What Is Dichloromethane (DCM)?
A Complete Guide for Industrial Buyers
Chemical identity · Properties · Applications · Regulations · Sourcing
🔗 View DCM Product Page📋 Table of Contents
🔬 1. Chemical Identity & Key Identifiers
Dichloromethane - commonly abbreviated as DCM and also known as methylene chloride - is a halogenated organic solvent with the molecular formula CH₂Cl₂. It is the simplest chlorinated methane derivative and one of the most industrially significant chlorinated solvents in production worldwide. The compound is a colorless, volatile liquid with a mildly sweet, ether-like odor.
Below is a complete set of chemical identifiers buyers and technical teams typically require when verifying a DCM shipment or registering the substance with regulatory authorities.
| Identifier | Value | Notes |
|---|---|---|
| IUPAC Name | Dichloromethane | Official systematic name |
| Common Synonyms | Methylene chloride; Methylene dichloride; DCM | All refer to the same compound |
| CAS Number | 75-09-2 | Primary identifier for customs & regulatory filings |
| EC Number | 200-838-9 | EU EINECS / REACH identifier |
| Molecular Formula | CH₂Cl₂ | One carbon, two hydrogen, two chlorine atoms |
| Molecular Weight | 84.93 g/mol | |
| UN Number | UN 1593 | Class 6.1 (Toxic), Packing Group III |
| HS Code | 2903.12 | Dichloromethane (customs tariff classification) |
| PubChem CID | 6344 | NCBI reference |
💡 Naming tip: "Dichloromethane" and "methylene chloride" are identical substances. In US regulatory documents and older trade literature you will encounter "methylene chloride" far more frequently; in European and Chinese documents "dichloromethane" and "DCM" are the preferred forms. Always verify the CAS number 75-09-2 when cross-referencing between naming conventions.
⚗️ 2. Physical & Chemical Properties
DCM's commercial appeal rests on a combination of properties that are difficult to replicate with a single alternative solvent: high solvency for a broad range of organic compounds, low boiling point enabling easy recovery, and a non-flammable flash point profile under standard test conditions (though it does form flammable vapor-air mixtures at elevated temperatures).
| Property | Value | Significance |
|---|---|---|
| Boiling Point | 39.6 °C (103 °F) | Easy ambient-pressure distillation & recovery |
| Melting Point | −96.7 °C | Liquid over very wide temperature range |
| Density (20 °C) | 1.325 g/cm³ | Heavier than water; settles in liquid-liquid extraction |
| Vapor Pressure (20 °C) | 47 kPa (350 mmHg) | High - significant evaporative loss in open systems |
| Refractive Index (nD²⁰) | 1.4242 | Purity check reference value |
| Viscosity (20 °C) | 0.44 mPa·s | Very low - excellent wetting and penetration |
| Dipole Moment | 1.60 D | Polar molecule - solvates polar & non-polar substrates |
| Dielectric Constant | 8.93 (25 °C) | Intermediate polarity - broadens solvation range |
| Water Solubility | 20 g/L at 20 °C | Slight; forms two phases - useful for extraction |
| Kauri-Butanol Value | 136 | Very high solvency power (toluene = 105 for reference) |
| Explosive Limits (LEL/UEL) | 13 – 23 vol% in air | Flammable at high concentrations despite no flash point |
🏭 3. Principal Industrial Applications
DCM's unique combination of high solvency, low boiling point, density greater than water, and moderate polarity makes it the solvent of choice for a remarkably diverse set of industrial processes. The six application clusters below account for the majority of global DCM consumption.
DCM is historically the most effective active agent in paint-stripping formulations, capable of lifting alkyd, epoxy, polyurethane, and acrylic coatings from metal, wood, and masonry substrates. Its high KB value and rapid penetration allow dwell times far shorter than alternative strippers.
DCM is a Class 2 solvent under ICH Q3C guidelines, widely used in API synthesis, recrystallization, and extraction steps. Its low boiling point facilitates complete removal from finished drug products under mild drying conditions, minimizing thermal degradation.
DCM selectively extracts caffeine from green coffee beans and tea leaves while leaving flavor compounds largely intact. The process operates at low temperatures and the residual DCM evaporates during subsequent roasting. This is one of the oldest food-grade applications of DCM.
DCM acts as both a carrier solvent and a surface activator in contact adhesives and solvent-welding applications for PVC, polycarbonate, and acrylic sheet. It dissolves the substrate surface, enabling molecular-level fusion at the bond interface upon evaporation.
In precision manufacturing - aerospace, electronics, and medical devices - DCM removes machining oils, drawing compounds, and flux residues from metal parts. Its non-flammability (under standard conditions) offers a safety advantage over hydrocarbon-based degreasers in enclosed workshops.
DCM is the go-to extraction solvent in organic chemistry laboratories and industrial processes. Its immiscibility with water, high density, and broad organic solubility make it ideal for liquid–liquid extraction of natural products, alkaloids, fine chemicals, and agrochemical intermediates.
| Application | Key Function of DCM | Typical DCM Purity | Key Industries |
|---|---|---|---|
| Paint stripping | Coating penetrant & swelling agent | Technical grade (≥99%) | Construction, automotive, aerospace |
| Pharma synthesis | Reaction & extraction solvent | Pharma grade (≥99.9%) | API, fine chemicals |
| Decaffeination | Selective caffeine extraction | Food grade | Food & beverage processing |
| Adhesives / welding | Carrier solvent & substrate activator | Technical grade (≥99%) | Plastics fabrication, furniture |
| Metal degreasing | Oil & flux removal | Technical grade (≥99%) | Aerospace, electronics, medical |
| Chemical extraction | Liquid–liquid partitioning | Lab / technical grade | Agrochemicals, natural products |
⚠️ 4. Safety Overview & Hazard Classification
DCM is classified as a hazardous substance under GHS and requires appropriate controls whenever it is handled in occupational settings. While it is not acutely lethal at typical industrial exposures, its toxicity profile - particularly chronic inhalation effects and IARC classification as a Group 1 carcinogen - demands respect and proper engineering controls.
Harmful if inhaled (H332). Suspected carcinogen - IARC Group 1. Metabolized to CO in vivo - risk to cardiac patients. CNS depressant at high concentrations.
No flash point by standard test. However, LEL 13% / UEL 23% - combustible vapor-air mixture possible in confined or heated spaces.
Not classified as aquatic hazard. Ozone-depleting potential is negligible (ODP ≈ 0). Volatile - migrates to atmosphere; classified as a VOC in most jurisdictions.
Local exhaust ventilation; respiratory protection above OEL; butyl rubber gloves; chemical splash goggles; closed-system handling preferred.
| Jurisdiction | OEL – TWA | OEL – STEL | Authority |
|---|---|---|---|
| USA (OSHA) | 25 ppm | 125 ppm | 29 CFR 1910.1052 |
| USA (ACGIH TLV) | 50 ppm | - | ACGIH 2024 |
| European Union | 100 ppm (353 mg/m³) | 300 ppm | Directive 2017/164/EU |
| China | 200 mg/m³ | - | GBZ 2.1 |
| UK | 100 ppm | 300 ppm | EH40 WEL |
🏛️ 5. Regulatory Status & Global Restrictions
DCM faces an evolving and jurisdiction-specific regulatory landscape. Buyers importing DCM must stay current with restrictions in their destination market, as the regulatory direction has been consistently toward tighter controls - particularly for consumer and semi-professional applications.
⚠️ Critical Regulatory Update: US EPA Paint Stripping Ban
Under TSCA Section 6(a), the US EPA finalized a rule in 2019 prohibiting the manufacture, import, processing, and distribution of DCM for consumer paint-stripping uses. As of 2023, commercial and industrial use restrictions have been significantly tightened, with requirements for workplace controls, exposure monitoring, and phased compliance schedules. Importers supplying customers in the United States must ensure end-use restriction compliance.
| Region / Authority | Current Status | Key Restriction / Requirement |
|---|---|---|
| USA (EPA / TSCA) | Restricted | Consumer paint-stripping banned; commercial/industrial use requires WCPP program compliance |
| European Union (ECHA / REACH) | Restricted | SVHC candidate; Annex XVII restriction limits consumer use; professional use allowed with controls |
| China | Permitted | Industrial use permitted; subject to occupational health standards (GBZ 2.1) and hazardous chemical regulations |
| UK (post-Brexit) | Transitional | UK REACH applies; consumer paint-stripping restricted; professional use under review |
| India | Permitted | Industrial use permitted; Factories Act / MSIHC rules apply for hazardous chemicals |
| Japan | Controlled | Designated chemical substance; reporting obligations; OEL strictly enforced |
📊 6. Market Overview & Price Drivers
Global DCM demand is estimated in the range of 700,000–900,000 tonnes per year, with China being the world's largest producer and a significant net exporter. Unlike alpha-methylstyrene (a phenol co-product with supply constraints tied to a separate value chain), DCM production can be adjusted more directly in response to demand signals, as it is manufactured by the chlorination of methane or methylene chloride in dedicated plants.
🏭 DCM Production Route (Methane Chlorination)
Methane
Chlorination
Methyl chloride
DCM ✅
Chloroform
Carbon tetrachloride
Note: The chlorination reaction produces all four chlorinated methanes simultaneously. Distillation separates them; the product ratio is adjusted by controlling Cl₂/CH₄ molar ratio and residence time.
- Rising natural gas / methane feedstock costs
- Tightening US/EU regulations reducing supply options
- Stricter environmental compliance at Chinese plants
- Growing pharmaceutical demand for high-purity grades
- Large-scale Chinese overcapacity in chlorinated solvents
- Reduced demand from paint-stripping bans
- Seasonal demand softness (construction sector)
- Weak chlor-alkali margins pressing producers to sell
🌐 7. Sourcing Guidance for Global Buyers
China is the world's largest DCM exporter, supplying buyers across Southeast Asia, South Asia, the Middle East, Africa, and Latin America. For buyers new to sourcing DCM from Chinese suppliers, the checklist below covers the essential evaluation criteria.
Confirm CAS 75-09-2 on all documentation. Request the Certificate of Analysis (COA) specifying purity (≥99.9% for pharma; ≥99.0% for technical), acidity (as HCl), water content, and APHA color value. For pharmaceutical customers, ensure the supplier can provide ICH Q3C Class 2 compliant documentation.
DCM is classified as UN 1593, Class 6.1 (Toxic), PG III. Ensure your supplier provides a compliant Dangerous Goods Declaration (DGD) for sea freight (IMDG) or IATA declarations for air. Improper classification is among the most common causes of customs delay.
Standard packaging: 200 L steel drums (net ≈ 250 kg); ISO tank containers (≈ 20 MT) for bulk orders. Drums must be UN-certified for Class 6.1. Confirm MOQ - Chinese exporters typically offer 1× 20-foot container (80–100 drums) as minimum for international orders.
If your destination market is the US or EU, confirm your end-use application is not covered by existing bans or restrictions. Supplying DCM for consumer paint-stripping into the US, for example, is prohibited regardless of where the material originates.
A reliable Chinese DCM supplier should be able to provide: commercial invoice, packing list, bill of lading, COA, SDS (in destination language if required), DGD, and a certificate of origin. For EU importers, confirm REACH registration status of the exporter's Only Representative if applicable.
🏢 Why Source DCM from Sinolook Chemical?
Sinolook Chemical Co., Ltd. exports specialty chemicals to 50+ countries and provides full trade documentation support for DCM shipments. We supply both technical grade and high-purity DCM with detailed COA, SDS in multiple languages, and compliant DGD for sea freight. Our team is experienced in handling international dangerous goods shipments to Southeast Asia, the Middle East, Africa, and South America.
❓ 8. Frequently Asked Questions
Q1: Is dichloromethane the same as methylene chloride?
Yes - completely. Both names refer to the same compound: CH₂Cl₂, CAS 75-09-2. "Dichloromethane" is the IUPAC systematic name preferred in European and scientific contexts; "methylene chloride" is the historical common name widely used in US trade and regulatory documents. You will also encounter the abbreviation "DCM" in laboratory and procurement settings.
Q2: Why does DCM have no flash point but can still be flammable?
DCM does not have a flash point in the traditional closed-cup test - meaning a sustained flame cannot be supported under standard conditions. However, it does have a flammable range (LEL 13%, UEL 23%) at elevated temperatures. In practice, DCM can burn if concentrations reach these levels in a confined or heated space. This combination - no standard flash point but combustible limits - makes it unusual: safer than most organic solvents under ambient conditions, but not inherently non-flammable.
Q3: What is the difference between technical grade and pharma grade DCM?
Technical grade DCM (≥99.0–99.5% purity) is adequate for paint stripping, degreasing, adhesive formulation, and general industrial extraction. Pharma grade DCM (≥99.9%) meets the tighter specifications of ICH Q3C, with lower limits on residual impurities such as chloroform and methanol, controlled acidity, and tighter color and water specifications. Pharma grade material is significantly more expensive and requires additional documentation for API applications.
Q4: Can I import DCM into the EU for industrial use?
Yes, industrial use of DCM remains permitted in the EU, but it is subject to REACH obligations (importers above 1 tonne/year must register or appoint an Only Representative), workplace exposure limits under Directive 2017/164/EU, and sector-specific restrictions on consumer applications. If you are a non-EU entity importing, your EU-based customers become the REACH registrant unless an OR arrangement is in place.
Q5: How is DCM shipped internationally?
DCM is shipped as a Class 6.1 dangerous good (UN 1593, PG III) by sea under IMDG rules. It is typically packed in 200 L UN-certified steel drums (18–20 drums per pallet, around 80 drums per 20-foot container) or in ISO tank containers for large volumes. Air freight is possible under IATA regulations but is expensive for bulk chemical shipments. Always request a compliant Dangerous Goods Declaration from the supplier before booking the vessel.
Q6: What are the main alternatives to DCM for paint stripping?
Common DCM substitutes in paint stripping include benzyl alcohol, N-methylpyrrolidone (NMP), dibasic esters (DBE), dimethyl sulfoxide (DMSO), and proprietary blend formulations based on these. None matches DCM's combination of speed, solvency, and easy evaporation at room temperature. Most alternatives require longer dwell times, higher application temperatures, or generate more waste - which is why DCM remains in use wherever regulations permit.
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