Knowledge Management System Of Institute of process engineering,CAS
|Alternative Title||The Mechanism Study of Cobalt-catalyzed Oxidative Esterification of Allylic C(sp3)-H Bonds and The Development of β-Damascenone Synthesis|
β-大马烯酮是一种由大马士革玫瑰中提取的、具有浓郁花香和果香的名贵香料，主要用于配制高档日化产品香精和食品香精，亦可用作烟草调香。目前，全球仅有瑞士Firmenich公司掌握工业化制备β-大马烯酮的工艺技术。近年来，随着香料工业的迅速发展，β-大马烯酮的应用范围更加广泛，需求量也有所增长。为满足国内市场的迫切需求，β-大马烯酮合成工艺的研究值得关注。本论文在实验室前期研究基础上，针对以β-紫罗兰酮为起始原料的合成工艺路线中最关键的最后一步β-二氢大马酮一锅法氧化脱氢制得β-大马烯酮进行放大实验研究，实现单次合成300g产品，溶剂用量减少50%，β-大马烯酮产率高于80%。并且通过改良提纯装置优化产品纯化工艺，实现快速分离百克量级产物，得到纯度为94%的β-大马烯酮产品。与此同时，针对β-大马烯酮现有合成工艺路线中最后一步氧化脱氢产率低、条件苛刻等问题，本论文以β-二氢大马酮的环内烯丙基位氧化官能化为目标，对Co(II)催化烯丙基位C(sp3)-H键的氧化酯化方法学进行研究，以探索新的β-大马烯酮合成路线，实现在过氧化物DTBP氧化条件下，CoCl2催化烯丙基C(sp3)-H键与羧酸的氧化酯化。通过机理研究，揭示碳氢化合物C(sp3)-H键的活化是该反应过程的决速步。反应过程中原位生成的[Co(III)]Ot-Bu不参与C(sp3)-H键中氢原子夺取（HAA）过程。同时，还发现Co(II)可以催化苄位C(sp3)-H键的氧化酯化。该催化体系应用于β-二氢大马酮的环内烯丙基位C(sp3)-H键的氧化酯化，产率达到61%；酯化产物经催化脱羧后生成β-大马烯酮。开发新的β-大马烯酮合成工艺路线，避免传统路线中N-溴代丁二酰亚胺（NBS）的使用。;β-Damascenone was firstly isolated from the essential oil of Rosa damascene, which is a precious perfume with strong flower flavor and fruit flavor. It was not only used as a component of cosmetics fragrance and edible flavor, but also used to improve the flavor of tobacco. The application scope of β-Damascenone is extending with the rapid development of the spice industry, and the demand is also increased. Consequently, various synthetic routes to β-Damascenone were available academically in the past decades. However, only Switzerland Firmenich Company presently has the corresponding industrial technology of man-made synthesis of β-Damascenone in the world.We were focused on the route leading to β-Damascenone started from β-ionone in the laboratory. In this study, the condition of the last step in terms of one pot oxidative dehydrogenation of β-damascone, was further optimized and the production could therefore be scaled up to 300g. A high yield of 80% is reached even when the amount of solvent is 50 v% decreased as compared with conditions for laboratory scale. In addition, it is possible to rapidly isolate β-Damascenone in a yield of 95% at a scale of hundreds grams with 94% purity through optimize the vacuum distillation unit.Despite the previous optimization, the yield of the last step of oxidative dehydrogenation of β-damascone is still low and comparatively harsh conditions were required for the production. In order to address this special issue, the methodology of cobalt-catalyzed oxidative esterification of allylic C(sp3)-H bonds was studied. A protocol of cross-esterification of various allyls and carboxylic acids catalyzed by cobalt oxidative in present of DTBP was developed. Mechanistic studies revealed that C(sp3)-H bond activation in the hydrocarbon was the turnover-limiting step and the in-situ formed [Co(III)]Ot-Bu did not engage in hydrogen atom abstraction (HAA) of a C-H bond. In addition, we also found it is possible that cobalt-catalyzed oxidative esterification of benzyl C(sp3)-H bonds. This protocol can be applied to oxidative esterification of the cyclic allylic C(sp3)-H bond of β-damascone to corresponding ester with 61% yield. Then, the obtained ester underwent BrΦnsted acid-catalyzed decarboxylation smoothly to form β-damascenone with a good yield, there by avoided the use of NBS in the traditional route.
|任天鹭. 钴催化烯丙基C(sp3)-H键氧化酯化机理研究及β-大马烯酮合成工艺优化[D]. 中国科学院大学,2017.|
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