Formation of humic substances in the reaction of D-glucose with p-toluidine in anhydrous ethanol
| Autor: | P. S. Kryukova, I. S. Cherepanov |
|---|---|
| Jazyk: | ruština |
| Rok vydání: | 2020 |
| Předmět: |
Pulmonary and Respiratory Medicine
Chemistry Condensation Aqueous two-phase system Infrared spectroscopy Chromophore Conjugated system Carbohydrate Photochemistry lcsh:Chemistry lcsh:Biochemistry chemistry.chemical_compound lcsh:QD1-999 D-Glucose Pediatrics Perinatology and Child Health lcsh:QD415-436 Spectroscopy |
| Zdroj: | Izvestiâ Vuzov: Prikladnaâ Himiâ i Biotehnologiâ (2020) |
| Popis: | The aim of the study was to investigate the processes of formation and structural group composition of the products formed during the reaction of D-glucose with p-toluidine in anhydrous ethanol using electronic and vibrational spectroscopy methods. The evolution of the profiles of the electronic spectra of working solutions shows the formation of a chromophore system: clear peaks at 380 and 440 nm are already present at a reaction time of 60 min. The appearance of an additional maximum at 520 nm (90, 120 min) likely corresponds to the formation of chromophores in condensed structures, as confirmed by a decrease in the values of the E 4 /Е 6 indices over time. The dynamics of the transformation of structural elements is also clearly seen in the analysis of IR spectra: as the reactions proceed, the CH aliphatic component of the structure decreases, while the aromatisation and functionalisation of products by chromophore groups increases. For products obtained between 90 and 120 min, a clear band at 1656 cm -1 , attributed to stretching vibrations of multiple bonds in conjugated C=C – C=O systems and azomethine fragments, indicates the of condensation reactions. In the spectra of insoluble solid products fractionated by water, the intensity of the bands at 1656 and 1190 cm -1 is significantly reduced; this is possibly due to the transfer of some of the coloured low molecular weight products to the aqueous phase. A comparison of the IR Fourier transform spectra of the final solid products with the spectra of natural and synthetic humic-like substances indicates their similar structural group composition. The intensity of the bands at 1620, 1508 and 815 cm -1 indicates a significant contribution of the aromatic component to the structure of the products of water-insoluble fractions; the water-soluble fractions mainly include aliphatic oxygen-containing structures resulting from the oxidative destruction of the initial carbohydrate. The synthesised products seem promising as convenient plant growth regulators with controlled release of the active substance. |
| Databáze: | OpenAIRE |
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