11. Interfacial Mechanism and Kinetics of Phase-Transfer Catalysis

the organic phase and aqueous phase play a crucial role in promoting the triphase reactionrate. However, this information is unclear.2. Characterization of LSLPTCPoly(styrene-co-chloromethylstyrene) crosslinked with divinylbenzene, which is immobilizedwith quaternary ammonium salts, was investigated for the synthesis of the finechemicals in our previous studies [161–166]. The microenvironment of the polymer supportplayed a crucial role in enhancing the reaction rate. More information about characterizationof the polymer structure, the interaction between organic solvent, resin, andaqueous solution, and the reuse of the catalyst is required to encourage application.Wu and Lee [166] report that 24 kinds of ion-exchange resin were used to clarify thischaracter of the resin, including six kinds of commercial ion-exchange microresin, fivekinds of laboratory-produced macroresin, and 13 kinds of laboratory-produced microresin,using instrumental analysis by TGA, EA, and SEM-EDS, and the reaction method.The densities of active sites in the resin, titrated using the Volhard method for commercialanion exchangers, were higher than those for laboratory-produced resins.ð69ÞScanning electron microscopy (SEM) analyzes electrons that are scattered from thesample’s surface, and monitors the morphological observation of the polymer resin. Theelemental analysis (EA) is effected by means of energy-dispersive X-ray spectrometer(EDS) methods. The chloride density was shown to be well distributed on the resin surfaceby X-ray images of chloride. It was also demonstrated that the active sites (-NR 4 Cl) in theresin were completely dispersed. Some other chemical compounds used for synthesizingthe polymer resin were also detected. Although the pretreatment of the resin was conductedby washing with water, NaOH solution, and acetone, the salts (Al, Si, and Ca) usedas reactants in the suspension method were slightly retained in the resin.The immobilized content of tri-n-butylamine in the resin was determined by theTGA, EA, and Volhard methods. The polymer backbone formed in a one-stage processwhere the decomposing temperature range was 300 –450 C. The immobilized resin (mi4-20) was formed in a two-stage process, where the ranges of decomposing temperature forthe two stages were 160 –200 C and 350 –450 C. Although it is tempting to divide the twostages into two distinctive units, the correlation between quaternary salt content andweight loss in the first was qualitative. The weight loss in the first step is equal to theimmobilized amount of the functional group of -NðC 4 H 9 Þ 3 . The accuracy of the analyticaltechnique was within 10%. The commercial ion-exchange resins were revealed in a threestageprocess. The decomposed compound and temperature for each decomposition stepare: imbibed water ( 100 C), functional group (160 –300 C), and polymer backbone(350 –450 C). The sequence of the imbibed capability of water is: IRA-900 ð20%Þ > A-Copyright © 2003 by Taylor & Francis Group, LLC