| HS Code | 701587 |
| Product Name | Dimethylformamide (DMF) Electronic/EL Grade |
| Chemical Name | N,N-Dimethylformamide |
| Cas Number | 68-12-2 |
| Chemical Formula | C3H7NO |
| Molecular Weight | 73.09 g/mol |
| Purity | ≥99.9% |
| Water Content | ≤100 ppm |
| Color | ≤10 APHA |
| Residue On Evaporation | ≤5 ppm |
| Boiling Point | 153°C |
| Melting Point | -61°C |
| Flash Point | 58°C (closed cup) |
| Density | 0.944 g/cm3 at 25°C |
| Refractive Index | 1.430 at 20°C |
| Dielectric Constant | 37 at 25°C |
| Solubility In Water | Miscible |
As an accredited Dimethylformamide Electronic/EL Grade factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Dimethylformamide Electronic/EL Grade, supplied in 4×4L glass bottles, nitrogen-purged with PTFE-lined caps for ultrapure integrity. |
| Container Loading (20′ FCL) | Loading 20′ FCL of Dimethylformamide Electronic/EL Grade: secure drums/IBCs, prevent contamination, handle as flammable/hazardous, ensure proper segregation and ventilation. |
| Shipping | Shipping: Transport as UN2265, N,N-dimethylformamide, Class 3, PG III. Use sealed, corrosion-resistant containers (stainless steel or fluorinated plastics) under inert gas to maintain electronic/EL grade purity. Label flammable and toxic. Provide secondary containment and ventilation. Comply with IMDG, ADR, IATA regulations. |
| Storage | Dimethylformamide Electronic/EL Grade should be stored in tightly sealed, clean containers under a dry nitrogen blanket to prevent moisture absorption and maintain ultra-high purity. Keep in a cool, well-ventilated area away from direct sunlight, heat sources, oxidizers, and acids. Use dedicated stainless steel or glass equipment to avoid contamination. |
| Shelf Life | Shelf life is typically 12 months when stored sealed under inert gas, in original container, away from light and moisture. |
For two-layer flexible copper-clad laminate production, electronic-grade dimethylformamide with water ≤0.03% and chloride ≤0.5 ppm is metered into a nitrogen-inerted jacketed reactor equipped with a double helical stirrer running at 20–40 rpm. Pyromellitic dianhydride is added to 4,4'-oxydianiline at a molar ratio of 1.00:1.01 in DMF to reach 18–22 wt% polyamic acid solids. The addition stage is held at 10–25°C using -5°C brine because the ring-opening exotherm raises local viscosity and initiates gel-particle formation if the local temperature exceeds 30°C. After 6–8 h of mixing, vacuum degassing at 50–100 mbar removes microvoids before the solution is slot-die coated onto low-profile rolled copper foil. Thermal imidization proceeds through a 130–350°C gradient oven, producing a two-layer flexible copper-clad laminate with dielectric thickness 12.5–25 µm. Peel strength is evaluated according to IPC TM-650 2.4.9, while dimensional stability is measured with IPC TM-650 2.2.4. Sodium and iron levels above 0.2 ppm in DMF can raise the dissipation factor of the cured polyimide under high-frequency conditions; therefore electronic-grade material is preferred over technical-grade DMF in this application. Solvent recovery by distillation is common, but amine by-products from slight DMF decomposition accumulate over repeated cycles and require a purge stream to maintain chloride and water limits.
DMF dissolves polyvinylidene fluoride homopolymer at 4–6 wt% in a high-shear dissolver fitted with a sawtooth impeller; tip speed is held at 15–25 m/s until the solution is clear. The binder solution then disperses 40–60 wt% aluminium oxide or boehmite powder, and the slurry is coated onto a 9–16 µm polyethylene separator substrate at 25–35 m/min. Phase inversion in a coagulation bath containing 25–35 wt% DMF at 20–40°C fixes the porous ceramic composite structure. Electronic-grade DMF with sodium ≤0.1 ppm, iron ≤0.1 ppm, and water ≤0.02% is specified because residual ions migrate into the cell during cycling and raise self-discharge. The coated substrate is dried at 60–80°C until headspace gas chromatography shows residual DMF ≤50 ppm. Adhesion is checked by cross-cut tape testing according to ISO 2409, while Gurley number is used to verify that the porous coating does not block gas transport. DMF’s closed-cup flash point of 58°C forces sealed coating heads and solvent recovery because vapor/air mixtures can form inside enclosed dryers. Published large-scale production data for DMF-based separator coating is limited compared with NMP-based systems; battery-cell qualification usually includes a specific moisture specification rather than a generic DMF assay alone.
In aluminium electrolytic capacitors rated for 400–450 V service, DMF is blended as a polar aprotic co-solvent to lower electrolyte viscosity while retaining dissociation of ammonium carboxylate solutes. A working electrolyte may contain 20–40 wt% electronic-grade DMF, 40–70 wt% ethylene glycol, and 5–15 wt% gamma-butyrolactone; exact proportions are proprietary and are adjusted until conductivity reaches 1–3 mS/cm at 25°C and the sparking voltage exceeds the rated voltage. DMF is pre-dried over molecular sieves to water ≤0.05% before blending because free water accelerates hydration of the anodic oxide film and increases leakage current. Vacuum impregnation is performed at 5–20 mbar for 30–120 s, followed by aging at 60–85°C under rated voltage to re-form the dielectric oxide. Low-temperature equivalent series resistance is tested according to IEC 60384-1; DMF improves the -40°C resistance but excessive DMF content softens the sealing rubber and reduces the flash point of the electrolyte. Published data for specific DMF-based capacitor electrolytes is limited, and capacitor manufacturers generally disclose the conductivity-temperature coefficient rather than the full solvent composition. The end-product is a radial lead-type aluminium electrolytic capacitor used in switch-mode power supplies and LED drivers.
Screen-printing stencils, slot-die lips, and needle dispensers contaminated with polyamic acid or polyimide varnish are immersed in electronic-grade DMF at 35–45°C in an ultrasonic bath operating at 40 kHz for 15–30 min. A nitrogen-assisted DMF spray at 0.5–1.0 MPa then removes softened polymer from blind holes and lip edges before the parts are flushed with semiconductor-purity isopropanol and deionized water meeting ASTM D1193 Type I resistivity 18.2 MΩ·cm at 25°C. Cleanliness is validated by extraction with an optical particle counter; components are rejected when particles larger than 0.5 µm exceed 10 particles/cm² after solvent evaporation. The process is limited to stainless steel and PTFE surfaces because DMF swells acrylics, polycarbonate, and many elastomers; EPDM seals are incompatible and must be isolated from solvent lines. Spent DMF is regenerated in a thin-film evaporator operating at 2–5 mbar with recovery typically above 90%, while distillation bottoms containing polymer solids are sent for incineration. Work exposure is maintained below 10 ppm 8-h time-weighted average through closed piping and local exhaust ventilation.
| Application | Primary standard/code | Controlled impurity or operational limit |
|---|---|---|
| Polyamic acid / flexible copper-clad laminate | IPC TM-650 2.4.9 | Water ≤0.03%; sodium ≤0.2 ppm |
| Ceramic-coated separator slurry | ISO 2409 | Water ≤0.02%; sodium ≤0.1 ppm |
| Aluminium electrolytic capacitor electrolyte | IEC 60384-1 | Water ≤0.05%; DMF 20–40 wt% |
| Polyimide-coated tooling rinse | ASTM D1193 Type I | Particles >0.5 µm below 10/cm² |
DMF is charged as a polar aprotic reaction medium for palladium-catalyzed carbon-nitrogen coupling of triarylamine hole-transport monomers; the solvent’s high dielectric constant stabilizes charged intermediates but its water level must be held below 0.03% to avoid hydrolyzing aryl halide intermediates. A pilot-scale batch charges 8–10 L DMF per kg of substrate, 1–2 mol% palladium acetate, and 2–4 mol% tri-tert-butylphosphine under nitrogen, with temperature controlled at 80–120°C for 6–12 h. Electronic-grade DMF is specified because sodium, iron, and copper each below 0.1 ppm reduce the risk of metal quenching in the final electroluminescent layer. Peroxide content must remain below 5 ppm to prevent oxidative side reactions that discolor the monomer. On completion the reaction mass is quenched into deionized water and extracted with toluene; DMF reports to the aqueous phase and is recovered by fractional distillation. Monomer purity is measured by HPLC and UV-Vis before gradient sublimation to ≥99.9%. This is typically a pilot-scale application; published data on specific reactor configurations is limited because monomer synthesis routes are proprietary.
When moisture-curing polyurethane conformal coatings are specified for printed circuit board assemblies, DMF is used as a thinning solvent at 10–30 wt% to reach a spray viscosity of 20–80 mPa·s at 25°C. Electronic-grade DMF with water ≤0.03% is required because moisture reacts with isocyanate groups, releasing carbon dioxide and creating bubbles in the cured film. Robotic selective spraying is performed with atomizing air at 0.2–0.4 MPa and needle travel speed of 200–400 mm/s; the wet coating is flash-dried for 10–15 min at 60°C to reduce solvent retention before a final cure. Dry film thickness is measured at 25–75 µm using an eddy current gauge, and dielectric withstand is tested according to IPC TM-650 2.5.7. The qualified coating system is assessed by IPC-CC-830B for conformal coating performance. DMF is used only in sealed dispensing modules with activated carbon adsorption because the solvent has a low odor threshold and an 8-h exposure limit of 10 ppm; it also attacks polycarbonate and acrylic board fixtures, so stainless steel or PTFE contact surfaces are specified. End-product is a moisture-cured polyurethane conformal coating for industrial power modules and automotive ECU boards.
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Dimethylformamide Electronic/EL Grade is a polar aprotic solvent supplied as a high-purity liquid for solvent-based wet processing in which ionic residue, fine particles, and protic contaminants must be controlled below ordinary industrial limits. The substance is identified by CAS 68-12-2, molecular formula HCON(CH3)2, and molar mass 73.09 g/mol. It is not a single mechanical model in the equipment sense; the Electronic/EL designation is a purity class that is read against the supplier certificate of analysis. The product is therefore differentiated from industrial-grade dimethylformamide by lower water, acidity, chloride, sulfate, and trace-metal ceilings, not by a change in chemical identity.
The liquid has a density near 0.9445 g/cm³ at 20°C as measured by ASTM D4052-22, a normal boiling point of 153°C at 101.3 kPa, and a closed-cup flash point near 58°C. Vapor pressure at 20°C is approximately 0.36 kPa, placing it between the faster evaporating ketone/acetate solvents and the slower evaporating N-methyl-2-pyrrolidone. Dynamic viscosity at 25°C is approximately 0.80 mPa·s, and the dielectric constant is 36.71. Because dimethylformamide is hygroscopic, the as-filled water value can rise during open handling in humid air; exposure should be minimized when relative humidity exceeds 60%.
Typical acceptance windows for an Electronic/EL-grade batch are shown below. These values are supplier-specific and should be compared with the certificate of analysis for the actual lot. The specification does not replace process validation for the intended electronic or polymer application.
| Parameter | Typical acceptance window | Analytical procedure |
|---|---|---|
| Assay, solvent basis | ≥ 99.9% | GC-FID internal normalization |
| Water | ≤ 50 mg/kg | Coulometric Karl Fischer titration, ASTM E203-16 |
| Acidity as formic acid | ≤ 20 mg/kg | Non-aqueous acid-base titration |
| Chloride | ≤ 0.2 mg/kg | Ion chromatography with conductivity detection |
| Sulfate | ≤ 0.3 mg/kg | Ion chromatography |
| Non-volatile residue | ≤ 5 mg/kg | ASTM D1353-13(2021) |
| Trace metals by ICP-MS | Na, K, Fe ≤ 50 µg/kg each; Cr, Ni, Cu ≤ 10 µg/kg each | EN ISO 17294-2:2016 after evaporation and acid digestion |
| Particles ≥ 0.5 µm | ≤ 5 particles/mL | Laser particle counting |
Because trace-metal values in the single-digit to sub-50 µg/kg range are close to the detection limits of routine analytical equipment, sampling container cleanliness and acid digestion background introduce measurable error. Lot release should use pre-cleaned high-density polyethylene or perfluoroalkoxy sample bottles and method blanks for each batch. Published data for this specific configuration is limited; the supplier method validation should be reviewed before changing analytical conditions.
In lithium-ion battery electrode manufacture, the Electronic/EL-grade product is evaluated as a dispersing medium for polyvinylidene fluoride binder and as a viscosity-controlling diluent for cathode or anode slurries. It is not functionally identical to N-methyl-2-pyrrolidone on every production line. Two process differences are dominant. First, dimethylformamide has a lower boiling point and higher vapor pressure, so dryer settings and solvent recovery condensers must be adjusted; a dryer zone set for N-methyl-2-pyrrolidone at 120–140°C may require a lower setpoint for dimethylformamide to avoid surface skinning of the wet film. Second, dimethylformamide is more hygroscopic; if solvent water exceeds 100 mg/kg, polyvinylidene fluoride dissolution can be retarded, and high-molecular-weight binder may associate, producing viscosity drift during holding.
In a production-scale planetary mixer with vacuum de-aeration, polyvinylidene fluoride is commonly pre-dissolved in dimethylformamide Electronic/EL Grade at 60–80°C with tip speeds in the 5–15 m/s range. The binder solution is then added to a pre-blended dry mixture of active material and conductive carbon. Slurry solids loading is formulation-dependent; nickel-manganese-cobalt cathodes are often compounded at 55–65 wt% total solids, while lithium iron phosphate formulations may be processed at lower solids. Control is normally based on Brookfield RVDV torque readings at 25°C and 10 rpm; viscosity targets on industrial electrode coating lines frequently fall between 3,000 and 25,000 mPa·s, but published data for this specific configuration is limited. The upper bound is set by transfer-pump and slot-die levelling behavior; the lower bound is set by sedimentation of dense active particles.
At the coating stage, the slot-die gap and line speed control wet-film thickness. For dimethylformamide-based slurries, the higher vapor pressure means exhaust air from the dryer carries a higher solvent load than an N-methyl-2-pyrrolidone-based line at the same wet-film thickness. Condensation recovery on chilled surfaces must maintain surface temperatures below the dew point of the solvent/air stream; otherwise solvent passes to the thermal oxidizer. Recovery columns using structured packing and vacuum stripping are used where dimethylformamide is recycled. If recovery returns amine-enriched dimethylformamide to the mixing vessel, slurry pH can drift upward and binder adhesion can be affected. Recovered solvent should therefore be monitored for total amine value and acidity, not only water, before reuse.
Thermal stability also limits dryer temperature. Dimethylformamide hydrolyzes slowly when heated in the presence of water and acid, forming formic acid and dimethylamine. The amine by-product can shift slurry pH and interfere with binder adhesion. When recovered-solvent amine concentration increases above the incoming Electronic/EL-grade certificate-of-analysis level, the recovered stream is typically diverted from the mixing area until redistillation restores specification.
Relative to industrial and reagent-grade dimethylformamide, the Electronic/EL-grade product differs primarily in the control of non-volatile residue and individual metal ions. Industrial-grade dimethylformamide may contain 10–100 mg/kg total non-volatile residue, enough to leave carbonaceous or metal-oxide deposits on electronic interfaces. EL-grade material limits residue after evaporation to ≤ 5 mg/kg. The lower residue reduces film contamination in microelectronic cleaning and in polymer film casting. Metal ions such as sodium, potassium, iron, and copper are controlled because mobile ions can degrade dielectric reliability, while transition metals can contribute to electrochemical side reactions or polymer degradation under thermal aging.
Comparative impurity ceilings are summarized below; the figures represent commonly accepted supplier ranges rather than a single global standard.
| Parameter | Industrial DMF | Reagent/ACS DMF | Electronic/EL-Grade DMF |
|---|---|---|---|
| Assay, GC | ≥ 99.5% | ≥ 99.8% | ≥ 99.9% |
| Water | ≤ 500 mg/kg | ≤ 200 mg/kg | ≤ 50 mg/kg |
| Acidity as formic acid | ≤ 50 mg/kg | ≤ 20 mg/kg | ≤ 20 mg/kg |
| Non-volatile residue | ≤ 20 mg/kg | ≤ 5 mg/kg | ≤ 5 mg/kg |
| Chloride | ≤ 1 mg/kg | ≤ 0.5 mg/kg | ≤ 0.2 mg/kg |
| Individual trace metals | Not uniformly specified | Not uniformly specified | Na, K, Fe ≤ 50 µg/kg; Cr, Ni, Cu ≤ 10 µg/kg |
| Particles ≥ 0.5 µm | Not specified | Not specified | ≤ 5 particles/mL |
Storage and handling boundaries are defined by the solvent’s hygroscopicity, flammability, and reactivity. The product should be stored in sealed stainless steel or high-density polyethylene containers under dry nitrogen. Stainless steel SS316L transfer lines and PTFE gaskets are common in dispensing systems. Long-term storage in carbon steel drums is not recommended when moisture and trace acid can accumulate and cause iron pickup, although carbon steel is often acceptable for dry industrial-grade dimethylformamide when moisture ingress is controlled.
Chemical incompatibility is significant with strong oxidizing agents, acid chlorides, halogenated compounds, and strong reducing agents; exothermic decomposition or gas release can occur. Contact with sodium hydride or alkali metals in the absence of a suitable diluent can be hazardous. The product should not be stored adjacent to concentrated nitric acid or perchlorates. If distillation is required, it should be performed under vacuum to limit thermal hydrolytic decomposition, and the distillate head fraction should be monitored for dimethylamine odor and amine number before reuse.
In the European regulatory context, dimethylformamide is classified as Repr. 1B and carries a skin notation. The binding occupational exposure limit under Directive (EU) 2019/1831 is 15 mg/m³ 8-hour time-weighted average and 30 mg/m³ short-term exposure limit. Engineering controls should include local exhaust ventilation at drum-off load points and enclosed transfer. The product is not formulated for consumer use.
