Description

α-Naphtholphthalein CAS NO 596-01-0 is a high-purity synthetic organic compound belonging to the phthalein dye class, widely recognized as a sensitive and reliable pH indicator. Its primary value lies in its distinct color change within specific pH ranges, making it an indispensable tool for precise endpoint detection in analytical chemistry and quality control processes. This chemical is essential for manufacturers and laboratories in the pharmaceutical, chemical synthesis, and educational sectors requiring accurate acid-base titrations and pH monitoring.

Application

• Primary use as a pH indicator in analytical chemistry, particularly for acid-base titrations.
• Endpoint detection in quality control (QC) and research and development (R&D) laboratories for pharmaceutical raw materials and intermediates.
• Component in prepared indicator solutions and test kits for educational and industrial use.
• Use in chemical synthesis as a precursor or intermediate for more complex dye molecules.
• Potential application in non-aqueous titration methods where specific pH ranges must be visually identified.

Basic Information

Product Name	α-Naphtholphthalein
CAS No.	596-01-0
Molecular Formula	C₂₈H₁₈O₄
Molecular Weight	418.44 g/mol
Synonyms	α-Naphtholphthalein; 3,3-Bis(4-hydroxy-1-naphthyl)-1(3H)-isobenzofuranone; 3,3-Bis(4-hydroxy-1-naphthyl)phthalide; 1-Naphtholphthalein; Naphtholphthalein; NSC 6178; Phthalein Violet; Indicator for pH 7.3-8.7
EINECS	209-882-6

Quality Control

Our α-Naphtholphthalein is manufactured under strict quality management systems to ensure batch-to-batch consistency and high performance. Each lot undergoes comprehensive analytical testing, including identity confirmation, purity assay, and impurity profiling. A Certificate of Analysis (COA) detailing all test results is provided with every shipment to support your quality assurance and regulatory compliance needs.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry, and well-ventilated area at controlled room temperature (15-25°C). Keep away from incompatible materials and sources of ignition.

Specification

Item	Specification
Appearance	Light greenish-gray to white crystalline powder
Identification (IR)	Conforms to structure
Assay (HPLC)	≥ 98.0%
Loss on Drying	≤ 1.0%
Residue on Ignition	≤ 0.1%
pH Transition Range	7.3 (colorless) to 8.7 (blue-green)
Solubility (Test Solution)	Clear in ethanol

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.