本研究擬評估以一種新穎的相間轉移催化技術合成酯類化合物的可行性。即以具有富含觸媒 (四級鹽類 )之液相催化由醋酸鈉與溴正己烷轉化合成醋酸己酯的固 -液反應，探討此固 -液 -液相系統的形成條件及其在批式反應器的反應情形。實驗結果顯示：使用高極性有機溶劑雖可提高溴正己烷轉化率，但觸媒會溶入有機相中而使觸媒不易回收，故 本系統以使用低極性溶劑 (如正辛烷 )為宜。添加微量的水可形成醋酸鈉固體、觸媒液相、有機液相的 SLL PTC 系統。攪拌速率為 600 rpm 時，轉化率最高，更高的攪拌速率反而使轉化率降低。適度增加醋酸鈉固體用量，能提高轉化率，但添加過多的醋酸鈉反而使轉化率降低。溴化四級銨鹽的碳鏈越 長，轉化率越高，但觸媒在有機相的溶解度也越高，不利觸媒的回收，溴化四正丁基銨較適宜作為本反應系統的觸媒，其最佳用量為 0.025 mol。系統中產物鹽類溴化鈉過多會抑制反應速率，且使反應由擬一階轉變為零階。高溫會產生較多的副產物，且觸媒的活性較容易衰退，反應溫度以 80 .degree.C 較適當。另外，添加二氧化鈦對本反應系統的助益不大。This study is for the purpose of evaluating the feasibility of synthesizing hexyl acetate from sodium acetate and n-hexyl bromide by a novel PTC technique. In this new technique, called as solid-liquid-liquid phase-transfer catalysis (SLL PTC), the liquid-solid reaction is catalyzed by a catalyst-rich liquid phase and quaternary salts are used as the catalyst. The factors influencing the formation of a SLL PTC system and the reaction behaviors in a batch reactor were investigated. Experimental results indicate that high polar organic solvents enhance the conversion, but the catalyst is difficultly reused owing to the dissolvation of the catalyst in the organic liquid phase. A nonpolar compound (such as n-octane) should be used as an organic solvent. When a small amount of water was added, a solid (sodium acetate) liquid (catalyst-rich)liquid (organic solvent) phase transfer catalysis system could be formed. The conversion increases as the agitation speed increases from 0 to 600 rpm but decreases as the agitation speed increases further from 600 to 1000 rpm. Adding an appropriate amount of sodium acetate gives a higher conversion, however, excess sodium acetate added cause the conversion to decrease. Quaternary salt with longer carbon chains enhances the reaction rate but is easier dissolved into the organic phase leading to the difficulty in the reuse of the catalyst. Tetra-n-butylammonium bromide might be a good choice used as the catalyst and its optimal amount is 0.025 mol. The reaction rate decreases with increasing the adding amount of sodium bromide to the system. In addition, the reaction order changes from first-order to zero-order when excess amounts of sodium bromide were existed in the system. The temperature may not too high as to cause a thermal decay of the catalyst and an increase in the side products. The optimal temperature is about 80 oC. Adding titanium oxide seemed helpless to increase the reaction rate.
