Isophthalic Acid CAS 121-91-5
| CAS No. | 121-91-5 |
| Molecular Formula | C8H6O4 |
| Molecular Weight | 166.13 g/mol |
| Category | Pharmaceutical Standards / API Standards |
| Availability | In Stock |
Chemical Structure
Description
Compared with other compounds in its class, the molecular weight of 166.13 g/mol gives Isophthalic Acid distinctive chromatographic separation conditions and mass-spectrometry parameter settings.
Isophthalic Acid (CAS 121-91-5), molecular formula C8H6O4 and molecular weight 166.13 g/mol, is a CATO reference standard with documented purity and traceability.
The molecular framework of Isophthalic Acid (C8H6O4) is characterized by a carboxylic acid group, a hydroxyl group, an ether linkage, an aromatic ring system. In reversed-phase chromatography, its retention is governed primarily by the polarity and ionization state of its functional groups, which provides a practical basis for HPLC-UV/DAD or LC-MS method development. The presence of an aromatic ring or conjugated system gives the compound characteristic absorption bands in the UV-Vis region, making it well suited to UV or diode-array detection (DAD).
Recommended for analytical method development and validation; each product is supplied with a full Certificate of Analysis (COA) ensuring ISO 17034 metrological traceability.
As a certified reference material (CRM), Isophthalic Acid meets the metrological traceability requirements of ISO/IEC 17025 laboratories. Batch-to-batch consistency is monitored via control charts to guarantee comparable assigned values across lots.
Physical & Chemical Properties
| Molecular Formula | C8H6O4 |
| Molecular Weight | 166.13 g/mol |
| Appearance | Off-white to pale yellow crystalline powder |
| Purity | >95% |
| Storage | Store at 2-8°C, protect from light, keep sealed and dry |
| Solubility (reference) | Soluble in methanol, ethanol, DMSO |
| Stability | May oxidize slowly on prolonged air exposure; Light-sensitive; avoid direct strong light; Hygroscopic; reseal immediately after opening |
| Degree of Unsaturation (DBE) | 6.0 |
| UV Absorption | UV-absorbing |
| Structural Features | Aromatic ring present |
| CAS Registry Year (est.) | 1957 |
Related Isophthalic Standards
- Isophthalic-2,4,5,6-d4 Acid (CAS 148472-48-4)
- Isophthalic acid-carboxy-<SUP>13</SUP>C<SUB>2</SUB> (CAS 112043-90-0)
- Isophthalic Acid, Bis-Methyl Ester (CAS 1459-93-4)
- Isophthalic acid compound with nonanedioic acid and dimethyl terephthalate and 2,2-dimethylpropane-1,3-diol and ethane-1,2-diol (1:1:1:1:1) (CAS 75701-44-9)
- Isophthalic Acid, Bis-n-Octyl Ester (CAS 4654-18-6)
Recommended Standards
- Lornoxicam Impurity 8 (CAS 13120-39-3)
- Terephthalic Acid (CAS 100-21-0)
- Norepinephrine Impurity 15 (CAS 29477-55-2)
- Phthalic Acid (CAS 88-99-3)
- 5-Chloro-N-(2-chlorobenzyl)pyrazine-2-carboxamide (CAS 1438853-89-4)
- 4-Amino-3-(difluoromethyl)-6-iodopicolinonitrile (CAS 1806835-45-9)
- 2-Chloro-1-(phenylsulfonyl)-1H-pyrrolo[2,3-b]pyridine (CAS 1227268-62-3)
- Ethyl 2-acetamido-3-((4-(tert-butyl)phenyl)amino)-3-oxopropanoate (CAS 866017-98-3)
- tert-Butyl 4-((3-aminopyridin-4-yl)oxy)piperidine-1-carboxylate (CAS 1422454-77-0)
- 5,6-difluoro-3,4-dihydroquinazolin-4-one (CAS 933823-89-3)
- 5-chloro-2-(propan-2-yloxy)pyridin-3-amine (CAS 1395038-94-4)
- 1-Oxa-8-azaspiro[4.5]decane, 2,2-dimethyl- (CAS 374794-94-2)
- (S)-1-(6-Bromobenzo[d]thiazol-2-yl)ethanamine (CAS 1447616-08-1)
- Des-Leu26-Tirzepatide (CAS CATO-CPTD788947)
Why CATO?
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