Overbased Calcium Sulfonate Detergent (High TBN)
CAS Number: 61789-86-4
Overbased calcium sulfonate is the primary detergent additive in engine oil formulations, providing acid neutralization, deposit prevention, and corrosion protection. The colloidal calcium carbonate core suspended in the sulfonate carrier delivers high TBN (300–400 mg KOH/g) to neutralize acidic combustion and oxidation byproducts throughout the oil drain interval. It is essential in heavy-duty diesel engine oils meeting API CK-4/FA-4 and marine diesel oil formulations.
Technical Specifications
| appearance | Brown to dark brown viscous liquid |
| sulfur content | 1.5–2.5 wt% |
| calcium content | 11.0–13.0 wt% |
| flash point (COC) | >160 °C |
| TBN (total base number) | 300–400 mg KOH/g |
| kinematic viscosity (100°C) | 30–100 mm²/s |
Applications
- Heavy-duty diesel engine oils (API CK-4, FA-4, CI-4 Plus)
- Marine diesel cylinder oils and trunk piston engine oils (TPEO)
- Passenger car motor oils (PCMO) as detergent/acid neutralizer
- Two-stroke and four-stroke marine engine lubricants
- Industrial and stationary gas engine oils
Key Features
- Very high TBN (300–400) provides reserve alkalinity for long-drain heavy-duty applications
- Colloidal calcium carbonate structure effectively neutralizes strong mineral and organic acids
- Combined detergency and acid neutralization prevents piston deposits and corrosion
- Compatible with all base oil types including Group I through Group IV synthetics
Grade Variants & Supplier Reference
Specific grades available from leading Chinese-market suppliers. Spec sheets and lead-time vary per grade — request a quote to confirm availability.
| Appearance | Brown red viscous liquid |
| S Content, m% | ≥2.0 |
| Ca Content, m% | ≥2.0 |
| Water Content, m% | ≤0.2 |
| Density (20℃), kg/m3 | 900-1000 |
| Flash Point (COC), ℃ | ≥180 |
| Mechanical Impurities, m% | ≤0.1 |
| Total Base Number, mgKOH/g | 20-35 |
| Kinematic Viscosity (100℃), mm2/s | ≤30 |
TBN ~17 mgKOH/g; used as rust inhibitor and emulsion stabilizer in metalworking fluids.
View on supplier site →| Appearance | Brown red viscous liquid |
| S Content, m% | 1.8-2.2 |
| Ca Content, m% | ≥6.5 |
| Water Content, m% | ≤0.2 |
| Density (20℃), kg/m3 | 1000-1050 |
| Flash Point (COC), ℃ | ≥180 |
| Mechanical Impurities, m% | ≤0.1 |
| Total Base Number, mgKOH/g | ≥145 |
| Kinematic Viscosity (100℃), mm2/s | 20-50 |
TBN ~150 mgKOH/g; classic medium-base detergent for industrial oils.
View on supplier site →| Appearance | Brown red viscous liquid |
| S Content, m% | ≥1.25 |
| Ca Content, m% | ≥11.5 |
| Water Content, m% | ≤0.2 |
| Density (20℃), kg/m3 | 1100-1150 |
| Flash Point (COC), ℃ | ≥180 |
| Mechanical Impurities, m% | ≤0.1 |
| Total Base Number, mgKOH/g | ≥295 |
| Kinematic Viscosity (100℃), mm2/s | 25-60 |
TBN ~300-400 mgKOH/g; primary detergent in PCMO and HDD engine oils (the "headline" overbased grade).
View on supplier site →Big 4 Equivalents Cross-Reference
Approximate functional equivalents from leading global additive houses (Lubrizol, Infineum, Afton Chemical, Chevron Oronite). Chemistry tier, treat rate, and additive synergy may differ — always verify against the supplier TDS before formulation lock-in.
- OS-30 (low TBN)
- OS-23/240 (medium TBN)
- OS-25/400 (overbased)
- M-7101 (low)
- M-7110 (medium)
- M-7115 (overbased)
- HiTEC 611 (low)
- HiTEC 614 (medium)
- HiTEC 6111 (overbased)
- OLOA 218 (low)
- OLOA 219 (medium)
- OLOA 246 (overbased)
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CAS Number
61789-86-4
Category
Automotive Lubricant AdditivesAvailability
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