• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제26회 춘계학술대회논문집
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• pp.229-232
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• 2006

Tetrahydrofuran(THF)과 Ethylene oxide(EO) 또는 EO를 단량체로 하여 양이온 개환중합을 이용한 새로운 합성방법으로 random 또는 tri-block HTPE(Hydroxyl-terminated polyether)를 합성할 수 있었다. 합성된 random과 tri-block HTPE를 IPDI/N-100혼합 디이소시아네이트 경화제와 촉매로 TPB(triphenylbismuth)를 사용하여 폴리우레탄을 제조하였으며, 혼합 이소시아네이트 화합물의 비율에 따른 폴리우레탄의 기계적 특성을 연구하였다. 그리고 폴리 우레탄 추진제 바인더 제조를 위한 prepolymer인 합성된 HTPE의 최적 경화 조건을 찾기 위해 HTPE의 후처리 과정, 우레탄 합성시 사용되는 촉매의 양 등의 영향에 대해 알아보았다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제30회 춘계학술대회논문집
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• pp.221-226
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• 2008

Hydroxy-terminated polyether의 새로운 합성방법인 양이온 개환 공중합에 의해서 Ethylene oxide와 Tetrahydrofuran을 공중합 하였다. 중합은 1,4-Butandiol 존재 하에 $BF_3$ THF를 촉매로 반응이 진행되어 잘 제어된 Polyetherdiol을 합성할 수 있었다. Polyurethane 반응은 Polyetherdiol과 경화제로써 I-PDI/N-100 혼합물을 사용하였고, 경화촉매로 TPB/MA 혼합물을 사용하여 합성하였다. 이렇게 합성된 Polyurethane은 현재 미국에서 시판중인 ATK HTPE를 이용한 Polyurethane과 기계적 특성과 경화 거동을 비교 분석하였다.

• 약학회지
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• 제42권5호
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• pp.500-506
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• 1998

Steroidal 2${\beta},\;3{\beta}$--epoxy compound was prepared from asiaticoside via six steps and reduced regioselectively with lithium aluminum hydride. Epoxide ring opening furnished 9 as a sole product at reflux condition through axial hydride attack at C-3.

• 한국군사과학기술학회지
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• 제8권2호
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• pp.67-76
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• 2005

We synthesized an energetic prepolymer(glycidyl dinitro propyl formal, GDNPF) for plastic-bonded explosive and measured its thermodynamic parameters. Glycidyl dinitro propyl formal(GDNPF) as an energetic monomer was epoxidized from allyl-2,2-dinitro propyl formal which is reacted with dinitro propyl alcohol and excess allyl alcohol, and then energetic polymer of GDNPF was polymerized by cationic ring opening polymerization. Thermodynamic parameters were obtained from the ceiling temperature($T_c$) values of 1 mole monomer at reaction temperature. We varied feed rate of monomer, concentration of initiator and monomer to control molecular weight and polydispersity of prepolymer (GDNPF). The activated monomer polymerization has been executed with precisely controlled feed of GDNPF monomer to reactor in the complex state catalyst generated by $BF_3{\cdot}(C_3H_5)_2$ and 1,4-butanediol in $C_2H_4Cl_2$. Number average molecular weight(Mn), polydispersity(Pd), hydroxy number and glass transition temperature($T_g$) of prepolymer(GDNPF) were $2,500{\sim}3,000,\;1.2{\sim}1,3,\;0.6{\sim}0.8eq/kg\;and\;-20{\sim}-25^{\circ}C$ respectively.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제31회 추계학술대회논문집
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• pp.231-236
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• 2008

양이온 개환중합법을 이용하여 Epichlorohydrin(ECH)과 Tetrahydrofuran(THF)을 공중합 하였다. 중합은 1,4-Butandiol 존재 하에 $BF_3THF$를 촉매로 사용하여 잘 제어된 Copolyetherdiol을 합성하였다. 분자량은 [monomer]/[diol]비를 조절하였고, 공중합체 조성은 ECH와 THF의 투입몰비를 변화하여 조절하였다. 합성된 Copolyetherdiol의 Chlorine기는$S_N2$반응을 이용하여 Azide기로 치환하였다. 합성된 고분자를 프리폴리머로 사용하여 경화제인 N-100/IPDI와 경화촉매인 TPB/MA 혼합촉매를 이용하여 Polyurethane을 합성하여 경화거동과 기계적 특성은 비교 분석하였다.

• Bulletin of the Korean Chemical Society
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• 제25권9호
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• pp.1379-1384
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• 2004

Rearrangements of 1,3-oxathiolane sulfoxides 8 and 9 in the presence of base are described from a mechanistic viewpoint of sigmatropic and elimination reactions. In the presence of triethylamine the (Z)-sulfoxide 8 gave the corresponding thiolsulfinate 10 by way of dimerization of the sulfenic acid intermediate 2 at room temperature while the (E)-sulfoxide 9 was recovered even after refluxing in ethyl acetate by the reversal of the [2,3]-sigmatropic rearrangement of the sulfenic acid 4. Triethylamine promoted the developing charge separation in the transition state of the sigmatropic rearrangement of the (Z)-sulfoxide 8 to facilitate the ring opening to the sulfenic acid 2. The reason for more facile ring opening of the (Z)-sulfoxide 8 in comparison with the corresponding (E)-sulfoxide 9 is attributable to the differences in the reactivity of the hydrogen adjacent to the carbonyl group. Triethylamine was not strong base to deprotonate the carbonyl-activated methylene hydrogen of the (E)-sulfoxide 9 but enough to catalyze the sigmatropic process of the sulfoxides. The sulfenic acid 2 dimerized to the thiolsulfinate 10 while the sulfenic acid 4 proceeded the sigmatropic ring closure. In the presence of strong base such as potassium hydroxide, the elimination reaction was predominant over the sigmatropic rearrangement. In this reaction condition, both sulfoxides 8a and 9a gave a mixture of the disulfide 12, the isomeric disulfide 14, and the sulfinic acid 13. Under the strong alkaline condition an elimination of activated hydrogen from the carbon adjacent to the carbonyl group to furnish the sulfenic acid 2a and the isomeric sulfenic acid 18. The formation of the transient intermediate in the reaction was proven by isolation of the isomeric disulfide 14. The reactive entity was regarded as the sulfenic acid rather than sulfenate anion under these reaction conditions.

• Bulletin of the Korean Chemical Society
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• 제8권2호
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• pp.96-101
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• 1987

2-Ethoxy-6-methoxy-5-cyano-3,4-dihydro-2H-pyran (1_a$), 2-n-butoxy-6-methoxy-5-cyano-3,4-dihydro-2H-pyr an (1b), 2-isobutoxy-6-methoxy-5-cyano-3,4-dihydro-2H-py ran ($1_c$), and 2-ethoxy-6-methoxy-3-methyl-5-cyano-3,4-dihydro -2H-pyran ($1_d$) were prepared by (4 + 2) cycloaddition reaction of methyl $\alpha$-cyanoacrylate with the corresponding alkyl vinyl ethers. Compounds $1_{a-d}$ were ring-open polymerized by cationic catalyst to obtain alternating head-to-head (H-H) copolymers. For comparison, head-to-tail (H-T) copolymer $3_a$ was also prepared by free radical copolymerization of the corresponding monomers. The H-H copolymer exhibited minor differences in its $1_H% NMR and IR spectra, but in the $^{13}C$ NMR spectra significant differences were observed between the H-H and H-T copolymers. Glass transition temperature ($T_g$) of H-H copolymer was higher than that of the H-T copolymer, but thermal decomposition temperature of the H-H copolymer was lower than that of the H-T copolymer. Compounds $1_a$, $a_b$, and $1_c$, copolymerized well with styrene by cationic catalyst, but compound 1d failed to copolymerize with styrene. All of the H-H and H-T copolymers were soluble in common solvents and the inherent viscosities were in the range 0.2-0.4 dl/g.

• 대한화학회지
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• 제34권2호
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• pp.165-170
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• 1990

광학활성인 $[Co(edta)]^- 착물과 [Co(Hedta)Cl]^- 착물의 반응성과 구조적인 변화를 여러 가지 촉매(H^+, OH^-, 그리고 Cd^{2+})의 존재하에서 연구하였다. Δ-[Co(edta)]- 착물에 촉매로서 H+ 또는 OH-를 각각 작용시키면 착물에 대한 리간드의 G-ring이 열리면서, 광학활성인 [Co(Hedta)OH_2]착물과 라세미-[Co(edta)OH]^{2-} 착물이 생성된다. (-)546-[Co(Hedta)Cl]- 착물에 촉매로서 Cd^{2+}$를 작용시키면, 고리닫힘이 일어나 Δ-[Co(edta)]-착물이 생성되어지고, 이 때 절대배치는 유지되어진다.

• Journal of Radiation Protection and Research
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• 제28권4호
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• pp.291-298
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• 2003

The KN-12 transport cask has been designed to transport 12 PWR spent nuclear fuel assemblies and to comply with the regulatory requirements for a Type B(U) package. The containment boundary of the cask is defined by a cask body, a cask lid, lid bolts with nuts, O-ring seals and a bolted closure lid. The containment vessel for the cask consists of a forged thick-walled carbon steel cylindrical body with an integrally-welded carbon steel bottom and is closed by a lid made of stainless steel, which is fastened to the cask body by lid bolts with nuts and sealed by double elastomer O-rings. In the cask lid an opening is closed by a plug with an O-ring seal and covered by the bolted closure lid sealed with an O-ring. The cask must maintain a radioactivity release rate of not more than the regulatory limit for normal transport conditions and for hypothetical accident conditions, as required by the related regulations. The containment requirements of the cask are satisfied by maintaining a maximum air reference leak rate of $2.7{\times}10^{-4}ref.cm^3s^{-1}$ or a helium leak rate of $3.3{\times}10^{-4}cm^3s^{-1}$ for normal transport conditions and for hypothetical accident conditions.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.323-327
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• 2004

The bubble flow from the wafer surface during plating process was studied in this paper. The plating shape in the opening of photoresist becomes gradated shape in the fountain plating system, because bubbles from the wafer surface are difficult to escape from the deep openings, vias. So, we designed the tilted electrode ring contact to get uniform bump height on all over the wafer and evaluated the film uniformity by SEM and ${\alpha}-step$. In ${\alpha}-step$ measurement, film uniformities in the fountain plating system and the tilted electrode ring contact system were ${\pm}16.6%,\;{\pm}4%$ respectively.