http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Mechanism of Polymerization Reaction of 4-[(n-Butylsulfinyl)methyl]-4'-(chloromethyl)benzene
변상용,조봉래,김환기,정진현 대한화학회 2008 Bulletin of the Korean Chemical Society Vol.29 No.12
The polymerization reaction of 4-[(n-butylsulfinyl)methyl]-4'-(chloromethyl)benzene (1a) with t-BuONa in CH2Cl2/monomethylformamide (MMF) (4/6) was studied kinetically. The reaction proceeds in two steps; the formation of a p-quinodimethane intermediate (M) followed by the polymerization of M. Results of kinetic studies and H-D exchange experiments reveal that the 1,6-elimination proceeds by the (E1cb)irr mechanism. The rate of the disappearance of M was increased by the carbanion and S2O8 2−, inhibited by TEMPO and unaltered by the addition of HCl. From these results, a free radical polymerization mechanism is proposed.
변상용,조봉래,Woong Sub Byun 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.6
Nitrile-forming eliminations from (E)-2,4,6-(NO_2)_3C_6H_2CH=NOC_6H_4-2-X-4-NO_2 (1) promoted by R_3NH/R_3NH^+ in 70 mol % MeCN(aq) have been studied kinetically. When X = NO_2, the reactions exhibited secondorder kinetics as well as Bronsted β = 0.63 and |β_(lg)| = 0.34-0.46, and an E2 mechanism is evident. As the leaving group was made poorer (X = H, Cl, and CF_3), Bronsted β value increased from 0.63 to 0.85-0.89 without much change in the |β_(lg)| value E2, indicating that structure of the transition state changed to an E1cb-like with extensive C_β-H bond cleavage, significant negative charge development at the β-carbon, and limited Cα-OAr bond cleavage.
변상용,김주창,조봉래 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.7
Ketene-forming elimination from 2-X-4-nitrophenyl furylacetates (1a-d) promoted by R2NH-R2NH2 + in 70 mol % MeCN(aq) has been studied kinetically. When X = Cl and NO2, the reactions exhibited second-order kinetics as well as Brönsted β = 0.37-0.54 and |βlg| = 0.31-0.45. The Brönsted β decreased with a poorer leaving group and |βlg| increased with a weaker base. The results are consistent with an E2 mechanism. When the leaving group was changed to a poorer one [X= H (1a) and OCH3 (1b)], the reaction mechanism changed to the competing E2 and E1cb mechanisms. A further change to the E1cb mechanism was realized for the reaction of 1a with i-Pr2NH/i-Pr2NH2 + in 70 mol % MeCN-30 mol % D2O. By comparing the kinetic results in this study with the existing data for ArCH2C(O)OC6H3-2-X-4-NO2, the effect of the β-aryl group on the ketene-forming elimination was assessed.
변상용,조봉래 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.7
Reactions of 4-nitrophenyl 2-thiophenecarboxylate (1a-e) with R2NH/R2NH2 + in 20 mol % DMSO (aq) have been studied kinetically. The 2nd order kinetics, βnuc = 0.88-0.98, and linear Hammett and Yukawa-Tsuno plots observed for these reactions indicate an addition-elimination mechanism in which the 2nd step is rate limiting. The βnuc value increased with a stronger electron-withdrawing 5-thienyl substituent, the Hammett plots are linear except for X = MeO, and Yukawa-Tsuno plots are linear with ρ = 0.79-1.32 and r = 0.28-0.93, respectively. The ρ value increased and r value decreased with a stronger nucleophile, indicating an increase in the electron density at the C=O bond and a decrease in the resonance demand. These results have been interpreted with enhanced N-C bond formation in the transition state with the reactivity increase.
변상용,백규철,한만소,김병태,조봉래 대한화학회 2017 Bulletin of the Korean Chemical Society Vol.38 No.11
Ketene-forming elimination from C4H3(O)CH2C(O)OC6H3-2-X-4-NO2 (1) promoted by R2NH in MeCN has been studied. The reactions produced elimination products and exhibited second-order kinetics with Brönsted β = 0.51, and |βlg| = 0.47–0.53, indicating that the reaction proceeds by the E2 mechanism via an E2-central transition state. Comparison of β, |βlg|, ΔH≠, and ΔS≠ values for R2NH-promoted eliminations from ArCH2C(O)OC6H3-2-X-4-NO2 reveals that the transition-state structures for Ar = furyl and thienyl are similar and more symmetrical than that for Ar = Ph. This outcome has been attributed to the greater double bond stabilizing ability of the former than that of the latter.
변상용 濟州大學校 産業技術硏究所 1999 산업기술연구소논문집 Vol.10 No.2
There is a trend of increasing inters for software components reuse. Reuse based on objects is belived efficient than that on functions. Objects are implemented by classes, therefore we are focused on reuse of classes. This study is concerned with an increasing reusabiliy through separating input interfaces and output interfaces from the classs that have ultimate input data or ultimate output data.
변상용 제주대학교 공과대학 첨단기술연구소 2001 尖端技術硏究所論文集 Vol.12 No.2
There is a trend of increasing interest for object-oriented software development. In the object-oriented requirement analysis phase, we construct use-case diagrams, class-diagrams and state-diagrams. However any of them can't provide information for data transfer between classes. In the data processing software, data flow between software components should be comprehended. And in the object-oriented design phase, we construct interaction-diagrams and detailed class-diagrams. but also any of them can't provide information for data transfer between classes or objects. Therefore this paper suggest class-diagrams and collaboration-diagrams with capability of data-transfer and data-return between software components.
변상용 제주대학교 산업기술연구소 1999 尖端技術硏究所論文集 Vol.10 No.2
There is a trend of increasing interest for software components reuse. Reuse based on objects is belived efficient than that on functions. Objects are implemented by classes, therefore we are focused on reuse of classes. This study is concerned with an increasing reusability through separating input interfaces and output interfaces from the classy that have ultimate input data or ultimate output data.
Fe(0)촉매를 이용한 Dienyne의 분자내 〔4+2〕고리화 첨가반응에 관한 연구
변상용 釜慶大學校 1998 釜慶大學校 論文集 Vol.3 No.2
The intramolecular formal iron-catalyzed 〔4+2〕 cycloaddition reaction of acetylenic dienes to produce bicyclic products has been investigated. With a typical iron(0) catalyst, prepared by the reduction of Fe(acac)3 with Et3Al in the presence of bipyridine ligand, the (E,E)-4, 4-dicarboethoxy-1-phenyldeca-1-yne-6, 8-diene proceeded competing via intramolecular carbocylization and bimolecular cycloaddition. However, under the similar condition except the chiral ligand, the 4, 4-dimethly〔 -3-(tert-mutyldimethylsiloxy)-1-pheny〕-6, 8-decadien-1-yen yielded exclusively bicyclic diene product(yield 86%).
Fe(0) 촉매를 이용한 Acetylenic Dienes 의 분자내 [4+2] 고리화 첨가반응에 관한 연구
변상용,Byeon, Sang Yong 대한화학회 1994 대한화학회지 Vol.38 No.1
Fe(0)촉매하에서 이중고리 생성물이 얻어지는 acetylenic diene을 반응시켜 분자내 [4+2]고리화 첨가반응을 조사하였다. 위 반응은 이분자 첨가반응과 분자내 탄소 고리화 반응이 경쟁적으로 진행된다고 알려져 있다. 그러나 Fe(0)촉매하에서 4,4-dimethyl-3-(tert-butyldimethylsiloxy)-1-phenyl-6,8-decadien-1-yne(11)의 고리화 반응은 단지 이중고리 생성물만이 얻어졌다(수득율 78.1%). 이 결과에서 dienyne의 4,4-위치에 치환된 dimethyl기가 Fe(0)촉매하의 고리화 반응조건에 안정함으로 인하여 분자내 고리화 반응이 촉진되는 것으로 생각된다. The intramolecular formal iron-catalyzed [4+2] cycloaddition reaction of acetylenic dienes to produce bicyclic products has been investigated. These reactions proceeded, competing via intramolecular carbocyclization and bimolecular cycloaddition. However, the iron-catalyzed bicyclic carbocyclization of 4,4-dimethyl-3-(tert-butyldimethylsiloxy)-1-phenyl-6,8-decadien-1-yne(11) yielded exclusively bicyclic diene product(yield 78.1%). From this result, we found that the substrate containing a dimethyl substitutent at the 4,4-position helped to promote the intramolecular reaction, which is stable to the iron catalyzed conditions.