Spectroscopic and theoretical studies of potassium sodium l-(+)-tartrate tetrahydrate and l-tartaric acid used as precursors for in situ laser-induced deposition of the catalytically active copper microstructures

Abstract

In this work we study the influence of l-(+)-КNaC4H4O6\u2009×\u20094H2O (KNaT) and l-H2C4H4O6 (H2T) on the complexation processes occurring during in situ laser-induced catalytic destruction of the organic components of the aqueous solutions with formation of the unsaturated hydrocarbons. For that purpose, ATR-FTIR, Raman, IR, and NIR spectroscopy as well as quantum chemical calculations were implemented. It was observed that hydration of T2− anion via carboxylate groups is stronger than that via hydroxyl groups. We also established the changes in the spectral characteristics of the absorption bands corresponding to vibrations of T2−, HT−, and H2T, at solid state-liquid and acid-salt transitions, depending on concentration of the solution components and the [OH−]/[H2T] ratio. Finally, it was shown that ethylene is a main product of the catalytic destruction of the copper tartrate complexes.