Thionyl chloride reaction with 3-buten

Polymeric crown ethers may also be bonded chemically to the silica surface. For that purpose, the support material is modified with 3-(N-methacryloylam-ino)-propyl groups, and subsequently co-polymerized with (4-methacryloylam-ino)-benzo-15-crown-5 [55]. Stationary phases, in which the crown ether molecules are chemically bonded to silica via Si-O-C linkages, are obtained with silica treated with thionyl chloride via reaction with 4-hydroxymethylbenzo-18-crown-6 (see Fig. 3-56, upper right). Since Si-O-C-bonds are prone to hydrolysis, water-free methanol is used as eluant for such stationary phases. Much more stable are silicas modified via Si-C-bonds (see Fig. 3-56, bottom left and right) that are prepared by using 4-vinylbenzo-18-crown-6 or 4-butene-18-crown-6 and... 

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