| Summary: | 碩士 === 國立臺灣師範大學 === 化學學系 === 82 ===
Crown ethers, e.p.18-crown-6 (18C6), monobenzo-15-crown-5 (B15c5) and 12-crown-4 (12C4), were applied as phase transfer catalysts for anionic polymerization of methyl methacrylate and Aldol condensation of phenyl acetaldehyde Lariat carboxylate crown ether, e,p. 2-(sym-dibenzo-16-crown-5oxy) dodecanoic acid (C10 H21 DB16C5 COOH), was synthesized and applied as ion transport carrier (Ionophore) for various metals ions and amino acids.
The solubility and activity of sodium amide (NaNH2) as an initaitor can be enhanced in presence of crown ethers which were able to complex with sodium ion of initator adn thus promote the anionic polymeriation of methy1 methacrylate in organic phase the catalytic ability of crown cthers, the 15 crown5 seems to be the best one, are in the order:15C5>B15C5>18C6>12C4.Effects of initiators, concentration of crown ethers, temperature and solvents on the polymerization of methyl methacrylate were also investigated and discussed the molecular weight of polymethyl methacrylate was determined with GPC (Gel permeation chromatography) method.
The lariat carboxylate crown ether alkyl substituted 2-(sym-dibenzxo-16-crown-5-oxy) was synthesized and applied as an ion transport carrier through liquid membrane for various metal ions such as alkali, alkali earth and transition metal ions and amino acid anions. the lariat carboxylate crown ether C10H21DB16C5COOH shhowed better ion transport ability than DB16C5COOH and B15C5 Effects of anion and pH in source layer were investigated An ion transport mechanism is proposed which included [OH-] and[H+] is strongly depended on the pH values of both source and target layer.
Various crown ethers were also applied catalysts for Aldol condensation of phenyl acetaldehyde with hydroxide (MOH). The elevation of temperature the increase in polarity of the reation solvent resulted in the increase of the reation yield. Effects of hydroxide and crown ethers were also investigated The reactive ability of hydroxide with 15 crown 5 as a catalyst are in the order: NaOH>KOH>LiOH.The Catalytic ability of various crown ethers for the condensation with NaOH as a reactant are in the order:15C5>B15C5>18C6>12C4.
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