11. Interfacial Mechanism and Kinetics of Phase-Transfer Catalysis

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SYMBOLSaactivity of quaternary salt in a solutionA interfacial area between the organic and aqueous phase ðm 2 )A s surface area of solid particles ðdm 2 )Aliquat 336 tricaprylmethylammonium chlorideCconcentration of quaternary saltC j iconcentration of component i in phase j (j ¼ org:, aq., cat.)C PhOQ dimensionless concentration of PhOQC# number of carbon atoms in each of the four alkyl chains in the quaternarycationD Q distribution coefficient of quaternary cation definedEQX T true extraction constant ðkmol=m 3 Þ 1jhydration number per quaternary salt in the organic phasek app apparent first-order reaction-rate constant (s 1 )k app;0 initial apparent reaction rate constant (1/min)k 2 forward reaction rate constant of the aqueous phase (kmol=m 3 minÞ 1k 2 reverse reaction rate constant of the aqueous phase ðkmol=m 3 minÞ 1k ireaction rate constantK iequilibrium constantK da dissociation constant of QX in the aqueous phase (kmol=m 3 )K do dissociation constant of QX in the organic phase (kmol=m 3 )K QY mass transfer coefficient of QY (m/min)K QX overall mass transfer coefficient of QX (kmol=m 3 min 1 )mdistribution coefficient of onium saltM H molecular weight of hydrophilic group in quaternary salt (e.g., N þ X )M T molecular weight of quaternary saltM TBAB molecular weight of TBABMX side product in the aqueous solutionMY aqueous reactantQ þ quaternary cationQX quaternary saltrspatial co-ordinate in radial directionr cmean radius of droplet containing organic phase and catalyst phase (m)r dmean radius of organic droplet (m)R freaction rate per unit area (mol=m 2 sÞRH reactantRX organic reactantR 0 X organic reactantttimeTabsolute temperature (K)TBAB tetra-n-butylammonium bromideTBAC tetra-n-butylammonium chlorideTBAI tetra-n-butylammonium iodideTBA-TBPO tetra-n-butylammonium 2,4,6-tribromophenoxideTBPB tetra-n-butylphosphonium bromideV volume of aqueous phase (m 3 )V aq volume of aqueous phase (L)volume of catalyst phase (L)V catCopyright © 2003 by Taylor & Francis Group, LLC
V org volume of organic phase (L)XanionXconversion of RX in the organic phaseYproduct yield[ ] molar concentration of species in brackets (kmol=m 3 )GreekG nvolume ratio (organic phase/aqueous phase)Hildebrand parametersGibbs free energymean activity coefficienteigenvaluesdimensionless spatial co-ordinate in radial directiondimensionless timeSubscripts0, i initial valueicompound iapp apparent valueobs observed valueSuperscriptsaqcatIjorgSðoverbarÞaqueous phasecatalyst phaseinterface between catalyst and organic phasesj phase (j ¼ org:, aq., cat).organic phasedroplet surface between catalyst and aqueous phasesspecies in the organic phaseCopyright © 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 and 58: V orgk obs ¼V org þD A V thirdk o
Page 59 and 60: @C orgRX@t@C catQY@t@C catQX@t¼ D
Page 61: tively. When the amount of the thir
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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