文档介绍：硕士论文 相转移催化法合成扁桃酸的工艺研究
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摘 要
本文研究了由苯甲醛和卤仿在相转移催化条件下合成扁桃酸的工艺,探讨了反应条件,特别是相转移催化剂的种类对反应的影响。结果表明,以相当于反应物量3%的TBAB作相转移催化剂,60℃反应5h,产物收率可达78%。实验中还发现除季铵盐外,叔胺对反应也具有良好的催化作用,提出了叔胺与二氯卡宾结合的催化机理。本文还探讨了手性相转移催化条件下扁桃酸异构体的不对称合成。发现以卤仿作溶剂时,手性相转移催化剂不能诱导扁桃酸的不对称合成;而在有外加溶剂存在时,手性相转移催化剂可以诱导其不对称合成,探讨了溶剂种类、反应时间、催化剂用量等因素对反应的对映选择性的影响。
关键词:扁桃酸,相转移催化,季铵盐,手性相转移催化,不对称合成,叔胺
硕士论文 相转移催化法台成扁桃酸的工岂础f究
Abstract
The synthesis of mandelic acid from benzaldehyde and chloroform in the presence of a phase transfer catalyst was studied and the effect of reaction factors,especially the phase transfer catalysts on the yield of the product was favorable conditions, at 60。C for 5 hours in the presence of a 3%of TBAB as catalyst。78%yield of the product was was found that in addition to quaternary ammonium salts, some tertiary amines can also be used as a catalyst for the mechanism involving the interaction between the tertiary amine and dichlorocarbene WaS proposed to explain the catalytic action of the tertiary asymmetric synthesis of mandelic acid in the presence of a chiral phase transfer catalyst was also show that if the reaction is carried out in chloroform no asymmetric synthesis was of an aromatic solvent to the reaction system does lead
to the observation of asymmetric effects of aromatic
solvents,catalyst amount used and reaction conditions on the enantiomer
excess(.)of the reaction were discussed.
Keywords:Mandelic aeid,Phase transfer catalysis,Quaternary ammonium
salts,Chiral phase transfer catalyst,Asymmetric synthesis,Tertiary
amine.
1I
硕士论文 相转移催化法合成扁桃酸的工艺研究
扁桃酸又名苦杏仁酸,化学名为CI一羟基苯乙酸,英文名称为
Q~hydroxy—Benzeneacetic acid或mandelic acid。其分子式为:
∥趾cH--COOHU
l
dH
扁桃酸的纯品为白色晶体,扁桃酸外消旋体的熔点为1 18。C一120 4C,R-"C,比旋光度为[Q]”。=。,。C,比旋光度为[n]”。=+。。它是制备第二代头孢抗生素的重要侧链修饰剂,也是一种重要的有机合成中间体。日本武田制药公司以用扁桃酸和Cis一三甲基环己醇为原料, 以硫酸作催化剂合成了三甲基环己基扁桃酸酯,反应过程