Abstract
中文摘要本文在探討利用相間轉移觸媒技術合成烯丙基多溴苯基醚的動力學及動態行為。由溴化烯丙基(Allyl bromide) 分別與2,4,6-三溴酚(2,4,6-Tribromophenol)及4-溴酚(4- Br omophenol)反應生成烯丙基2,4,6-三溴苯基醚(Allyl 2,4,6-tribromophenylether)及烯丙基4-溴苯基醚(Ally 4- bromophenyl ether) ，其中前者可作為阻燃劑之添加劑，後者則作為殺蟲劑。應用相間轉移觸媒能在溫和的反應條件獲得極高的產率，有效改進以往製造方法之缺點。在2,4,6-三溴酚與溴化烯丙基的反應系統，本文深入探兩相系統之反應機構，由不同的操作條件，獲得中間產物2,4,6-三溴苯氧基化四丁基銨(Tetrabutyl ammonium2,4,6- tribromophenoxide) 之變化情形，並測定觸媒與中間產物在兩相間之分布係數與質傳係數，有機相與水相反應速率，提出系統之動態模式，成功地描述了此液－液相反應。所測得之氯苯╱水兩相系統之參數表示如下：（１）溴化四丁基銨之分布係數與質傳係數分布係數（圖表省略）質傳係數（圖表省略）（２）2,4,6-三溴苯氧基化四丁基銨之分布係數與質傳係數分布係數質傳係數(3)水相反應速率(圖表省略)（４）有機相反應速率（圖表省略）經由觀察中間產物隨時間之變化情形，而知在過水相反應物或低觸媒用量的反應條件下，可使用虛擬一階反應動力式來描述系統，當水相反應物之用量低於有機相反應物用量時，則中間產物於誘導期後隨時間之變化而逐漸減低。同時，利用Damkohler 數探討觸媒及中間產物之質量傳送對整體反應的影響，而確認有機相反應為速率決定步驟。對於2,4,6-三溴酚及4-溴酚與溴化烯丙基的觸媒反應進行最適操作條件的探討，顯示攪拌速率大於600 rpm 時可忽略質傳阻力，操作條件則包括觸媒用量、反應物用量、溶劑種類、觸媒種類及溫度等，確認了多溴酚與溴化烯丙基的反應機構屬於SN2 ，而對烯丙基2,4,6-三溴苯基醚與烯丙基4-溴苯基醚應用溴化四丁基銨來合成之活化能分別為13.8 Kcal/mole與12.7 kcal/mole。另以聚苯乙烯顆粒為擔體之固定化相間轉移觸媒進行烯丙基2,4,6-三溴苯基醚之合成，同時提出一簡易方法來求得反應物之有效擴散係數(Effective diffusivity) ，配合Thilel模數的定義，獲知本反應系統屬擴散與反應合併控制，同時亦尋求三相反應之最適操作條件，獲得其視活化能為11.7 kcal/mole，並提出液－液－固相間轉移觸媒反應在批式反應器之動態模式來描述系統，結果顯示，在各種操作條件下，模擬的結果與實驗結果甚為接近。因此，此動態模式可適用於本反應系統。///////ABSTRACTThe objectives of this dissertation are to synthesize allylpolybromophenyl ether by phase transfer catalysis technique and to studytheir kinetics as well as dynamic behaviors. The reaction systems are theallylation of 2,4,6-tribromophenol and 4-bromophenol to produce allyl2,4,6-tribromophenyl ether and allyl 4-bromophenyl ether,respectively. Theformer is used as the additive of flame retardant,the latter asinsecticide. Using phase transfer catalysis to synthesize such finechemicals,the yield can be as high as 100 % in short reaction time. ThePTC technique thus greatly and effectively enhances the manufacturingmethod of these two chemicals.For the reaction of 2,4,6-tribromophenol and allyl bromide,the mechanismof two-phase reaction was studied in detail. The change of intermediatespecies--tetrabutyl ammonium 2,4,6-tribromophenoxide during the reactionat different conditions was measured to understand the behavior of the PTcatalyst. A dynamic model was proposed to describe the dynamic behavior ofthe system successfully. The parameters such as mass transfer coefficientsof catalysts, aqueous and organic phase reaction rate constants, Theresults in chlorobenene/water system were as follows:(1)Distribution and mass transfer coefficients of Bu4NBrDistribution coefficient:Mqbr=7.1×10﹣2-0.56 CMass transfer coefficient:Kqbr A=2.69 (min-1)(2)Distribution and mass transfer coefficient of tetrabutyl ammonium 2,4,6-tribromophenoxideDistribution coefficient:Maroq=(8+0.05T)+(78.3T-1165)CMass transfer coefficient:KaroqA=3.84+0.06T(min-1)(3)Aqueous phase reaction rateKaq=3.2×107 exp[-4840/(T+273.16)](M-1min-1)(4)Organic phase reaction rateKorg=3.3×109 exp[-7016/(T+273.16)](M-1min-1)Pseudo first order kinetics can be applied to describe the overallreaction for the conditions of using excess amount of aqueous of reactantor low quantity of catalyst. As the amount of reactant in the aqueousphase is smaller than that in the organic phase, the concentration ofintermediate species is gradually decreased after the induction period.The effects of mass transfer rate of the catalyst and intermediate on theoverall reaction were discussed by using the concept of Damkohler number.The organic phase reaction was thus determined as the controlling step fortwo phase reaction.The optimized operating conditions for the reactions of allyl bromide with2,4,6-tribromophenol and 4-bromophenol were studied. The results show thatthe mass transfer resistance can be neglected for agitation speed largerthan 600 rpm. The operating conditions include:amounts of catalyst andreactant,etc.The results also show that the reaction mechamism of allyl bromide withpolybromophenol is confirmed as Sn2. The apparent activation energies for2,4,6-tribromophenol and 4-bromophenol system with tetrabutyl ammonoumbromide as the catalyst were measured as 13.8 kcal/mole and 12.7kcal/mole,respectively.The immobilized phase transfer catalyst with polystyrene as support wasalso used to synthesize allyl 2,4,6-tribromophenyl ether. A simplifiedmethod for estimating the effective diffusivity of reactants within thecatalyst particle was proposed. Combining the definition of Thiele modulusin Triphase catalysis, the 2,4,6-tribromophenol system was determized asreaction and diffusion control. The optimized operating condition for thetriphase reaction was studied, the apparent activation energy was measuredas 11.7 kcal/mole. A dynamic model simulating the liquid-liquid-solidreaction in a batch reactor was proposed to describe the triphase system.It shows that the simulation results are very consistent with theexperimental data. Therefore, the dynamic model can be used in thissystem.