5-Aminoisophthalic Acid (CAS 99-31-0): Chemical Profile, Synthesis Pathways, and Industrial Significance
In the landscape of multifunctional aromatic compounds, few intermediates match the synthetic versatility of 99-31-0 β the registered CAS number for 5-Aminoisophthalic Acid (5-AIPA). This bifunctional organic molecule carries both a primary amino group and two carboxylic acid moieties on a single benzene ring, giving it a reactivity profile that serves organic synthesis, coordination chemistry, polymer science, and pharmaceutical research simultaneously.
As global demand for high-performance specialty chemicals rises, sourcing this compound with verified purity and traceable batch documentation has become a critical requirement for industrial buyers and research institutions alike. Jay Finechem, a recognized specialty chemical supplier, maintains a consistent supply of 99-31-0 at industrial-grade purity to support these applications across sectors.
Molecular Architecture and Physicochemical Properties
Structural Features of 5-Aminoisophthalic Acid
5-Aminoisophthalic Acid belongs to the class of aminobenzenedicarboxylic acids. Its IUPAC name is 5-amino-1,3-benzenedicarboxylic acid, and it is also referred to as 5-aminobenzene-1,3-dicarboxylic acid in systematic nomenclature.
The molecular structure features:
A central benzene ring as the aromatic scaffold
Two carboxylic acid groups (-COOH) positioned symmetrically at the 1 and 3 positions (meta configuration)
One primary amine group (-NHβ) at the 5 position
Molecular formula: CβHβNOβ
Molecular weight: 181.15 g/mol
The meta placement of carboxyl groups (characteristic of the isophthalic acid backbone) combined with the 5-amino substituent creates a non-linear, asymmetric coordination geometry. This geometry is critical for building porous framework architectures where linearity would otherwise limit structural diversity.
Molecular Formula :- CβHβNOβ
Molecular Weight :- 181.15 g/mol
Melting Point :- > 300Β°C
Boiling Point :- ~314Β°C (estimated)
Appearance :- White to off-white crystalline powder
Solubility :- Soluble in water and polar organic solvents
The high melting point indicates strong intermolecular hydrogen bonding between carboxyl groups and amino groups in the solid state β a factor that contributes to its stability during storage and transport.
Synthesis and Manufacturing Considerations
5-Aminoisophthalic Acid is typically produced through one of two established routes:
Route 1 β Nitration followed by reduction: Isophthalic acid undergoes selective nitration at the 5-position using mixed acid conditions. The resulting 5-nitroisophthalic acid is then subjected to catalytic hydrogenation (using Pd/C or Raney nickel) or chemical reduction (using iron/acetic acid or tin/HCl) to yield the target amino compound.
Route 2 β Directed functionalization: In more controlled laboratory settings, directed metalation strategies allow selective introduction of the amino group onto pre-functionalized isophthalic acid derivatives, though this route is less common at industrial scale due to cost.
Purity and Quality Control
For downstream industrial use, purity standards are non-negotiable. Key analytical methods used to characterize and verify CAS 99-31-0 include:
HPLC β for quantitative purity assay (typically β₯98%)
NMR spectroscopy (ΒΉH and ΒΉΒ³C) β for structural confirmation
FT-IR spectroscopy β for functional group verification
Elemental analysis β to confirm C, H, N, O ratios
Melting point determination β as a rapid identity check
Any deviation in the amino group content or the presence of residual nitro intermediates can significantly impact reactivity in downstream synthesis β making batch-specific Certificates of Analysis (COAs) essential for compliance.
Industrial and Research Applications of CAS 99-31-0
Metal-Organic Framework Synthesis
The most scientifically dynamic application of 99-31-0 is in the construction of metal-organic frameworks (MOFs). As a ditopic carboxylate ligand with an appended amino group, 5-AIPA functions as an organic linker that coordinates to metal nodes β including lanthanides, copper, zinc, and cobalt β to form porous crystalline architectures.
Published research has demonstrated that 5-AIPA-based MOFs exhibit:
Structural diversity ranging from 1D ladder-like chains to 3D framework topologies
Post-synthetic modification capacity via the free -NHβ group (enabling amine functionalization without framework collapse)
Applications in gas adsorption, selective sensing, and electrocatalytic reduction of hydrogen peroxide
Semiconducting behavior relevant to Schottky barrier diode development
The ability to modify the amine post-synthetically without disrupting the MOF skeleton makes 5-AIPA a far more flexible linker than simple dicarboxylate ligands.
Pharmaceutical and Fine Chemical Intermediates
In pharmaceutical chemical processing, 5-Aminoisophthalic Acid serves as a starting material or intermediate in the synthesis of:
Heterocyclic scaffolds such as benzimidazoles, quinazolinones, and related ring systems
Dendrimer cores β including chiral methacrylamide dendrimers with ester groups, synthesized via condensation with the amino moiety
Diagnostic contrast agent precursors β where the bifunctional nature allows conjugation with imaging moieties
API intermediates β particularly in CNS, oncology, and anti-infective drug programs
Purity requirements in this segment are stringent, often demanding β₯99% HPLC purity with controlled levels of genotoxic impurities under ICH Q3A guidelines.
Reactive Dye and Pigment Chemistry
5-AIPA is an established dye intermediate in the production of reactive, disperse, and acid dyes. The free amino group participates in diazotization reactions to form diazonium salts, which are then coupled with appropriate coupling components to yield azo dye structures.
Key performance attributes of 5-AIPA-derived dyes include:
High molar extinction coefficients due to extended aromatic conjugation
Excellent light fastness and wash fastness ratings β critical for textile applications
Compatibility with fiber-reactive dyeing processes on cellulosic and protein fibers
From a chemical sourcing perspective, consistent amine content in the raw material directly determines dye yield and color strength β making supplier selection a technical, not just commercial, decision.
High-Performance Polymer Chemistry
5-Aminoisophthalic Acid participates in condensation polymerization as a bifunctional monomer. Notable polymer applications include:
Poly(5-aminoisophthalic acid) β produced via oxidative polymerization, with potential conductive polymer applications
Polybenzimidazole copolymers β synthesized by condensation with 3,3β²-diaminobenzidine, yielding thermally stable materials (PBIANI) for membrane and aerospace use
Composite silica membranes β blended with polyvinyl alcohol (PVA) for diffusion dialysis in acid recovery processes
Polyamide and polyimide backbones β used in high-temperature engineering plastics for automotive and electronics sectors
The dual reactive sites (amine + two carboxylic acids) allow incorporation into polymer chains via either the amine or the acid functionality, giving formulation chemists significant structural flexibility.
Regulatory and Safety Profile
CAS 99-31-0 is classified under Acute Toxicity Category 4 (Oral) and Eye Irritant Category 2 per GHS classification. Standard industrial handling protocols apply:
Use nitrile or neoprene gloves and safety goggles during handling
Ensure adequate ventilation in processing areas
Store in a tightly sealed container in cool, dry conditions away from oxidizing agents
Avoid inhalation of dust during weighing and transfer operations
Buyers operating in regulated markets should request:
SDS (Safety Data Sheet) β for hazard communication compliance
Certificate of Analysis (COA) β for batch traceability
Purity assay report β HPLC-based confirmation
Country of origin documentation β for import/export customs clearance
Jay Finechem provides complete documentation for each shipment, supporting buyers in meeting their local quality control and regulatory requirements without delays.
Sourcing CAS 99-31-0 from Jay Finechem
Jay Finechem operates as a specialty chemical supplier with a strong sourcing and distribution network across India and export markets. For buyers evaluating 99-31-0 from Jay Finechem, key commercial advantages include:
Verified purity batches with COA available on request
Flexible order quantities β suitable for research labs and manufacturing scale
Technically informed customer support for product and application queries
Timely dispatch with appropriate chemical packaging standards
Competitive pricing benchmarked against international supply sources
"Our R&D team relies on consistent amine content for MOF synthesis reproducibility. Jay Finechem has been one of the few Indian suppliers where purity specs actually match what's on the COA. We've reordered multiple times without issues." β Research Chemist, Advanced Materials Laboratory, Pune
"We switched to Jay Finechem for our dye intermediate procurement after facing batch inconsistency with another vendor. The documentation turnaround is fast and the product performs well in our azo coupling reactions." β Technical Manager, Specialty Dyes Division, Ahmedabad
Q1. What is the difference between 5-Aminoisophthalic Acid and isophthalic acid? Isophthalic acid has two carboxylic acid groups at the 1 and 3 positions of benzene, with no other substituents. 5-Aminoisophthalic Acid (CAS 99-31-0) adds a primary amine group at the 5 position, giving it bifunctional reactivity that isophthalic acid alone does not possess.
Q2. What purity grade is recommended for MOF synthesis? For metal-organic framework applications, a minimum purity of 98% (HPLC) is generally recommended. Higher purity grades (β₯99%) are preferred for research-grade MOF crystal growth where defect minimization is critical.
Q3. Can 5-AIPA be used as a ligand in coordination chemistry without modification? Yes. The free carboxylate groups coordinate directly to metal centers in their deprotonated form. The amino group can remain free for post-synthetic modification or can itself coordinate to softer Lewis acid metal centers, depending on reaction conditions.
Q4. What analytical tests should I request when sourcing CAS 99-31-0? Request HPLC purity, melting point confirmation, FT-IR spectrum, and elemental analysis. For pharmaceutical use, also request a genotoxic impurity screening report and residual solvent analysis per ICH guidelines.
Q5. Is bulk supply of 5-Aminoisophthalic Acid available from Jay Finechem? Yes. Jay Finechem supports bulk procurement for industrial buyers. Contact them via their product page to discuss volume pricing, lead times, and packaging specifications.
For chemical safety, regulatory classification, and substance identity verification, the ECHA Substance Information Portal provides authoritative data on aromatic amines and carboxylic acid derivatives used across regulated industries.
As industries push deeper into advanced materials, precision pharmaceuticals, and functional polymer design, the demand for chemically pure and reliably sourced intermediates grows sharper. 99-31-0 occupies a unique position in this landscape β its bifunctional architecture makes it indispensable across dye synthesis, MOF construction, polymer chemistry, and drug intermediate manufacturing.
Sourcing this compound from a supplier who understands both the chemistry and the commercial requirements is what separates smooth production from costly disruptions.
Connect with Jay Finechem today to request batch specifications, pricing, and documentation for 5-Aminoisophthalic Acid β and put your chemical sourcing exactly where it needs to be: verified, consistent, and ready for your next production cycle.