3-Chlorophthalic Anhydride CAS 117-21-5
| CAS No. | 117-21-5 |
| Molecular Formula | C8H3ClO3 |
| Molecular Weight | 182.56 g/mol |
| Category | Pharmaceutical Standards / API Standards |
| Availability | In Stock |
Chemical Structure
Description
3-Chlorophthalic Anhydride (CAS 117-21-5), molecular formula C8H3ClO3 and molecular weight 182.56 g/mol, is a CATO reference standard with documented purity and traceability.
Structurally, 3-Chlorophthalic Anhydride (C8H3ClO3) contains a carboxylic acid group, a hydroxyl group, an ether linkage, chlorine substitution, an aromatic ring system. The molecule exhibits a degree of unsaturation (DBE) of 7.0, corresponding to approximately 7 ring(s) or double-bond equivalent(s). With a molecular weight of 182.56 g/mol, it falls into the medium-molecular-weight range. Halogen substitution (F/Cl/Br/I) produces a distinctive isotope pattern in mass spectrometry, a valuable aid for qualitative confirmation.
This reference standard is suitable for quantitative analysis on major chromatographic platforms including HPLC, GC, LC-MS/MS, and GC-MS, serving as an external calibration standard or a system suitability test reference material.
The assigned purity is verified by mass-balance and quantitative NMR (qNMR) approaches, with the expanded uncertainty reported at a 95% confidence level (k=2). Batch homogeneity and stability are independently assessed for every lot.
Physical & Chemical Properties
| Molecular Formula | C8H3ClO3 |
| Molecular Weight | 182.56 g/mol |
| Appearance | Off-white to pale yellow crystalline powder. (slight halide-like odor) |
| Purity | >95% |
| Storage | Store at 2-8°C, protect from light, keep sealed and dry, keep tightly closed to prevent evaporation |
| 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; Contains ester bond; hydrolyzes under strong alkaline conditions |
| Degree of Unsaturation (DBE) | 7.0 |
| UV Absorption | UV-absorbing |
| Structural Features | Aromatic ring present |
| CAS Registry Year (est.) | 1957 |
| Halogen Content | Cl-containing |
Related Chlorophthalic Standards
Recommended Standards
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- 3-Amino-4-(3,4-dimethoxyphenyl)-N-mesityl-6-(p-tolyl)thieno[2,3-b]pyridine-2-carboxamide (CAS 443740-34-9)
- PIVALALDEHYDE OXIME (CAS 10341-66-9)
- 6-(2,2-Difluoroethoxy)pyridine-2-carboxylic acid (CAS 1423754-84-0)
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- Tert-butyl n-{4-[2-(4-formylpiperazin-1-yl)-2-oxoethyl]phenyl}carbamate (CAS 1000932-68-2)
- 2-Hydrazinyl-5-methylpyrimidin-4-amine (CAS 33705-11-2)
- 5-Cyclopropyl-1-methyl-1H-1,2,4-triazole-3-carbaldehyde (CAS 877133-27-2)
- 3-[(2,6-Dichlorophenyl)methyl]-2-methyl-1-(1H-1,2,4-triazol-3-yl)-1,4-dihydropyridin-4-one (CAS 882747-68-4)
- 3-Fluoro-5-(2-methylpropoxy)phenol (CAS 1881328-26-2)
- Liraglutide Impurity 31 (CAS CATO-C4X-199231)
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