SYNTECH

Basic Chemical Identity

• Full Name: Sodium 2-propene-1-sulfonate
• Abbreviation: SAS, ALS
• CAS No.: 2495-39-8
• EINECS: 219-676-5
• Molecular Formula: C₃​H₅​NaO₃​S
• Molecular Weight: 144.12 g/mol
• Structural Formula: H₂​C=CH−CH₂​−SO_3​Na
• MDL No.: MFCD00051416

1. Fundamental Physical & Chemical Properties

Solid Grade (Powder SAS)

1. Appearance: White crystalline powder / white granular solid
2. Melting Point: 242 °C (decomposes above 300 °C, no boiling point)
3. Solubility:
   • Fully miscible / highly soluble in water & short-chain alcohols (methanol, ethanol)
   • Slightly soluble in benzene, insoluble in aliphatic hydrocarbons
4. LogP (20 °C): -0.32 (strong hydrophilicity)
5. Thermal Stability: Dry powder is heat-stable; aqueous solution easily polymerizes under long-term heating
6. pH (1% aqueous solution): 6.5 ~ 9.0 (weakly neutral to mild alkaline)
7. Density (solid bulk): ~1.206 g/cm³

Liquid Grade (35% ALS Aqueous Solution, Industrial Mainstream)

35% ALS liquid drum

1. Appearance: Clear colorless to pale yellow transparent liquid
2. Concentration Standard: 35 ± 0.5 wt%
3. Density (20–23 °C): 1.19 ~ 1.28 g/cm³
4. pH Range: 6.0 ~ 11.5 (varies by manufacturer)
5. Miscibility: Fully miscible with water in all ratios
6. Viscosity: Low viscosity, free-flowing liquid at room temp

Chemical Reactivity

• Contains dual functional groups:
  1. Hydrophilic anionic sulfonate group −SO3​Na: water-soluble, adsorption active
  2. Unsaturated allyl vinyl group −CH=CH2​: free-radical copolymerizable monomer
• Undergoes radical polymerization alone or copolymerizes with acrylic acid, acrylamide, acrylonitrile, vinyl monomers
• Weak anion, no strong corrosivity to carbon steel at room temperature

2. Industrial Quality Specifications

A. Dry Solid SAS (Powder, Three Grades)

Test Item	Top Grade	First Grade	Qualified Grade
SAS Purity (dry basis, min)	98.0 %	97.0 %	95.0 %
NaCl Impurity (max)	1.0 %	1.3 %	1.5 %
Residual Na2​SO3​ (max)	0.10 %	0.10 %	0.30 %
Iron (Fe²⁺, max)	0.0003 %	0.0003 %	0.0030 %
Moisture (H₂O, max)	0.8 %	1.5 %	3.0 %
Appearance	Uniform white crystal	White crystal	Off-white crystal

Source: Standard industrial enterprise specification Q/LZ07-2008

B. 35% Liquid ALS (Electroplating Grade)

Index	Standard Value
Active SAS Content	≥35.0 wt%
Sodium Sulfite (Na2​SO3​)	≤0.30 %
Sodium Chloride (NaCl)	≤1.0 %
Iron Ion	≤5 ppm
Color (APHA)	≤150 (light yellow allowed)
pH (undiluted)	6.0 ~ 8.0
No visible suspended solids / polymer gel	Pass

3. Key Industrial Applications

1. Electroplating Primary Brightener (Largest Use)
   • Acid nickel plating: dosage 0.1–5 g/L; refines grain, improves throwing power, ductility & leveling, eliminates low-current-area darkening
   • Acid copper, alkaline zinc, Ni-Co alloy plating as grain refiner & auxiliary brightener
2. Polymer Co-monomer
   • Acrylic fiber third monomer: enhances dye uptake, anti-static & heat resistance
   • Water treatment scale/corrosion inhibitor: copolymerized with AA/AM/MA to produce low-molecular-weight dispersants for CaCO₃, Ca₃(PO₄)₂ scale control
   • Emulsifier, chain transfer agent for acrylic emulsion polymerization
3. Other Fields
   • Dyeing auxiliaries, textile anti-static agent
   • Organic synthesis & pharmaceutical intermediates

4. Storage, Packaging & Shelf Life

Packaging

• Solid powder: 25 kg woven bag / aluminum foil vacuum bag
• 35% liquid ALS: 25 kg HDPE blue plastic drum

Storage Rules

• Store in cool, dry, ventilated warehouse; avoid direct sunlight & high temperature
• Seal tightly to prevent moisture absorption (solid grade)
• Separate from strong oxidants & strong acids

Shelf Life

• Sealed intact packaging: 24 months (2 years) at ambient temperature

5. Safety Profile Brief

• Non-dangerous goods for road/sea transport
• Mild irritant to eyes & skin; avoid prolonged direct contact
• In case of splashing: rinse skin/eyes with plenty of clean water
• No flammability risk; stable under normal handling conditions