N-Methyl-2-pyrrolidone
Hygroscopic, photo -sensitive, colorless to yellowish liquid with a faint amine-like odor
Liquid
1.03 g · cm -3
-24 ° C
203 ° C
32 Pa ( 20 ° C)
Miscible with water, ethanol, acetone, diethyl ether, ethyl acetate, chloroform, benzene,
1.470 at 20 ° C.
Risk
20 ml · m -3 or 82 mg · m-3
3914 mg · kg -1 ( LD50, rat, oral)
Template: Infobox chemical / molecular formula search available
N-methyl- 2-pyrrolidone ( NMP) can be seen as lactam N- methylaminobutyric acid and thus is a γ -lactam.
Production and representation
In the synthesis of NMP is γ -butyrolactone, which has previously been produced catalytically from formaldehyde and acetylene via several intermediates, reacted with methylamine.
Properties
N -methyl-2 -pyrrolidone is a photosensitive, hygroscopic, colorless to yellowish liquid with a faint amine-like odor, which is miscible with water. The aqueous solution is alkaline. The viscosity at 25 ° C is 1.65 mPa · s, surface tension 40.7 mN / m. Under normal pressure, the compound boils at 203 ° C. The vapor pressure function is given by Antoine corresponding log10 (P) = A- ( B / ( T C)) (P in kPa, T in K) with A = 7.4, B = 2570 and C = 0 in the temperature range of 361 K to 477 K.
The density of NMP decreases with increasing temperature. The function of the temperature dependence can with a quadratic equation by ρ = α β · γ · T T2 with α = 1.26202, β = -7.0026 · 10-4 and γ = -2.8771 · 10-7 described be.
NMP has a refractive index of commercially available glass is very close ( 1.4700 ). Consequently disappear glass rods and glass pipettes optically almost in this chemical.
NMP is above the flash point of 86 ° C flammable vapor - air mixtures. The explosion range is between 1.3 vol - % ( 45 g/m3) as the lower explosive limit ( LEL) and 9.5 vol - % ( 392 g/m3 ) and upper explosive limit (UEL ). The ignition temperature is 265 ° C. The fabric falls within the temperature class T3. NMP decomposes at a temperature above 300 ° C, carbon monoxide, carbon dioxide, nitrous gases and hydrogen cyanide. The conductivity is 2.10 -6 S / m at 25 ° C.
On treatment with hydrogen chloride, a solid hydrochloride can be obtained, which melts at 86-88 ° C.
Use
NMP is often used because of its heat stability and high polarity solvent. It is suitable as a solvent for polymers such as acrylates, epoxies, polyurethanes, polyvinyl chloride, polyimide, polyamide imide and for many organic syntheses. Other important applications include paint removal ( stripping) and the preparation of polyurethane foam (PU - foam). An important industrial application is the extraction of 1,3- butadiene from C4 hydrocarbon streams dar. It is also used for absorption of acidic components in gas scrubbing.