Publication: Bazı amino asitlerin proton ayrışması tepkimelerinin makro ve mikro denge sabitlerine çözücü ve sıcaklığın etkisinin incelenmesi
Abstract
Amaç: L-alanin, β-alanin ve gama amino bütirik asitin makroskopik ve mikroskopik protonlanma sabitleri ve proton-ligand sistemleri için termodinamik parametreleri (entalpi, entropi ve serbest enerji değişimleri) 5; 20; 35°C’de sadece su ve ACN-su (%25 ACN ve %50 ACN (h/ h) karışımlarında 0,1000 mol L–1 NaClO4 sabit iyonik kuvvette potansiyometrik yöntem ile belirlenmesi. Gereç ve Yöntem: Potansiyometrik titrasyonlar L- alanin, alanin metil ester, β-alanin, βalanin metil ester, gama amino bütirik asit ve 4-amino bütirat için 5,0; 20,0; 35,0°C'te su ve ACN-su (%25 ACN ve %50 ACN (h/ h)) karışımlarında gerçekleştirildi ve çözeltilerin protonlanma sabitleri Irving ve Rossotti yöntemine göre hesaplandı. Bulgular: L-Alanin, β-alanin ve gama amino bütirik asitin mikroskopik protonasyon sabitleri genellikle sıcaklık artışıyla azalma eğilimindedir. Su ve ACN-su karışımlarında L-Alanin, L-Alanin metil esteri, β-alanin ve β-alanin metil esterinin protonasyon reaksiyonları genellikle entalpi yönündedir. Sonuç: L-Alanin, L-Alanin metil esterin, β-alanin ve β-alanin metil esterinin termodinamik parametreleri (entalpi, entropi ve serbest enerji değişimleri) protonasyon sabitinin ACN-su karışımlarının ekzotermik olduğunu gösterir. Serbest enerji değişimleri tüm durumlarda negatiftir ve reaksiyonlar kendiliğinden gerçekleşir.
Objective: L- alanine, β-alanine and gamma amino butyric acid’s macroscopic and microscopic protonation constants and thermodynamic parameters (enthalpy, entropy, and free energy changes) for the proton–ligand systems have been determined at 5; 20; 35°C, in water and ACN-water (25% ACN and 50% ACN (v/ v)) mixtures at constant ionic strength of 0.1000 mol L–1 NaClO4 by potentiometric method Material and Methods: Potentiometric titrations for L- alanine, L- alanine methyl ester, β-alanine, β-alanine methyl ester, gamma amino butyric acid and methyl 4-aminobutyrate were performed at 5; 20; 35°C in ACN-water (25% ACN and 50% ACN (v/ v)) mixtures and protonation constants of the solutions were determined according to the Irving and Rossotti method. Results: L-Alanine and β-alanine gamma amino butyric acid’s microscopic protonation constants generally tend to decrease with temperature rise. L-Alanine, L-Alanine methyl ester, β-alanine, β-alanine methyl ester, gamma amino butyric acid and Methyl 4- aminobutyrate protonation reactions in ACN-water mixtures generally favor enthalpydriven. Conclusion: L-Alanine, L-Alanine methyl ester, β-alanine, β-alanine methyl ester, gamma amino butyric acid and Methyl 4-aminobutyrate’s thermodynamic parameters (enthalpy, entropy, and free energy changes) demonstrates protonation constant in ACNwater mixtures are exothermic. The free energy changes are negative in all situations, and reactions are spontaneous.
Objective: L- alanine, β-alanine and gamma amino butyric acid’s macroscopic and microscopic protonation constants and thermodynamic parameters (enthalpy, entropy, and free energy changes) for the proton–ligand systems have been determined at 5; 20; 35°C, in water and ACN-water (25% ACN and 50% ACN (v/ v)) mixtures at constant ionic strength of 0.1000 mol L–1 NaClO4 by potentiometric method Material and Methods: Potentiometric titrations for L- alanine, L- alanine methyl ester, β-alanine, β-alanine methyl ester, gamma amino butyric acid and methyl 4-aminobutyrate were performed at 5; 20; 35°C in ACN-water (25% ACN and 50% ACN (v/ v)) mixtures and protonation constants of the solutions were determined according to the Irving and Rossotti method. Results: L-Alanine and β-alanine gamma amino butyric acid’s microscopic protonation constants generally tend to decrease with temperature rise. L-Alanine, L-Alanine methyl ester, β-alanine, β-alanine methyl ester, gamma amino butyric acid and Methyl 4- aminobutyrate protonation reactions in ACN-water mixtures generally favor enthalpydriven. Conclusion: L-Alanine, L-Alanine methyl ester, β-alanine, β-alanine methyl ester, gamma amino butyric acid and Methyl 4-aminobutyrate’s thermodynamic parameters (enthalpy, entropy, and free energy changes) demonstrates protonation constant in ACNwater mixtures are exothermic. The free energy changes are negative in all situations, and reactions are spontaneous.