Furigay Maxwell H, Boucher Maria M, Mizgier Nikola A, Brindle Cheyenne S
Department of Chemistry, Trinity College.
Department of Chemistry, Trinity College;
J Vis Exp. 2018 Apr 2(134):57639. doi: 10.3791/57639.
The purification of organic compounds is an essential component of routine synthetic operations. The ability to remove contaminants into an aqueous layer by generating a charged structure provides an opportunity to use extraction as a simple purification technique. By combining the use of a miscible organic solvent with saturated sodium bisulfite, aldehydes and reactive ketones can be successfully transformed into charged bisulfite adducts that can then be separated from other organic components of a mixture by the introduction of an immiscible organic layer. Here, we describe a simple protocol for the removal of aldehydes, including sterically-hindered neopentyl aldehydes and some ketones, from chemical mixtures. Ketones can be separated if they are sterically unhindered cyclic or methyl ketones. For aliphatic aldehydes and ketones, dimethylformamide is used as the miscible solvent to improve removal rates. The bisulfite addition reaction can be reversed by basification of the aqueous layer, allowing for the re-isolation of the reactive carbonyl component of a mixture.
有机化合物的纯化是常规合成操作的重要组成部分。通过生成带电荷结构将污染物转移到水层中的能力为利用萃取作为一种简单的纯化技术提供了机会。通过将互溶的有机溶剂与饱和亚硫酸氢钠结合使用，醛类和活性酮类可成功转化为带电荷的亚硫酸氢盐加合物，然后通过引入不互溶的有机层将其与混合物中的其他有机成分分离。在此，我们描述了一种从化学混合物中去除醛类（包括空间位阻较大的新戊醛和一些酮类）的简单方法。如果酮类是空间位阻较小的环状或甲基酮，则可以分离出来。对于脂肪族醛类和酮类，使用二甲基甲酰胺作为互溶溶剂以提高去除率。通过将水层碱化可使亚硫酸氢盐加成反应逆转，从而实现混合物中活性羰基成分的重新分离。
