Abstract
中文摘要本論文以不具毒性，熱穩定性高且易與金屬離子形成錯合物之聚乙二醇為相間轉移觸媒，研究在由酚鈉鹽與烯丙基氯反應合成烯丙基苯基醚反應中，聚乙二醇所扮演的角色及其應用潛力。在乙醇溶液均勻相反應系統中結果顯示，在酚鈉鹽與烯丙基氯的反應中，真正的活性反應物是（pho-）自由離子而非（phONa）離子對，而聚乙二醇的主要功能是促進酚鈉鹽離子對的解離，提供更多的（phO-）自由離子，增加反應速率。根據實驗所得的反應機構及離散結合座模式，可由一數學模式來描述在聚乙二醇存在下的均勻相反應系統為：（圖表省略）聚乙二醇在水一油兩相中的反應，以電導度測量結果顯示其反應機構為離子萃取機構。由於聚乙二醇具有與金屬陽離子錯合能力且是很好的有機溶劑，故聚乙二醇的加入，不僅提高了油相的反應速率，水相亦然。根據本研究所倡導的反應機構及聚乙二醇特性，其兩相反應動力學模式可表示為：（圖表省略）即油相的酚陰離子濃度與所加入的聚乙二醇量有正比關係，與水相的酚陰裡子濃度有二次正比關係。而烯丙基氯在水相中的溶解度與加入之聚乙二醇量有正比關係。因此，在兩相的反應系統中，聚乙二醇觸媒適合於高水相金屬鹽濃度的反應條件下進行。在液─液兩相反應中的溶劑效應研究結果顯示，偽質子溶劑的種類對含與不含聚乙二醇的反應速率比值，（-r）i, p/（-r）i,b，沒有影響，且其值不大（約2.2 左右），而偽質子溶劑的極性愈小，其總反應速率愈高，即n-decane > cyclohexane >ethy1 ether > chlorobenzene > dichloromethane 。而質子溶劑的改變，其影響則非常大，如以PEG-400 完全取代質子溶劑相中的水，其反應速率是不含PEG 的n-decane/H2O系統的60倍。而在n-decane/（H2O:PEG-400）兩相系統中，當PEG-400含量比例高於60% 時，其反應完全發生在（H2O:PEG-400 ）相中。雖然在n-decane/（H2O:PEG-400 ）兩相反應中，100%所得的反應速率最高，但在不同H2O:PEG-400 比例下求得的均勻相反應速率常數指出，在70% 的PEG-400 溶液中其反應速率常數最大。///////ABSTRACTIn this dissertation, polyethylene glycols (PEGs), which are cheap,non-toxic, high thermal stability, and easy recovey by conventionalseparation technique are used as the phase transfer catalysts. The maincharacteristic of PEGs is able to form complexes with metal cations. Theprimary purpose of the present research is to study the role and itsapplication potential of PEGS in the allylation of phenoxide with allylchloride (or allyl bromide).In the experiments of homogeneous EtoH solution, the reaction mechanism ofphenoxied allylation with allyl chloride, from which the sodiuum phenoxiedallylation with allyl chloride, from which the sodium phenoxide willdissociate into free ions and complexes will form from sodium cation withPEGs, is proposed. The free ions of the dissociated phenoxide is verifiedas the active component in the allylation. Based on the prosposed reactionmechanism and the discrete binding-site model, the homogeneous phasereaction of phenoxide allylation under the existing of PEGs can bedescribed by the following mathematical model:（圖表省略）In the two-phase heterogeneous reactio system, PEGs are also used as thephase transfer catalysts. The ion-extraction mechanism, which is verifiedby the electroconductomeric method, is proposed. The reaction takes place,either in ther organic phase or in the aqueous phase. This is due to theeasy formation of complexes from PEGs with metal cations and employment ofan excellent solvent. Based on the proposedeaction mechanism and thecharacteristics of PEGs, the kinetic model of the two-phase reactionsystem can be expressed as:（圖表省略）This model leads to a rigid conclusion that the phenoxide ionsconcentration in the organic phase is linear proportional to the amount ofPEGs added and is also proportional to the phenoxide concentration in theaqueous phase with a power of two. Therefore, it is more favorable to makethe reaction system in a high aquenous metal salts concentration by usingPEG as a phase transfer catalyst.In studying the effects of solvents in a two-phase phase transfercatalytic reaction by PEGs, the rectivity ration(-r)i,p/(-r)i,b, eitherwith PEGs or without PEGs is insensitive to the kinds of the organicsolvents used. The overall reactivity of the reaction is increased byusing an organic solvent with small polarigy., i.e.,n-decane >cyclohexane> tyhyl ether > chlorobenzene > dichloromethane. However, the aqueousphase solvent will dramatically influence the reactivity. The experimentalresults indicates that the reactivity of the reaction in using PEG-400 forreplacing water as the aqueous phase is about 60 times of the reactivityin a n-decane/H2O reaction system. The experimental results also indicatesthat the reaction completely occurs in the H2O:PEG-400 phase when thevolume content of PEG is greater than 60%. In the n-decane/(H2O:PEG-400)Two-phase reaction, the greatest reactivity of the reaction was carriedout in a 100% volume of PEG in (H2O:PEG-400) Phase. However, the greatestreactivity of the reaction occurred at a 70% PEG homogeneous solution.