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Historical & Industrial Context:
Methyl naphthalene sulfonates have been commercially significant since the early 20th century.
They are key products from the sulfonation of methylnaphthalene oil fractions obtained from coal tar or petroleum refining.
These compounds serve as versatile anionic surfactants, dispersants, and intermediates in a wide array of industries, including construction, agrochemicals, textiles, and dye manufacturing.
Their properties are highly dependent on the position of the methyl and sulfonate groups on the naphthalene ring.
Chemical Family:
They belong to the class of arylsulfonic acid salts, specifically alkylnaphthalenesulfonates. The "methyl" group acts as a short alkyl chain, modifying the hydrophobicity compared to plain naphthalenesulfonates.
COMPREHENSIVE TECHNICAL DOSSIER 1: METHYL NAPHTHALENE-2-SULFONATE
1. CHEMICAL IDENTIFICATION & NOMENCLATURE
IUPAC Name: 2-Methylnaphthalene-1-sulfonate (Note: The "2-sulfonate" often refers to the commercial mixture; the specific isomer where sulfonate is at position 1 and methyl at position 2 is dominant).
Common Name: 2-Methyl-1-naphthalenesulfonic acid derivative.
CAS Registry Number: [To be confirmed per specific isomer; e.g., 2-methylnaphthalene-1-sulfonic acid is 86-87-3. The ester form is less common.]
EC Number: 201-708-4 (for 2-methyl-1-naphthalenesulfonic acid)
Synonyms:
2-Methyl-1-naphthalenesulfonate,β-Methylnaphthalene-α-sulfonate,NSC 403689 (for acid form)
1-Sulfo-2-methylnaphthalene,Molecular Formula: C₁₁H₁₀O₃S (Acid form)
Molecular Weight: 222.26 g/mol (Acid form)
Chemical Structure: A naphthalene ring with a methyl (-CH₃) group at the 2-position and a sulfonate (-SO₃H) group at the 1-position.
2. MANUFACTURING PROCESS & INDUSTRIAL SYNTHESIS
This compound is typically not isolated as a pure ester. It is primarily encountered as an intermediate in the production of its sodium salt or as a component of sulfonated methylnaphthalene mixtures. The synthesis involves:
Feedstock: 2-Methylnaphthalene (from coal tar or petroleum).
Sulfonation: Reaction with concentrated sulfuric acid (H₂SO₄) or oleum (fuming H₂SO₄) at controlled temperatures (40-80°C). The electrophilic aromatic substitution favors the 1-position due to the ortho/para-directing effect of the methyl group.
Reaction: 2-Methylnaphthalene + H₂SO₄ → 2-Methylnaphthalene-1-sulfonic Acid + H₂O
Esterification (If Produced): The resulting sulfonic acid can be esterified with an alcohol (e.g., methanol) under acidic conditions to yield the methyl ester.
Reaction: R-SO₃H + CH₃OH → R-SO₃CH₃ + H₂O (where R is the methylnaphthalene moiety)
TECHNICAL FUNCTIONS & MECHANISM OF ACTION
Primary Function: Intermediate; precursor to surfactants and dispersants.
Mechanism: As a surfactant/dispersant (in its salt form), the hydrophobic methylnaphthalene moiety adsorbs onto particle surfaces (e.g., cement, pigments, pesticides). The hydrophilic sulfonate group extends into the water phase, creating a negative charge (zeta potential) and electrostatic repulsion between particles, preventing agglomeration and promoting dispersion.
INDUSTRIAL & COMMERCIAL APPLICATIONS
Primary Application: Chemical Intermediate. Primarily converted to its sodium salt (Sodium 2-methylnaphthalene-1-sulfonate) for commercial use.
Niche Use: As a specialty ester in organic synthesis or as a plasticizer intermediate.
REGULATORY STATUS
REACH: Likely registered as part of substance group "sulfonated methylnaphthalene, sodium salt."
Handled as an industrial chemical intermediate with standard safety precautions.
SAFETY INFORMATION ABOUT METHYL NAPHTHALENE SULFONATES
First aid measures:
Description of first aid measures:
General advice:
Consult a physician.
Show this safety data sheet to the doctor in attendance.
Move out of dangerous area:
If inhaled:
If breathed in, move person into fresh air.
If not breathing, give artificial respiration.
Consult a physician.
In case of skin contact:
Take off contaminated clothing and shoes immediately.
Wash off with soap and plenty of water.
Consult a physician.
In case of eye contact:
Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician.
Continue rinsing eyes during transport to hospital.
If swallowed:
Do NOT induce vomiting.
Never give anything by mouth to an unconscious person.
Rinse mouth with water.
Consult a physician.
Firefighting measures:
Extinguishing media:
Suitable extinguishing media:
Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Special hazards arising from the substance or mixture
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas
Advice for firefighters:
Wear self-contained breathing apparatus for firefighting if necessary.
Accidental release measures:
Personal precautions, protective equipment and emergency procedures
Use personal protective equipment.
Avoid breathing vapours, mist or gas.
Evacuate personnel to safe areas.
Environmental precautions:
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
Methods and materials for containment and cleaning up:
Soak up with inert absorbent material and dispose of as hazardous waste.
Keep in suitable, closed containers for disposal.
Handling and storage:
Precautions for safe handling:
Avoid inhalation of vapour or mist.
Conditions for safe storage, including any incompatibilities:
Keep container tightly closed in a dry and well-ventilated place.
Containers which are opened must be carefully resealed and kept upright to prevent leakage.
Storage class (TRGS 510): 8A: Combustible, corrosive hazardous materials
Exposure controls/personal protection:
Control parameters:
Components with workplace control parameters
Contains no substances with occupational exposure limit values.
Exposure controls:
Appropriate engineering controls:
Handle in accordance with good industrial hygiene and safety practice.
Wash hands before breaks and at the end of workday.
Personal protective equipment:
Eye/face protection:
Tightly fitting safety goggles.
Faceshield (8-inch minimum).
Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
Skin protection:
Handle with gloves.
Gloves must be inspected prior to use.
Use proper glove
removal technique (without touching glove's outer surface) to avoid skin contact with this product.
Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices.
Wash and dry hands.
Full contact:
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
Splash contact
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
It should not be construed as offering an approval for any specific use scenario.
Body Protection:
Complete suit protecting against chemicals, The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
Respiratory protection:
Where risk assessment shows air-purifying respirators are appropriate use a fullface respirator with multi-purpose combination (US) or type ABEK (EN 14387) respirator cartridges as a backup to engineering controls.
If the respirator is the sole means of protection, use a full-face supplied air respirator.
Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).
Control of environmental exposure
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
Stability and reactivity:
Chemical stability:
Stable under recommended storage conditions.
Incompatible materials:
Strong oxidizing agents:
Hazardous decomposition products:
Hazardous decomposition products formed under fire conditions.
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas.
Disposal considerations:
Waste treatment methods:
Product:
Offer surplus and non-recyclable solutions to a licensed disposal company.
Contact a licensed professional waste disposal service to dispose of this material.
Contaminated packaging:
Dispose of as unused product
