1.06202

1-Naphtholbenzein

pH indicator, Reag. Ph Eur

• Synonym(s): 1-Naphtholbenzein
• Empirical Formula (Hill Notation): C₂₇H₁₈O₂
• CAS Number: 145-50-6
• Molecular Weight: 374.43
• UNSPSC Code: 12352115
• EC Index Number: 205-656-3
• NACRES: NB.21

Properties

• product name: 1-Naphtholbenzein, indicator Reag. Ph Eur
• agency: reag. Ph. Eur.
• Quality Level: 200
• form: solid
• loss: ≤7% loss on drying, 105°C
• visual transition interval: 8.0-9.6, apricot to turquoise
• mp: 243-245 °C
• bulk density: 120‑300 kg/m³
• λmax: 622-626 nm (perchloric acid (0,1 mol/l) in acetic acid)
• storage temp.: 2-30°C
• InChI: 1S/C27H18O2/c28-25-16-14-23(19-10-4-6-12-21(19)25)27(18-8-2-1-3-9-18)24-15-17-26(29)22-13-7-5-11-20(22)24/h1-17,28H/b27-24+
• InChI key: VDDWRTZCUJCDJM-SOYKGTTHSA-N

Description

Application

• Use of turbidimeter for measurement of solid catalyst system component in a reactor feed.: This study discusses the application of a turbidimeter to measure the concentration of solid catalyst components in a reactor feed, highlighting its significance in optimizing catalytic processes (Elsevier, 2020).

Analysis Note

Identity (IR-spectrum): passes test
Identity (UV/VIS-Spectrum): passes test
Absorption maximum λ_max.(perchloric acid (0,1 mol/l) in acetic acid): 622 - 626 nm
Spec. Absorptivity A 1%/1cm (λ_max; 0.005 g/l;perchloric acid (0,1 mol/l) in acetic acid;calculated on dried substance): 640 - 950
Transition range: pH 8,0 - pH 9,6; apricot - turquoiseblue
Loss on Drying (105°C): ≤ 7 %
Suitability as indicator (for non-aqueous titration): passes test

Safety Information

• hcodes: H413
• pcodes: P273 - P501
• Hazard Classifications: Aquatic Chronic 4
• Storage Class: 11 - Combustible Solids
• wgk_germany: WGK 2
• flash_point_f: Not applicable
• flash_point_c: Not applicable