Journal of the Chemical Society. Perkin transactions II p. 1827 - 1830 (1983)
Update date:2022-08-11
Topics:
Anelli, Pier Lucio
Montanari, Fernando
Quici, Silvio
In nucleophilic aliphatic substitutions carried out under liquid-liquid phase-transfer conditions, the catalytic activity of tributylphosphonium groups directly bonded to a polystyrene matrix through a methylene bridge decreases by about one order of magnitude on passing from 10 to 69percent ring substitution; log kobs. is linearly related to the loading of the catalytic sites.When tributylphosphonium groups are bonded to the polymer matrix by a linear spacer chain of 13 atoms for 10-30percent ring substitution, kobs. increases 1.7-3.1 times with respect to directly bonded catalysts.However, for spaced catalysts with 60percent ring substitution, the observed rate increase is 4.1-10-fold.This behaviour is explained by the combination of two opposing effects: (i) a polarity increase at the catalytic site by increasing percentage ring substitution leading to a decrease of nucleophilic activity of the anions; (ii)a polarity decrease at the catalytic site by insertion of spacer chains, due to the intrinsic lipophilicity of the alkyl chains as well as the more even distribution of catalytic sites within the polymer matrix.The reactivities of the catalysts, all prepared from chloromethylated polystyrene (200-400 mesh), are independent of the size of particles separated by sieves.
View MoreContact:86-371-63655023
Address:No.85,jinshui road,zhengzhou,China
Anhui Xinyuan Technology Co.,Ltd
website:http://www.ahxytech.com/
Contact:0086-559-3515800
Address:Huangshan City of Anhui Province Huizhou Huizhou District Road, 21-9
Chengdu Chengnuo New-Tech Co., Ltd
Contact:0086-028-85749078
Address:4 Jiuyang road,Jiulong industrial port,Chengdu, China
Nanjing Spring & Autumn Biological Engineering Co., Ltd.
Contact:86-18051083338
Address:南京市玄武区胜利村路2号C1004室(QQ:2736722164)
LinHai Cina Chemical Co., LTD.
Contact:0576-85580989
Address:Pharma-chem zone,Duqiao,Linhai,Zhejiang,China
Doi:10.1271/bbb.69.145
(2005)Doi:10.1016/j.ejmech.2014.09.022
(2014)Doi:10.1023/B:RUCB.0000030813.05424.1f
(2004)Doi:10.1007/BF00923521
()Doi:10.1021/ja01243a501
(1943)Doi:10.1016/S0020-1693(00)80946-9
(1990)