N -methyl-2-pyrrolidone

Structural formula
General
Surname	N -methyl-2-pyrrolidone
other names	1-methyl-2-pyrrolidone 1-methylpyrrolidin-2-one ( IUPAC ) N -methylbutyrolactam N -methyl-γ-lactam N -methyl-2-pyrrolidinone
Molecular formula	C 5 H 9 NO
Brief description	hygroscopic, photosensitive, colorless liquid with an amine-like odor
External identifiers / databases
CAS number 872-50-4 EC number 212-828-1 ECHA InfoCard 100,011,662 PubChem 13387 ChemSpider 12814 DrugBank DB12521 Wikidata Q33103
properties
Molar mass	99.13 g mol −1
Physical state	liquid
density	1.03 g cm −3 (20 ° C)
Melting point	−24 ° C
boiling point	203 ° C
Vapor pressure	0.32 h Pa (20 ° C) 0.7 hPa (30.6 ° C) 1.33 hPa (40 ° C) 2.5 hPa (50 ° C)
solubility	miscible with water, ethanol , acetone , diethyl ether , ethyl acetate , chloroform , benzene
Refractive index	1.470 (20 ° C)
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 315-319-335-360D P: 201-308 + 313-305 + 351 + 338-302 + 350
Authorization procedure under REACH	of particular concern : toxic for reproduction ( CMR )
MAK	DFG : 20 ml m −3 or 82 mg m −3 Switzerland: 20 ml m −3 or 80 mg m −3
Toxicological data	3914 mg kg −1 ( LD 50 ,  rat ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

N -Methyl-2-pyrrolidone ( NMP ) is a chemical compound . It can be seen as a lactam of N -methylaminobutyric acid and is therefore a γ-lactam .

Extraction and presentation

In the industrial synthesis of NMP, γ-butyrolactone , which was previously catalytically generated from formaldehyde and acetylene via several intermediate stages , is reacted with methylamine .

properties

Physical Properties

N -Methyl-2-pyrrolidone is a light-sensitive, hygroscopic, colorless to yellowish liquid with a weak amine-like odor, which is miscible with water. The viscosity at 25 ° C is 1.65 mPas, the surface tension 40.7 mN / m. The compound boils at 203 ° C. under normal pressure. According to Antoine, the vapor pressure function results from log ₁₀ ( 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 be calculated with a quadratic equation according to ρ = α + β · T + γ · T ² with α = 1.26202, β = −7.0026 · 10 ⁻⁴ , γ = −2.8771 · 10 ⁻⁷ and T = temperature can be described in Kelvin.

Density of NMP

Temperature in ° C	25th	32	40	60	80	100
Density in g cm −3	1.0278	1.0215	1.0144	0.9968	0.9790	0.9606

The specific heat capacity increases with temperature.

Specific heat capacity of NMP

Temperature in ° C	0	25th	50	100
Specific heat capacity in kJ kg −1 K −1	1.70	1.78	1.86	2.03

Important thermodynamic quantities are given in the following table:

Compilation of the most important thermodynamic properties

property	Type	Value [unit]	Remarks
Standard enthalpy of formation	Δ f H 0 liquid Δ f H 0 gas	−265.73 kJ mol −1 −210.85 kJ mol −1	as a liquid as a gas
Enthalpy of combustion	Δ c H 0 liquid	−2988.05 kJ mol −1	as a liquid
Critical temperature	T c	721.7 K
Critical pressure	p c	45.2 bar
Critical density	ρ c	3.22 mol·l −1
Enthalpy of fusion	Δ f H	18.1 kJ mol −1	at the melting point
Enthalpy of evaporation	Δ V H	49.5 kJ mol −1	at normal pressure boiling point

NMP has a refractive index very close to that of commercially available glass (1.4700). As a result, glass rods and glass pipettes almost disappear optically in this chemical.

Chemical properties

NMP is a very weak base. On treatment with hydrogen chloride , a solid hydrochloride can be obtained which melts at 86-88 ° C. The aqueous solution has an alkaline reaction. A 10% aqueous solution has a pH of 7.7 to 8.0. The compound is chemically very stable. The lactam ring can only be opened with strong acids and bases, resulting in 4- N -methylaminobutyric acid . NMP has only limited stability towards oxygen , with the oxidation starting at the 5-position and N- methylsuccinimide being formed via various intermediate stages . This product can be specifically made from NMP using ruthenium tetroxide as an oxidizing agent. The compound reacts with halogenating agents such as phosgene or phosphorus pentachloride to form 2-chloro-1-methylpyrrolidinium chloride, which reacts with various nucleophiles, e.g. B. amines or alkoxides can be reacted further.

NMP acts as a catalyst in the synthesis of carboxylic acid chlorides from the carboxylic acids. With strong bases such as lithium diisopropylamide , NMP can be deprotonated in the 3-position, forming an amide enolate structure that can be reacted with alkyl halides or aryl bromides.

Safety-related parameters

NMP forms flammable vapor-air mixtures above the flash point of 86 ° C. The explosion range is between 1.52% by volume (63 g / m ³ ) as the lower explosion limit (LEL) and 9.5% by volume (392 g / m ³ ) as the upper explosion limit (UEL). A correlation of the lower explosion limit with the vapor pressure function results in a lower explosion point of 79 ° C. The limit oxygen concentration at 200 ° C is 8.1 vol%. The limit gap width was determined to be 0.93 mm. This results in an assignment to explosion group IIA. The ignition temperature is 265 ° C. The substance therefore falls into temperature class T3. NMP decomposes at a temperature above 300 ° C, producing carbon monoxide , carbon dioxide , nitrous gases and hydrogen cyanide . The conductivity is 2 · 10 ⁻⁶  S / m at 25 ° C.

use

NMP is often used as a solvent because of its thermal stability and high polarity . It is suitable as a solvent for polymers such as acrylates , epoxies , polyurethanes , polyvinyl chloride , polyimides , polyamide-imide and for numerous organic syntheses. Other important applications include paint removal and the production of polyurethane foam ( PU foam ). An important technical application is the extraction of 1,3-butadiene from C4 hydrocarbon streams. It is also used for the absorption of acidic components in gas scrubbing.

Individual evidence

1. ↑ ^{a b c d e f g h i j k l m n o p q r s t} Entry on N-methyl-2-pyrrolidone in the GESTIS substance database of the IFA , accessed on January 15, 2020(JavaScript required) .
2. ↑ ^{a b c} data sheet 1-Methyl-2-pyrrolidinone from Sigma-Aldrich , accessed on June 16, 2011 ( PDF ).
3. ↑ Entry on 1-methyl-2-pyrrolidone in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
4. ↑ Entry in the SVHC list of the European Chemicals Agency , accessed on January 6, 2015.
5. ↑ Swiss Accident Insurance Fund (Suva): Limit values ​​- current MAK and BAT values (search for 872-50-4 or N-methyl-2-pyrrolidone ), accessed on September 19, 2019.
6. ↑ Entry on N-methyl-2-pyrrolidone in the ChemIDplus database of the United States National Library of Medicine (NLM) .
7. ↑ ^{a b c d e f g h} R.B .; Harreus, R. Backes, J.-O. Eichler, R. Feuerhake, C. Jäckel, U. Mahn, R. Pinkos, R. Vogelsang: 2-Pyrrolidone , in: Ullmanns Enzyklopädie der Technischen Chemie , Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 2011; doi : 10.1002 / 14356007.pub2 .
8. ↑ ^{a b} E. Brandes, W. Möller: Safety-related parameters - Volume 1: Flammable liquids and gases. Wirtschaftsverlag NW - Verlag für neue Wissenschaft GmbH, Bremerhaven 2003.
9. ^ ^{A b} P. Kneisl, JW Zondlo: Vapor pressure, liquid density, and the latent heat of vaporization as functions of temperature for four dipolar aprotic solvents. In: Journal of Chemical & Engineering Data . 32, 1987, pp. 11-13, doi : 10.1021 / je00047a003 .
10. ↑ ^{a b c} Steele, WV; Chirico, RD; Nguyen, A .; Hossenlopp, IA; Smith, NK: Determination of ideal-gas enthalpies of formation for key compounds in Am. Inst. Chem. Eng. Symp. Ser. (AIChE Symp. Ser.), 1990, 138-154.
11. ↑ ^{a b} Gude, MT; Teja, AS: The Critical Properties of Several n-Alkanals, Tetralin and NMP in Experimental Results for DIPPR 1990-91 Projects on Phase Equilibria and Pure Component Properties, 1994, 1994, DIPPR Data Series No. 2, p. 174-83.
12. ↑ ^{a b} Teja, AS; Anselme, MJ, The critical properties of thermally stable and unstable fluids. II. 1986 results, AIChE Symp. Ser., 1990, 86, 279, 122-127.
13. ↑ Lisicki, Z .; Jamróz, ME: (Solid + liquid) equilibria in (polynuclear aromatic + tertiary amide) systems in J. Chem. Thermodyn. 32 (2000) 1335-1353, doi : 10.1006 / jcht.2000.0685 .
14. ↑ Palczewska-Tulinska, M .; Oracz, P .: Vapor Pressures of 1-Methyl-2-pyrrolidone, 1-Methyl-azepan-2-one, and 1,2-Epoxy-3-chloropropane in J. Chem. Eng. Data 52 (2007) 2468-2471, doi : 10.1021 / je700398k .
15. ↑ ^{a b} entry on N-methyl-2-pyrrolidone. In: Römpp Online . Georg Thieme Verlag, accessed on February 7, 2012.
16. ↑ S. Yoshifuji, Y. Arakawa, Y. Nitta: Ruthenium Tetroxide Oxidation of N-Alkyllactams in Chem. Pharm. Bull. 35 (1987) 357-363, doi : 10.1248 / cpb.35.357 , pdf .
17. ↑ ^{a b} Eilingsfeld, H .; Seefelder, M .; Weidinger, H .: Amide Chloride and Carbamide Chloride in Angew. Chem. 72 (1960) 836-845, doi : 10.1002 / anie.19600722208 .
18. ↑ ^{a b} Eilingsfeld, H .; Seefelder, M .; Weidinger, H .: Syntheses with amide chlorides, I. Reactions on the functional group NN-disubstituted carboxamide chlorides in Chem. Ber. 96 (1963) 2671-2690, doi : 10.1002 / cber.19630961023 .
19. ↑ Hullot, P .; Cuvigny, T .; Larcheveque, M .; Normant, H .: Milieux hyperbasiques: preparation et alkylation de carbanions en α d'amides N, N-disubstitués. Application à la synthèse de la d, l-pipéritone in Can. J. Chem. 54 (1976) 1098-1104, doi : 10.1139 / v76-157 , pdf .
20. ↑ Stewart, JD; Fields, SC; Kochhar, KS; Pinnick, HW: α-Arylation of pyrrolidinones in J. Org. Chem. 52 (1987) 2110-2113, doi : 10.1021 / jo00386a045 .
21. ^ Osterberg, PM; Niemeier JK; Welch, CJ; Hawkins, JM; Martinelli, JR; Johnson, TE; Root, TW; Stahl, SS: Experimental Limiting Oxygen Concentrations for Nine Organic Solvents at Temperatures and Pressures Relevant to Aerobic Oxidations in the Pharmaceutical Industry in Org. Process Res. Dev. 19 (2015) 1537–1542, doi : 10.1021 / op500328f .