Technical Specifications
| Property | Unit | Typical Value | Test Method |
|---|---|---|---|
| Appearance | White flake | Visual | |
| Purity | % | 99.5 | GC |
| Melting Point | °C | 52.5 | ASTM E324-23 |
| Phosphorus | % | 9.0 | ASTM D4951 |
| Sulfur | % | 9.3 | ASTM D4951 |
* 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 · organophosphorus ester
(C₆H₅O)₃P=S (C₁₈H₁₅O₃PS, MW 342.35)
Triphenyl phosphorothionate — an ashless, all-aryl organophosphorus ester carrying both phosphorus and sulfur for high-thermal-stability antiwear/EP.
What Is Triphenyl Phosphorothioate (TPPT)?
CheMost-T9339 is triphenyl phosphorothioate (TPPT) — an ashless, metal-free antiwear and extreme-pressure (EP) additive. It is a discrete organophosphorus ester, (C₆H₅O)₃P=S, supplied as a 99.5%-pure white flake carrying 9.0% phosphorus and 9.3% sulfur, and is used to bring antiwear protection to industrial oils that must stay ash-free — antiwear hydraulic oils, transmission oils and turbine oils.
Phosphorus antiwear additives work by carrying phosphorus to the metal surface, where it adsorbs and reacts under load to form a protective phosphate/phosphorothioate film that prevents wear. TPPT carries both phosphorus and sulfur in one molecule, so it builds an antiwear film with mild EP support. Because it is all-aryl (three phenyl groups), it has high thermal stability compared with alkyl phosphates — valuable in hot turbine and hydraulic systems — and it also contributes antioxidancy.
Its defining feature is that it is ashless: unlike ZDDP, it contains no zinc or metal, so it leaves no sulphated ash. That makes it the antiwear additive of choice where ZDDP’s ash, metal or volatility are unwanted — turbine oils, ashless hydraulic fluids and modern low-ash formulations.
How TPPT Works
Phosphorus antiwear film
Under boundary lubrication the molecule delivers phosphorus to the metal surface, where it adsorbs and reacts to form a tenacious antiwear film that carries the load and prevents metal-to-metal wear.
Combined P + S action
Carrying 9.0% phosphorus and 9.3% sulfur in one molecule, TPPT builds the antiwear film with mild extreme-pressure support — a balanced, ashless EP/AW contribution.
High thermal stability
The all-aryl (triphenyl) structure resists thermal breakdown far better than alkyl phosphates, so the additive survives the high temperatures of turbine and hydraulic service.
Ashless & antioxidant
No metal means no sulphated ash; the molecule also contributes antioxidancy, supporting long oil life in ash-sensitive systems.
The Ashless Advantage — TPPT vs ZDDP
The most common antiwear additive is ZDDP (zinc dialkyldithiophosphate), but its zinc contributes sulphated ash and it can be volatile and sensitive at high temperature. TPPT delivers phosphorus antiwear protection without any metal or ash and with higher thermal stability, so it is chosen where ZDDP is unsuitable: turbine oils (which demand ashless, demulsible, oxidation-stable chemistry), ashless hydraulic fluids, and other low-ash or zinc-free formulations. Where ash is acceptable, TPPT can also be used alongside ZDDP to lift antiwear performance.
Applications
CheMost-T9339 is used as the ashless antiwear/EP component in formulations targeting the duties below:
Antiwear hydraulic oils
Ashless antiwear protection for hydraulic systems, including zinc-free and low-ash hydraulic fluids where ZDDP is to be avoided.
Turbine & transmission oils
High-thermal-stability antiwear and antioxidancy for steam/gas turbine oils and transmission fluids that must stay ashless and oxidation-stable.
Industrial gear oils & greases
Ashless EP/antiwear support in industrial gear oils and greases, on its own or combined with a sulfur-carrier EP additive.
Finished-oil performance approvals (e.g. turbine-oil and hydraulic specifications) belong to the fully formulated oil, not to an individual additive 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 ashless phosphorus antiwear additive, TPPT is used at low levels, roughly 0.1–1%, dosed to the four-ball / FZG antiwear target. A small amount supplies meaningful phosphorus to the surface; over-treat gives little extra benefit and adds phosphorus to the system.
TPPT is typically the ashless antiwear backbone of a turbine or hydraulic package, often combined with an antioxidant and a metal deactivator; in gear oils it is paired with a sulfur-carrier EP additive (the S–P synergy). The exact level depends on the antiwear 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 TPPT — Complementary Additives
Sulfur-carrier EP additives
Sulfurized isobutylene and sulfurized olefin add extreme-pressure load-carrying; the phosphorus antiwear film plus the sulfur EP film is the classic S–P synergy for gear oils.
ZDDP (where ash is acceptable)
Where sulphated ash is allowed, TPPT can be combined with ZDDP to lift antiwear performance; where it is not, TPPT is the ashless replacement.
Antioxidants
In turbine and hydraulic oils, antioxidants and TPPT’s own antioxidancy together extend oil life under high-temperature, long-drain service.
Metal deactivators
Benzotriazole passivates copper and yellow metals, rounding out a turbine/hydraulic package alongside the ashless antiwear and antioxidant.
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
Ashless antiwear / turbine-oil formulation and treat-rate guidance from our technical team.
Packaging & Supply
CheMost-T9339 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
20 kg bag (white flake).
Minimum order
By bag or pallet — 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 triphenyl phosphorothioate (TPPT)?
It is an ashless organophosphorus antiwear/EP additive, (C₆H₅O)₃P=S (CAS 597-82-0), supplied as a 99.5%-pure white flake with 9.0% phosphorus and 9.3% sulfur. It delivers phosphorus to the metal surface to form an antiwear film with mild EP support, and is used in ashless hydraulic, turbine, transmission and gear oils.
Why use TPPT instead of ZDDP?
ZDDP is the most common antiwear additive, but its zinc adds sulphated ash and it can be thermally sensitive. TPPT gives phosphorus antiwear protection with no metal or ash and higher thermal stability, so it is preferred in turbine oils, ashless hydraulic fluids and low-ash formulations. Where ash is acceptable, the two can be combined.
Is it ashless?
Yes — TPPT contains no metal, so it contributes no sulphated ash. That is its defining advantage for ash-sensitive applications such as steam and gas turbine oils and zinc-free hydraulic fluids.
What treat rate should I use?
As an ashless phosphorus antiwear additive, TPPT is typically used at low levels, around 0.1–1%, dosed to the four-ball / FZG antiwear target. The exact level depends on the antiwear requirement, the base oil and the rest of the additive package; our technical team can assist.
How is it supplied, and how fast can I get a sample?
It is supplied as a white flake in 20 kg bags 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.