OP-4 octylphenol ethoxylate, chemically named octylphenol polyoxyethylene (4) ether (also known as Triton X-45, emulsifier OP-4), is a non-ionic surfactant. Its molecular structure has an ethylene oxide (EO) addition number of about 4, and the hydrophilic group is relatively short, resulting in a low HLB value (8.8). It is insoluble in water but dispersible, and can dissolve in various oils and organic solvents, showing excellent water-in-oil (W\/O) emulsifying ability.
This product has high purity (effective content ≥99%), with free alcohol and moisture controlled below 1.0%. It has good chemical stability and can maintain stable performance in acid, alkali, and hard water media. The product has low foaming characteristics, a surface tension of about 28 mN\/m (1% aqueous dispersion, 25°C), and a critical micelle concentration (CMC) of about 1.1×10⁻⁴ mol\/L, making it suitable for industrial systems requiring foam control.
In terms of safety, the flash point is above 150°C, making it non-flammable; the acute oral toxicity LD₅₀ > 2000 mg\/kg, which is low toxicity. However, this product is irritating to skin and eyes (H315, H319), and is very toxic to aquatic life with long-lasting effects (H410). Personal protection should be used during handling, and discharge into water bodies must be strictly avoided.
| Parameter Category | Parameter Name | Specification\/Value |
|---|---|---|
| Basic Physicochemical Properties | Appearance | Pale yellow to yellow oily liquid |
| Ionic Type | Non-ionic | |
| Molecular Formula | C₈H₁₇C₆H₄O(CH₂CH₂O)ₙH, n≈4 | |
| Molecular Weight | ~382 | |
| Effective Content | ≥99% | |
| Density (25°C) | 1.02~1.04 g\/cm³ | |
| Refractive Index (20°C) | 1.490~1.500 | |
| Kinematic Viscosity (25°C) | ~300 mPa·s | |
| Thermodynamic Properties | Melting Point | < 0°C |
| Flash Point (Typical) | > 150°C | |
| Chemical Stability | Stable at room temperature | |
| Solubility and Surface Properties | HLB Value | 8.8 |
| Cloud Point | None (insoluble in water) | |
| Solubility | Soluble in oils and organic solvents, dispersible in water | |
| Surface Tension (1% aqueous dispersion, 25°C) | ~28 mN\/m | |
| CMC (25°C) | ~1.1×10⁻⁴ mol\/L | |
| Foam Properties | Low foaming | — |
| Quality Indicators | pH Value (1% aqueous solution) | 5.0~7.0 |
| pH Value (5% aqueous solution) | 5.0~7.0 | |
| Hydroxyl Value | 145~155 mg KOH\/g | |
| Acid Value | ≤1 mg KOH\/g | |
| Saponification Value | ≤1 mg KOH\/g | |
| Iodine Value | ≤0.5 gI₂\/100g | |
| Moisture Content | ≤1.0% | |
| Impurity Control | Free Alcohol | ≤1% |
| Heavy Metals (as Pb) | ≤10 mg\/kg | |
| Arsenic (As) | ≤2 mg\/kg | |
| Amine Value\/Tertiary Amine Content | ≤0.5 mg KOH\/g \/ ≤0.1% | |
| Safety Data | Oral LD₅₀ (Rat) | > 2000 mg\/kg (Low toxicity) |
| Hazard Classification | H315 Skin irritation, H319 Eye irritation, H410 Aquatic toxicity | |
| Packaging Specifications | 50kg plastic drum \/ 200kg plastic drum \/ IBC tote |
Based on its low HLB value (8.8) and excellent oil solubility, OP-4 is mainly recommended for the following scenarios: