| HS Code | |
| Name | Dimethylformamide |
| Iupacname | N,N-Dimethylformamide |
| Casnumber | 68-12-2 |
| Ecnumber | 200-679-5 |
| Molecularformula | C3H7NO |
| Molecularweight | 73.09 g/mol |
| Appearance | Colorless liquid |
| Odor | Faint amine-like odor |
| Boilingpoint | 153 °C |
| Meltingpoint | -61 °C |
| Density | 0.944 g/cm3 at 20 °C |
| Vaporpressure | 0.36 kPa at 20 °C |
| Solubilityinwater | Miscible |
| Flashpoint | 58 °C |
| Autoignitiontemperature | 440 °C |
| Viscosity | 0.92 mPa·s at 20 °C |
| Refractiveindex | 1.4305 at 20 °C |
| Unnumber | 2265 |
As an accredited Dimethylformamide factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Dimethylformamide is supplied in 200 L steel drums with sealed bung closures, clearly labeled for safe industrial storage and transport. |
| Container Loading (20′ FCL) | Dimethylformamide loaded into a 20′ FCL container, properly sealed, secured, labeled, and documented for compliant hazardous chemical ocean shipment. |
| Shipping | Dimethylformamide is transported as UN2265, Hazard Class 3, Packing Group III flammable liquid. Ship in UN-approved packaging with correct flammable-liquid labels, shipping papers, and emergency information. Store and transport away from ignition sources in ventilated areas, using PPE because of its toxicity and skin-absorption hazards. Proper documentation and segregation are essential. |
| Storage | Store dimethylformamide in a cool, dry, well-ventilated, fire-resistant area away from heat, sparks, open flames, and direct sunlight. Keep containers tightly closed, properly labeled, and upright. Use compatible containers such as glass or steel; avoid certain plastics. Segregate from oxidizers, strong acids, bases, and halogens. Ground and bond during transfer. DMF is hygroscopic, so protect from moisture. |
| Shelf Life | Dimethylformamide typically has a shelf life of about two years when stored sealed, dry, cool, dark, and protected from moisture. |
In wet-process polyurethane synthetic leather, dimethylformamide functions as the continuous phase for one-component and two-component polyurethane resins, not merely as a viscosity reducer. The resin is dissolved to 25–35 wt% solids using propylene or high-accuracy drum mixers, producing a Brookfield dope viscosity between 8,000 mPa·s and 25,000 mPa·s at 25 °C. The dope is applied by doctor-blade or comma-roll coating onto a needlepunched nonwoven base, then passed through a coagulation bath holding a DMF-water mixture. The bath is normally maintained at 20–30 wt% DMF and 35–45 °C. Water diffuses into the cast film while DMF diffuses outward, precipitating polyurethane and generating a microporous cell structure. The exchange rate is governed by the DMF concentration gradient and bath temperature rather than by simple contact time. A bath concentration above 30 wt% slows precipitation, forms a dense surface skin, lowers water-vapour permeability, and produces a stiff hand feel. A bath concentration below 20 wt% accelerates skin formation prematurely, trapping solvent in deeper layers, creating pinholes, and reducing peel adhesion. Countercurrent wash trains at 70–80 °C reduce residual DMF before drying; recovered DMF is distilled under vacuum and returned to the mixing section, while the final rinse is controlled to below 0.5 wt% DMF to limit product odour and workplace exposure. Finished synthetic leather is evaluated for tensile strength and elongation according to ISO 3376, for finish adhesion according to ISO 11644, and for colour fastness to rubbing according to ISO 105-X12.
| Parameter | Wet-process polyurethane coagulation operating window |
|---|---|
| PU solids in DMF dope | 25–35 wt% |
| Brookfield dope viscosity at 25 °C | 8,000–25,000 mPa·s |
| Coagulation bath DMF | 20–30 wt% |
| Coagulation bath temperature | 35–45 °C |
| Final wash DMF | <0.5 wt% |
Dry-spinning of polyacrylonitrile precursor fibre in DMF starts with polymer loadings from 24 wt% to 32 wt%. At these solids, the dope exhibits non-Newtonian shear-thinning behaviour, and filtration through sintered stainless-steel cartridges with absolute ratings between 5 µm and 10 µm is required to remove gel particles before the spinneret pack. Spinneret capillaries with diameters from 150 µm to 300 µm discharge the dope into a heated inert-gas chamber, where air or nitrogen at 120–180 °C flashes DMF from the filament surface. Internal solvent diffuses toward the surface as the filament solidifies. If the chamber dew point exceeds -40 °C, water uptake into the hygroscopic DMF phase can cause pinholes and reduce filament tenacity. A dope solids level above 32 wt% raises the risk of gelation and filter plugging, while a level below 24 wt% produces thin-walled filaments with internal voids after solvent evaporation. Residual DMF before hot stretching is controlled to below 0.5 wt% because remaining solvent plasticizes the fibre and destabilizes the drawing window. Solvent-laden gas is cooled to condense DMF, then purified by vacuum distillation to remove dimethylamine and water. Tensile properties of single filaments are measured according to ASTM D3822, with tenacity and elongation tracked batch-to-batch to detect drift in drying uniformity.
DMF-water mixtures are used to modify relative volatility between butadiene and butenes during extractive distillation of mixed C4 streams. The solvent is fed to the upper tray section of a first column while the C4 mixture enters lower, and butadiene-rich solvent is withdrawn from the bottom. Butenes and lighter paraffins exit overhead. Rich solvent passes to a stripping column operated under vacuum, where butadiene is released and solvent is regenerated. Water content in the DMF solvent is maintained between 5 wt% and 15 wt%. Water raises solvent selectivity for butadiene but also increases reboiler energy demand and reduces butadiene solubility at fixed temperature. A solvent-to-feed mass ratio commonly spans 3:1 to 7:1; increasing the ratio improves butadiene recovery but concentrates trace acetylenes in the rich solvent and raises downstream hydrogenation load. Reboiler temperature is constrained because DMF degrades at elevated temperature in the presence of acidic impurities, releasing dimethylamine and carbon monoxide. Regeneration columns are typically operated below 150 °C at reduced absolute pressure to limit solvent decomposition and reboiler fouling. Solvent selectivity degrades when iron salts or oxygenated species accumulate, so a small solvent purge and neutralising additive are required to protect column metallurgy. Published data for a specific column configuration is limited, but industrial practice favours structured packing over trays in the extractive column to reduce residence time and thermal stress on the DMF-water mixture.
In solid-phase peptide synthesis, DMF is used to swell polystyrene-based and PEG-grafted resins, dissolve Fmoc-amino acids, and carry coupling reagents such as HBTU, HOBt, and DIPEA into the resin pores. The solvent must be low in water, formic acid, and dimethylamine because water reduces coupling yield and dimethylamine causes premature Fmoc removal. Supplied DMF for peptide synthesis is typically controlled to a water content below 500 ppm and a dimethylamine content below 50 ppm. Residual DMF in the final peptide is removed by precipitation, filtration, and vacuum drying, but trace solvent can remain in lyophilised product. Regulatory control follows ICH Q3C: DMF is a Class 2 solvent with a permitted daily exposure of 8.8 mg/day and a concentration limit of 880 ppm in the finished drug substance when used without further justification.
| Solvent | ICH Q3C class | Permitted daily exposure | Concentration limit |
|---|---|---|---|
| Dimethylformamide | Class 2 | 8.8 mg/day | 880 ppm |
| Dimethylacetamide | Class 2 | 10.9 mg/day | 1090 ppm |
| N-Methyl-2-pyrrolidone | Class 2 | 5.3 mg/day | 530 ppm |
Formulation of emulsifiable concentrates and some suspension concentrates uses DMF as a co-solvent for crystalline active ingredients that are insufficiently soluble in standard aromatic hydrocarbon systems, typically at 5–10 wt% of the formulation. Regulatory pressure under EU classification and global harmonisation has reduced this application where lower-toxicity co-solvents can deliver the same active loading.
When a polyamic acid intermediate is dissolved in DMF for flexible printed circuit coating, the solvent must support 15–20 wt% solids from pyromellitic dianhydride and 4,4’-oxydianiline without phase separation during slot-die or comma coating. The solution viscosity is usually maintained between 3,000 mPa·s and 10,000 mPa·s at 25 °C to control wet-film uniformity on copper foil. DMF is hygroscopic, so the coating head is enclosed and supplied with dried air or nitrogen to prevent moisture uptake. Water contamination hydrolyses polyamic acid, reduces molecular weight, and releases dimethylamine, which can destabilise the wet film before imidisation. The coated foil enters a staged oven with temperatures from 150 °C to 350 °C to drive off DMF and complete ring closure to polyimide. Residual DMF must be removed before the final cure zone; solvent trapped in the film causes blisters, pinholes, and reduced copper adhesion. Peel strength of the cured polyimide film on copper is evaluated using a 90° peel fixture at 50 mm/min, with failure mode inspection for cohesive film splitting versus adhesive failure at the copper interface.
Membrane casting from polysulfone or polyethersulfone solutions uses DMF as the primary solvent at 15–25 wt% polymer solids. The solution is cast at 150–250 µm wet thickness onto a polyester or polypropylene support and submerged in water, where DMF-water exchange creates an asymmetric pore structure. Quench temperature between 10 °C and 40 °C shifts the demixing path and changes the molecular weight cut-off of the final membrane. Residual DMF in the quench water is recovered by reverse osmosis preconcentration followed by vacuum distillation, preventing discharge into wastewater and returning solvent to the casting room.
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N,N-Dimethylformamide (DMF), CAS 68-12-2, EC 200-679-5, molecular formula C3H7NO, molecular weight 73.09 g/mol, is an aprotic dipolar solvent supplied as a clear, hygroscopic liquid with a boiling point of 153 °C at 101.3 kPa, melting point −61 °C, density 0.944 g/cm³ at 25 °C (ASTM D4052-22), dynamic viscosity 0.92 mPa·s at 25 °C (ASTM D445), flash point 58 °C closed cup (ISO 2719), autoignition temperature 445 °C, vapor pressure 0.49 kPa at 20 °C, dielectric constant 36.7, dipole moment 3.82 D, and complete water miscibility. The material is produced by catalytic carbonylation of dimethylamine followed by distillation that separates methanol, formic acid, dimethylamine, and high-boiling oligomers. Commercial model designations commonly distinguish anhydrous DMF 99.8%, low-amine DMF 99.9%, polyurethane-grade DMF with water ≤0.05%, and pharmaceutical-grade DMF with reduced endotoxin burden. Principal uses include polyacrylonitrile wet spinning, polyurethane synthetic leather impregnation and top-coat thinning, solid-phase peptide synthesis, extraction of acetylene from olefin streams, and reaction media for nucleophilic substitution and Vilsmeier–Haack formylation.
Typical commercial release limits depend on the downstream polymer system rather than on a single universal grade. The table lists common anhydrous specifications; polyurethane-grade material usually adds dimethylamine and iron constraints. For active pharmaceutical ingredient synthesis, residual solvent control is governed by ICH Q3C: DMF is a Class 2 solvent with a permitted daily exposure of 8.8 mg/day and a concentration limit of 880 ppm when no other Class 2 solvents are present.
| Property | Limit | Method |
|---|---|---|
| Assay as DMF | ≥99.80% | GC-FID, in-house method validated per ICH Q2(R1) |
| Water content | ≤0.05% | ASTM E203-24 |
| Dimethylamine | ≤0.005% | acid-base titration after distillation |
| Acidity as formic acid | ≤0.005% | ASTM D1613-17 |
| Color, APHA | ≤10 | ASTM D1209-00(2019) |
| Density at 25 °C | 0.943–0.945 g/cm³ | ASTM D4052-22 |
| Distillation range | 152–154 °C | ASTM D1078-11(2019) |
| Evaporation residue | ≤0.005% | ASTM D1353-13(2021) |
| Iron | ≤0.05 mg/kg | ICP-OES after wet digestion |
Dimethylamine and acidity limits are not bulk-purity indicators only; they control polymerization kinetics and storage stability. In polyester polyol/MDI systems diluted with DMF, dimethylamine above 0.005% neutralizes acidic catalysts and shifts the isocyanate-to-hydroxyl stoichiometry, while acidity above 0.005% as formic acid promotes ester hydrolysis in drum storage at 35 °C and produces hydroxyl number drift measurable by ASTM D4274-21. When DMF is used as an isocyanate prepolymer diluent, water above 0.05% generates carbon dioxide and increases reactor pressure. Polyurethane impregnation lines therefore pre-dry the solvent over 4A molecular sieves or by azeotropic distillation with toluene when Karl Fischer titrimetry (ASTM E203-24) exceeds 0.05%.
Solvent quality affects polyacrylonitrile dope rheology in wet-spinning lines. A spinning dope containing 18–22 wt% acrylonitrile copolymer in DMF is filtered through 25 µm absolute stainless-steel mesh and extruded through spinnerettes into an aqueous DMF coagulation bath. Residual dimethylamine in recycled DMF raises dope pH, accelerates thermal gelation, and increases pressure drop across plate-and-frame filter presses. Production data from lines operating with 45–55% recycled solvent indicate that dimethylamine in the recovered stream should be held below 0.01% to prevent filament breakage and spinneret plate fouling. Published data for this specific recycle threshold is limited, but the failure mode is consistent with base-catalyzed chain transfer during dope aging at 80 °C.
DMF solvates cations through the oxygen atom and retains a high donor number of 26.6 kcal/mol; dimethyl sulfoxide has a donor number of 29.8 kcal/mol, dimethylacetamide 27.8 kcal/mol, and N-methyl-2-pyrrolidone 27.3 kcal/mol. The dielectric constant of DMF is lower than that of dimethyl sulfoxide (36.7 versus 46.7), and the viscosity is approximately half that of dimethyl sulfoxide at 25 °C (0.92 mPa·s versus 1.99 mPa·s). These differences allow DMF to be used in high-solids polyurethane solutions where viscosity limits pumping and knife coating. Dimethyl sulfoxide can offer higher solvation power for polar ionic transition states. DMF is also a stronger hydrogen-bond acceptor than acetone and acetonitrile but weaker than dimethyl sulfoxide and N-methyl-2-pyrrolidone; its Kamlet–Taft β parameter is approximately 0.69.
In solid-phase peptide synthesis, DMF is used as the coupling and deprotection solvent because it swells polystyrene and PEG resins and dissolves Fmoc-protected amino acids at concentrations used in automated synthesizers. DMF differs from dichloromethane in its higher boiling point, lower volatility, and ability to maintain resin bed permeability during repeated cycles. Water in the DMF causes partial Fmoc deprotection failure and lowers coupling efficiency; peptide synthesis grades are therefore dried and tested to ≤0.1% water by ASTM E203-24. Unlike dimethyl sulfoxide, DMF does not freeze at 4 °C and is compatible with continuous-flow peptide synthesizers, but it reacts with strong bases such as sodium hydride and with coupling reagents that release chloride.
In acetylene recovery, DMF absorbs acetylene from cracked gas streams in packed columns operating at 20–30 °C and 0.8–1.2 MPa, then releases acetylene by flash desorption at 80–100 °C. The solvent must contain low water and dimethylamine to avoid hydrolysis of compressor seals and fouling of reboiler tubes. Compared with acetone and N-methyl-2-pyrrolidone, DMF offers a favorable acetylene solubility-to-viscosity ratio at absorber temperature, but its vapor pressure requires a downstream demister and carbon bed to maintain emission compliance.
DMF can dissolve polyvinylidene fluoride binder at 5–8 wt% solids at 50 °C, but its use as a direct replacement for N-methyl-2-pyrrolidone in lithium-ion battery electrode slurries changes drying and condensation load. DMF boils at 153 °C versus 202 °C for N-methyl-2-pyrrolidone, and its vapor pressure at 20 °C is 0.49 kPa versus approximately 0.04 kPa for N-methyl-2-pyrrolidone. Slot-die coating lines designed for N-methyl-2-pyrrolidone recovery require condenser capacity upgrades when DMF is substituted, and the lower solution viscosity may alter coated-web thickness control. The lower boiling point permits drying at 110–130 °C in ovens with lower energy input than systems that commonly operate above 150 °C. DMF and N-methyl-2-pyrrolidone differ in occupational exposure limits and CLP classification text; both are Class 2 residual solvents, with DMF PDE 8.8 mg/day and N-methyl-2-pyrrolidone PDE 5.3 mg/day.
Thermal degradation is accelerated by strong bases above 50 °C. In the presence of sodium hydride or potassium tert-butoxide, DMF can decompose exothermically to dimethylamine and carbon monoxide; lithium aluminum hydride and acid chlorides also require controlled addition. The solvent hydrolyzes in acidic or alkaline aqueous media to formic acid and dimethylamine, with the hydrolysis rate increasing sharply above 60 °C. Solvent recovery systems that distill DMF at atmospheric pressure must maintain pot temperature below 160 °C and avoid long residence times to limit dimethylamine formation.
Recovered DMF from polyacrylonitrile spinning is separated from water by rectification at 10–20 kPa using a column with 15–20 theoretical plates and a reflux ratio of 0.5–1.0. The overhead water cut contains dimethylamine and formic acid; the base distillate DMF is polished through activated carbon to remove color bodies and metal ions. Loss rates in an operating line are commonly 1–3% of total solvent inventory per shift, with condenser fouling caused by polymer fines being the main bottleneck. This recycling step determines the economic boundary between DMF and dimethylacetamide in acrylic fiber manufacture because dimethylacetamide recovery requires higher reboiler temperatures and more hydrolysis-resistant materials.
DMF, dimethylacetamide, N-methyl-2-pyrrolidone, and dimethyl sulfoxide are all dipolar aprotic solvents, but their thermal, toxicological, and solvation profiles differ sufficiently to affect equipment design and final residual solvent control. The table below lists comparative physical and toxicological values used in process selection.
| Property | DMF | Dimethylacetamide | N-Methyl-2-pyrrolidone | Dimethyl Sulfoxide |
|---|---|---|---|---|
| Boiling point at 101.3 kPa | 153 °C | 165 °C | 202 °C | 189 °C |
| Vapor pressure at 20 °C | 0.49 kPa | 0.33 kPa | 0.04 kPa | 0.06 kPa |
| Dielectric constant at 25 °C | 36.7 | 37.8 | 32.2 | 46.7 |
| Dipole moment | 3.82 D | 3.72 D | 4.09 D | 3.96 D |
| Dynamic viscosity at 25 °C | 0.92 mPa·s | 1.02 mPa·s | 1.65 mPa·s | 1.99 mPa·s |
| ICH Q3C class / PDE | Class 2 / 8.8 mg/day | Class 2 / 10.9 mg/day | Class 2 / 5.3 mg/day | Class 3 / 50 mg/day |
DMF has a lower boiling point and higher vapor pressure than dimethylacetamide and N-methyl-2-pyrrolidone, which reduces drying energy but increases condenser and carbon-bed load. Dimethylacetamide is often selected for polyimide film casting because its slightly higher donor number and different amide hydrolysis products affect polymer chain alignment, while DMF remains common in polyurethane and acrylic fiber processes. Dimethyl sulfoxide has the highest dielectric constant and does not carry the same reprotoxic classification, but its higher freezing point (18.5 °C versus DMF −61 °C) complicates outdoor tank storage in cold climates.
Engineering controls for DMF handling include closed-loop transfer from ISO tank containers with vapor recovery, nitrogen blanketing at 98–101 kPa pressure, and local exhaust ventilation at drumming stations. Personnel exposure is assessed by air sampling and urine N-methylformamide biomonitoring; biological monitoring guidance values vary by jurisdiction, with ACGIH recommending a BEI of 30 mg/L for N-methylformamide in urine at end of shift, and the European Commission setting a biological limit value of 15 mg/L in some jurisdictions. DMF is incompatible with strong oxidizers, acid chlorides, sodium hydride, lithium aluminum hydride, and carbon tetrachloride under certain conditions. Storage tanks should be fabricated from carbon steel or stainless steel with a desiccant vent or nitrogen blanket to prevent water uptake above 0.05% in humid air at relative humidity above 60%.
