Oxalic acid is one of the oldest known acids. It was first isolated from wood sorrel (Oxalis acetosella).
While pinpointing the absolute oldest acid is difficult due to the limitations of historical record-keeping and the nature of acids themselves, oxalic acid holds a strong claim to this title based on its early isolation and identification. Many other acids, such as those found in the digestion process or those that have existed naturally in the environment for eons, were not identified or understood as 'acids' until much later in human history.
The discovery and identification of acids throughout history is intrinsically linked to the development of chemistry as a scientific discipline. Early civilizations undoubtedly encountered and used acidic substances, but their understanding of the chemical nature of these substances was limited. The identification of oxalic acid represents an early milestone in our understanding of this important class of chemicals.
Other Relevant Information from References:
- Early Chemistry and Food: The provided references highlight the central role of chemistry in the history of food production, preservation, and consumption. This includes mentions of acids, though not specifically identifying the "oldest". (https://www.sciencemuseum.org.uk/objects-and-stories/chemistry/food-chemical-history)
- Hydrochloric Acid: While the reference discusses hydrochloric acid, it does not determine its age relative to other acids. (https://www.jstor.org/stable/27757245)
- Fertilizers and Sulfuric Acid: The development of chemical fertilizers in the 19th century utilized sulfuric acid, demonstrating its importance in industrial processes. This does not, however, establish it as the oldest acid. (https://acsess.onlinelibrary.wiley.com/doi/10.2136/sssaj1977.03615995004100020020x)
- Ancient Amino Acids and Proteins: The discovery of ancient amino acids and proteins in fossils provides insights into the early forms of life but does not directly address the question of the oldest acid. (https://www.nature.com/articles/s41598-019-42938-9, https://hub.jhu.edu/2023/02/27/protein-origin-life/)
The references pertaining to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) focus on their health benefits and are not relevant to the question of the oldest acid. (https://pubmed.ncbi.nlm.nih.gov/33573174/, https://pubmed.ncbi.nlm.nih.gov/26822516/) Similarly, references on folic acid and penicillin are not pertinent to this question. (https://pmc.ncbi.nlm.nih.gov/articles/PMC3257747/, https://www.acs.org/education/whatischemistry/landmarks/flemingpenicillin.html)
