''N''-Methyl-2-pyrrolidone (NMP) is an
organic compound
Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...
consisting of a 5-membered
lactam
A lactam is a Cyclic compound, cyclic amide, formally derived from an amino alkanoic acid through cyclization reactions. The term is a portmanteau of the words ''lactone'' + ''amide''.
Nomenclature
Greek_alphabet#Letters, Greek prefixes in alpha ...
. It is a colorless liquid, although impure samples can appear yellow. It is miscible with water and with most common organic solvents. It also belongs to the class of dipolar
aprotic solvents such as
dimethylformamide
Dimethylformamide, DMF is an organic compound with the chemical formula . Its structure is . Commonly abbreviated as DMF (although this initialism is sometimes used for 2,5-dimethylfuran, dimethylfuran, or dimethyl fumarate), this colourless liqui ...
and
dimethyl sulfoxide
Dimethyl sulfoxide (DMSO) is an organosulfur compound with the formula . This colorless liquid is the sulfoxide most widely used commercially. It is an important polar aprotic solvent that dissolves both polar and nonpolar compounds and is ...
. It is used in the petrochemical, polymer and battery industries as a solvent, exploiting its nonvolatility and ability to dissolve diverse materials (including
polyvinylidene difluoride, PVDF).
It has a strong dipole moment and hydrogen bonding due to its cis-amide conformation.
Preparation
NMP is produced industrially by a typical ester-to-amide conversion, by treating
gamma-butyrolactone with
methylamine
Methylamine, also known as methanamine, is an organic compound with a formula of . This colorless gas is a derivative of ammonia, but with one hydrogen atom being replaced by a methyl group. It is the simplest primary amine.
Methylamine is sold ...
. Alternative routes include the partial
hydrogenation
Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to redox, reduce or Saturated ...
of
''N''-methylsuccinimide and the reaction of
acrylonitrile
Acrylonitrile is an organic compound with the formula and the structure . It is a colorless, volatile liquid. It has a pungent odor of garlic or onions. Its molecular structure consists of a vinyl group () linked to a nitrile (). It is an im ...
with methylamine followed by
hydrolysis
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water ...
. About 200,000 to 250,000 tons are produced annually.
[
]
Applications
NMP is used to recover certain hydrocarbons
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic; their odor is usually faint, and may b ...
generated in the processing of petrochemical
Petrochemicals (sometimes abbreviated as petchems) are the chemical products obtained from petroleum by refining. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable s ...
s, such as the recovery of 1,3-butadiene
1,3-Butadiene () is the organic compound with the formula CH2=CH-CH=CH2. It is a colorless gas that is easily condensed to a liquid. It is important industrially as a precursor to synthetic rubber. The molecule can be viewed as the union of two ...
and acetylene
Acetylene (Chemical nomenclature, systematic name: ethyne) is a chemical compound with the formula and structure . It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is u ...
. Its good solvency properties have also led to NMP's use to dissolve a wide range of polymer
A polymer () is a chemical substance, substance or material that consists of very large molecules, or macromolecules, that are constituted by many repeat unit, repeating subunits derived from one or more species of monomers. Due to their br ...
s. Specifically, it is used as a solvent for surface treatment of textile
Textile is an Hyponymy and hypernymy, umbrella term that includes various Fiber, fiber-based materials, including fibers, yarns, Staple (textiles)#Filament fiber, filaments, Thread (yarn), threads, and different types of #Fabric, fabric. ...
s, resins, and metal coated plastics or as a paint stripper. It is also used as a solvent in the commercial preparation of polyphenylene sulfide
Polyphenylene sulfide (PPS) is an organic polymer consisting of aromatic rings linked by sulfides. Synthetic fiber and textiles derived from this polymer resist chemical and thermal attack. PPS is used in filter fabric for coal boilers, paperm ...
.
NMP is used in the production of aramid
Aramid fibers, short for aromatic polyamide, are a class of heat-resistant and strong synthetic fibers. They are used in aerospace and military applications, for ballistic-rated bulletproof vest, body armor cloth, fabric and ballistic composites ...
fibers Twaron
Twaron (a brand name of Teijin Aramid) is a para-aramid, high-performance yarn. It is a heat-resistant fibre, helps in ballistic protection and cut protection. Twaron was developed in the early 1970s by the Dutch company Akzo Nobel's division E ...
and Kevlar
Kevlar (para-aramid) is a strong, heat-resistant synthetic fiber, related to other aramids such as Nomex and Technora. Developed by Stephanie Kwolek at DuPont in 1965, the high-strength material was first used commercially in the early 1970s as ...
. In the pharmaceutical industry, ''N''-methyl-2-pyrrolidone is used in the formulation for drugs by both oral and transdermal delivery routes.polyvinylidene fluoride
Polyvinylidene fluoride or polyvinylidene difluoride (PVDF) is a highly non-reactive thermoplastic fluoropolymer produced by the polymerization of vinylidene difluoride. Its chemical formula is (C2H2F2)''n''.
PVDF is a specialty plastic use ...
binder.
Purisol process
In the Purisol process, developed by Lurgi AG
Air Liquide S.A. ( , ; literally "liquid air") is a French multinational company which supplies industrial gases and services to various industries including medical, chemical and electronic manufacturers. Founded in 1902, after Linde it is t ...
in the 1960s, a cold (ca. −15 °C) aqueous solution of NMP is used to remove hydrogen sulfide
Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is toxic, corrosive, and flammable. Trace amounts in ambient atmosphere have a characteristic foul odor of rotten eggs. Swedish chemist ...
from sour gas and from hydrodesulfurization
Hydrodesulfurization (HDS), also called hydrotreatment or hydrotreating, is a catalytic chemical process widely used to desulfurization, remove sulfur (S) from natural gas and from oil refinery, refined petroleum products, such as gasoline, g ...
facilities. It offers some advantages over the Selexol
Selexol is the trade name for an Amine gas treating, acid gas removal solvent that can separate acid gases such as hydrogen sulfide and carbon dioxide from feed gas streams such as synthesis gas produced by gasification of coal, coke, or heavy hydr ...
process in that it is more selective for hydrogen sulfide. Furthermore, it promotes the hydrolysis of some carbonyl sulfide
Carbonyl sulfide is the chemical compound with the linear formula . It is a colorless flammable gas with an unpleasant odor. It is a linear molecule consisting of a carbonyl double bonded to a sulfur atom. Carbonyl sulfide can be considered to ...
, a common component of sour gas:
:
This hydrolysis step further enriches the hydrogen sulfide content of the off-gas when the NMP is stripped. The sulfur-rich gas is well suited for a Claus unit, which affords solid elemental sulfur.
Safety
N-Methyl-2-pyrrolidone (NMP) is classified as a reproductive toxicant (H360D: May damage the unborn child) and can cause skin and eye irritation and respiratory irritation (H315, H319, H335). Studies show NMP exposure can increase the risk of developmental toxicity, including miscarriage and fetal death.
See also
* 2-Pyrrolidone
* 1,3-Dimethyl-2-imidazolidinone (DMI)
References
{{DEFAULTSORT:Methyl-2-pyrrolidone, N-
Amide solvents
Pyrrolidones
Excipients
Methyl compounds