这项实验将演示一个简单的技术, 以滴定和获得准确浓度的锂试剂, n-丁基 (n-邓布利多)。锂试剂是非常和的水分敏感, 必须采取适当的护理, 以保持质量的试剂, 使其可以成功地用于反应。n-邓布利多滴定实验应定期进行, 以获得准确的浓度之前使用的化学反应. 随后, 我们将演示添加的滴定n-邓布利多苯甲醛。

1. 滴定的制备

对在 N₂下装有搅拌杆的火焰干燥圆底烧瓶, 添加二酸 (250 毫克, 1.18 摩尔) 和无水呋喃 (5 毫升)。

2. 滴定的n-邓布利多

计算使用二酸所需的n-邓布利多溶液 (hexanes) 的近似量。使用注射器, 慢慢地添加 n-邓布利多滴的解决方案。反应混合物将临时地变成黄色和回到一个无色的解答以每下落。
继续添加n...

对过程1-3 的n-邓布利多的滴定的代表性结果

过程步骤	反应混合物的颜色
1。1	无色
2。1	黄色, 然后无色
2。2	深黄色
3。1	1.18 摩尔二 acid/1 mL n-邓布利多 = 1.18 M n... Log in or to access full content. Learn more about your institution’s access to JoVE content here 在本实验中, 我们演示了如何使用二酸来确定一个n-邓布利多溶液的浓度。我们还通过在苯甲醛中加入n-邓布利多进行了反应。准确的浓度的n-邓布利多是重要的成功应用在许多反应。n-邓布利多是常用的锂-卤交换反应制备 aryllithium 或 vinyllithium 试剂, 这可以随后用于 c-c 键形成反应。此外, 它可以作为基础或核, 根据反应条件。 Log in or to access full content. Learn more about your institution’s access to JoVE content here N-butyllithium, abbreviated n-BuLi, is an organolithium reagent that is frequently used as a strong base or as a nucleophile. N-butyllithium is commercially available as a solution in alkanes such as hexane or heptane. These solutions are stable when properly stored, but still degrade upon aging and exposure to water or oxygen. When using an n-butyllithium solution to prepare lithium di-isopropylamide, another type of strong base, it is essential that a precise amount is used in the reaction. For this reason, titration experiment Log in or to access full content. Learn more about your institution’s access to JoVE content here Explore More Videos Privacy Terms of Use Policies Contact Us Recommend to library JoVE NEWSLETTERS Research JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive Education JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site Authors Overview Publishing Process Editorial Board Scope and Policies Peer Review FAQ Submit Librarians Overview Testimonials Subscriptions Access Resources Library Advisory Board FAQ ABOUT JoVE Overview Leadership Blog Copyright © 2024 MyJoVE Corporation. All rights reserved