Dimethylformamide
Properties
| State | Liquid |
| Color | Colorless |
| Solubility | Miscible with water and most organic solvents |
| Melting Point | -61°C |
| Boiling Point | 153°C |
About Dimethylformamide
DMF is the polar aprotic solvent that defined a generation of synthesis. The amide carbonyl gives it a dielectric constant of 36.7 and a dipole moment of 3.86 D, which means it dissolves salts of nucleophiles like KCN, NaN3, and LiBr at high concentration without hydrogen-bonding to the anions. That free anion problem is exactly what you want for SN2: a Finkelstein reaction (RCl + NaI → RI + NaCl) runs orders of magnitude faster in DMF than in acetone, and the cesium-fluoride-mediated displacements that make so many fluorinated APIs are unworkable in protic solvent. DMF is also the medium of choice for amide-coupling chemistry — HATU, HBTU, and PyBOP all dissolve and activate carboxylic acids most cleanly in DMF, which is why solid-phase peptide synthesis runs in DMF (with diisopropylethylamine and Fmoc deprotection in 20% piperidine in DMF). The other major synthetic role is as a formylating agent: DMF activated by phosphoryl chloride forms the Vilsmeier reagent (a chloroiminium ion), which performs electrophilic aromatic formylation on electron-rich arenes and heterocycles like pyrroles, indoles, and activated phenols. Industrially DMF is the spinning solvent for polyacrylonitrile fibers (Orlon, acrylic) and the wet-processing solvent for polyurethane synthetic leather production — shoe and bag manufacturing in Asia is a major DMF demand center. The catch is reproductive toxicity. DMF is a Category 1B reprotoxin, hepatotoxic on chronic exposure, and readily absorbed through skin. The EU REACH Authorization process restricted its use in 2021, and pharmaceutical manufacturers are increasingly switching to greener replacements like Cyrene, NBP, or 2-MeTHF where the chemistry permits.
Where you'll encounter it
If you have ever loaded an Fmoc-amino-acid coupling onto a solid-phase peptide synthesizer, the wash and reaction solvent flowing through that column is DMF, end to end. The same bottle on the same shelf gets used for SNAr displacements on activated aryl halides, for Suzuki and Stille couplings where the catalyst likes a polar coordinating solvent, and for any reaction involving a salt-form nucleophile that needs to actually dissolve. Anyone who has spent time in a process group has also seen the new green-chemistry solvent guides flagging DMF for replacement.
Common Uses
- Polar aprotic reaction solvent for SN2 displacements, SNAr, and amide-bond coupling reactions
- Vilsmeier-Haack formylation reagent with POCl3 for installing CHO groups on electron-rich aromatics and heterocycles
- Solid-phase peptide synthesis wash and coupling solvent for Fmoc and Boc strategies on Wang and Rink resins
- Wet-process spinning solvent for polyacrylonitrile fibers (acrylic, modacrylic) in textile manufacturing
- Coating solvent for synthetic-leather polyurethane impregnation in shoe and bag production at scale
- Co-solvent in PVDF and PVF polymer processing for capacitor films and lithium-ion battery binder slurries
- Reaction solvent for Suzuki, Heck, and Stille palladium-catalyzed cross-couplings with polar substrates
- Recrystallization and slurry solvent for high-melting heterocyclic intermediates in API process chemistry
Safety Information
Reproductive toxicant Category 1B (presumed human reproductive hazard, particularly developmental toxicity). Hepatotoxic on chronic exposure — DMF metabolism by CYP2E1 produces N-methylformamide and methyl isocyanate, both of which contribute to liver injury, and chronic occupational exposure has caused documented liver enzyme elevations and steatosis. Readily absorbed through skin. ACGIH TLV is 10 ppm 8-hour TWA with a skin notation; OSHA PEL is 10 ppm with a skin designation. Biological exposure index uses urinary N-methylformamide. GHS: H226 (flammable, flash point 58 °C), H312 (harmful in skin contact), H319 (eye irritation), H332 (harmful if inhaled), H360D (may damage the unborn child). REACH Annex XIV: DMF was added to the Authorization List with a sunset date of December 2023 for most uses. Handle in a fume hood with butyl-rubber gloves (nitrile permeates within an hour), avoid skin contact at all costs, and check whether your application qualifies for a green-solvent replacement.
This safety summary is for educational reference only and may not be complete. It is not a substitute for Safety Data Sheets (SDS), medical advice, or professional chemical safety guidance. Always consult appropriate SDS and qualified professionals before handling chemicals.