Dimethyl Sulfate (DMS)
1. Basic Identification
IUPAC Name: Dimethyl sulfate
Synonyms: Methyl sulfate, Sulfuric acid dimethyl ester, DMS
EINECS No.: 203-400-3
MDL No.: MFCD00008461
Molecular Formula: \(\boldsymbol{C_2H_6O_4S}\)
Molecular Weight: 126.13
SMILES: COS(=O)(=O)OC
UN Number: UN 1595
HS Code: 2920909090
Hazard Classification: Class 6.1 Highly Toxic Substance + Class 8 Corrosive Substance, Packing Group I
Chemical Category: Strong methylating agent, fine chemical intermediate for dyes, pharmaceuticals, pesticides
2. Physical & Chemical Properties
Appearance
Colorless oily transparent liquid, faint onion-like irritating odor; fumes slightly in humid air, slowly hydrolyzes releasing sulfuric acid and methanol.
Physical Constant Table
| Parameter | Standard Value | Remarks |
| Melting Point | -32 ℃ | Liquid under normal storage temperature |
| Boiling Point | 188 ℃ (decomposes) | Decomposes at boiling point, cannot be distilled at atmospheric pressure |
| Density (20 ℃) | 1.332–1.335 g/mL | Heavier than water, sinks rapidly |
| Refractive Index \(n_{20/D}\) | 1.387–1.389 | Purity detection index |
| Closed Cup Flash Point | 83 ℃ | Low flammability risk |
| Vapor Pressure (20 ℃) | 0.4 mmHg | Vapor highly toxic to respiratory tract |
| Water Behavior | Slow hydrolysis in cold water, rapid exothermic hydrolysis under alkaline heating: \(\boldsymbol{(CH_3)_2SO_4 + 2H_2O = H_2SO_4 + 2CH_3OH}\) |
|
| Organic Miscibility | Miscible with ethanol, acetone, benzene, toluene, chloroform; reacts violently with amines, strong alkalis |
|
Core Chemical Characteristics
- Powerful electrophilic methylating reagent
Methylates phenols, amines, thiols, carboxylic acid salts under mild neutral/weak alkaline conditions; far higher activity than methyl chloride, core building block for nitrogen/oxygen methylated intermediates. - Hydrolysis instability
Long-term contact with moisture gradually loses activity, generates corrosive sulfuric acid; must be sealed and moisture-proof stored. - Corrosive property
Liquid and hydrolysis products erode skin, mucous membranes and metal equipment. - Incompatible hazardous materials: Sodium hydroxide, ammonia, primary/secondary amines, strong oxidants, water, edible raw materials
3. Export Industrial Quality Specifications
Premium Methylation Synthetic Grade ≥99.0% (Mainstream Export)
| Test Item | Standard Spec | Test Method |
| Dimethyl Sulfate Main Content | ≥99.0 wt% | GC / Potentiometric titration |
| Free Sulfuric Acid | ≤0.10 % | Acid-base titration |
| Methanol Residual | ≤0.05 % | GC |
| Moisture Content | ≤0.05 % | Karl Fischer Titration |
| Color (APHA) | ≤30 | Platinum-Cobalt Colorimetry |
| Distillation decomposition residue | ≤0.10 % | Gravimetry |
| Appearance | Colorless clear oily liquid without suspended precipitate | Visual Inspection |
Low-Acid Pharma Special Grade
Free sulfuric acid ≤0.03%, dedicated for high-purity pharmaceutical intermediate methylation.
4. Main Industrial Applications
4.1 Dye Industry (Largest Consumption)
- Methylation raw material for cationic dyes, basic dyes, reactive dyes; produces N-methyl aromatic amine dye intermediates to improve dye solubility and color brightness.
- Synthesis of methyl-substituted azo pigment couplers, enhancing light fastness of textiles.
4.2 Pharmaceutical Fine Chemicals
- Methylation reagent for antihistamines, antibiotics, cardiovascular APIs; selective methylation of phenolic hydroxyl and amino groups.
- Raw material for vitamin series, quaternary ammonium salt drug intermediates.
4.3 Pesticide Industry
- Building block for herbicides, fungicides and insecticides; constructs methyl heterocyclic active skeletons with high biological activity.
- Synthesis of plant growth regulator methyl ammonium salt derivatives.
4.4 Other Fields
- Analytical chemical methylating derivatization reagent for chromatographic detection.
- Catalyst auxiliary for ion exchange resin modification.
5. Toxicology, Health Hazards & First Aid
Toxicity Profile
- Acute Oral LD50 (Rat): ~205 mg/kg (Class 6.1 highly toxic)
- Dermal hazard: Rapidly absorbed through intact skin; cumulative systemic toxicity, severe chemical corrosion, blisters and tissue necrosis.
- Inhalation hazard: Trace vapor causes irreversible damage to nasopharynx, trachea and lungs; high concentration induces fatal pulmonary edema, suspected carcinogen.
- Eye hazard: Liquid splashing causes severe corneal dissolution, permanent blindness risk.
- Environmental hazard: Strongly acidic hydrolysis wastewater, highly toxic to all aquatic organisms, persistent pollution.
Typical Chronic & Acute Poisoning Symptoms
Inhalation: Throat burning, continuous cough, hemoptysis, dyspnea; skin contact: erythema, blisters, deep ulceration; systemic poisoning: nausea, vomiting, liver/kidney failure.
Complete First-Aid Procedures
- Inhalation: Evacuate victim to fully ventilated fresh air immediately, pure oxygen inhalation; emergency hospital treatment to prevent pulmonary edema.
- Skin Contact: Strip all contaminated clothing completely; continuously flush affected skin with large-volume cold running water for minimum 30 minutes to wash away residual liquid and hydrolysis acid.
- Eye Contact: Force open upper/lower eyelids, irrigate eyes with abundant flowing cold water uninterrupted for ≥30 minutes; mandatory emergency ophthalmic rescue.
- Oral Intake: DO NOT induce vomiting; drink large amounts of milk or pure water for dilution, rush to hospital for digestive tract mucosa protection and detoxification therapy.
6. Storage, Handling & Incompatibility Rules
Mandatory Storage Conditions
- Warehouse classification: Special Class6.1 highly toxic + Class8 corrosive dual-hazard liquid warehouse, completely isolated from water sources, alkalis, amines, food raw materials.
- Temperature control: Ambient storage ≤25 ℃, cool dry warehouse, strict dehumidification, relative humidity below 40%.
- Sealing requirement: 200L anti-corrosion lined carbon steel drum with double PTFE sealing gaskets, fully airtight sealed; warehouse equipped with toxic acid gas leakage alarm.
- Static control: All transfer pipelines fully grounded; only non-sparking copper tools allowed for feeding and sampling.
- Shelf life: 12 months under intact airtight packaging.
Strictly Separated Incompatible Materials
Caustic soda, ammonia, methylamine, ethylamine, tap water, hydrogen peroxide, edible chemicals.
Safe Operation Specifications
- Operators wear fully enclosed gas-proof respirator, heavy-duty acid-resistant full-body protective suit, full-face impact safety goggles, thick fluororubber anti-corrosion gloves.
- All feeding, transfer and sampling operations under fully sealed negative pressure fume hood; open flames and static sparks completely prohibited within 15-meter radius.
- Small leakage: Cover liquid with dry inert sand, isolate all water sources, collect waste into sealed high-toxicity corrosive hazardous waste metal barrels; strictly avoid water flushing leakage.
- Large leakage: Evacuate all personnel to upwind safe zone, build sand retaining dikes to contain liquid, block all rainwater and sewage pipelines to prevent massive hydrolysis toxic acid mist diffusion.
7. Export Packaging & Global Transportation Regulations
Standard Export Packaging Modes
- Industrial methylation grade: 200L anti-corrosion plastic lined seamless carbon steel drum
- Small batch pharma grade: 25L thick-wall plastic-lined iron drum
- Lab reagent package: 1L / 5L brown glass bottle with shockproof carton outer packaging
UN Transport Compliance Rules
UN 1595, Class6.1 Highly Toxic Substance + Class8 Corrosive Substance, Packing Group I
- Road transport: Special high-toxicity corrosive dual-hazard dangerous goods vehicles, full explosion-proof electrical components, leakage collection trays, dual dry powder & CO₂ fire extinguishers.
- Ocean shipment: IMDG dual hazard labels (Toxic + Corrosive + Marine Pollutant), single-layer stacking only, strictly segregated from food, alcohol, water-containing cargo holds.
- Loading ban: Mixed loading with water-based goods, alkaline chemicals, edible products, metal powders is completely forbidden.
Full Export Document Package
- Batch Certificate of Analysis (COA)
- GHS-compliant MSDS / SDS
- Technical Data Sheet (TDS)
- Marine Dangerous Goods High-Risk Declaration
- REACH Registration Compliance File
- Highly toxic chemical operation compliance certificate
8. GHS Global Hazard Label Statements
Signal Word: Danger
Hazard Statements:
H300 Fatal if swallowed
H310 Fatal in contact with skin
H314 Causes severe skin burns and eye damage
H330 Fatal if inhaled
H341 Suspected of causing genetic defects
H350 May cause cancer
H373 May cause damage to organs through prolonged or repeated exposure
H400 Very toxic to aquatic life
H410 Very toxic to aquatic life with long lasting effects
Precautionary Statements:
P261 Avoid breathing toxic corrosive vapor/mist
P280 Wear gas-proof respirator, full acid-resistant protective suit, gloves and eye/face protection
P301+P310 IF SWALLOWED: Call poison center / emergency doctor immediately
P305+P351+P338 IF IN EYES: Rinse continuously with plenty of cold water for at least 30 minutes and seek emergency ophthalmic treatment at once
P403+P235 Store in cool, dry, airtight high-toxic corrosive warehouse, completely isolated from moisture
P501 Dispose of waste liquid as highly toxic halogen-free corrosive hazardous waste in accordance with local environmental protection laws
9. Fire Emergency Disposal Plan
Approved Fire Extinguishing Agents
- Primary: Dry chemical powder, carbon dioxide (CO₂), dry sand
Forbidden Agents
Water, water-based foam, water mist (contact triggers violent hydrolysis, releases massive toxic sulfuric acid mist, splashing expands hazard range infinitely)
Fire Site Operation Steps
- Full evacuation of all personnel to upwind safe zone ≥500 meters, cut all water supply pipelines near fire area.
- Cool surrounding sealed storage drums with dry powder isolation, strictly prevent any water from contacting dimethyl sulfate liquid.
- Collect all residual liquid and solid waste after fire, deliver to professional high-toxicity hazardous waste incineration plant for harmless treatment; rainwater washing waste into soil, rivers and sewers is strictly prohibited.
10. Printable Export COA Template
CERTIFICATE OF ANALYSIS
Product Name: Dimethyl Sulfate (DMS)
CAS No.: 107-34-6
Grade: Export Dye & Pharmaceutical Methylation Industrial Grade
Batch No.: ____________
Net Weight: 200kg/drum
Manufacture Date: ____________
| Test Item | Standard Spec | Test Result | Test Method |
| Dimethyl Sulfate Purity | ≥99.0 % |
| GC Gas Chromatography |
| Free Sulfuric Acid | ≤0.10 % |
| Acid-Base Titration |
| Methanol Residual | ≤0.05 % |
| GC |
| Moisture Content | ≤0.05 % |
| Karl Fischer Titration |
| Color (APHA) | ≤30 |
| Platinum-Cobalt Colorimetry |
| Thermal Decomposition Residue | ≤0.10 % | Gravimetry |
|
| Appearance | Colorless clear oily liquid without turbidity or sediment | Visual Inspection |
|
Conclusion: This batch complies with export industrial standard of Dimethyl Sulfate.
Inspector Signature: ____________
Issuance Date: ____________
11. E-commerce Listing Copy (Alibaba / Echemi Direct Use)
Product Title
Dimethyl Sulfate DMS CAS 107-34-6 99% Colorless Toxic Corrosive Oily Liquid Strong Methylating Agent Raw Material for Cationic Dye Antihistamine API Herbicide Intermediate
Short Description
Dimethyl sulfate (C₂H₆O₄S, CAS 107-34-6) high-purity highly toxic corrosive oily liquid, powerful industrial methylating reagent. Core intermediate for cationic textile dyes, antihistamine pharmaceutical APIs and selective herbicide synthesis. Complete UN1595 high-toxic dual-hazard dangerous goods export documents COA, MSDS and TDS for bulk drum sea shipment.
Full Description
Dimethyl sulfate (DMS) is the most widely used strong industrial methylating fine chemical, supplied as colorless oily liquid with ≥99% purity. It efficiently realizes N/O-methylation of aromatic amines and phenols under mild conditions, occupying irreplaceable core position in dye, pharmaceutical and pesticide industrial chains. It is highly toxic via inhalation and skin penetration, suspected carcinogen, and hydrolyzes to produce corrosive sulfuric acid when exposed to moisture, requiring strict full moisture-proof airtight storage and fully enclosed explosion-proof operation.
Core downstream application sectors: methylation synthesis raw material for cationic, basic and reactive textile dyes; building block for antihistamine, antibiotic and cardiovascular pharmaceutical intermediates; synthetic precursor of crop-selective herbicides and fungicides; chromatographic derivatization reagent for analytical chemistry. We supply standard industrial general grade and low-free-acid high-end pharmaceutical special grade.
Packed in 200L plastic-lined sealed anti-corrosion steel drums for full-container sea freight. Classified UN1595 dual-hazard dangerous goods (highly toxic + corrosive + marine pollutant), we provide complete IMDG high-toxicity transport, commodity inspection and REACH compliance certificates for long-term bulk supply to dye factories, pharmaceutical fine chemical plants and pesticide manufacturing enterprises.
