽 분자쇄의 에스테르기를 공격하는 alcoholysis 반응이 가장 빠르고 카르복실기가 에스테르를 공격하는 acidolysis 및 두 고분자 주쇄의 에스테르기 상호간에 발생하는 transesterification 반응들은 alcoholysis 반응에 비해 느린 것으로 알려져 있다. (중략)

• Bulletin of the Korean Chemical Society
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• 제35권12호
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• pp.3423-3424
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• 2014

• Fibers and Polymers
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• 제4권2호
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• pp.59-65
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• 2003

PLA/LPCL/HPCL blends composed of poly(lactic acid) (PLA), low molecular weight poly($\varepsilon$-caprolactone) (LPCL), and high molecular weight poly($\varepsilon$-caprolactone) (HPCL) were prepared by melt blending for bioabsorbable fila-ment sutures. The effects of blend composition and blending time on the ester interchange reaction by alcoholysis in the PLA/LPCL/HPCL blends were studied. Their thermal properties and the miscibility due to the ester interchange reaction were investigated by $^1{H-NMR}$, DSC, X-ray, and UTM analyses. The hydroxyl group contents of LPCL in the blends decreafed by the ester interchange reaction due to alcoholysis. Thus, the copolymer was formed by the ester interchange reaction at $200^{\circ}C$ for 30-60 minutes. The thermal properties of PLA/LPCL/HPCL blends such as melting temperature and heat of fusion decreased with increasing ester interchange reaction levels. However, the miscibility among the three poly-mers was improved greatly by ester interchange reaction. Tensile strength and modulus of PLA/LPCL/HPCL blend fibers increased with increasing HPCL content, while the elongation at break of the blend fibers increased with increasing LPCL content.

• Bulletin of the Korean Chemical Society
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• 제16권4호
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• pp.377-379
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• 1995

• Bulletin of the Korean Chemical Society
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• 제25권6호
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• pp.881-888
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• 2004

By applying a catalytic amount of indium trichloride, regioselective ring-opening of epoxides to ${\beta}$-hydroxy ethers was established. While the alcoholysis of styrene oxides produed $S_N1$-type product, the alcoholysis of ${\alpha}$-heteroatom-substituted epoxides predominantly produced $S_N2$-type product.

• 약학회지
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• 제35권5호
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• pp.368-371
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• 1991

For the development of new antiulcer agents 5, 6-dihydroimidazo[2, 1-b]- thiazoles substituted at the 3-position are sythesized. Thus, the reaction of 3-chloromethyl-5, 6-dihydroimidazo[2, 1-b]thiazole(2) with thiourea and subsequently with 3-chloro-propionitrile gives 3-[3-[5, 6-dihydroimidazo[2, 1-b]thiazolyl]methylthio]propionitrile(4), which by partial alcoholysis with methanol is converted into methyl-3-[3-[5, 6-dihydro-imidazo[2, 1-b]thiazoyl]methylthio]propionimidate(5) . This compound(5) is treated finally with sulfamide or sulfonamides. 3-[3-[5, 6-dihydroimidazo[2, 1-b]thiazoyl]methylthiol-N$^{2}$-sulfamoyl-propionamidine(6) inhibited gastric acid secretion (45%) when administered intraduodenally (100 mg/kg) to pylorus-ligated rats.

• Bulletin of the Korean Chemical Society
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• 제23권6호
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• pp.824-829
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• 2002

New di-N-cyanomethylated tetraaza macrocycle 2.13-bis(cyanomethyl)-5.16-dimethyl-2,6,13,17-tetraazatricyclo[$16.4.0.0^7.12$]docosane $(L^2)$ has been prepared by the reaction of 3, 14-dimethyl-2,6,13,17-tetraazatricyclo $(L^1)$ with bromoacetonitrile. The square-planar complexes $[ML^2](ClO_4)_2(M=Ni(II)$ or Cu(II) can be prepared by the reaction of $L^2$ with the corresponding metal ion in acetonitrile. The cyanomethyl groups of $[ML^2](ClO_4)_2readily$ react with water to $yield[ML^3](ClO_4)_2$ containing pendant amide groups. The trans-octahedral complexes $[ML^4](ClO_4)_2$, in which two imidate ester groups are coordinated to the metal ion, can be also prepared by the reaction of $[ML^2](ClO_4)_2with$ methanol under mild conditions. The hydrolysis and alcoholysis reactions of $[ML^2](ClO_4)_2are$ promoted by the central metal ion, in spite of the fact that the cyanomethyl group is not involved in intramolecular coordination. The reactions are also promoted by a base such as triethylamine but are retarded by an $acid(HClO_4).Interestingly$, the imidate ester groups of $[ML^4]^2$ are unusually resistant to hydrolysis even in 0.1 M $HCIO_4$ or 0.1 M NaOH aqueous solution. Crystal structure of $[NiL^4](ClO_4)_2shows$ that the Ni-N (pendant imidate ester group) bond is rlatively strong; the Ni-N bond distance is shorter then the Ni-N(tertiary) distance and is similar to the Ni-N (secondary) distance.

• 한국세라믹학회지
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• 제55권6호
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• pp.562-569
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• 2018

We propose an economic and facile method for the preparation of silica nanoparticles through a two-step process utilizing chlorosilane residues. Mixed chlorosilane residue was alcoholized with absolute ethanol as a first step to form tetraethoxysilane (TEOS). The TEOS was then utilized as a silicon source to synthesize silica nanoparticles in a sol-gel method. The alcoholysis process was designed and optimized utilizing the Taguchi experimental design method and the yield of TEOS was as high as 82.2% under optimal synthetic conditions. Similarly, the Taguchi method was also utilized to study the effects of synthesis factors on the particle size of silica nanoparticles. The results of statistical analysis indicate that the concentration of ammonia has a greater influence on particle size compared to the mass fractions of TEOS and polyethylene glycol (4.6% and 9.7%). The purity of the silica particles synthesized in our experiments is high, but the specific surface area and pore volume are small.

• Bulletin of the Korean Chemical Society
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• 제18권11호
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• pp.1186-1191
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• 1997

Solvolyses of methanesulfonyl chloride (CH3SO2Cl) in water and methanol have been studied theoretically using ab initio self-consistent reaction field (SCRF) molecular orbital method. All stationary structures including transition state on the potential energy surface in solution have been found and compared with the gas phase structures. The overall reaction occurs via a concerted SN2 mechanism with a non-cyclic trigonal bipyramidal transition state, and the activation barrier is lowered significantly in solution. The transition state for the hydrolysis reaction is looser than that for the methanolysis reaction, and this is in accord with the experimental findings that an SN2 type mechanism, which is shifted toward an SN1 process or an SAN process in the hydrolysis and alcoholysis reaction, respectively, takes place. The catalytic role of additional solvent molecules appears to be a purely general-base catalysis based on the linear transition structures. Experimental barrier can be estimated by taking into account the desolvation energy of nucleophile in the reaction of methanesulfonyl chloride with bulk solvent cluster as a nucleophile.

• 한국식품영양과학회지
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• 제42권6호
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• pp.933-940
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• 2013

본 연구는 urea fractionation을 통하여 포화도 함량이 5.8%, 28.4%, 39.2%, 50.7%, 72.3%인 우지 alcoholysis 반응물을 제조하고, 이를 유상(oil phase)으로 ultrasonic processor 및 고압균질기를 이용하여 emulsion을 제조한 후 이에 대한 유화 안정성과 산화 안정성을 실험하였다. 유화 안정성(ES)을 관찰한 결과 ES값은 46.0(${\Sigma}$SFA5), 39.5(${\Sigma}$SFA28), 32.7(${\Sigma}$SFA39), 32.6(${\Sigma}$SFA50) 및 27.3(${\Sigma}$SFA72)로써 포화도가 낮은 emulsion일수록 높은 안정성을 보였으며, Turbiscan을 이용하여 시료 emulsion의 creaming 및 clarification 특성을 조사한 결과도 ES 결과와 유사하게 나타났다. 고압균질기로 제조한 emulsion 시료에 대하여 30일간 산화특성 및 안정성 연구를 진행한 결과, 제조한 emulsion의 hydroperoxides 함량이 1.880(${\Sigma}$SFA5), 1.267(${\Sigma}$SFA28), 1.062(${\Sigma}$SFA39), 0.342(${\Sigma}$SFA50) 및 0.153(${\Sigma}$SFA72)mg $H_2O_2/mL$로 서로 유의적 차이(p<0.05)를 나타내면서 불포화도가 높은 emulsion 시료일수록 hydroperoxide의 함량이 높았고, TBARS 값은 저장 30일에 6.229(${\Sigma}$SFA5), 6.801(${\Sigma}$SFA28), 6.246(${\Sigma}$SFA39), 4.419(${\Sigma}$SFA50) 및 4.226(${\Sigma}$SFA72) mg TBA/mL로 ${\Sigma}$SFA50과 ${\Sigma}$SFA72가 다른 emulsion 시료보다 유의적으로(p<0.05) 낮은 값을 보이며 산화 안정성이 우수하였다.