Zinc Dioctyl Primary Alkyl Dithiophosphate, often abbreviated as ZDP or more specifically as a type of ZDDP (Zinc Dialkyldithiophosphate), is a high-performance anti-wear and antioxidant additive used widely in lubricants, especially engine oils, hydraulic fluids, and gear oils.
🧪 Chemical Identity
- Chemical Class: Zinc dialkyldithiophosphate (ZDDP)
- Structure: Zinc coordinated with two dithiophosphate ligands derived from primary octyl alcohols
- Formula (general):
Zn[(RO)(RO)P(S)S]₂
where R = n-octyl or 2-ethylhexyl
🔍 Key Functions in Lubricants
✅ 1. Anti-Wear Protection
- Forms a protective tribofilm (zinc-phosphate glassy layer) on metal surfaces under pressure and heat.
- Reduces wear, especially in boundary lubrication conditions (e.g., cam lobes, gears, tappets).
✅ 2. Antioxidant Action
- Inhibits oil oxidation by neutralizing radicals and hydroperoxides.
- Prevents viscosity increase, sludge, and varnish.
✅ 3. Corrosion Inhibition
- Provides protection against corrosion for iron, steel, and non-ferrous metals.
⚙️ Advantages of Dioctyl Primary Alkyl ZDDP
| Feature | Benefit |
|---|---|
| Primary alkyl structure | More thermally stable than secondary alkyl ZDDPs |
| Octyl chain | Balanced solubility and film-forming ability |
| Excellent film strength | Ideal for high-load applications (engine, gear) |
📈 Typical Use in Lubricants
| Application | Treat Rate (%) | Notes |
|---|---|---|
| Engine oils | 0.8–1.2 | Often used with detergents/dispersants |
| Hydraulic oils | 0.2–0.6 | In ashless or zinc-containing formulations |
| Gear oils | 0.6–1.0 | Combined with EP agents |
| Greases | 0.5–1.0 | Enhances extreme pressure properties |
⚠️ Considerations
| Issue | Details |
|---|---|
| Ash content | ZDDPs contain metallic zinc, contributing to ash in oils |
| Phosphorus limit | Modern engine specs (e.g., API SN, SP, ILSAC GF-6) restrict phosphorus (~800 ppm) due to catalyst poisoning concerns |
| Thermal stability | Can decompose at very high temperatures (>250°C) |
| Not biodegradable | Not suitable for eco-sensitive or biodegradable lubricants |
🔬 Related Compounds
| Variant | Description |
|---|---|
| Secondary ZDDP | More reactive, faster tribofilm formation, but less stable |
| Primary ZDDP (C8) | Dioctyl-based, slower but durable film |
| Ashless DTP (no zinc) | Environmentally friendly alternatives |
🛢️ Summary
Zinc Dioctyl Primary Alkyl Dithiophosphate is:
- A proven, cost-effective anti-wear and antioxidant additive
- Preferred in high-temperature, high-load lubricant systems
- Common in motor oils, hydraulic fluids, and greases
Table of Contents
Zinc Dioctyl Primary Alkyl Dithiophosphate, often simply referred to as Zinc Dithiophosphate or ZDDP, is a chemical compound primarily used as an additive in lubricating oils, especially in engine oils. It is known for its anti-wear and anti-oxidation properties, which make it a crucial component in protecting engines and machinery from wear and corrosion.
Here’s a breakdown of its components:
- Zinc (Zn): This element provides anti-wear properties by forming a protective layer on metal surfaces. It reacts with the metal surfaces to create a sacrificial barrier that helps reduce friction and prevent metal-to-metal contact, thus minimizing wear and extending the lifespan of engine components.
- Dioctyl Primary Alkyl: This part of the compound refers to the chemical structure of the dithiophosphate. “Dioctyl” indicates the presence of eight carbon atoms in the alkyl chain, and “primary alkyl” means that the alkyl group is directly attached to the central phosphorus atom.
- Dithiophosphate: This is the functional group that coordinates with the metal surfaces and forms a protective film. Dithiophosphates contain two thiol (sulfur-hydrogen) groups and a central phosphorus atom.
The primary function of Zinc Dioctyl Primary Alkyl Dithiophosphate in lubricating oils is to:
- Reduce Wear: ZDDP forms a protective layer on metal surfaces, particularly in high-pressure areas where friction can cause wear. This layer helps prevent direct metal-to-metal contact and reduces the risk of surface damage.
- Prevent Oxidation: ZDDP also has antioxidant properties, which means it helps prevent the oxidation of oil molecules at high temperatures. Oxidation can lead to the formation of sludge, deposits, and viscosity changes in the oil, affecting its performance.
- Corrosion Protection: The zinc component of ZDDP can protect metal surfaces from corrosion by forming a barrier that prevents moisture and corrosive agents from coming into direct contact with the metal.
It’s worth noting that while ZDDP is highly effective in enhancing the lubrication and protection of engines, its use has decreased in recent years due to concerns about its impact on catalytic converters in modern vehicles. ZDDP can form phosphates that might interfere with the functioning of catalytic converters, which are essential for reducing exhaust emissions. As a result, lubricant manufacturers have been working on developing alternative additives that offer similar benefits without causing issues for catalytic converters.
Our product:
T203 Zinc Dioctyl Primary Alkyl Dithiophosphate
T203 is Zinc Dioctyl Primary Alkyl Dithiophosphate. This product has excellent anti-oxidation corrosion resistance and extreme pressure anti-wear properties, the thermal stability is particularly good, oil-soluble and additive compatibility and anti-emulsifying properties. This product and the detergent T105, T106 and dispersant T154, T155 compound, used in high-grade diesel engine oil, and other additives can be used for anti-wear hydraulic oil.
Welcome to contact us:
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