1.06246

1-Naphtholphthalein

pH indicator

• Synonym(s): 1-Naphtholphthalein
• Empirical Formula (Hill Notation): C₂₈H₁₈O₄
• CAS Number: 596-01-0
• Molecular Weight: 418.44
• MDL number: MFCD00036202
• UNSPSC Code: 12352115
• EC Index Number: 209-875-5
• NACRES: NA.21

Properties

• product name: 1-Naphtholphthalein, indicator
• Quality Level: 200
• form: solid
• loss: ≤5% loss on drying, 110°C
• visual transition interval: 7.1-8.3, pink-brown to blue
• mp: 253-255 °C
• bulk density: 350 kg/m³
• Amax: 470-485 nm (buffer pH 7.1); 649-654 nm (buffer pH 8.3)
• storage temp.: 2-30°C
• InChI: 1S/C28H18O4/c29-25-15-13-23(17-7-1-3-9-19(17)25)28(22-12-6-5-11-21(22)27(31)32-28)24-14-16-26(30)20-10-4-2-8-18(20)24/h1-16,29-30H
• InChI key: HQHBAGKIEAOSNM-UHFFFAOYSA-N

Description

Analysis Note

Identity (UV/VIS-Spectrum): passes test
Transition range: pH 7.1 - pH 8.3pinkbrownish - blue
Absorption maximum λ 1 (buffer pH 7.1): 470 - 485 nm
Absorption maximum λ 2 (buffer pH 8.3): 649 - 654 nm
Spec. Absorptivity A 1%/1cm (λ1_max; 0.01 g/l; buffer pH 7.1; calc. on anhydrous substance): 100 - 180
Spec. Absorptivity A 1%/1cm (λ2_max; 0.01 g/l; buffer pH 8.3; calc. on anhydrous substance): 360 - 520
Loss on drying (110 °C): ≤ 5 %

Safety Information

• Storage Class: 11 - Combustible Solids
• wgk_germany: WGK 3
• flash_point_f: Not applicable
• flash_point_c: Not applicable