ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Oxazines as acid-base indicators. IX. Determination of weak bases in nitromethane and in the mixture, chloroform-dioxane

Z. Stránský and V. Stužka

Department of Organic, Analytical and Physical Chemistry, Faculty of Natural Sciences, Palacký University, Olomouc

Abstract: A number of weak bases was determined in nitromethane and in a mixture chloroform—dioxan 1 1 using a series of oxazine dyes as indicators. Moreover, amidopyrine was determined in the presence of quinine, or caffeine by differential method. The range of potentials, where colour change of indicators occurs was determined in nitromethane, thereby predicting the use of them. The basicity of indicators used decreases as listed below: 2-hydroxy-5-(4-chlorophenylimino)-9-dimethylamino-5H-benzo[a]phenoxazine, 5-(4-chlorophenylimino)-9-dimethylamino-5H-benzo[a]phenoxazine, 5-(4-nitrophenylimino)- 9-dimethylamino-5H-benzo[a]phenoxazine, 9-diethylamino-5H-benzo[a]phenoxazone- 5, 9-dimethylamino-5H-benzo[a]phenoxazone-5, 9H-benzo[a]phenoxazone-9 and 9 -hydroxy - 5H-benzo[a]phenoxazone -5.

Full paper in Portable Document Format: 226a424.pdf (in Czech)

Chemical Papers 22 (6) 424–430 (1968)