Synthesis, structure and characterization of a new glycolate: sodium glycolate-glycolic acid (1/1)
1College of Life Science, Nanjing Normal University, Nanjing 210023, People's Republic of China.
Abstract:
Among various glycolates, potassium glycolate glycolic acid (PGGA), ammonium glycolate glycolic acid (AGGA) and rubidium glycolate glycolic acid (RGGA) are isostructural, with the general formula A(C2H3O3)(C2H4O3) (A = K, NH4 and Rb). However, whether Na+ can occupy the A site and its effects on structure and properties remained unknown. This study synthesized sodium glycolate glycolic acid (SGGA), analyzed its composition, structure, vibrational spectra and thermal behaviour, and compared the results with PGGA. SGGA has the formula Na+·C2H3O3-·C2H4O3 or Na(C2H3O3)(C2H4O3), with orthorhombic crystallinity. Although the salt lacks chiral C atoms, it crystallizes in the unique chiral space group P212121. Among various glycolates, only PGGA and RGGA display relatively similar powder X-ray diffraction (PXRD) patterns, while those of other glycolates are distinctly different, providing a key basis for distinguishing A(C2H3O3)(C2H4O3) glycolates. Although SGGA and PGGA show closely related vibrational spectra and thermal behaviour due to structural similarities, differences are observed in certain spectral peaks. Moreover, PGGA decomposes into carbonates at a marginally higher temperature than SGGA. This work provides insight into glycolic acid bonding and the structural role of Na+ in glycolates, guiding new mineral discovery.
Related Concept Videos
Alkylation of β-Diester Enolates: Malonic Ester Synthesis
Base-Catalyzed Aldol Addition Reaction
Nomenclature of Carboxylic Acid Derivatives: Acid Halides, Esters, and Acid Anhydrides
The IUPAC and common names of acid halides are derived from the corresponding carboxylic acids, by changing “ic acid” to “yl halide.” For example, as shown below, the IUPAC name ethanoyl chloride is derived from ethanoic acid, and the common name, acetyl chloride, is obtained from acetic acid.
Structures of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
Structures of Aldehydes and Ketones
In aldehydes (Figures 1a and 1b), the...
Chemistry of Carbohydrates


