The alpha-Naphtholphthalein, with the CAS registry number 596-01-0, is also known as 3,3-Bis(4-hydroxy-1-naphthyl)phthalide. It belongs to the product categories of Industrial/Fine Chemicals; Pharmacetical; Analytical Chemistry; Indicator (pH); pH Indicators; N; Stains and Dyes; Stains & Dyes, A to; Indicators; pH Indicators-Solids; Titration. Its EINECS registry number is 209-875-5. This chemical's molecular formula is C₂₈H₁₈O₄ and molecular weight is 418.44. What's more, both its IUPAC name and systematic name are the same which is called 3,3-Bis(4-hydroxynaphthalen-1-yl)-2-benzofuran-1-one. It can be used as a pH indicator.

Physical properties about alpha-Naphtholphthalein are: (1)ACD/LogP: 4.195; (2)# of Rule of 5 Violations: 0; (3)ACD/LogD (pH 5.5): 4.20; (4)ACD/LogD (pH 7.4): 4.18; (5)ACD/BCF (pH 5.5): 907.53; (6)ACD/BCF (pH 7.4): 876.07; (7)ACD/KOC (pH 5.5): 4558.06; (8)ACD/KOC (pH 7.4): 4400.09; (9)#H bond acceptors: 4; (10)#H bond donors: 2; (11)#Freely Rotating Bonds: 4; (12)Polar Surface Area: 66.76 Å²; (13)Index of Refraction: 1.77; (14) Molar Refractivity: 123.793 cm³; (15)Molar Volume: 297.955 cm³; (16)Polarizability: 49.075×10^-24cm³; (17)Surface Tension: 70.109 dyne/cm; (18)Density: 1.404 g/cm³; (19)Flash Point: 247.012 °C; (20)Enthalpy of Vaporization: 106.914 kJ/mol; (21)Boiling Point: 705.559 °C at 760 mmHg; (22)Vapour Pressure: 0 mmHg at 25 °C.

Preparation of alpha-Naphtholphthalein: this chemical can be prepared by 1-naphthol with phthalic anhydride. This reaction needs reagent concentrated sulfuric acid at temperature of 60 °C. The reaction time is 19 hours.

When you are dealing with this chemical, you should be very careful. This chemical may cause inflammation to the skin or other mucous membranes. And it is irritating to eyes, respiratory system and skin. Therefore, you should wear suitable protective clothing. In case of contacting with eyes, you should rinse immediately with plenty of water and seek medical advice.

You can still convert the following datas into molecular structure:
(1) SMILES: O=C1OC(c2ccccc12)(c4c3ccccc3c(O)cc4)c6c5ccccc5c(O)cc6
(2) InChI: 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
(3) InChIKey: HQHBAGKIEAOSNM-UHFFFAOYSA-N