Emulsifier OS (also known as AEO, Peregal, fatty alcohol polyoxyethylene ether, CAS number: 68439-50-9) has its core active ingredient being sodium secondary alkyl sulfonate, with a molecular formula representable as R-CH(CH₃)SO₃Na. It is a typical anionic surfactant. As a flagship product of Guoli Chemical, OS has good water solubility, and the sulfonate group in its molecular structure endows it with excellent emulsifying power and hard water resistance. It is widely used in pesticide formulation processing, textile printing and dyeing auxiliaries, and industrial cleaning fields. The product appears as a light yellow to yellowish brown oily liquid with an active content of ≥99%.
Emulsifier MS-1 has its core active ingredient being octylphenol polyoxyethylene ether maleate, which is a nonionic/anionic composite surfactant modified by maleic anhydride esterification. Its molecular structure contains both polyoxyethylene ether segments (nonionic hydrophilic groups) and carboxylic ester groups (anionic hydrophilic groups), combining the excellent emulsifying and wetting properties of nonionic surfactants with the dispersion stability of anionic types. The product appears as a reddish brown viscous liquid with a monoester content of ≥90%.
From a chemical structure perspective, although both OS and MS-1 belong to the anionic surfactant system, their hydrophilic group sources are different: the hydrophilicity of OS comes from the sulfonate group, while that of MS-1 comes from the synergistic effect of carboxylic ester salt and polyoxyethylene ether segments. This allows them to complement each other in compounding applications, covering a wider range of oil phase systems and pesticide active ingredient types.
| Parameter | Emulsifier OS | Emulsifier MS-1 |
|---|---|---|
| Chemical Name | Sodium secondary alkyl sulfonate | Octylphenol polyoxyethylene ether maleate |
| Ionic Type | Anionic | Nonionic/Anionic composite |
| Appearance (25°C) | Light yellow to yellowish brown oily liquid | Reddish brown viscous liquid |
| Active Content | ≥99% | ≥99% |
| HLB Value | No separate data (overall product HLB value 12-14) | No separate data (overall product HLB value 12-14) |
| Cloud Point | No cloud point (ionic type characteristic) | Approximately 65-75°C (1% aqueous solution) |
| pH Value (1% aqueous solution) | 5.5-7.5 | 5.5-7.5 |
| Penetration Power (1% aqueous solution) | Approximately 5-15 seconds (canvas disc method) | Approximately 5-15 seconds (canvas disc method) |
| Surface Tension (1%, 25°C) | Approximately 30-35 mN/m | Approximately 30-35 mN/m |
| Monoester Content | — | ≥90% |
Emulsifier OS, due to its sulfonate structure, is particularly suitable for use in emulsion in water (EW), suspension concentrate (SC) and other aqueous pesticide formulation systems. Its strong anionic nature provides excellent dispersion power and electrolyte resistance. The recommended dosage is generally 3%-8% of the total formulation (the specific recipe needs to be determined through experiments).
Emulsifier MS-1, due to its octylphenol polyoxyethylene ether maleate structure, has good affinity for aromatic hydrocarbons, alcohols and other organic solvents, making it more suitable for emulsifiable concentrate (EC), microemulsion (ME) and other formulation systems containing high proportions of organic solvents. Its polyoxyethylene ether segments also provide good wetting and spreading properties, offering significant advantages in tank-mix adjuvant applications. The recommended dosage is generally 5%-10% of the total formulation.
In actual pesticide processing, OS and MS-1 are often used together, leveraging their different hydrophilic-lipophilic balance characteristics for synergistic effects, which can simultaneously improve the performance of the formulation in multiple dimensions such as emulsification, dispersion, and wetting.