Phthalic Acid, Mono-Methyl Ester CAS 4376-18-5
| CAS No. | 4376-18-5 |
| Molecular Formula | C9H8O4 |
| Molecular Weight | 180.16 g/mol |
| Category | Pharmaceutical Standards / API Standards |
| Availability | In Stock |
Chemical Structure
Description
Phthalic Acid, Mono-Methyl Ester (CAS 4376-18-5), molecular formula C9H8O4 and molecular weight 180.16 g/mol, is a CATO reference standard with documented purity and traceability.
Owing to a carboxylic acid group, a hydroxyl group, an ether linkage, an aromatic ring system, Phthalic Acid, Mono-Methyl Ester is typically off-white to pale yellow crystalline powder. Its solid-state physicochemical attributes — including a molecular weight of 180.16 g/mol — guide the selection of appropriate sample preparation and analytical techniques. 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).
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 | C9H8O4 |
| Molecular Weight | 180.16 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.) | 1958 |
Related Phthalic Standards
- Phthalic-13C6 Acid (CAS 1313734-99-4)
- Phthalic-3,4,5,6-d4 Acid (CAS 87976-26-9)
- Phthalic Acid-13C2 (CAS 254110-94-6)
- Phthalic-13C Acid (CAS 70838-83-4)
- Phthalic Acid (CAS 88-99-3)
- Phthalic Acid 4,5-cis-Dihydrodiol (CAS 130073-64-2)
- Phthalic anhydride-<SUP>13</SUP>C<SUB>6</SUB> (CAS 1173019-01-6)
- Phthalic-d4 Anhydride (CAS 75935-32-9)
Recommended Standards
- Topiramate EP Impurity E (D-fructopyranose) (CAS 6347-01-9)
- 4-Methylphthalic Acid (CAS 4316-23-8)
- D-Gulose (CAS 4205-23-6)
- D-Talose (CAS 2595-98-4)
- 4-(Cyclopentylmethyl)thiomorpholine 1,1-dioxide (CAS 477864-23-6)
- N-(3-(2-Oxopyrrolidin-1-yl)phenyl)methanesulfonamide (CAS 953141-80-5)
- 2-methylimidazo[1,2-b]pyridazin-6-amine (CAS 154704-35-5)
- 1-Phenylbenzo[f]quinolin-3(4H)-one (CAS 64257-50-7)
- 2-Azaspiro[4.4]Nonan-7-ol hydrochloride (CAS 2306272-60-4)
- N-(2-Hydroxyethyl)-N-methyl-2-(methylamino)-acetamide hydrochloride (CAS 1219982-17-8)
- 2-Amino-1-(4-chloro-3-fluorophenyl)propane-1,3-diol (CAS 1496196-31-6)
- 5-((2-Methyl-4-(4-methylphenyl)-1,3-thiazol-5-yl)methyl)-1,3,4-oxadiazol-2-amine (CAS 1018239-48-9)
- 1-[(4-Bromophenyl)methyl]-N3,N3,N5,N5-tetramethyl-1H-1,2,4-triazole-3,5-diamine (CAS 338748-24-6)
- Liraglutide (14-31)TFA Salt (CAS CATO-C4X-19927)
Why CATO?
- ISO 17034 accredited reference material producer (CNAS + ANAB dual accreditation)
- 130,000+ catalog items in stock, COA supplied with every batch
- Worldwide shipping with full export documentation (HS code guidance available)
- Technical support: +86 18665070610 / Nicole.chen@cato-chem.com