中国炼油与石油化工 ›› 2012, Vol. 14 ›› Issue (2): 7-17.

• Scientific Research • 上一篇    下一篇

不同双氧水为氧化剂反应体系中环己酮Baeyer-Villiger氧化机理研究

夏长久,朱斌,林民,舒兴田   

  1. 石油化工科学研究院
  • 收稿日期:2012-02-21 修回日期:2011-12-04 出版日期:2012-06-30 发布日期:2012-06-30
  • 通讯作者: 林民 E-mail:minlin@tom.com
  • 基金资助:
    重脱残渣油加氢处理催化剂及反应工程基础

Study toward the Mechanisms of Cyclohexanone Baeyer-Villiger Oxidation with hydrogen peroxide under Various Reaction Systems

  • Received:2012-02-21 Revised:2011-12-04 Online:2012-06-30 Published:2012-06-30

摘要: 绿色高效的环己酮Baeyer-Villiger氧化反应生产ε-己内酯对合成新高分子材料具有重要的意义。本文详细介绍了以双氧水为氧化剂的五种不同反应体系环己酮Baeyer-Villiger氧化反应机理类型。1.非催化反应机理,即在无催化剂存在下,环己酮的羰基氧原子受到双氧水和/或即酮羰基经过二次氢氧自由基进攻而形成“Criegee”中间体,再经重排反应生成ε-己内酯;3.固体质子酸催化机理,;4.固体Lewis酸催化活化酮羰基机理,通过增强环己酮的 π*C=O 轨道与Sn-β分子筛HOMO轨道间的“供给-接受”电子作用力而使酮羰基更易接受亲核试剂的进攻;5.固体Lewis酸催化活化双氧水机理,即Ti-OOH物种中π*(OO)→de(Ti)的跃迁导致了HOMO轨道转化为SOMO轨道,从而导致O-O键对C=O的亲电进攻能力增强。最后我们综合比较了各种环己酮Baeyer-Villiger氧化途径的差异,并为未来环己酮氧化发展方向就行了展望。

关键词: 反应机理, Baeyer-Villiger, Lewis 酸, Br?nsted 酸, 热活化自由基, 过氧化氢

Abstract: The green and effective Baeyer-Villiger oxidation reaction of cyclohexanone to prepare ε-Caprolactone is of particular importance in the synthesis of new polymer materials. We have discussed here several mechanism types of cyclohexanone Baeyer-Villiger oxidation with H2O2 in different reaction systems. Five main types have been addressed. 1) Noncatalyzed reaction type, the C=O of ketones is activated by H+, which is electrolytic dissociated from H2O2 and H2O, to improve the capability of C=O group to accept the electron pairs;2)Thermally activated radical reaction type, where the Criegee interminate is produced via two-steps of radical reaction with ·OH attack, with many more hydroxy radicals are excited in the presence of TS-1 zeolite ;3) Br?nsted acid catalysis reaction type, both O-O moiety and C=O group could be activated by Br?nsted acid; 4) Solid Lewis acid catalyzed C=O of the substrate activation reaction type, by enhancing the donor-acceptor interaction between the antibonding π*C=O orbital of cyclohexanone and HOMO of Sn-β zeolite; 5) Solid Lewis acid catalyzed H2O2 to form Me-OOH oxidative species, by employing the highest occupied molecular orbital (HOMO) of Ti-OOH becoming a singly occupied molecular orbital(SOMO), with the O-O group highly electrophilic to attack the C=O of cyclohexanone in Baeyer-Villiger oxidation. In the end, we also compare the different mechanisms and give our opinions on the development direction of catalytic materials for eco-friendly Baeyer-Villiger oxidation of cyclohexanone in the years to come.

Key words: reaction mechanism, Baeyer-Villiger, Lewis acid, Br?nsted acid, thermally radical, hydrogen peroxide