Sodium Cumene Sulfonate (SCS) CAS 28348-53-0

Introduction to Sodium Cumene Sulfonate

Sodium Cumene Sulfonate (SCS) is the sodium salt of cumene (isopropylbenzene) sulfonic acid, classified as a short-chain alkylbenzene sulfonate hydrotrope. Unlike conventional surfactants that form micelles, SCS operates below its critical micelle concentration (CMC ~120 g/L) to disrupt intermolecular association between longer-chain surfactants, thereby solubilizing incompatible ingredients and maintaining single-phase clarity in concentrated liquid formulations. At 2–8% active addition, it prevents cloudiness, layering, and viscosity spikes caused by high electrolyte loads or mixed surfactant incompatibility.

The 40% liquid grade is preferred for direct blending into aqueous detergent systems, while the 93% powder grade suits dry-blend applications and export scenarios where freight cost per active kilogram is critical. Storage risk differs by form: the liquid grade freezes below 0 °C (32 °F) and may require gentle warming before pumping; the powder grade is hygroscopic and cakes above 70% RH. Store liquid in sealed HDPE containers at 5–40 °C (41–104 °F); store powder in moisture-barrier bags below 35 °C (95 °F).

Key Features of Sodium Cumene Sulfonate

• Superior hydrotropic solubilization. At 3–5% active addition, SCS maintains optical clarity in formulations containing > 20% combined surfactant (SLES + AEO + CAPB) and > 5% inorganic electrolyte, eliminating phase separation during 12-month shelf storage.
• Broad surfactant-system compatibility. Fully miscible with anionic (SLES, LAS, MES), nonionic (AEO-9, APG), and amphoteric (CAPB, BS-12) systems without neutralizing foam or compromising detergency.
• Viscosity moderation without thickener conflict. Reduces excessive viscosity in high-solids liquid detergents by 30–50%, improving pumpability and pourability while remaining compatible with salt-thickening and polymer-thickening mechanisms.
• Electrolyte tolerance booster. Allows formulators to raise NaCl or sodium citrate levels for cost optimization without triggering turbidity or gelation, particularly valuable in hard-water regions.
• Rapid biodegradation. OECD 301B ready biodegradability > 90% in 28 days, meeting EU Detergent Regulation (EC) 648/2004 and US EPA Safer Choice hydrotrope criteria.

Sodium Cumene Sulfonate Chemical & Physical Properties

Applications of Sodium Cumene Sulfonate

Liquid laundry detergents and dishwashing liquids: Add 2–6% (active basis) to solubilize high-load surfactant blends (SLES + LAS + AEO-9) and prevent turbidity when electrolyte (NaCl, sodium citrate) exceeds 4%. Maintains pourable viscosity at 25 °C (77 °F) and prevents gel-layer formation at 5 °C (41 °F) cold-storage conditions. Compatible with enzymes (protease, amylase) and optical brighteners.

Industrial and institutional (I&I) cleaners: Use at 3–8% in alkaline degreasers (pH 12–14, NaOH 5–15%) to solubilize nonionic surfactants and prevent cloud-point precipitation above 60 °C (140 °F). Also effective in acidic toilet bowl cleaners (HCl or citric acid systems) to maintain single-phase clarity.

Agricultural formulation adjuvant: Incorporate at 1–5% in SL (soluble liquid) and SC (suspension concentrate) pesticide formulations to improve active ingredient dissolution, enhance leaf-surface spreading, and stabilize emulsion systems against Ostwald ripening during 54 °C (129 °F) accelerated storage tests.

Textile wetting and leveling agent component: Blend at 5–15% into textile auxiliary concentrates to improve compatibility of anionic wetting agents with cationic dye-fixing agents in jet-dyeing processes. Reduces foam build-up compared to conventional hydrotropes in high-shear padding mangles.

Paper deinking flotation aid: Add at 0.5–2.0% to alkaline flotation deinking systems (pH 9–10, NaOH/Na2SiO3) to disperse detached ink particles and prevent redeposition onto recycled fibers, improving ISO brightness by 2–4 points.

Storage & Safety Precautions for Sodium Cumene Sulfonate

• Storage (40% Liquid): Keep in sealed HDPE drums or IBC totes at 5–40 °C (41–104 °F). Protect from freezing; if solidified below 0 °C (32 °F), gently warm to 20–30 °C (68–86 °F) with drum heaters or warm water circulation—do not exceed 50 °C (122 °F). Avoid prolonged storage above 40 °C (104 °F) to prevent slow color darkening.
• Storage (93% Powder): Keep sealed in original kraft bags with PE liner at 5–35 °C (41–95 °F), relative humidity below 65%. The powder is hygroscopic; exposure above 70% RH causes caking within 48 hours. Do not store near strong acids or oxidizers. Shelf life 24 months unopened.
• Safety: Not classified as hazardous under GHS. The 40% liquid is a mild eye irritant (Category 2B); the 93% powder may cause transient respiratory irritation if inhaled as dust. Wear safety glasses and nitrile gloves during transfer. For bulk powder handling, use N95/P2 dust mask and local exhaust ventilation.
• Transport: Sodium Cumene Sulfonate is Non-DG under IATA/IMDG/ADR. No UN number, no packing group. Liquid: ship in standard 200 kg drums or IBC totes in dry containers; ensure drum bungs are oriented upward. Powder: ship on shrink-wrapped pallets; protect from rain and container condensation during sea transit.
• QC note: Verify active matter by two-phase titration (liquid) or gravimetric drying (powder, 105 °C / 221 °F, 2 h). Check pH within specification. For liquid grade, confirm clarity (no haze) at 25 °C (77 °F); slight cloudiness at 5 °C (41 °F) is reversible upon warming. Reject if color exceeds Gardner 3 (liquid) or Klett 40 (powder).

Sodium Cumene Sulfonate FAQ

Q: How does Sodium Cumene Sulfonate compare to Sodium Xylene Sulfonate (SXS) as a hydrotrope?

A: Both are effective hydrotropes, but SCS (cumene = C9 hydrophobe) provides stronger solubilization power per unit mass than SXS (xylene = C8 hydrophobe). SCS typically requires 10–20% lower dosage to achieve equivalent clarity in high-electrolyte systems. SCS also exhibits better compatibility with nonionic surfactants at elevated temperatures (above 50 °C / 122 °F), making it preferred for I&I alkaline cleaners.

Q: The 40% liquid drum arrived frozen solid in winter transit. Is the product damaged?

A: No. Freezing is a reversible physical change for the 40% aqueous solution. Slowly warm the drum in a heated warehouse (20–30 °C / 68–86 °F) or use a certified drum band heater set below 50 °C (122 °F). Once thawed and gently mixed, the hydrotrope retains 100% performance. Do not use open flames or steam lances directly on HDPE drums.

Q: Should I choose the 40% liquid or 93% powder grade for my formulation?

A: Choose 40% liquid if your process involves direct aqueous blending (liquid detergents, I&I cleaners)—it requires no dissolution step and integrates inline. Choose 93% powder if you manufacture dry-blend products, need lower freight cost per active kilogram for long-distance export, or require precise gravimetric dosing in solid formulations. Both grades deliver identical hydrotropic performance on an active-matter basis.