Related Experiment Video
Updated: Jan 2, 2026

Qualitative Identification of Carboxylic Acids, Boronic Acids, and Amines Using Cruciform Fluorophores
Published on: August 19, 2013
Study of the spectroscopic properties and deprotonation of 6-bromo-2-naphthoic acid
Dzmitryi Ushakou1, Tomasz Wróblewski1
1Pomeranian University in Słupsk, str. Arciszewskiego 22b, 76-200 Słupsk, Poland.
Abstract:
The present work studies the UV-Vis spectroscopic properties of 6-bromo-2-naphthoic acid (BNA) dissolved in methanol, tetrahydrofuran (THF) and ethyl acetate. It has been found that there are significant differences between the emission spectra for the samples with different concentrations of BNA in methanol. Also, the analogical changes have been observed in the case of the samples of BNA in THF and ethyl acetate which have been studied immediately after preparation and 24 h after preparation. It could be explained by deprotonation processes that take place in BNA. Moreover, it has been found that the anion formation process in BNA is more intensive in the case of methanol solvent in comparison with the cases of THF and ethyl acetate. This fact could be explained by the different polarity of these solvents. As methanol is characterized by higher polarity, the deprotonation is more intensive in the case of this solvent. To verify our assumption the quantum-chemical calculations have been also performed. It has been found that the enthalpy of dissociation (the bond-dissociation energy) is equal to 183.2, 200.2 and 205.4 kcal/mol for BNA dissolved in methanol, THF and ethyl acetate, respectively. It explains why the deprotonation process in methanol is more intensive than in THF and ethyl acetate. Thereby, the study shows that the obtained theoretical calculations are in good agreement with the experimental results.
More Related Videos
Related Concept Videos
NMR Spectroscopy of Benzene Derivatives
Spectroscopy of Carboxylic Acid Derivatives
NMR and Mass Spectroscopy of Carboxylic Acids
While α protons of carboxylic acids absorb at 2–2.5 ppm, β protons absorb further upfield.
Carboxylic acids are easily identified by dissolving them in deuterium oxide, which results in a rapid exchange of the acidic protons with deuterium. This leads to the...
¹H NMR: Complex Splitting
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
NMR Spectroscopy of Aromatic Compounds
NMR Spectroscopy Of Amines

