11. Interfacial Mechanism and Kinetics of Phase-Transfer Catalysis

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FIG. 10Conceptual scheme for dispersed droplet and third liquid layer in TLPTC.MY in the aqueous phase undergoes a substitution reaction with the organic reactant RX toform the product RY. Under some appropriate conditions, by introducing extra inorganicsalts or reactants into the system, a separate liquid phase appears and is composed of PTcatalyst (QX), active intermediate (QY), a little water, and organic solvent. The third liquidlayer at the aqueous/organic interface exists if the solubility of QY in both the organic andaqueous phases is limited. This reaction system is shown in the following scheme:ð174ÞIn the third liquid phase system, the organic phase is considered as the dispersedphase with spherical and rigid droplets, and with a high distribution coefficient of catalystbetween aqueous and third phases. The rates of change of RX in the organic phase andQY/QX in the third phase are formulated as follows [234]:Copyright © 2003 by Taylor & Francis Group, LLC
@C orgRX@t@C catQY@t@C catQX@t¼ D RXr 2¼ D QYr 2¼ D QXr 2@r 2 @C org RX@r @r @r 2 @Ccat QY@r @r @r 2 @Ccat QX@r @rfor r r dfor r d r r cfor r D r r cð175Þð176Þð177ÞIn which r d is the radius of the organic droplet and r c is the radius of the organic dropletplus the thickness of the catalyst layer. The relationship between r c and r d isr c ¼ 1 þ V 1=3catrV d ð178ÞorgThe initial and boundary conditions areat t ¼ 0;at r ¼ 0;at r ¼ r d ;C orgRX ¼ C RX;0for 0 r r dC catQX ¼ 0; C catQY ¼ 0 for r D r r c ð179Þ@C orgRX¼ 0@r3 @CD orgRX ¼r dRX@r3 @CD catQYr dr dQY@r3 @CD catQX ¼QX@rk 2 C orgRX Ccat QY¼ k 2 C orgRX Ccat QYk 2 C orgRX Ccat QYThe distribution coefficients of QY and QX, m QY and m QX , are defined asm QY ¼ CcatðsÞ QYC aqðsÞQYAt r ¼ r c ;and m QX ¼ CcatðsÞ QXC aqðsÞQXD QY@C catQY@r@CQXcatD QX ¼@r¼ K QYC aqQYK QX ðC catQX1CQYcatm QYm QY C aqQX Þð180Þð181Þð182Þð183Þwhere K QY and K QX denote the mass transfer coefficients of QY and QX, respectively. Inthe aqueous phase, the rates of change of MY, QY, and QX aredC aqMY¼ kdt 1 C aqMY Caq QXdC aq QY¼ kdt 1 C aq3 VcatMY Caq QXK QYr c V aqdC aq QXVcatC catðsÞQXmdtQX C aqQX¼ K QX3r cV aqC aqQY1C catðsÞQYm QYk 1 C aqMY Caq QXð184Þð185Þð186ÞCopyright © 2003 by Taylor & Francis Group, LLC
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11Interfacial Mechanism and Kinetic
Page 3 and 4:
Other factors in selecting asuitabl
Page 5 and 6:
1. Applications in BiologyOrsini et
Page 7 and 8: Tundo et al. [15] reported an effic
Page 9 and 10: transfer of catalyst from the react
Page 11 and 12: A summary of characteristic kinetic
Page 13 and 14: dy 1ady o¼ QYy ody 2ody o¼ QXy
Page 15 and 16: (a) Pseudo-Steady-State LLPTC model
Page 17 and 18: The order of magnitude of D Q for q
Page 19 and 20: E T Q þ ;H 2 O ¼ ½Qþ Š½X :jH
Page 21 and 22: Gustavii [101] and Bockries and Red
Page 23 and 24: The mass transfer resistances stron
Page 25 and 26: The extractive effectiveness factor
Page 27 and 28: Quaternary onium salts, crown ether
Page 29 and 30: 26 > Dowex 1 2 > A-27 IRA-410 > I
Page 31 and 32: C 6 H 6 > C 6 H 5 CH 3 and the tren
Page 33 and 34: Many experimental studies on three-
Page 35 and 36: FIG. 4 Yields of products and conve
Page 37 and 38: transfer of organic or aqueous reac
Page 39 and 40: [187-196]. Several reactions that c
Page 41 and 42: the solid salt directly reacts with
Page 43 and 44: solubility in the organic phase, th
Page 45 and 46: QCl þ AcONa ðsÞ ÐQCl:AcONa ðs
Page 47 and 48: curve of the product SeK 2 . The pa
Page 49 and 50: Taking the mass balance for the cat
Page 51 and 52: The ion-exchange reaction occurs at
Page 53 and 54: in both aqueous and organic phases
Page 55 and 56: Type I.The catalyst resides in the
Page 57: V orgk obs ¼V org þD A V thirdk o
Page 61 and 62: tively. When the amount of the thir
Page 63 and 64: V org volume of organic phase (L)Xa
Page 65 and 66: 44. Halpern, HA Zahalka, Y Sasson,
Page 67 and 68: 140. SL Regen. Angew Chem, Int Ed E
Page 69: 223. SD Naik, LK Doraiswamy. AIChE
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11. Interfacial Mechanism and Kinetics of Phase-Transfer Catalysis

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