Ethers, acid cleavage block polymers

For the synthesis, 2-cyanoethyltriethoxysilane was prehydrolyzed in an HCl-containing solution of the polymer template, and afta- 30 min tetraethoxysilane was added. The solid product, which was recovered by filtration, was obtained after 20 h reaction at 40 °C and subsequent aging for one day at 90 °C. The problematic step of template removal was made possible by a process developed earlier by us, involving ether cleavage of the block copolymer by ca. 50% sulftiric acid [27]. This process extracts the block copolymer and incidentally hydrolyzes the cyano group to result directly... 

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