Tolytriazole sodium salt
[CAS 64665-57-2]

Identification

• Classification: Pharmaceutical intermediate >> OLED material intermediate
• Name: Tolytriazole sodium salt
• Synonyms: Sodium 4(or 5)-methyl-1H-benzotriazolide
• Molecular Formula: C₇N₃H₆Na
• Molecular Weight: 155.13
• CAS Registry Number: 64665-57-2
• EC Number: 265-004-9
• SMILES: CC1=C2C(=CC=C1)[N-]N=N2.[Na+]

Safety Data

• Hazard Symbols: GHS05;GHS07;GHS09 Danger
• Risk Statements: H302-H314-H318-H335-H411
• Safety Statements: P260-P261-P264-P264+P265-P270-P271-P273-P280-P301+P317-P301+P330+P331-P302+P361+P354-P304+P340-P305+P354+P338-P316-P317-P319-P321-P330-P363-P391-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Serious eye damage	Eye Dam.	1	H318
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin corrosion	Skin Corr.	1C	H314
Skin corrosion	Skin Corr.	1B	H314
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Reproductive toxicity	Repr.	2	H361
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Reproductive toxicity	Repr.	2	H361d
Acute toxicity	Acute Tox.	3	H301
Acute toxicity	Acute Tox.	2	H302

chemBlink Chemical Story

Tolytriazole sodium salt, CAS 64665-57-2, is the sodium salt of methylbenzotriazole/tolyltriazole. PubChem records the formula C7H6N3Na and identifies the parent in its displayed structure as methylbenzotriazole. Regulatory inventories also describe this CAS as the sodium salt of 4(or 5)-methyl-1H-benzotriazole, reflecting the isomeric character often encountered in commercial tolyltriazole materials.

Its main industrial role is corrosion inhibition, especially for copper and copper alloys. Benzotriazole-type molecules adsorb at metal surfaces through their nitrogen-rich triazole system and can form protective interfacial complexes or films. Adding a methyl group modifies solubility and hydrophobic character, while converting the acidic triazole proton to a sodium salt improves compatibility with water-based formulations.

PubChem incorporates EPA use information listing CAS 64665-57-2 as a corrosion inhibitor and anti-scaling agent, with additional use in antifreeze-related systems. This fits the practical advantage of the sodium form: it can be supplied in concentrated aqueous solutions and incorporated into cooling-water, metalworking or other water-containing systems more readily than a less soluble neutral heterocycle.

Once dissolved, the chemistry should not be imagined as a rigid sodium ion permanently attached to one nitrogen. Acid-base equilibria, isomerism and interaction with metal surfaces determine the species present. The sodium salt is therefore best understood as a formulation and delivery form of the tolyltriazole corrosion-inhibiting framework.

This CAS entry also illustrates why names matter in industrial chemistry. “Tolyltriazole” may refer to methylbenzotriazole isomers or mixtures, whereas database structures can display one representative parent. For purchasing, analytical or regulatory work, the CAS identity and product specification should therefore be checked rather than assuming every tolyltriazole product has exactly the same isomer composition.

References:
1. PubChem, Sodium tolyltriazole, CID 23687327, CAS 64665-57-2.
2. CAS Common Chemistry, Sodium tolyltriazole, CAS 64665-57-2.
3. Finšgar M, Milošev I. Inhibition of copper corrosion by 1,2,3-benzotriazole: a review. Corros Sci. 2010;52:2737-2749.

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