High-Purity Solvents, Polyurethane (PU) and Resin

Dimethylacetamide (DMAC)

Dimethylacetamide (DMAC), identified by CAS number 127-19-5, is a highly versatile, colorless, and high-boiling polar aprotic solvent with the chemical formula $CH_3CON(CH_3)_2$. As a strategic member of the amide family, it is characterized by its exceptional thermal and chemical stability, making it an indispensable medium in both large-scale industrial manufacturing and specialized laboratory synthesis. DMAC is completely miscible with water and a vast array of organic solvents. This property, combined with its high dielectric constant, allows it to dissolve a wide variety of organic and inorganic compounds, including difficult-to-process polymers. While it shares similarities with Dimethylformamide (DMF), DMAC is often preferred in high-temperature processes due to its superior resistance to hydrolysis and higher boiling point. However, from a safety perspective, DMAC is classified as a Substance of Very High Concern (SVHC) due to reproductive toxicity, necessitating rigorous engineering controls and personal protective equipment (PPE) during handling.

Attributes

Key Features and Benefits

Exceptional Solvating Power: Capable of dissolving complex polymers such as polyacrylonitrile (PAN), polyurethanes, and polyimides that are insoluble in common solvents.
High Thermal Stability: Maintains chemical integrity at elevated temperatures, facilitating reactions that require sustained heat without solvent degradation.
Broad Miscibility: Exhibits universal solubility, mixing freely with water, alcohols, ethers, and aromatic hydrocarbons, providing flexibility in formulation.
Low Volatility: With a high boiling point ($165^circ C$), it minimizes evaporative losses in industrial closed-loop systems compared to lower-boiling alternatives.
Reaction Medium Efficiency: Acts as an effective catalyst or medium for nucleophilic substitutions and other polar reaction mechanisms.

Specifications

Technical Highlights

Molecular Weight: 87.12 g/mol.
Physical State: Clear, hygroscopic liquid with a faint ammonia-like odor.
Boiling Point: $165.1^circ C$ at 760 mmHg.
Flash Point: $66^circ C$ ($151^circ F$) (Closed Cup), classifying it as a combustible liquid (GHS Category 4).
Density: 0.937 g/cm³ at $20^circ C$.
Dielectric Constant: 37.8 (at $25^circ C$), enhancing its ability to stabilize ionic intermediates.
Vapor Pressure: 1.5 mmHg at $25^circ C$.
Safety Profile: Classified as Repr. 1B; exposure must be limited to established TWA (typically 10 ppm) to prevent systemic toxicity.

Download Technical Data Sheet (TDS)

Practical industry uses

Applications

Synthetic Fiber Production: Serves as the primary solvent for the wet-spinning and dry-spinning of Spandex (elastane) and Acrylic fibers.
Pharmaceutical Synthesis: Widely utilized as a reaction solvent and crystallization medium for antibiotics, such as cephalosporins, and various APIs.
Polymer Manufacturing: Essential in the production of high-performance polyimide films, specialized coatings, and adhesives.
Electronics Industry: Employed as a high-efficiency component in photoresist strippers and in the fabrication of flexible printed circuits.
Membrane Technology: Used in the phase-inversion process to manufacture dialysis membranes and water purification filters.
Agrochemicals: Functions as a specialized solvent for the synthesis of advanced pesticides and herbicides.