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ALKYL HALOFORMATE ESTER류와 1-ADAMANTYL THIOCOMPOUND류의 가용매 분해반응에 대한 반응성 및 물리화학적 특성연구

Title
ALKYL HALOFORMATE ESTER류와 1-ADAMANTYL THIOCOMPOUND류의 가용매 분해반응에 대한 반응성 및 물리화학적 특성연구
Other Titles
REACTIVITY AND PHYSICOCHEMICAL PROPERTIES FOR THE SOLVOLYSES OF ALKYL HALOFORMATE ESTERS AND 1-ADAMANTYL THIOCOMPOUNDS
Author
성미혜
Advisor(s)
경진범
Issue Date
2013-08
Publisher
한양대학교
Degree
Doctor
Abstract
제 1 부 ALKYL HALOFORMATE ESTER류의 가용매 분해반응에 대한 속도론적 연구 순수 및 이성분 혼합 용매 내에서 methyl, ethyl, n-propyl, neopentyl 및 t-butyl fluoroformate의 가용매 분해반응에 대한 반응 속도를 여러 온도에서 적정법을 이용하여 측정하였다. 1차, 2차 및 3차 alkyl fluoroformate들에 대한 가용매 분해반응 속도 순은 70% TFE 용매를 제외한 100% MeOH, 100% EtOH 및 80% EtOH 용매 내에서 kMe > kEt ≈ kn-Pr ≈ ki-Bu ≈ kNeop ≈ kn-Oct > ki-Pr > kt-Bu >> k1-Ad 임을 알았으며, ethyl, i-propyl 그리고 t-butyl fluoroformate와 같이 α-carbon group의 알킬기가 증가할수록 반응 속도는 감소하고, β-carbon group에 알킬기가 증가한 경우에는 속도 상수의 영향이 거의 없음을 알 수 있었다. 1차와 2차인 ROCOF의 속도 비 (kF/kCl) 는 모든 용매 내에서 속도 결정 단계가 첨가 반응인 이분자성 첨가-제거 반응의 특성을 나타내었으며, 3차인 1-adamantyl fluoroformate는 대부분의 용매 내에서 이온화 반응에 대한 특성을 보였다. 그리고 t-butyl fluoroformate 및 1-adamantyl fluoroformate를 제외한 모든 물질에서 확장된 Grunwald-Winstein 식을 적용한 결과 이분자성 첨가-제거 반응을 나타내었다. 또한 모든 alkyl fluoroformate류의 가용매 분해반응에 대한 활성화 파라미터들과 용매 동위원소 효과를 계산하였다. 특히 t-butyl fluoroformate의 활성화 엔트로피 값은 속도 결정 단계가 이온화 반응과 일치하는 적은 음의 값을 나타내었다. 이상의 결과들과 이전에 연구된 alkyl chloroformate류들과 비교하고, 이 반응들에 대한 메커니즘을 규명하였다. 제 2 부 1-ADAMANTYL CHLOROTHIOFORMATE 와 1-ADAMANTYL FLUOROTHIOFORMATE 의 가용매 분해반응에 대한 속도론적 연구 여러 용매 내에서 1-adamantyl chlorothioformate 및 1-adamantyl fluorothioformate의 가용매 분해반응에 대한 속도 상수를 25.0 oC와 50.0 oC에서 각각 측정하였다. 두 물질들의 가용매 분해반응 속도를 단순 및 확장된 Grunwald-Winstein 식에 적용하였다. 각 물질에 대한 Grunwald-Winstein 식의 자료와 생성물 연구로부터, 1-adamantyl chlorothioformate의 가용매 분해반응은 모든 용매 내에서 이온화 반응 경로 [1-Ad+Cl- 또는 (1-AdSCO)+Cl-]가 지배적이었으며, 1-adamantyl fluorothioformate의 가용매 반응은 친핵성도가 크고 이온화력이 매우 적은 용매 내에서는 첨가-제거 반응이 지배적이나, 그 이외의 용매 내에서는 주된 반응이 이온화 반응임을 알았다. 가용매 분해반응의 생성물에 대한 선택성들은 이미 연구된 1-adamantyl, 2-adamantyl 유도체 및 benzyl chloroformate의 값들과 매우 유사하였다. 97% TFE 및 70% TFE 용매 내에서 이탈기의 가용매 분해반응에 대한 속도 비 (kF/kCl = ~10-6) 들은 속도 결정 단계인 전이상태에서 결합 파괴의 특징을 나타내었다. 또한 1-adamantyl chlorothioformate 와 1-adamantyl fluorothioformate의 가용매 분해반응에 대한 용매 동위원소 효과와 활성화 파라미터들을 결정하였다. 이상의 결과들을 이전에 보고된 1-adamantyl chloroformate 및 1-adamantyl fluoroformate와 비교하였다. |Part 1 Kinetic Studies for the Solvolyses of Alkyl Haloformate Esters The rate constants for the solvolyses of methyl, ethyl, n-propyl, neopentyl and t-butyl fluoroformates have been measured using a titrimetric method at various temperatures in pure and binary solvent mixtures. The order of rate constants of the above substrates in relation to those previously studied for primary, secondary, and tertiary alkyl haloformates, is kMe > kEt ≈ kn-Pr ≈ ki-Bu ≈ kNeop ≈ kn-Oct > ki-Pr > kt-Bu >> k1-Ad in 100% MeOH, 100% EtOH, and 80% EtOH, but not in 70% TFE. The increased bulkiness of the alkyl group (branching at the α-carbon group adjunct to the oxygen atom in alkyl fluoroformates) in ethyl, i-propyl, and t-butyl fluoroformates decreased the rate of the reaction. The rate ratios for ethyl-, n-propyl-, i-butyl-, neopentyl-, and n-octyl fluoroformates in 100% MeOH, 100% EtOH, and 80% EtOH were all close to unity. This indicates that the electronic and/or steric influences coming from the presence of a branching β-alkyl group adjacent to an oxygen atom in the alkyl haloformates were negligible. The kF/kCl values for solvolyses of primary and secondary alkyl fluoroformates were very similar to those for n-octyl fluoroformate, consistent with a bimolecular addition-elimination mechanism, proceeding through a tetrahedral intermediate. Application of the extended Grunwald-Winstein (G-W) equation to solvolyses of primary and secondary alkyl fluoroformates in a variety of pure and binary solvents indicated an addition-elimination pathway in the full range of solvents except t-butyl fluoroformate and1-adamantyl fluoroformate. The kinetic solvent isotope effects (KSIEs) and the activation parameter values for the solvolyses of all alkyl fluoroformates were calculated. The small negative values for the entropies of activation of solvolysis of t-butyl fluoroformate were particularly consistent with the ionization nature of the proposed rate-determining step. The results were also compared with those reported earlier for alkyl chloroformates and mechanistic conclusions were drawn. Part 2 Kinetic Studies for the Solvolyses of 1-Adamantyl Chlorothioformate and 1-Adamantyl Fluorothioformate The rate constants of solvolysis of 1-adamantyl chlorothioformate and 1-adamantyl fluorothioformate have been measured at 25.0 oC and 50.0 oC in a wide range of solvents, respectively. The simple and extended Grunwald-Winstein equations have been applied to determine the reaction rates of two substrates. From the results of the Grunwald-Winstein equation analyses and the product studies for each substrate, there was evidence for two and/or three competing reaction channels. In 1-adamantyl chlorothioformate solvolysis, the ionization pathway [1-Ad+Cl- or (1-AdSCO)+Cl-] was dominant (m = 0.84) in all solvents. For 1-adamantyl fluorothioformate, an addition-elimination reaction dominates in solvents of very high nucleophilicity and very low ionizing power (l = 2.71, m = 1.03, and l/m = 2.63), and only in the more ionizing and least nucleophilic solvents (m = 0.86) the principal reaction involved ionization. For mixtures of hydroxylic solvents, the selectivities for the formation of solvolysis products are very similar to those observed in conventional solvolyses of 1-adamantyl, 2-adamantyl derivatives, and benzyl chloroformate. The kF/kCl ratios for solvolysis-decomposition in 97% TFE and 70% TFE were in the range of ~10-6, suggesting appreciable C-X bond breaking in the transition state of the rate-determining step. The kinetic solvent isotope effects (KSIEs) and activation parameters for the solvolyses of 1-adamantyl chlorothioformate and 1-adamantyl fluorothioformate were also determined. These observations were compared with those previously reported for the solvolyses of 1-adamantyl chloroformate and 1-adamanty fluoroformate.; Part 1 Kinetic Studies for the Solvolyses of Alkyl Haloformate Esters The rate constants for the solvolyses of methyl, ethyl, n-propyl, neopentyl and t-butyl fluoroformates have been measured using a titrimetric method at various temperatures in pure and binary solvent mixtures. The order of rate constants of the above substrates in relation to those previously studied for primary, secondary, and tertiary alkyl haloformates, is kMe > kEt ≈ kn-Pr ≈ ki-Bu ≈ kNeop ≈ kn-Oct > ki-Pr > kt-Bu >> k1-Ad in 100% MeOH, 100% EtOH, and 80% EtOH, but not in 70% TFE. The increased bulkiness of the alkyl group (branching at the α-carbon group adjunct to the oxygen atom in alkyl fluoroformates) in ethyl, i-propyl, and t-butyl fluoroformates decreased the rate of the reaction. The rate ratios for ethyl-, n-propyl-, i-butyl-, neopentyl-, and n-octyl fluoroformates in 100% MeOH, 100% EtOH, and 80% EtOH were all close to unity. This indicates that the electronic and/or steric influences coming from the presence of a branching β-alkyl group adjacent to an oxygen atom in the alkyl haloformates were negligible. The kF/kCl values for solvolyses of primary and secondary alkyl fluoroformates were very similar to those for n-octyl fluoroformate, consistent with a bimolecular addition-elimination mechanism, proceeding through a tetrahedral intermediate. Application of the extended Grunwald-Winstein (G-W) equation to solvolyses of primary and secondary alkyl fluoroformates in a variety of pure and binary solvents indicated an addition-elimination pathway in the full range of solvents except t-butyl fluoroformate and1-adamantyl fluoroformate. The kinetic solvent isotope effects (KSIEs) and the activation parameter values for the solvolyses of all alkyl fluoroformates were calculated. The small negative values for the entropies of activation of solvolysis of t-butyl fluoroformate were particularly consistent with the ionization nature of the proposed rate-determining step. The results were also compared with those reported earlier for alkyl chloroformates and mechanistic conclusions were drawn. Part 2 Kinetic Studies for the Solvolyses of 1-Adamantyl Chlorothioformate and 1-Adamantyl Fluorothioformate The rate constants of solvolysis of 1-adamantyl chlorothioformate and 1-adamantyl fluorothioformate have been measured at 25.0 oC and 50.0 oC in a wide range of solvents, respectively. The simple and extended Grunwald-Winstein equations have been applied to determine the reaction rates of two substrates. From the results of the Grunwald-Winstein equation analyses and the product studies for each substrate, there was evidence for two and/or three competing reaction channels. In 1-adamantyl chlorothioformate solvolysis, the ionization pathway [1-Ad+Cl- or (1-AdSCO)+Cl-] was dominant (m = 0.84) in all solvents. For 1-adamantyl fluorothioformate, an addition-elimination reaction dominates in solvents of very high nucleophilicity and very low ionizing power (l = 2.71, m = 1.03, and l/m = 2.63), and only in the more ionizing and least nucleophilic solvents (m = 0.86) the principal reaction involved ionization. For mixtures of hydroxylic solvents, the selectivities for the formation of solvolysis products are very similar to those observed in conventional solvolyses of 1-adamantyl, 2-adamantyl derivatives, and benzyl chloroformate. The kF/kCl ratios for solvolysis-decomposition in 97% TFE and 70% TFE were in the range of ~10-6, suggesting appreciable C-X bond breaking in the transition state of the rate-determining step. The kinetic solvent isotope effects (KSIEs) and activation parameters for the solvolyses of 1-adamantyl chlorothioformate and 1-adamantyl fluorothioformate were also determined. These observations were compared with those previously reported for the solvolyses of 1-adamantyl chloroformate and 1-adamanty fluoroformate.
URI
https://repository.hanyang.ac.kr/handle/20.500.11754/133054http://hanyang.dcollection.net/common/orgView/200000422185
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GRADUATE SCHOOL[S](대학원) > APPLIED CHEMISTRY(응용화학과) > Theses (Ph.D.)
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