Synthesis of an Active Quaternary Phosphonium Salt and Its Application to the Wittig Reaction: Kinetic Study

合成活性季鏻鹽之動力學研究及其對Wittig反應之應用

王茂齡(Maw-Ling Wang) ； 劉彥君(Biing-Lang Liu) ； 林賢傑(Shan-Je Lin)

《Journal of the Chinese Institute of Chemical Engineers》 38卷5&6期 (2007/11) Pp. 451-459

摘要

本研究率先合成制備一個活性4-甲基苯甲酸甲酯三苯基溴化鏻季鏻鹽((4-Mcthyl) methyl benzoatyl triphenyl phosphonium bromide BrPPh3 CH2(C6H4) COOCH3, MBPB)，並同時經由Wittig反應應用於合成液晶中間體之MBPB試劑之合成乃經由三個反應步驟達成，即(1)首先利用N-溴琥珀醯亞胺(N-bromosuccinimide, NBS, C4H4NO2Br)與4-甲基苯甲基酸(toluic acid, CH3(C6H4)COOH, TA)合成4-溴甲基對苯甲基酸苯甲基酸甲酸((4-bromomethyl)methyl benzoate, Br Ch2(C6H4)COOCH, BTA)，(2)再將BTA與甲醇(CH3OH)進行酯化反應合成4-溴甲基對苯甲基酸甲酸((4-bromomethyl) methyl benzoate, Br CH2(C6H4)COOCH3,BME)及(3)由BME與三苯基膦(PPh3, triphenyl phosphine)合成吾人所要的活性季鏻鹽(MBPB)，以利進行Wittig反應，上述之三種反應皆分別在有機勻相反應，而此三種反應之動力學模式本研究工作倡導，對於第一個反應之反應條件對轉化率之影響皆深入之探討。
另外，由上述合成之MBPB試劑乃應用於對壬氧苯甲醛(4-nonyloxybenzoic aldehyde)在鹼性溶液／有機溶劑二相介質中合成cis-及trans-式之2-對壬基氧苯甲基1-苯烯酸甲酯(4-(nonyloxy)styryl) benzoate, n-C9H19(C6H4)CH=CH(C6H4)COOCH3, MNSB)，經由此反應可獲得高選擇率及高轉化率。

並列摘要

The synthesis of liquid crystal methyl [4-(nonyloxy) styryl]benzoate was achieved in four stages. First, toluic acid [1]was brominated with N-bromosuccinimide in refluxing CCl4 to form 4-bromotoluic acid [2] (BTA); second, BTA was esterified with methanol in SOCl2/CH2Cl2 to afford methyl (4-bromomethyl) benzoate [3] (BME); third, BME was condensed with triphenylphosphine (PPh3) in CH2Cl2 to produce the active Wittig reagent methyl (4-methylbenzoate) triphenylphosphonium bromide [4] (MBPB) and fourth, MBPB reacted with 4-nonyloxybenzaldehyde to produce MNSB in high yield. Each of these four reactions was carried out in a separate homogeneous organic solution and the effects of the reaction conditions in each reaction as well as a kinetic model for each individual reaction were studied. Furthermore, the active reagent was applied to the reaction of 4-nonyloxybenzaldehyde (n-C9H19O(C6H4)CHO) to synthesise cis-(E) and trans-(Z) methyl [4-(nonyloxy) styryl] benzoate (n-C9H19(C6H4)CH=(C6H4)COOCH3) from a two-phase medium alkaline solution of NaOH/organic solvent. High conversion and high selectivity were obtained via this reaction.

並列關鍵字

Quaternary phosphonium salt ； Liquid crystal intermediate ； Wittig reaction ； Kinetics