Driving an equilibrium acetalization to completion in the presence of water
Driving an equilibrium acetalization to completion in the presence of water
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DOI：
10.1039/c4ra07116f
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发表时间：
2014-08
期刊：
影响因子：
3.9
通讯作者：
Maki Minakawa;Yoichi M. A. Yamada;Y. Uozumi
中科院分区：
文献类型：
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作者：
Maki Minakawa;Yoichi M. A. Yamada;Y. Uozumi
通过与醇缩合由羰基底物形成缩醛是经典的可逆平衡反应，其中必须除去形成的水以驱动反应完成。本文提出了一种在水存在下二醇与羰基底物发生缩醛化反应的新方法。聚（4-苯乙烯磺酸）与聚（4-乙烯基吡啶）的复合在微流反应器的微通道中的两个平行层流之间的界面处产生聚合酸的催化膜。催化膜在反应中提供有机层和含水层之间的可渗透屏障，并允许水排放到微反应器的出口以完成缩醛化。各种羰基底物与二醇的缩合在水的存在下在微流装置中进行，以得到相应的缩醛，产率高达97%，停留时间为19至38秒。
Formation of an acetal from a carbonyl substrate by condensation with an alcohol is a classical reversible equilibrium reaction in which the water formed must be removed to drive the reaction to completion. A new method has been developed for acetalization of carbonyl substrates by diols in the presence of water. Complexation of poly(4-styrenesulfonic acid) with poly(4-vinylpyridine) generates a catalytic membrane of polymeric acid at the interface between two parallel laminar flows in a microchannel of a microflow reactor. The catalytic membrane provides a permeable barrier between the organic layer and water-containing layer in the reaction, and permits discharge of water to the outlet of the microreactor to complete the acetalization. Condensation of a variety of carbonyl substrates with diols proceeded in the presence of water in the microflow device to give the corresponding acetals in yields of up to 97% for residence times of 19 to 38 s.