TOLYLTRIAZOLE

Tolyltriazole protects copper and copper alloys by forming a durable surface film.
Cooling fluids, metalworking products and industrial cleaners widely use Tolyltriazole.
Reliable corrosion control makes Tolyltriazole valuable in demanding water-based systems.

CAS Number: 29385-43-1
EC Number: 249-596-6
Molecular Formula: C₇H₇N₃
Molecular Weight: 133.15 g/mol
MDL Number: MFCD00167158

Synonyms: TTA, Methylbenzotriazole, Methyl-1H-benzotriazole, 4/5-Methyl-1H-benzotriazole, 4-Methyl-1H-benzotriazole, 5-Methyl-1H-benzotriazole, 4/5-Methylbenzotriazole, 4-Methyl-1H-benzo[d][1,2,3]triazole, 7-Methyl-1H-benzotriazole, Tolytriazole, 4/5-Toluyltriazole, Cobratec TT 100, Preventol CI 7-100, 1H-Benzotriazole 4(5)-methyl-, 1H-Benzotriazole 4(or 5)-methyl-, 1H-4/5-Methyltriazole, HC-3281, MFCD00167158, MFCD00055391, DTXSID0026171, UNII QKK8999IZA, 5-methyl CAS 136-85-6, 4-methyl CAS 29878-31-7, CAS 29385-43-1, EC 249-596-6

A light-yellow to off-white granular solid with a characteristic odour, tolyltriazole shares the fundamental benzotriazole corrosion-inhibition mechanism — chemisorption onto copper and copper-alloy surfaces through its ring nitrogen atoms to form a stable, multilayer, water-insoluble Cu–TTA coordination polymer passivation film — while offering enhanced solubility in organic solvents relative to benzotriazole, making it the preferred isomeric form for many lubricant, metalworking fluid, and antifreeze formulations where dissolved-state delivery at higher concentrations in organic carrier media is required. The methyl substituent on the benzene ring of tolyltriazole increases its lipophilicity (relative to unsubstituted benzotriazole) and improves miscibility with hydrocarbon and synthetic lubricant base oils, which is the primary reason why TTA is the predominant azole corrosion inhibitor used in lubricating and hydraulic oil formulations globally.

Uses of Tolyltriazole:
Tolyltriazole is used as the primary copper and yellow metal corrosion inhibitor in closed-loop cooling water systems (including HVAC chilled-water circuits, industrial process cooling, and district cooling), cooling towers, heat exchangers, and condensers, where it is dosed at 1–50 ppm to form a stable Cu–TTA passivation film on copper tube surfaces, preventing pitting corrosion, galvanic attack, and copper dissolution; tolyltriazole can be used in combination with scale inhibitors, biocides, and dispersants in complete water treatment programmes and is compatible with all common cooling water treatment chemicals.
Tolyltriazole is used as a metal deactivator, corrosion inhibitor, and antioxidant additive in automotive and industrial lubricant formulations — engine motor oils, gear oils, automatic transmission fluids, compressor oils, turbine oils, hydraulic oils, and greases — at concentrations of 0.05–0.5%, where it protects copper and bronze alloy bearings, bushings, thrust washers, and valve train components from corrosive attack by decomposition products of sulphur-containing extreme-pressure (EP) and anti-wear (AW) additives (ZDDP, polysulphides), and functions simultaneously as an oxidation inhibitor in internal combustion engine oils; TTA is preferred over benzotriazole in lubricant applications because of its superior solubility in hydrocarbon base oils.
Tolyltriazole is used in automotive antifreeze and engine coolant formulations (ethylene glycol and propylene glycol based, both OAT and HOAT types) at concentrations of 0.01–2.0% to protect copper, brass, and aluminium components of the cooling system — radiators, heater cores, water pump impellers, and oil coolers — from corrosive attack; it is also used in brake fluid formulations as a copper corrosion inhibitor; in both applications, TTA provides broad-spectrum yellow metal protection across the full service temperature and pH range of the coolant or brake fluid.
Tolyltriazole is used in metalworking fluids — water-miscible cutting oils, grinding fluids, and neat cutting oils — as a copper alloy corrosion inhibitor (preventing discolouration and pitting of brass and bronze workpieces and machine components); in pickling, cleaning, and polishing solutions for copper, brass, and bronze (preventing flash corrosion and tarnishing of the treated metal surface during acid treatment); in phosphate conversion coating baths for yellow metals; and in electroplating and electropolishing bath formulations for copper substrate protection.
Tolyltriazole is used as a silver protection agent in automatic dishwasher detergent tablets, powders, and liquids, forming a silver-TTA complex on silver cutlery and silverware that prevents tarnishing and pitting during the dishwashing cycle — an application shared with benzotriazole (BTA) but where TTA may be preferred in detergent systems requiring enhanced solubility in the liquid phase; this application is a recognised pathway for TTA entry into municipal wastewater streams.
Tolyltriazole is used as a vapour-phase corrosion inhibitor (VCI) for copper and copper alloy surfaces in anti-rust oils, anti-rust greases, and VCI packaging (impregnated papers, films, and emitters) used to protect copper electrical components, precision instruments, and copper artefacts during storage and international shipping; as a polymer stabiliser in cable insulation and polymeric compounds to prevent metal-catalysed oxidative degradation (preventing copper-induced degradation of polyolefin cable insulation in proximity to copper conductors); and as a UV absorber and photostabiliser in polymer and coatings applications.
Tolyltriazole is used in electronics manufacturing in flux formulations, PCB (printed circuit board) cleaning chemicals, and OSP (Organic Solderability Preservative) surface finish processes for protecting copper traces and pads from oxidation; as a corrosion inhibitor in chemical mechanical planarisation (CMP) slurries for copper interconnect processing in semiconductor manufacturing (alongside EDTA and other chelants); as a photographic anti-fogging agent; as a plant growth regulator; and as a building block in the synthesis of specialty chemicals, pharmaceutical intermediates, dyes, and fine chemicals.

Benefits and Advantages of Tolyltriazole:
Tolyltriazole provides superior solubility in hydrocarbon mineral oils, synthetic ester base oils, and polyalphaolefin (PAO) base oils relative to benzotriazole at equivalent concentrations, enabling direct dissolution into the lubricant base oil without the use of carrier solvents or co-solvents; this superior oil solubility is the primary technical differentiation of TTA from benzotriazole in lubricant, hydraulic fluid, and metalworking fluid applications, and allows higher active concentrations to be achieved in the lubricant additive package.
Tolyltriazole retains the same fundamental corrosion inhibition mechanism as benzotriazole — chemisorptive formation of a multilayer Cu–TTA coordination polymer passivation film via N → Cu coordination bonds — and achieves copper corrosion inhibition at the same low ppm concentrations in aqueous systems (1–50 ppm in cooling water) and the same low percentage concentrations in oil-based lubricants (0.05–0.5%); the methyl group substitution does not significantly alter the film stability, pH tolerance range, or compatibility with co-additives relative to benzotriazole, making TTA a direct functional equivalent of BTA across all corrosion inhibition applications.
Tolyltriazole is compatible with the full range of co-additives used in cooling water treatment (phosphates, phosphonates, molybdates, scale inhibitors, biocides, dispersants), lubricant additive chemistry (ZDDP, amine antioxidants, phenolic antioxidants, sulphonate detergents, dispersants), and metalworking fluid chemistry (amines, borate buffers, biocides, surfactants); this broad formulation compatibility — combined with commercial availability in multiple physical forms (granules, fine granules, flakes, powder) and liquid forms (sodium tolyltriazole in water, TTA in glycol or amine solution) — makes it a universal co-additive for copper protection across aqueous and non-aqueous industrial formulations.
Tolyltriazole is a direct methylated analogue of benzotriazole with an established multi-decade track record in industrial cooling water, lubricant, and metalworking fluid applications, providing formulators with well-documented performance data, ecotoxicological characterisation, and regulatory compliance information; its REACH Registration (01-2119979081-35) confirms its legal status for use within the European Economic Area as an existing substance, and its WGK Germany classification of 3 (highly hazardous to water) reflects its environmental persistence rather than acute health hazard.

Features of Tolyltriazole:
Tolyltriazole is a light yellow to off-white or light beige granular solid or powder at room temperature with a characteristic odour; melting point 80–88°C (lit., grade-dependent); boiling point >200°C; molecular formula C₇H₇N₃; molecular weight 133.15 g/mol; insoluble in water; soluble in ethanol, benzene, toluene, chloroform, and other organic solvents; soluble in dilute alkaline (lye) aqueous solutions; SMILES Cc1cccc2c1nn[nH]2 (4-methyl isomer); InChIKey CMGDVUCDZOBDNL-UHFFFAOYSA-N (4-methyl isomer); purity ≥99.5% commercial grade; moisture ≤0.2%; ash content ≤0.05%; aqueous pH 5.0–6.5.
Tolyltriazole is the commercial mixture of the 4-methyl-1H-benzotriazole isomer (CAS 29878-31-7, also known as 4-methyl-1H-benzo[d][1,2,3]triazole or 7-methyl-1H-benzotriazole) and the 5-methyl-1H-benzotriazole isomer (CAS 136-85-6, EC 205-265-8, PubChem CID 8705, ChEBI CHEBI:83455, ChEMBL ChEMBL2148100, ChemSpider 8381) in approximately equal proportions (50:50 by weight), with small amounts of their 7- and 6-methyl tautomers; the 5-methyl isomer (CAS 136-85-6) has UNII O9DI72TU6U; both isomers have a bicyclic structure consisting of a benzene ring fused to a 1,2,3-triazole ring, with the methyl substituent at the 4 or 5 position of the benzene ring relative to the triazole nitrogen; synthesis proceeds via diazotisation of the respective methyl-o-phenylenediamine isomer.
Tolyltriazole forms a protective passivation film on copper, copper alloys, silver, and (to a limited extent) aluminium surfaces via the same chemisorptive mechanism as benzotriazole: N → Cu coordination bonds from all three triazole ring nitrogen atoms anchor the first TTA monolayer to the copper surface, and subsequent multilayer growth via Cu(I)–TTA coordination polymerisation builds an insoluble, three-dimensional Cu(I)–TTA coordination polymer network that acts as a physical barrier to oxygen, water, chloride, and sulphide attack; this film is effective across a broad pH range (pH 5–11), stable to washing, wiping, and moderate mechanical stress, and effective in both aqueous and gaseous environments.
Tolyltriazole is a recognised persistent environmental contaminant (polar organic persistent pollutant, POPP) in surface water and groundwater: like benzotriazole, it is poorly removed in conventional wastewater treatment plants (WWTP) and has been detected at concentrations >0.1 µg/L in rivers, lakes, groundwater, and treated drinking water globally; the primary environmental input pathways are dishwasher detergent use (TTA-containing silver protection rinse aids entering municipal WWTP influent) and cooling water blowdown (TTA-dosed open cooling tower blowdown discharging to surface water); WGK Germany: 3 (highly hazardous to water); GHS: H411 (toxic to aquatic life with long lasting effects).

Chemical Properties of Tolyltriazole:
Tolyltriazole mixture: CAS 29385-43-1, formula C₇H₇N₃, MW 133.15 g/mol, EC 249-596-6, REACH 01-2119979081-35, ECHA InfoCard 100.045.073, DTXSID0026171; 5-methyl isomer: CAS 136-85-6, EC 205-265-8, PubChem CID 8705; 4-methyl isomer: CAS 29878-31-7; SMILES (4-methyl): Cc1cccc2c1nn[nH]2; InChI (4-methyl): InChI=1S/C7H7N3/c1-5-3-2-4-6-7(5)9-10-8-6/h2-4H,1H3,(H,8,9,10); InChIKey (4-methyl): CMGDVUCDZOBDNL-UHFFFAOYSA-N; MDL MFCD00167158; UNII QKK8999IZA.
Key chemical reactions of tolyltriazole: (1) complexation with Cu(I) → multilayer Cu(I)–TTA coordination polymer passivation film (chemisorption via N → Cu coordination bonds — primary mechanism of copper corrosion inhibition); (2) chelation with Ag(I) → silver–TTA complex (application in dishwasher silver protection); (3) complexation with Zn(II), Pb(II), Ni(II), and other metal ions (corrosion inhibition for non-copper metals); (4) N-alkylation and N-acylation reactions (synthetic transformations for specialty chemical synthesis); (5) formation of sodium salt (NaTTA) in alkaline aqueous solution — sodium tolyltriazole is a liquid form commercially used for easier dosing in water treatment applications; (6) synthesis route: diazotisation of methyl-o-phenylenediamine (3-methyl- or 4-methyl-o-phenylenediamine) with NaNO₂/AcOH → TTA mixture (analogous to benzotriazole synthesis).
Tolyltriazole is chemically stable under normal ambient storage conditions; it is stable in dilute acids and alkalis across a broad pH range; it undergoes complexation with metal ions (Cu, Ag, Zn, Ni, Pb) as its primary industrial application; it is incompatible with ammonia and strong amines (avoid storage with ammonia and alkalis per storage guidelines), oxygen at elevated temperature, phosphorus, antimony powder, and strong oxidising agents; it is combustible — keep away from fire, heat, and combustibles (sawdust, shavings, straw); it does not hydrolyse under normal conditions; as a polar organic persistent pollutant, it is not readily biodegradable.

Production of Tolyltriazole:
Tolyltriazole is produced by diazotisation of methyl-o-phenylenediamine isomers — specifically 3-methyl-o-phenylenediamine and 4-methyl-o-phenylenediamine — with sodium nitrite (NaNO₂) in the presence of acetic acid under controlled temperature conditions analogous to the synthesis of benzotriazole; the two methyl-o-phenylenediamine isomers react to form the 4-methyl and 5-methyl benzotriazole isomers respectively (together with small amounts of tautomers), producing the commercial tolyltriazole mixture in approximately 50:50 ratio; the crude product is purified, filtered, and dried to give the commercial granule, flake, or powder product at ≥99.5% purity.
Commercial tolyltriazole is available in: granular (standard commercial form, preferred for handling — reduces dust exposure); fine granular; flakes; powder; liquid forms including sodium tolyltriazole aqueous solution (NaTTA, ~50% w/w in water, used for direct dosing in water treatment systems) and TTA dissolved in glycol or amine solutions for antifreeze and coolant concentrate applications; purity ≥99.5%; packaging: 25 kg moisture-proof woven bags (two PE inner liners); 500 kg or 1,000 kg moisture-proof big bags (two PE inner liners); valve bags; fibre drums; net weight 20 kg, 25 kg, 500 kg available.

Tolyltriazole Material Safety Data Sheet (MSDS):

Handling of Tolyltriazole:
Tolyltriazole is a combustible solid; prevent dust dispersion and inhalation (dust may be an irritant at elevated concentrations); avoid prolonged skin contact (may cause skin sensitisation with repeated contact); wear appropriate PPE — dust mask, safety glasses, chemical-resistant gloves, and protective clothing; no open flames; keep away from heat sources; do not eat, drink, or smoke during handling; maintain strict hygiene; avoid generating aerosols.
Tolyltriazole is harmful to aquatic organisms with long-lasting effects (GHS H411); do not allow the substance or formulations containing it to enter drains, watercourses, soil, or groundwater; dispose of waste and contaminated packaging per applicable national and local regulations for environmentally hazardous substances.

Tolyltriazole SDS:

Stability and Reactivity of Tolyltriazole:

Chemical stability:
Tolyltriazole is stable under normal ambient storage conditions; it is stable to dilute acids and alkalis at ambient temperature.
It decomposes on heating above its decomposition temperature producing toxic nitrogen-containing fumes; it is combustible — keep away from open flames and strong oxidising agents.

Reactivity:
Tolyltriazole reacts with metal ions (Cu, Ag, Zn, Ni, Pb) to form coordination complex passivation films — its primary industrial application.
It forms sodium salt (NaTTA) in alkaline aqueous solution; it is incompatible with ammonia, strong oxidising agents, and strong alkalis at elevated temperature.

Conditions to avoid:
Open flames and heat sources — combustible.
Ammonia, alkalis, oxygen (elevated temperature), phosphorus, antimony powder — do not store or transport together.
Combustibles (sawdust, shavings, straw) in proximity.
Sunlight — store away from direct sunlight.

Incompatible materials:
Ammonia and strong nitrogen-containing bases.
Strong oxidising agents.
Phosphorus, antimony powder.
Combustible organic materials.

Hazardous decomposition products:
Toxic nitrogen-containing fumes upon combustion or thermal decomposition.
CO and CO₂ upon combustion.

Handling and Storage of Tolyltriazole:

Handling:
Prevent dust dispersion; use local exhaust ventilation; employ appropriate dust-control measures.
Wear dust mask, safety glasses, chemical-resistant gloves, and protective clothing.
No open flames; strict hygiene; do not eat, drink, or smoke during handling.
Avoid prolonged or repeated skin contact.

Storage:
Store in a dry, cool, well-ventilated place away from direct sunlight.
Isolate from fire and heat sources.
Do not store or transport with ammonia, oxygen, phosphorus, antimony powder, alkalis, or combustible organic materials.
Keep away from sawdust, shavings, straw, and other combustibles.
Packaging: 25 kg moisture-proof woven bags (two PE inner liners); 500/1,000 kg big bags.

First Aid Measures for Tolyltriazole:

Inhalation: Move to fresh air; if dust inhalation causes persistent respiratory irritation, consult a physician.
Skin contact: Remove contaminated clothing; rinse thoroughly with water and wash with soap and water; if skin sensitisation or allergic reaction develops, consult a physician.
Eye contact: Rinse with plenty of water for several minutes; if redness or irritation persists, consult a physician.
Ingestion: Rinse mouth; give water to drink; seek medical advice.

Firefighting Measures for Tolyltriazole:

Suitable extinguishing media: Water spray, CO₂, dry chemical, foam.
Specific hazards: Combustible solid; dust may form explosive mixtures in air; combustion produces toxic nitrogen-containing fumes, CO and CO₂; keep away from combustible materials during fire response.
Protective equipment for firefighters: SCBA and full protective clothing; prevent contaminated runoff from entering waterways.

Accidental Release Measures for Tolyltriazole:

Personal precautions: Wear dust mask, gloves, and safety glasses; prevent dust generation; no open flames in release area.
Environmental precautions: Tolyltriazole is harmful to aquatic organisms and a persistent environmental contaminant; do not allow entry into drains, watercourses, or soil; notify environmental authorities for significant releases.
Clean-up methods: Collect with vacuum or shovel (moisten first to prevent dust if appropriate); place in labelled, closed containers; dispose per applicable regulations for environmentally hazardous chemical waste.

Exposure Controls / Personal Protective Equipment for Tolyltriazole:

Engineering controls: Local exhaust ventilation for powder/dust operations; general ventilation for ambient solid-state handling; closed-system dosing for liquid forms (sodium TTA solution).
Eye protection: Safety glasses; chemical splash goggles for liquid handling.
Hand protection: Chemical-resistant gloves (nitrile or neoprene); note repeated skin contact risk.
Respiratory protection: Dust mask (P2) for powder/granule handling; OV+P2 cartridge for operations generating aerosols or elevated dust concentrations.

Tolyltriazole Identifiers:
CAS Number (mixture): 29385-43-1
CAS Number (5-methyl isomer): 136-85-6
CAS Number (4-methyl isomer): 29878-31-7
EC Number: 249-596-6 (mixture); 205-265-8 (5-methyl isomer)
EINECS: 249-596-6
REACH Registration: 01-2119979081-35
ECHA InfoCard: 100.045.073
MDL Number: MFCD00167158
DTXSID: DTXSID0026171
UNII: QKK8999IZA (mixture); O9DI72TU6U (5-methyl isomer)
PubChem CID (5-methyl): 8705
ChEBI (5-methyl): CHEBI:83455
ChemSpider (4-methyl): 109219; (5-methyl): 8381
IUPAC Name: 4-Methyl-1H-benzotriazole / 5-Methyl-1H-benzotriazole (mixture)
Molecular Formula: C₇H₇N₃
Molecular Weight: 133.15 g/mol
SMILES (4-methyl): Cc1cccc2c1nn[nH]2
InChI (4-methyl): InChI=1S/C7H7N3/c1-5-3-2-4-6-7(5)9-10-8-6/h2-4H,1H3,(H,8,9,10)
InChIKey (4-methyl): CMGDVUCDZOBDNL-UHFFFAOYSA-N
WGK Germany: 3 (highly hazardous to water)
GHS: H411 (toxic to aquatic life with long lasting effects)
Environmental: Persistent organic pollutant (POPP); commonly detected >0.1 µg/L in surface water

Properties of Tolyltriazole:
Physical state: Solid (granular)
Appearance: Light yellow to off-white or light beige granules, fine granules, flakes, or powder; characteristic odour
Molecular formula: C₇H₇N₃
Molecular weight: 133.15 g/mol
Melting point: 80–88°C (lit., grade-dependent)
Boiling point: >200°C
Water solubility: Insoluble (soluble in dilute alkaline aqueous solutions)
Organic solvent solubility: Ethanol, benzene, toluene, chloroform, organic solvents generally; soluble in dilute lye
Purity: ≥99.5% (commercial grade)
Moisture: ≤0.2%
Ash content: ≤0.05%
Aqueous pH: 5.0–6.5
GHS: H411
WGK Germany: 3
Biodegradability: Not readily biodegradable; persistent environmental contaminant
Storage: Dry, cool, ventilated; away from sunlight, fire, heat, ammonia, alkalis, and combustibles

Tolyltriazole Properties — Specifications:
Product name: Tolyltriazole (TTA)
CAS Number: 29385-43-1
EC Number: 249-596-6
Molecular Formula: C₇H₇N₃
Molecular Weight: 133.15 g/mol
Appearance: Light yellow to off-white granules, fine granules, flakes, or powder
Purity: ≥99.5%
Melting point: 80–88°C
Moisture: ≤0.2%
Ash content: ≤0.05%
Aqueous pH: 5.0–6.5
GHS: H411 (toxic to aquatic life with long lasting effects)
WGK Germany: 3
Storage: Dry, cool, ventilated; away from sunlight, fire, heat, ammonia, alkalis
Packaging: 25 kg moisture-proof woven bags (2 PE inner liners); 500/1,000 kg big bags; valve bags; fibre drums
Documents: CoA, SDS, REACH registration confirmation

Names of Tolyltriazole:
Tolyltriazole
TTA
Tolytriazole
Methylbenzotriazole
Methyl-1H-benzotriazole
4/5-Methyl-1H-benzotriazole
4-Methyl-1H-benzotriazole
5-Methyl-1H-benzotriazole
4-Methyl-1H-benzo[d][1,2,3]triazole
7-Methyl-1H-benzotriazole
4-Methyl-2H-benzotriazole
4-Methyl-1H-1,2,3-benzotriazole
1H-Benzotriazole 4(5)-methyl-
1H-Benzotriazole 4(or 5)-methyl-
1H-4/5-Methyltriazole
4/5-Toluyltriazole
Cobratec TT 100
Preventol CI 7-100
HC-3281
MFCD00167158
MFCD00055391
DTXSID0026171
UNII QKK8999IZA
CAS 29385-43-1
CAS 136-85-6 (5-methyl isomer)
CAS 29878-31-7 (4-methyl isomer)
EC 249-596-6