• Alkyd and oil-based paints
• Epoxy primers and topcoats
• Polyurethane coatings
• Acrylic and latex paints
• Nitrocellulose lacquers
• Chlorinated rubber coatings
• Marine antifouling coatings

• Aerospace (aircraft maintenance, MRO)
• Automotive refinishing
• Construction & infrastructure
• Metal fabrication & rework
• Furniture restoration (wood substrates)
• Industrial equipment refurbishment

DCM's inertness to most reagents makes it the preferred medium for many reactions: Friedel-Crafts acylations, peptide coupling, Grubbs metathesis, oxidations (Swern, Dess–Martin), and reductions. Its low freezing point (−97 °C) enables cryogenic reactions common in asymmetric synthesis.

After aqueous workup, DCM is the go-to organic phase for extracting the product from the aqueous layer. Its high density ensures reliable phase separation in continuous extractors and centrifugal contactors. Partition coefficients of most APIs strongly favor the DCM phase.

DCM - often in binary mixtures with methanol, ethanol, or diethyl ether - is used for API recrystallization. The low boiling point allows gentle evaporation at controlled rates, producing consistent crystal habits and polymorphic forms without thermal degradation.

In preparative purification (silica gel column chromatography), DCM/methanol or DCM/hexane gradients resolve a wide range of pharmaceutical intermediates. DCM's UV transparency above 235 nm is essential for fraction monitoring by UV detector.

DCM extracts alkaloids, terpenes, flavonoids, and essential oils from plant biomass with high selectivity. In the pharmaceutical supply chain, DCM is used to isolate quinine from cinchona bark, caffeine from tea leaves, and various opioid precursors from poppy. In nutraceutical production, it extracts lipid-soluble vitamins and carotenoids.

In agrochemical synthesis, DCM extracts herbicide, fungicide, and insecticide intermediates from aqueous reaction mixtures. Its selectivity over water-soluble by-products and its high partition coefficients for chlorinated and aromatic compounds make it particularly effective in this sector.

PVC pipe joints, fittings, and profile assemblies are routinely bonded with DCM-based cements in plumbing, irrigation, and construction. The high solvency of DCM for PVC, combined with fast evaporation, gives short set times and high bond strength.

In sign-making, optical component assembly, and display fabrication, DCM creates transparent, nearly invisible bonds between polycarbonate and acrylic (PMMA) panels. The optical clarity of the bond is superior to most adhesive alternatives.

DCM serves as the solvent carrier in polychloroprene (neoprene) and polystyrene-based contact adhesives used in shoe manufacturing, furniture lamination, and automotive interior assembly. Its fast evaporation rate gives short open times and immediate handling strength.

DCM removes hydraulic fluids, lubricants, and sealants from aluminium alloy components, turbine blades, and precision fasteners. Its non-flammability is a significant advantage in hangar and workshop environments with strict fire safety requirements.

Flux residues from soldering and rosin from wave-soldering processes are effectively removed by DCM without attacking most board substrates. Fast evaporation leaves no residue, critical for high-frequency and high-voltage circuit reliability.

Implants, surgical instruments, and catheter components require particle- and residue-free surfaces before sterilization. DCM's ability to remove even trace hydrocarbon contamination makes it a validated cleaning agent in ISO 13485-regulated environments.

Q1: What is dichloromethane mainly used for?

DCM's four largest industrial applications are: (1) paint and coating removal in aerospace, automotive, and construction industries; (2) pharmaceutical API synthesis as a reaction solvent, extraction medium, and recrystallization solvent; (3) liquid–liquid extraction for natural products, agrochemicals, and fine chemicals; and (4) adhesives and plastic solvent welding for PVC, polycarbonate, and acrylic substrates. Food-grade decaffeination and metal degreasing are important secondary applications.

Q2: Can DCM be replaced by other solvents in pharmaceutical synthesis?

For some reactions, yes - greener alternatives like 2-MeTHF, cyclopentyl methyl ether (CPME), or ethyl acetate can substitute DCM for certain extractions and reactions. However, no single green solvent replicates DCM's combination of very low boiling point, high density, intermediate polarity, and non-flammability. Pharmaceutical manufacturers increasingly evaluate green chemistry alternatives under ICH M7 and CHEM21 solvent selection guides, but DCM remains in use where alternatives compromise yield, purity, or safety.

Q3: Is DCM used in food production - is the resulting product safe?

DCM is used in the decaffeination of coffee and tea, and is approved for this use by the FDA (residual limit: 10 ppm) and EU (2 ppm). At these residual levels, the safety risk is negligible: a cup of DCM-decaffeinated coffee contains far less than 1 µg DCM - orders of magnitude below any toxicologically significant dose. The roasting step for coffee eliminates virtually all DCM before the product reaches consumers.

Q4: What is the difference between technical grade and pharmaceutical grade DCM?

Technical grade DCM (≥99.0–99.5%) is appropriate for paint stripping, degreasing, adhesive formulation, and general industrial extraction. Pharmaceutical grade (≥99.9%) meets ICH Q3C Class 2 requirements with tighter limits on residual chloroform (≤10 ppm), methanol, acidity, water content, and non-volatile matter. Pharma grade is significantly more expensive and requires batch-specific documentation. Using technical grade in a pharmaceutical process without re-testing is not acceptable under GMP.

Q5: Does DCM attack all plastics, or only some?

DCM dissolves or swells many common thermoplastics - PVC, polycarbonate, ABS, polystyrene, and PMMA (acrylic) are particularly susceptible. This is exploited in solvent welding applications. However, DCM does not attack polyethylene (PE), polypropylene (PP), PTFE, or PVDF - which is why these materials are used for DCM-safe containers, tubing, and drum liners. Always verify chemical compatibility before selecting container materials for DCM service.

Q6: How should I specify DCM when requesting a quotation from a Chinese supplier?

A complete DCM specification inquiry should include: (1) intended end-use application (determines grade); (2) required GC purity (e.g., ≥99.5%); (3) chloroform content limit; (4) water content limit (Karl Fischer); (5) acidity limit (as HCl); (6) APHA color limit; (7) packaging preference (200 L steel drums or ISO tank); (8) destination port and Incoterm; (9) whether a full COA and SDS are required. Providing these upfront allows suppliers to quote precisely and avoids back-and-forth on specification alignment.