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Indicators and stains

alpha-Naphtholphthalein

Also known as Naphtholphthalein, 3,3-Bis(4-hydroxy-1-naphthyl)phthalide, 1(3H)-Isobenzofuranone, 3,3-bis(4-hydroxy-1-naphthalenyl)-

CAS 596-01-0Formula C28H18O4Molar mass 418.45 g/molEC 209-875-5
GHS signal word: Warning. Pictograms: Harmful or irritant 10 suppliers listed
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alpha-Naphtholphthalein chemical structure, C28H18O4, CAS 596-01-0
2D chemical structure

Key facts

What buyers check first

All properties
CAS number
596-01-0
Formula
C28H18O4
Molar mass
418.45 g/mol
EC number
209-875-5
HS code
293220
Category
Indicators and stains

What is alpha-Naphtholphthalein?

Plain description, key identifiers and synonyms

alpha-Naphtholphthalein is a chemical substance with the molecular formula C28H18O4 and a molar mass of 418.45 g/mol. Its CAS registry number is 596-01-0. The IUPAC name is 3,3-bis(4-hydroxynaphthalen-1-yl)-2-benzofuran-1-one.

Identifiers

Registry numbers, names and line notations, tap to copy

IUPAC name
3,3-bis(4-hydroxynaphthalen-1-yl)-2-benzofuran-1-one
CAS number
596-01-0 CAS number cross-checked
EC number
209-875-5
Molecular formula
C28H18O4
UNII
2QEG1706NN
MDL number
MFCD00036202
InChIKey
HQHBAGKIEAOSNM-UHFFFAOYSA-N
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
SMILES (canonical and isomeric)
C1=CC=C2C(=C1)C(=CC=C2O)C3(C4=CC=CC=C4C(=O)O3)C5=CC=C(C6=CC=CC=C65)O

Synonyms

  • Naphtholphthalein
  • 3,3-Bis(4-hydroxy-1-naphthyl)phthalide
  • 1(3H)-Isobenzofuranone, 3,3-bis(4-hydroxy-1-naphthalenyl)-
  • 1-Naphtholphthalein
  • 3,3-Bis(4-hydroxynaphthalen-1-yl)isobenzofuran-1(3H)-one
  • a-naphtholphthalein
  • 3,3-bis(4-hydroxynaphthalen-1-yl)-2-benzofuran-1-one
  • 3,3-bis(4-hydroxynaphthalen-1-yl)-1,3-dihydro-2-benzofuran-1-one
  • naphtholphthalein blue
  • a-Naphtolphtalein
  • alpha Naphtholphthalein
  • alpha-Naphtholphthaleine
  • 3,3-bis(4-hydroxy-1-naphthyl)isobenzofuran-1-one
  • 3,3-Bis(4-hydroxy-1-naphthyl)isobenzofuran-1(3H)-one
  • 3,3-Bis(4-hydroxynaphthalenyl)-1(3H)-isobenzofuranone
  • p-alpha-naphtholphthalein
  • di-p-alpha-naphtholphthalide
  • alpha-Naphtholphthalein, practical grade
  • 1,1'-Naphthol-4,4'-phthalein
  • 1-Naphtholphthalein 1-Naphtholphthalein, indicator
  • 3,3-bis(4-hydroxynaphthyl)-3-hydroisobenzofuran-1-one
  • 3,3-Bis(4-hydroxy-1-naphthyl)-2-benzofuran-1(3H)-one #
  • 3,3-bis(4-hydroxynaphthalen-1-yl)-2-benzofuran-1(3H)-one
  • 3,3-Bis(4-hydroxy-1-naphthyl)-1,3-dihydroisobenzofuran-1-one

Physical and chemical properties

Measured values and descriptors computed from the structure

Physical and chemical properties

Measured values, check the supplier specification for your grade

No measured properties are recorded for this substance yet. Ask suppliers for a technical data sheet.

Values vary by grade. Ask suppliers for the COA or TDS of the batch you buy.

Computed descriptors

Calculated from the structure, useful for screening and formulation

Molecular weight
418.45 g/molcalc.
Exact mass
418.1205 Dacalc.
LogP (octanol/water)
5.87calc.
Topological polar surface area
66.76 Ųcalc.
Hydrogen bond donors
2calc.
Hydrogen bond acceptors
4calc.
Rotatable bonds
2calc.
Heavy atoms
32calc.
Rings
6calc.
Aromatic rings
5calc.
Fraction sp3 carbons
0.04calc.
Formal charge
0calc.
Stereocentres
0calc.
Lipinski rule of five
Passes (1 violation)calc.

Calculated for screening. Confirm critical figures with the supplier.

Murcko scaffold

The ring system that remains when every side chain is removed

Murcko scaffold of this chemical, O=C1OC(c2cccc3ccccc23)(c2cccc3ccccc23)c2ccccc21

O=C1OC(c2cccc3ccccc23)(c2cccc3ccccc23)c2ccccc21

6 rings, 30 atoms.

1 other chemical share this scaffold

Safety and hazards

GHS classification summary, not a safety data sheet

GHS signal word
Warning
GHS07: Harmful or irritant
Harmful or irritant

Hazard statements

  • H315Causes skin irritation.
  • H319Causes serious eye irritation.
  • H335May cause respiratory irritation.
Precautionary statements (16)
  • P261Avoid breathing dust, fume, gas, mist, vapours or spray.
  • P264Wash skin thoroughly after handling.
  • P264 + P265Wash skin thoroughly after handling. Do not touch eyes.
  • P271Use only outdoors or in a well-ventilated area.
  • P280Wear protective gloves, protective clothing, eye protection and face protection.
  • P302 + P352If on skin: Wash with plenty of water.
  • P304 + P340If inhaled: Remove person to fresh air and keep comfortable for breathing.
  • P305 + P351 + P338If in eyes: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
  • P319Get medical help if you feel unwell.
  • P321Specific treatment (see supplemental first aid instructions on the label).
  • P332 + P317If skin irritation occurs: Get medical help.
  • P337 + P317If eye irritation persists: Get medical help.
  • P362 + P364Take off contaminated clothing. And wash it before reuse.
  • P403 + P233Store in a well-ventilated place. Keep container tightly closed.
  • P405Store locked up.
  • P501Dispose of contents and container in accordance with local regulations.

GHS classification summary, not a safety data sheet (SDS). Classifications can differ by supplier, grade and concentration. Always check the supplier's SDS.

Full safety data and first aid

alpha-Naphtholphthalein suppliers

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Where suppliers are based

10 suppliers in 4 countries

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alpha-Naphtholphthalein price

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Uses and applications

What the substance is used for, by industry and function

Regulatory status

Inventories, regulations and trade controls that list this substance

No regulatory list memberships are recorded for this substance yet. Always check the rules of the importing and exporting country before trade.

HS code and trade data

Customs classification and reported world trade statistics

Global trade

World import and export statistics for the HS code alpha-Naphtholphthalein is traded under.

HS 2932.20Indicative HS code

Lactones

World exports in 2024
$1.97B
−4.7% vs 2023, imports $2.07B
2019 to 2024
Top exporters
  1. China56.3%
  2. India * partner reported7.4%
  3. Germany7.3%
Top importers
  1. United States14.2%
  2. India * partner reported13.5%
  3. Brazil8.5%

* Partner reported figures, a lower bound.

Reported customs values in USD, not prices.Full trade data

The HS code shown for alpha-Naphtholphthalein is indicative (it was assigned by structure rules). Confirm the classification with your customs broker before shipping.

Frequently asked questions

Quick answers about alpha-Naphtholphthalein, based on the data on this page

What is alpha-Naphtholphthalein?

alpha-Naphtholphthalein is a chemical substance with the molecular formula C28H18O4 and a molar mass of 418.45 g/mol. Its CAS registry number is 596-01-0. The IUPAC name is 3,3-bis(4-hydroxynaphthalen-1-yl)-2-benzofuran-1-one.

What is the CAS number of alpha-Naphtholphthalein?

The CAS registry number of alpha-Naphtholphthalein is 596-01-0.

What is the molecular formula and weight of alpha-Naphtholphthalein?

The molecular formula of alpha-Naphtholphthalein is C28H18O4 and its molar mass is 418.45 g/mol.

What is alpha-Naphtholphthalein used for?

Known uses and roles of alpha-Naphtholphthalein include indicators and stains in research and laboratory.

Is alpha-Naphtholphthalein hazardous?

alpha-Naphtholphthalein carries the GHS signal word "Warning". Main hazards: causes skin irritation, causes serious eye irritation, may cause respiratory irritation. This summary is not an SDS, always read the supplier safety data sheet.

What is the HS code of alpha-Naphtholphthalein?

alpha-Naphtholphthalein is usually classified under HS code 293220 (Lactones). This is indicative, confirm it with your customs broker before shipping.

Where can I buy alpha-Naphtholphthalein?

CompoundList lists 10 suppliers of alpha-Naphtholphthalein in India, China, Iran and United States. Send one free request to get and compare quotes. Your contact details stay private until you accept a quote.

Where can I buy alpha-Naphtholphthalein in India?

6 suppliers in India list alpha-Naphtholphthalein on CompoundList. Filter the suppliers list by country and send a request to compare prices, grades and delivery times.

What is the price of alpha-Naphtholphthalein?

Suppliers quote alpha-Naphtholphthalein on request because prices depend on grade, purity, quantity and destination. A free request on CompoundList gets you several quotes to compare.

Guides for buyers

Practical guides that help when you source, ship or handle alpha-Naphtholphthalein

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Data last updated 7 Oct 2026. Details may have changed, please confirm them with the supplier. Report an error on this page
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