Кислотно-основні властивості систем SO2 – Am (KOH) – Тропеолін OOO – H2O (Am – етаноламіни, морфолін)
Alternative Title
SO2 – Am (KOH) – tropeolin OOO– H2O (Am – ethanolamines, morpholine) systems acid-base properties
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Date
2022
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Одеський національний університет імені І. І. Мечникова
Abstract
Здійснено спектрофото- та кольорометричне дослідження протеолітичних рівноваг
в системах SO2 – Am (KOH) – Тропеолін OOO (TrOOO) – H2O (Am – етаноламіни,
морфолін) при CTrOOO = 1,12×10–4 М, CAm(KOH) = 0,1 М, T = 293 К. Встановлено
взаємозв’язок кольорометричних функцій (повної колірної відмінності та питомої
колірної відмінності) систем SO2 – Am – TrOOO – H2O із молярною рефракцією Am,
емпіричною функцією pKa – lgPow, що об’єднує їх основність та гідрофільність, константами утворення амонієвих сульфітів та гідросульфітів, характеристиками pH-
(dpH/dpQSO2), редокс (dЕ/dpQSO2) і кондуктометричних (∆κ) кривих титрування водних
розчинів Am газоподібним оксидом сірки (IV).
The study of data on acid-base properties of model systems SO2 – KOH – TrOOO – H2O and SO2 – Am – TrOOO – H2O (TrOOO – tropeoline OOO; Am – diethanolamine (DEA), triethanolamine (TEA), N‑methylmonoethanolamine (MMEA) and morpholine (Mf) at 293 K using pH-, spectrophotometry and colorimetry methods are presented. There is a pronounced isosbestic point at 415 nm in the electronic absorption spectra of the systems SO2– Am –TrOOO– H2O (Am = MMEA, MEA and TEA; pH ≤ 7.5; T = 293 K), which indicates the presence of a dynamic equilibrium between ion-molecular forms. According to the width of the absorption spectra, the bases in the region of 2.0 ≤ pH ≤ 8.0 can be arranged in the following row: MEA > Mf > KOH > DEA > TEA > MMEA. The bases can be arranged in the following rows for the effect on optical density at 490 nm: KOH > Mf ≥ MEA > DEA ≥ TEA (at 5.5 ≤ pH < 9.0); KOH = MEA = Mf > DEA = TEA (at pH < 6.0). According to the values of optical density at 360 nm in the region of 2.0 ≤ pH < 8.5, the bases can be arranged in the following row: Mf > KOH ≥ MEA ≥ DEA > MMEA > TEA. The total color difference (ΔE76) and specific color difference (SCD) values were calculated by colorimetric method as a function of pH. The acid–base dissociation constants in the SO2 – Am (KOH) – TrOOO – H2O systems significantly depend on the structure and physicochemical properties of the organic base and differ significantly from those in the HCl (HClO4, H2SO4) – MEA – TrOOO – H2O systems. The interrelation of colorimetric functions was established (total color difference and specific color difference) of SO2 – Am – TrOOO – H2O systems with molar refraction Am, empirical function pKa – lgPow, which combines the basicity and hydrophilicity of Am, formation constants of ammonium sulfites and hydrosulfites, pH- (dpH/dpQSO2 ), redox- (dЕ/dpQSO2 ) and conductometric (Dk) titration curves of Am aqueous solutions with gaseous sulfur dioxide.
The study of data on acid-base properties of model systems SO2 – KOH – TrOOO – H2O and SO2 – Am – TrOOO – H2O (TrOOO – tropeoline OOO; Am – diethanolamine (DEA), triethanolamine (TEA), N‑methylmonoethanolamine (MMEA) and morpholine (Mf) at 293 K using pH-, spectrophotometry and colorimetry methods are presented. There is a pronounced isosbestic point at 415 nm in the electronic absorption spectra of the systems SO2– Am –TrOOO– H2O (Am = MMEA, MEA and TEA; pH ≤ 7.5; T = 293 K), which indicates the presence of a dynamic equilibrium between ion-molecular forms. According to the width of the absorption spectra, the bases in the region of 2.0 ≤ pH ≤ 8.0 can be arranged in the following row: MEA > Mf > KOH > DEA > TEA > MMEA. The bases can be arranged in the following rows for the effect on optical density at 490 nm: KOH > Mf ≥ MEA > DEA ≥ TEA (at 5.5 ≤ pH < 9.0); KOH = MEA = Mf > DEA = TEA (at pH < 6.0). According to the values of optical density at 360 nm in the region of 2.0 ≤ pH < 8.5, the bases can be arranged in the following row: Mf > KOH ≥ MEA ≥ DEA > MMEA > TEA. The total color difference (ΔE76) and specific color difference (SCD) values were calculated by colorimetric method as a function of pH. The acid–base dissociation constants in the SO2 – Am (KOH) – TrOOO – H2O systems significantly depend on the structure and physicochemical properties of the organic base and differ significantly from those in the HCl (HClO4, H2SO4) – MEA – TrOOO – H2O systems. The interrelation of colorimetric functions was established (total color difference and specific color difference) of SO2 – Am – TrOOO – H2O systems with molar refraction Am, empirical function pKa – lgPow, which combines the basicity and hydrophilicity of Am, formation constants of ammonium sulfites and hydrosulfites, pH- (dpH/dpQSO2 ), redox- (dЕ/dpQSO2 ) and conductometric (Dk) titration curves of Am aqueous solutions with gaseous sulfur dioxide.
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Keywords
кольорометрія, етаноламіни, морфолін, водні розчини, оксид сірки (IV), colorimetry, ethanolamines, morpholie, aqueous solutions, sulfur dioxide
Citation
Вісник Одеського національного університету = Odesa National University Herald