Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/3501
標題: Kinetics Study of Methoxybenzoylation of p-Methoxyphenol over Phase-Transfer Catalysts
以相間轉移觸媒催化對-甲氧基酚之甲氧基苯甲醯化反應動力學研究
作者: 廖秉恆
Liao, Ping-Heng
關鍵字: Phase-transfer catalyst
相間轉移觸媒
Kinetics
substituted-benzoylation
Immobilized catalyst
動力學
取代醯化作用
固定化觸媒
出版社: 化學工程學系
摘要: 本研究探討的是相間轉移觸媒環境下催化對-甲氧基酚之甲氧基苯甲醯化,產物為4-甲氧基苯甲酸甲氧基苯酯,是具有扁平長分子軸構造,在結構左右具有極性置換基,為一種顯示液晶性物質,本研究在發展利用固-液-液相間轉移系統與液-液相間轉移系統來合成此物質: 在固-液-液系統先利用苯乙烯和氯甲基苯乙烯共聚合得到固體高分子相間轉移觸媒擔體,並將三級胺固定化在巨孔口和微孔口觸媒上,由結果只要利用少量的2.5%交聯度、粒徑為80-120 mesh、官能基三丁基胺巨孔口觸媒,在反應一小時後產率即可達到98%以上,總反應速率隨平均粒徑的增加而降低,這顯示在三相反應系統下,甲氧基酚之取代醯化反應同時受粒內擴散與本質反應之影響。然而,觸媒的特性與結構也影響著觸媒反應活性,相同交聯度下,巨孔口觸媒活性較微孔口觸媒活性佳。取代醯化反應可以用一完整動力學模式描述,且由實驗結果可知可由虛擬一階反應動力式描述。 在液-液相反應系統中,除了兩相反應物因素外,各項探討的變因包括:攪拌效應、觸媒添加量效應、水量添加效應、有機溶劑種類效應、觸媒種類效應、溫度效應等,利用相間轉移觸媒對取代反應有很大的幫助,當不加觸媒產率很低,而加入觸媒TBAB後,反應隨著觸媒量增加而明顯的增加,且整個反應亦可用虛擬一皆來表示,而且在溫和的條件下使用少量觸媒TBPB產率可達到95%,而由實驗數據可知最佳的氫氧化鈉用量為氫氧化鈉與甲氧基酚莫耳比率為1.5時為最佳,氫氧化鈉量太少對反應沒有提昇的效果,不同種觸媒對於系統的活性大小為TBPB>TBAB>TBAI>Aliquat 336>TBAHS>PEG600> PEG1000.
e of phase-transfer catalysts,volume ratio of aqueous and solvent, and so on. From the experimental data shown, the substitution reaction was greatly enhanced by applying phase-transfer catalysis. Without the addition of any catalyst, the product yield is very low, while the reaction rate increases with increasing the amounts of TBAB catalyst added ,and the overall reaction rate can be well described by the pseudo-first-order kinetics. And using TBPB as the ,the product yield was obtained above 95% under very mild conditions. An optimal quantity of NaOH is located on 1.5 of the molar ratio of NaOH to 4-methoxyphenol. Too less amount of NaOH cannot conduct the deprotonation reaction effectively.The order of catalytic efficiency is TBPB>TBAB>TBAI> Aliquat 336>TBAHS>PEG600> PEG1000.
URI: http://hdl.handle.net/11455/3501
Appears in Collections:化學工程學系所

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