Phase inversion characteristics of three-liquid-phase phase transfer catalytic systems using symmetric quaternary ammonium salts as the catalysts

• Main Authors: Chen,I-Ling, 陳怡伶
• Other Authors: Chiang,Chien-Lih
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/89126571835636707961

碩士 === 國立成功大學 === 化學工程學系 === 87 === The system with three-liquid phase transfer catalysis reaction is one of the research fields of great potential in the chemical engineering industries. The formation of the third liquid phase (TLP) can increase the reaction rate substantially. In another aspect, the TLP can simplify the steps of separation, thus the catalyst can be reused. For the applications in the industries, dispersion characteristics of this kind of heterogeneous system is very important in the equipment design. In this article, some common symmetric quaternary ammonium salts, including hydrophilic (tetrapropyl ammonium bromide, tetrabutyl ammonium bromide, tetrapentyl ammonium bromide) and hydrophobic catalysts (tetrahexyl ammonium bromide), are used as catalysts to catalyze the reaction between n-butyl bromide and sodium phenolate trihydrate which takes place in a batch agitation. Also we study the phase inversion characteristics of this kind of systems by the conductivity-measuring method. We found that adding catalyst to the system, no matter the catalyst added is hydrophilic or hydrophobic, the ambivalent region of the system will become broader as the catalyst concentration increases. And the more hydrophilic the catalyst, the more narrow the ambivalent region. For W/O inverses to O/W, the addition of hydrophobic catalyst has no significant effect on the phase inversion hold-up(o) value of the system. The phase inversion hold-up(o) values of the systems contain hydrophilic catalysts become smaller if the TLP occurs, no matter the inversion is from W/O to O/W or from O/W to W/O. For W/O inverses to O/W, the phase inversion hold-up(o) values of the systems which contain hydrophobic catalysts and have the TLP formed are higher than those of the pure-pure system. For the factors which affect the formation of the third liquid phase, no matter the catalyst added is hydrophilic or hydrophobic, the amount of the TLP formed increases with the increasing concentrations of catalyst and sodium phenolate trihydrate. The increase of the concentration of n-butyl bromide increases the amount of the TLP for the system contains hydrophobic catalysts but has no effect on the amount of the TLP for the system contains hydrophilic catalysts. The existence of NaOH is directly related to the formation of the TLP for the system contains hydrophilic catalysts, but has no direct relation to the formation of the TLP for the system contains hydrophobic catalysts. From the above reasons, we know that the mechanisms of the formation of the TLP for the system with hydrophilic and hydrophobic catalyst are different. Generally speaking, the Tc values of the systems contain the TLP or NaOH are higher than those of the other systems. For the most systems, the Tc values of the O/W dispersion type are higher than those of the W/O dispersion type.