Technical Specifications
| Property | Unit | Typical Value | Test Method |
|---|---|---|---|
| Appearance | Light brown transparent liquid | Visual | |
| Density at 20 °C | kg/m³ | 970 | ASTM D4052 |
| Viscosity at 40 °C | mm²/s | 355 | ASTM D445 |
| Flash Point | °C | 190 | ASTM D93 |
| Color | 0.7 | ASTM D1544 | |
| Total Base Number | mgKOH/g | 198 | ASTM D2896 |
| Nitrogen | % | 4.58 | ASTM D5762 |
| RBOT | min | 480 | ASTM D2272 |
* Typical values from batch production. Batch-specific COA available on request.
Technical content reviewed by the CheMost additives team · Specifications last reviewed
Molecular Structure
Molecular structure · aminic antioxidant
Diphenylamine core (C₁₂H₁₁N), C4/C8-alkylated · CAS 68411-46-1
An alkylated diphenylamine — the N–H donates a hydrogen to trap peroxy radicals; C4/C8 alkylation provides oil solubility and high-temperature persistence.
What Is Octylated Butylated Diphenylamine (AO57)?
CheMost-AO57 is a liquid octylated/butylated diphenylamine (an alkylated diarylamine) — an aminic antioxidant with good oil solubility. It is made by alkylating diphenylamine with a C4 (butyl) and a C8 (octyl) group, which is why it carries a high nitrogen content (4.58%) and a high base number (TBN 198), yet stays a pourable, light-brown liquid that blends easily.
Antioxidants are grouped into primary types — which trap free radicals directly — and secondary types, which decompose the peroxides that radicals form. AO57 is a primary antioxidant: the amine N–H donates a hydrogen atom to a propagating peroxy radical, breaking the oxidation chain before it can degrade the oil. Aminic antioxidants are valued because they keep working at high temperature, where simpler phenolics volatilise or lose effectiveness.
Its defining role is hot-running, oxidation-stressed service. AO57 is used as the high-temperature radical trap in industrial, automotive, turbine and heat-transfer oils, and it works in concert with phenolic antioxidants and ZDDP — a synergy this page explains below.
How AO57 Works
Aminic radical trap
The diarylamine N–H donates a hydrogen to a peroxy radical, converting it to a stable, non-propagating species and interrupting the autoxidation chain — the primary-antioxidant mechanism.
High nitrogen, high base reserve
At 4.58% nitrogen and TBN 198, a small dose delivers a large population of radical-trapping amine sites, so the additive carries a deep oxidation reserve into long-drain service.
High-temperature persistence
The C4/C8 alkyl chains give oil solubility and low volatility, so AO57 stays in the oil and keeps trapping radicals at temperatures where small-molecule phenolics evaporate.
Heterosynergism with phenolics
Amine and phenol trap radicals by different routes (heterosynergism); the phenol regenerates the amine, so the aminic + phenolic pair lasts far longer than either alone.
Antioxidant Types Compared — Where AO57 Fits
Lubricant antioxidants split into aminic and phenolic primary types plus liquid/solid forms. The table places AO57 against CheMost’s other antioxidant grades so you can pick by temperature, form and synergy. All figures are from each grade’s data sheet.
| Grade | Class | Form | Key spec | Temperature niche |
|---|---|---|---|---|
| AO57 (this page) | Aminic (alkylated diphenylamine) | Liquid | N 4.58% · TBN 198 | High-temperature primary AO |
| AO135 | Phenolic ester (HMW) | Liquid | 100% active | High-temp, low-volatility |
| BHT | Phenolic (simple) | Solid | Purity 99.9% | Low–moderate temperature |
| AO52 | Phenolic (mixed blend) | Liquid | Free phenol 0.5% | Low-end industrial / turbine |
The headline pairing is AO57 (aminic) + AO135 (phenolic) — different mechanisms that regenerate each other for maximum oxidation life.
Applications
CheMost-AO57 is used as the high-temperature aminic primary antioxidant in formulations targeting the duties below:
Industrial & circulating oils
Long-life oxidation protection for industrial, circulating and heat-transfer oils that run hot, where the aminic radical trap outlasts simple phenolics.
Turbine & compressor oils
Deep oxidation reserve (RBOT 480 min) for steam/gas turbine and compressor oils that demand long oil life and oxidation stability.
Engine & heavy-duty diesel oils
The aminic backbone of the antioxidant system in passenger-car and heavy-duty engine oils, paired with a phenolic for high-temperature deposit and viscosity control.
Greases & specialty fluids
High-temperature oxidation protection in greases and specialty lubricants where the liquid, oil-soluble form blends in cleanly.
Finished-oil performance approvals (e.g. API, ACEA or OEM engine-oil specifications) belong to the fully formulated oil, not to an individual antioxidant component.
Treat Rate
The data sheet specifies the product but not a per-application dosage, so the figures below are indicative, derived from the chemistry and our formulating experience — confirm the final level.
First-order estimate. As an aminic primary antioxidant, AO57 is used at roughly 0.1–1% (commonly 0.25–0.75%), dosed to the oxidation target (RBOT/RPVOT, ASTM D2272). A little supplies a large radical-trapping reserve; over-treating adds nitrogen with diminishing return.
AO57 is rarely used alone: pairing it with a phenolic such as AO135 lets each run at a lower level than it would solo (heterosynergism), and ZDDP adds a secondary, peroxide-decomposing antioxidant on top. The exact level depends on the oxidation target, the base oil and the rest of the package.
Treat rates are indicative, not fixed dosages. CheMost can provide formulation and treat-rate support on request.
Formulating With AO57 — Complementary Additives
Phenolic antioxidant (AO135)
The classic aminic + phenolic couple: different radical-trapping mechanisms that regenerate one another (heterosynergism), covering both moderate and high temperature. The data sheet itself recommends AO57 with AO135.
ZDDP
ZDDP is a secondary antioxidant — it decomposes the peroxides that radicals form — and adds antiwear; AO57 synergises with it for a complete oxidation + wear defence (a TDS-noted pairing).
Metal deactivator (BTA)
Dissolved copper catalyses oxidation; a metal deactivator such as benzotriazole passivates yellow metals so the antioxidants are not consumed fighting metal-catalysed degradation.
Rust inhibitors
Turbine and circulating oils pair the antioxidant system with a rust inhibitor to protect ferrous surfaces — together they form the core of a long-life industrial-oil package.
Documentation, Qualification & Regulatory Support
Standard documentation — Certificate of Analysis (COA, per shipment), Technical Data Sheet (TDS) and Safety Data Sheet (SDS, GHS/CLP) — is provided. The full TDS is available on request rather than as a public download. Additional support is available on request:
Regulatory documentation
REACH, TSCA and country-specific market-registration documentation support available on request.
Third-party inspection
SGS / Intertek / BV pre-shipment inspection can be arranged on request.
Custom grades & packaging
Custom packaging and grades on request.
Formulation support
Antioxidant-system and treat-rate guidance from our technical team.
Packaging & Supply
CheMost-AO57 is stocked and shipped worldwide, with a typical lead time of 1–15 days and a 36-month shelf life at ambient temperature. Samples and quotations are answered within 12 hours.
Packaging
190 kg metal drum · 900 kg IBC tank.
Minimum order
1 drum / 1 IBC — contact us for your quantity.
Incoterms
FOB · CIF · EXW, to suit your freight arrangement.
Loading ports
All major Chinese ports.
Frequently Asked Questions
What is octylated butylated diphenylamine?
It is a liquid aminic antioxidant (CAS 68411-46-1) — diphenylamine alkylated with butyl (C4) and octyl (C8) groups for oil solubility. It is a primary antioxidant: the amine N–H traps free radicals, with a high nitrogen content (4.58%) and TBN 198, used in industrial, turbine, automotive and heat-transfer oils.
Aminic or phenolic — which antioxidant should I use?
Use both. Aminic antioxidants like AO57 excel at high temperature; phenolics like AO135 or BHT work well at moderate temperature. Combined, they regenerate one another (heterosynergism) and outlast either alone — which is why most premium packages use an amine + phenol pair.
Does AO57 work with ZDDP?
Yes. ZDDP is a secondary antioxidant that decomposes peroxides (and adds antiwear); AO57 is a primary radical trap. The two attack oxidation at different points, so they synergise — the data sheet notes AO57 synergises with ZDDP.
What treat rate should I use?
As an aminic primary antioxidant, AO57 is typically used at about 0.1–1% (often 0.25–0.75%), dosed to the oxidation target and usually paired with a phenolic. The exact level depends on the oxidation requirement, the base oil and the rest of the package; our technical team can assist.
How is it supplied, and how fast can I get a sample?
It is supplied as a light-brown liquid in 190 kg metal drums and 900 kg IBC tanks with a 36-month shelf life, and shipped worldwide. As a manufacturer and sourcing partner (Est. 2013), CheMost answers sample and quotation requests within 12 hours.