What is the pKa value of Pyridine-2,3-dicarboxylic Acid?
Pyridine-2,3-dicarboxylic acid, also known as quinolinic acid, is a heterocyclic organic compound with a wide range of applications in the chemical and pharmaceutical industries. As a supplier of Pyridine-2,3-dicarboxylic acid, understanding its properties, including the pKa values, is crucial for both us and our customers in terms of handling, reactions, and product development.
Chemical Structure and Basic Properties
Pyridine-2,3-dicarboxylic acid has a pyridine ring with two carboxylic acid functional groups at positions 2 and 3. The presence of these carboxylic acid groups gives it acidic properties. The molecular formula of Pyridine-2,3-dicarboxylic acid is C7H5NO4, and its molecular weight is approximately 167.12 g/mol. The compound exists as a white to light - yellow crystalline powder at room temperature.
Significance of pKa Values
The pKa value is a quantitative measure of the acidity of an acid in a solution. It is defined as the negative logarithm (base 10) of the acid dissociation constant (Ka). A lower pKa value indicates a stronger acid, meaning that it more readily donates a proton in solution.
For a diprotic acid like Pyridine-2,3-dicarboxylic acid, there are two pKa values corresponding to the dissociation of each carboxylic acid group. The first pKa (pKa1) represents the dissociation of the first carboxylic acid group, and the second pKa (pKa2) represents the dissociation of the second carboxylic acid group.
The pKa values are important for several reasons. In chemical reactions, they help predict the direction and equilibrium of acid - base reactions. For example, when Pyridine-2,3 - dicarboxylic acid reacts with a base, the pKa values determine at what pH the acid will donate its protons and how stable the resulting conjugate bases will be. In pharmaceutical applications, the pKa values can affect the solubility, stability, and bioavailability of drugs derived from or containing Pyridine-2,3 - dicarboxylic acid.
Experimental Determination of pKa Values
The pKa values of Pyridine-2,3 - dicarboxylic acid are typically determined experimentally using techniques such as potentiometric titration. In a potentiometric titration, a solution of Pyridine-2,3 - dicarboxylic acid is titrated with a strong base, and the pH of the solution is measured as a function of the volume of the added base. The inflection points in the titration curve correspond to the pKa values.
The reported pKa values for Pyridine-2,3 - dicarboxylic acid in the literature are pKa1 ≈ 2.43 and pKa2 ≈ 4.76 at 25 °C and in an ionic strength environment. These values indicate that the first carboxylic acid group is relatively more acidic than the second one. The difference in the pKa values can be attributed to the electronic and inductive effects within the molecule. Once the first proton is removed, the negative charge on the resulting carboxylate group can affect the electron density around the second carboxylic acid group, making it more difficult to remove the second proton.
Impact of pKa on Applications
In Chemical Synthesis
In chemical synthesis, the pKa values of Pyridine-2,3 - dicarboxylic acid are critical for designing reactions. For example, when using Pyridine-2,3 - dicarboxylic acid as a reactant in an esterification reaction, the pH of the reaction medium needs to be carefully controlled. If the pH is too high, the acid may exist predominantly in its conjugate base form, and the reaction rate may be affected. If the pH is too low, side reactions may occur.
The pKa values also play a role in the formation of metal - ligand complexes. Pyridine-2,3 - dicarboxylic acid can act as a ligand for many metal ions. The ability of the acid to donate protons and coordinate with metal ions is influenced by the solution pH, which is related to its pKa values.
In Pharmaceutical Industry
As a key intermediate, Pyridine-2,3 - dicarboxylic acid is used in the synthesis of drugs such as Nikethamide Intermediate Quinolinic Acid. The pKa values affect the pharmacokinetic properties of these drugs. For example, the solubility of a drug in different physiological fluids can be pH - dependent due to the dissociation of the carboxylic acid groups in Pyridine-2,3 - dicarboxylic acid moieties. In the gastrointestinal tract, the varying pH levels can influence the absorption of drugs containing Pyridine-2,3 - dicarboxylic acid.
Another application is in the synthesis of Nikethamide Intermediate 2,3 - Pyridinedicarboxylic Acid. The pKa values are important for controlling the reaction conditions to ensure the formation of the desired product with high yield and purity.
Moreover, Pyridine-2,3 - dicarboxylic acid is also used as Imidazolinone Material CAS NO 89 - 00 - 9 Quinolinic Acid. In the formulation of these materials, the pKa values help in optimizing the stability and performance of the final product.
Our Role as a Supplier
As a supplier of Pyridine-2,3 - dicarboxylic acid, we understand the importance of providing high - quality products with well - characterized properties, including accurate pKa values. We ensure that our Pyridine-2,3 - dicarboxylic acid is produced through reliable synthesis methods and undergoes strict quality control procedures.
We also offer technical support to our customers. Our team of chemists can assist customers in understanding how the pKa values of Pyridine-2,3 - dicarboxylic acid can impact their specific applications. Whether it is for research purposes, chemical synthesis, or pharmaceutical development, we can provide guidance on handling, storage, and reaction conditions based on the pKa values.
Contact for Procurement
If you are interested in purchasing Pyridine-2,3 - dicarboxylic acid for your research or industrial needs, we invite you to contact us for further details and to discuss possible procurement terms. Our expertise and high - quality products can meet your requirements in various applications related to this important compound.
References
- Handbook of Chemistry and Physics. 90th Edition. CRC Press.
- Journal of Chemical Education. Various articles on acid - base chemistry and pKa determination.
- Organic Chemistry textbooks related to heterocyclic compounds and acid - base reactions.