Journal of Solution Chemistry p. 1113 - 1124 (1990)
Update date:2022-08-03
Topics:
Liwo, Adam
Sokoloswki, Krzysztof
Wawrzynow, Alicja
Chmurzynski, Lech
Using a UV-spectrophotometric method, an attempt has been made to estimate quantitatively the influence of traces of water in aprotic solvents on the acidic-basic equilibria involving heterocyclic N-oxides.The N-oxides under study were pyridine N-oxide, (PyO), 4-methoxy-pyridine N-oxide (4-MeOPyO), and 2-, 3-, and 4-picoline N-oxide (2-, 3-, and 4-PicO).For particular N-oxide the UV-spectra of acetonitrile solutions containing the free base and/or its simple or semiperchlorate have been recorded.To carry out the calculations various equilibrium models which include the protolytic equilibrium with water and basic species present in the solvent have been tested using the program STOICHO which is based on nonlinear regression analysis.It turned out that apart from the acidic-basic dissociation of a protonated N-oxide and cationic homoconjugation (the equilibria which are usually considered in such systems) it is absolutely necessary to take into account the protolytic equilibria between the cationic acid and water present as impurity.Implications concerning investigations of other equilibrium systems in aprotic solvents and, in particular, the quality of the acidity constants for the calibration agents used in potentiometry are discussed.
View MoreLishui Nanming Chemical Co., Ltd
Contact:+86-0578-2134101,2697830
Address:No.19 Tongji Road Shuige Industrial zone
Dalian RSD International Trade Co.,Ltd.
Contact:86-22-60875058 58610575
Address:Wantong International Areas, Hongqiao District, Tianjin, China.China
AUSHUN PHARMACEUTICAL TECHNOLOGY CO,.LTD
Contact:+86-25-86883560 15951806178
Address:14 Dayingbi, Zhujiang Rd. East, Nanjing, Jiangsu, China.
Hangzhou Hysen Pharma co.,Ltd.
website:http://www.hysenpharma.cn/
Contact:0086-571-88298791
Address:#701,Gudun Road Hangzhou
Shanghai agrotree chemical co.,ltd.
Contact:+86-21-50117563
Address:Room 8A,liangfeng building,No.8 dongfang RD.pudong,shanghai,China
Doi:10.1021/jo900133g
(2009)Doi:10.1002/ardp.19352730505
(1935)Doi:10.1016/S0040-4039(03)00670-1
(2003)Doi:10.1002/ejoc.200200626
(2003)Doi:10.1039/jr9550000803
(1955)Doi:10.1016/S0040-4039(00)90258-2
(1966)