Ｃｈａｒａｃｔｅｒｉｓｔｉｃｓ ｏｆ Ｐｈａｓｅ Ｉｎｖｅｒｓｉ ｏｎ ｉｎ ａ Ｐｈａｓｅ Ｔｒａｎｓｆｅｒ Ｃａｔａｌｙｓｉｓ Ｓｙｓｔｅｍ ｗｉｔｈ Ｔｈｒｅｅ Ｌｉｑｕｉｄ Ｐｈａｓｅｓ

• Main Authors: Li, Ju-Yau, 李珠瑤
• Other Authors: Chiang Chien-Lih
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/66961020381437171814

碩士 === 國立成功大學 === 化學工程學系 === 84 === Recently many researches have been dedicated to the phase transfer catalysisreaction systems. In some of these systems, the formation of the third liquidphase(TLP) dramatically accelerates the reaction rate and simplifies the sepa-ration process. Studies on this field will be of great potential in the indus-try. In view of the industrial application, the stability of the system, invo-lving two or three immiscible liquids,is of much importance in the operations.Increasing the volume fraction of the dispersed phase will result in the incr-ease of the mass transfer areas, promote the drops coalescence rate and event- ually lead to the phase inversion, i.e. the dispersed phase becomes the conti-nuous phase and vice versa. In this study,the characteristics of phase invers-ion in a phase transfer catalysis system with three liquid phases are examinedin a batch vessel using the conductivity-measuring method, in which the react-ion of n-butyl bromide with phenyl benzoate is catalyzed by the tetrabutyl-ammonium bromide. It is found that, without the formation of TLP, an increasein the catalyst concentration tends to make water the continuous phase ,whilethe ion-pairsformed by catalyst and reactant retards the happening of phaseinversion andenlarges the ambivalent region. The W/O disersions are likely tobe formed if TLP are present in the systems. The addition of NaOH will reducethe phase inversion hold-up remarkably , while the presence of NaBr will helpwater to be continuous. Temperature , catalyst concentrations and reactantsalso affect the phase inversion hold-up. Systems with TLP would have longerTc ( CoalescenceTime) than those without TLP. When NaOH or KOH is added intothe system , Tc will be shortened. Delayed phase inversion time (Td) is foundto be longer for the systems with lower phase inversion hold-ups,and much moresensitive to thesystems with TLP. Also , it increases with increasing rotorspeeds for all the systems. Photographs indicate that the drop sizes in asystem containing TLP are quite tiny. Interfacial tension is relevant to thedrop size in the systems without TLP. Complex drops are observable in most ofthe W/O type dispersions.