Commercial N,N-dimethylformamide (DMF, CAS 68-12-2) is a clear, hygroscopic, water-miscible polar aprotic solvent with molecular weight 73.09 g/mol, boiling point 153 °C at 101.3 kPa, and density 0.944 g/cm³ at 20 °C by ASTM D4052. The solvent has a closed-cup flash point near 58 °C by ASTM D93, a lower explosive limit of 2.2 vol%, and an autoignition temperature of approximately 445 °C. Storage in mild steel or stainless steel under dry nitrogen is standard; copper and aluminium contact is avoided because decomposition to dimethylamine and carbon monoxide is accelerated at elevated temperature. Technical DMF is routinely specified with minimum assay 99.5%, maximum water 0.05%, acidity as formic acid 0.003%, and APHA colour 10. Higher-purity pharmaceutical, peptide-synthesis, and dehydration-grade lots are qualified against the methods summarised below.

What Moisture Limits Protect DMF in Organometallic and Peptide Coupling Work?

Water in DMF competes with the substrate during carbodiimide-mediated coupling and can hydrolyse uronium reagents such as HATU and HBTU, reducing coupling efficiency in solid-phase peptide synthesis. For Fmoc-based synthesis, dimethylamine formed by DMF hydrolysis is particularly detrimental because it prematurely removes the Fmoc group and generates truncated sequences. Anhydrous DMF used in this route is therefore dried over activated 3 Å molecular sieves to water below 50 ppm, followed by filtration to remove sieve fines. Batch-to-batch variability on production lines is observed when drum headspace moisture is not excluded during solvent transfer, because the solvent rapidly absorbs atmospheric water at relative humidity above 30%. Compendial DMF referenced to USP-NF General Chapter <467> and ICH Q3C is treated as a Class 2 residual solvent with permitted daily exposure 8.8 mg/day and concentration limit 880 ppm when DMF remains in an active pharmaceutical ingredient after drying. Acidity as formic acid becomes a secondary specification because acid-catalysed hydrolysis generates dimethylamine; a maximum of 0.002% for anhydrous material is commonly applied. In organometallic chemistry, DMF supports lithium amide bases and transition-metal-catalysed cross-coupling only when free water is maintained below 100 ppm, otherwise protonation of carbanions and catalyst deactivation occur. Published data for enzyme-catalysed coupling in neat DMF is limited, and the solvent is normally selected after compatibility screening with the protected resin, base, and activator system.

On continuous dry-spinning lines for polyacrylonitrile, DMF is circulated as the coagulation-stable solvent for dope solid contents between 20% and 30% by mass. The solvent is recovered from water-extraction baths by fractional distillation and returned to the dope mixing vessel under vacuum. Dope filtration at 10 µm nominal is maintained before spinnerets to limit gel slug defects, and water ingress above 0.5% by mass is controlled because PAN solubility drops sharply. Spinning-cell temperatures are typically operated at 120–180 °C, with solvent-laden air passed through carbon adsorption or water scrubbers to reduce stack emissions below local permit thresholds. Production-scale extruders for PAN dope are jacketed and use positive-displacement metering pumps; batch-to-batch viscosity drift is associated with incomplete DMF recovery from the coagulation train, which raises residual solids and increases pressure drop across spinneret packs. Recovered solvent is dehydrated to below 0.1% water before reuse and is monitored for pH and acid degradation products because oxidation generates formic acid and dimethylamine, which alter polymer dissolution, gelation, and filament tensile properties.

When DMF Is Selected for Polyurethane Resin Dilution Under REACH Restrictions

DMF functions as a strong solvent for high-molecular-weight polyurethane resins in wet-process synthetic leather and coating lines because it dissolves the polymer and remains miscible with water in coagulation baths. In the European Union, placing DMF on the market as a substance or in mixtures at concentrations equal to or greater than 0.3% is restricted under REACH Annex XVII Entry 76, unless the downstream user operates under derived no-effect level conditions, worker training, and exposure monitoring requirements. DMF is classified under CLP as Repr. 1B H360D, Acute Tox. 4 H312/H332, and Eye Irrit. 2 H319. Typical coagulating lines maintain water/DMF baths at 20–40 °C; polymer precipitation rate is controlled by bath composition, temperature, and residence time in the coagulation tank. Residual solvent in flexible polyurethane products is driven off in multi-chamber drying ovens and measured by headspace gas chromatography against maximum permitted concentrations in EU product standards and brand restricted substance lists. Published data for specific oven exhaust configurations is limited, so emissions abatement must be verified on site. Glove selection uses laminated film or butyl rubber tested to EN ISO 374; natural rubber and neoprene permeability at 23 °C can exceed breakthrough within minutes, making DMF unsuitable for operations without engineered skin protection. Aluminium transfer lines or unlined copper fittings are not recommended at temperatures above 60 °C.

DMF is also used as a polar aprotic reaction medium in the synthesis of active pharmaceutical intermediates and crop-protection molecules where high dielectric strength is required for nucleophilic displacement. In production-scale batches, solvent loading can exceed 10 m³ per reactor, and thermal stability at reaction temperature is monitored by gas chromatography for dimethylamine and formic acid accumulation. The miscibility of DMF with water permits quench and extraction but also creates wastewater treatment demands; distillation recovery after water washing is standard for closed-loop plants. Because DMF is a Class 2 residual solvent with a low odour threshold, tank vent carbon adsorption and vapour return lines are specified for bulk unloading. DMF also appears in laboratory formulations for sample dissolution, membrane preparation, and electrospinning; in these smaller-scale uses, the same water and acidity specifications apply, though published data for custom electrospinning formulations is limited.

Request a DMF Quotation: Volume, Grade and Destination Form

A procurement enquiry for N,N-dimethylformamide should be structured under the request format Request a DMF Quotation: Volume, Grade and Destination Form. Delivered volume is stated in metric tons or litres at 20 °C, and the grade should specify assay, water, acidity, residual dimethylamine, and colour against ASTM D4052, ASTM D1364, ASTM D1613, and ASTM D1209. Destination form determines packaging and logistics: 200 L epoxy-phenolic lined steel drums, 1000 L UN-approved IBCs, or dedicated stainless steel ISO tank containers with nitrogen padding and relief sizing. For international movement, UN 2265 and IMO Class 3 apply; several import jurisdictions require certificate of analysis translation and destination storage temperature below 40 °C. Bulk shipments above 20 metric tons are usually arranged in dedicated stainless steel ISO tanks fitted with top and bottom outlets; the carrier should confirm vapour tightness, earthing, and pump compatibility with the maximum viscosity at 0 °C. The requested grade should be matched to the end-use because dehydration-grade material is not interchangeable with polyurethane resin grade when low amine and low water specifications are not declared.