Siloxane basicity toward strong acid in nonpolar solution
Siloxane basicity toward strong acid in nonpolar solution
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硅氧烷在非极性溶液中对强酸的碱性
DOI：
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发表时间：
1991
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通讯作者：
B. Shepherd
中科院分区：
文献类型：
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作者：
B. Shepherd
本文研究了10种硅氧烷和一种醚在苯中的相对碱度，通过测定底物与参比碱（4-氯-2-硝基苯胺）竞争酸（三氟甲磺酸）的热力学常数RB·HA+S·RB+S·HA. Keq值被认为是碱度的量度，其顺序为：全甲基直链硅氧烷（Me 3Si（OSiMe 2）nOSiMe 3，n=0-3）>正醚>HMe 2SiOSiMe 2 H>支链硅氧烷（（Me 3SiO）3SiMe，（Me 3SiO）4Si）>环状硅氧烷（（Me 2SiO）n，n=3-5）
The relative basicities of ten siloxanes and an ether were studied in benzene by determining from visible spectroscopic measurements the thermodynamic constants for the competition between the substrate and a reference base (4-chloro-2-nitroaniline) for acid (trifluoromethanesulfonic acid): RB•HA+S⇇RB+S•HA. The K eq values were considered as a measure of basicity with the following order established and explained by inductive effects in the protonated species: permethyl linear siloxanes (Me 3 Si(OSiMe 2 ) n OSiMe 3 , n=0-3)>dibutyl ether>HMe 2 SiOSiMe 2 H>branched siloxanes ((Me 3 SiO) 3 SiMe, (Me 3 SiO) 4 Si)>cyclic siloxanes ((Me 2 SiO) n , n=3-5)