Asetonitril-Su İkili Karışımlarında Piroksikam ve Tenoksikam'ın Potansiyometrik pKa Tayini

Year 2012, Volume: 7 Issue: 1, 34 - 44, 04.06.2012

Ebru Çubuk Demiralay Hülya Yılmaz

Abstract

İyonlaşma sabiti (pKa) çözünebilirlik sınırlaması olmaksızın doğru tahmin edilebilen parametrelerden birisidir. Sunulan bu çalışmada, piroksikam ve tenoksikamın asit- baz davranışı çalışılmıştır. Potansiyometrik metot kullanılarak, piroksikam ve tenoksikamın pKa değerleri asetonitril-su ikili karışımlarının farklı yüzdelerinde tayin edilmiştir (asetonitril içeriği hacimce % 30 ile 45 arasında). Bu bileşiklerin sudaki pKa değerleri mol kesri ve Yasuda-Shedlovsky eşitlikleri kullanarak hesaplanmıştır. Deneysel pKa değerleri SPARC and Marvin Sketch paket programlarından türetilmiş tahmini değerlerle karşılaştırılmıştır.

Keywords

Potansiyometrik titrasyonlar, Asetonitril, pKa, Yasuda- Shedlovsky eşitliği

Potentiometric pKa Determination of Piroxicam and Tenoxicam in Acetonitrile-Water Binary Mixtures

Abstract

Ionization constant (pKa) is one among the parameter to be estimated with accuracy, irrespective of solubility constraints. In the present study, acid-base behaviour of the piroxicam and tenoxicam was studied. By using the potentiometric method, pKa values of piroxicam and tenoxicam have been determined in different percentage of acetonitrile-water binary mixtures (acetonitrile content between 30 and 45% in volume). Aqueous pKa values of these compounds were calculated by mole fraction and Yasuda - Shedlovsky equations. The experimental pKa values were compared to the corresponding predicted values derived by SPARC and Marvin Sketch software packages.

Keywords

Potentiometric titrations, Acetonitrile, pKa, Yasuda- Shedlovsky Equation

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• Hülya Yılmaz e-mail: [e-mail]