Published May 1998
| Version v1
Journal article
pH in reverse micelles: the acid dissociation constant of the 7-hydroxy coumarin in Water/AOT/Isooctane water-in-oil microemulsions
Description
The apparent pKa of the 7-hydroxycoumarin (Umbelliferone) was spectrophotometrically measured in a Water/AOT/Isooctane microemulsion in the presence of Tris, Ammonia, and Carbonate buffer solutions. The apparent pKa increases of about 2 units, in comparison with the pKa measured in bulk water, for the smallest values of the molar ratio Water/AOT, and decrease with the radius of the nanodroplets. The results are discussed taking into account the profile of the electrical potential drop into the water pool and the possible partition of the Umbelliferone between the aqueous core and the surfactant
Abstract (Italian)
Il pKa apparente della 7-idrossicumarina (Umbelliferone) e' stato misurato spettrofotometricamente in una microemulsione Acqua/AOT/Isoottano in presenza di soluzioni tampone di Tris, Ammoniaca e Carbonato. Il pKa apparente aumenta di circa 2 unita', rispetto a quello misurato in soluzione acquosa microomogenea, per i valori piu' bassi del rapporto Acqua/AOT e diminuisce con l'aumentare del raggio delle micelle inverse. I risultati sono discussi tenendo conto della distribuzione del potenziale elettrico entro la microfase acquosa e dell'eventuale distribuzione della 7-idrossicumarina tra la microfase acquosa e il surfattanteAdditional details
Publishing Information
- Journal Title
- Annali di Chimica (Rome)
- Journal Volume
- 88
- Journal Issue
- 5-6
- Journal Page Range
- p. 299-317
- ISSN
- 0003-4592
- CODEN
- ANCRAI
INIS
- Country of Publication
- Italy
- Country of Input or Organization
- Italy
- INIS RN
- 29062323
- Subject category
- S37: INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY;
- Descriptors DEI
- AQUEOUS SOLUTIONS; CHEMICAL REACTION KINETICS; COUMARIN; DISSOCIATION; DISTRIBUTION FUNCTIONS; MICELLAR SYSTEMS; MICROEMULSIONS; PH VALUE; SPECTROPHOTOMETRY; SURFACTANTS
- Descriptors DEC
- ANTICOAGULANTS; COLLOIDS; DISPERSIONS; DRUGS; EMULSIONS; ESTERS; HEMATOLOGIC AGENTS; HETEROCYCLIC COMPOUNDS; HOMOGENEOUS MIXTURES; KINETICS; LACTONES; MIXTURES; ORGANIC COMPOUNDS; ORGANIC OXYGEN COMPOUNDS; PYRANS; REACTION KINETICS; SOLUTIONS