N-Methylmorpholine-N-oxide, NMO or NMMO is an organic compound

Organic compound

An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...

. This heterocyclic amine oxide

Amine oxide

An amine oxide, also known as amine-N-oxide and N-oxide, is a chemical compound that contains the functional group R3N+-O−, an N-O bond with three additional hydrogen and/or hydrocarbon side chains attached to N. Sometimes it is written as R3N→O or, wrongly, as R3N=O.In the strict sense the...

 and morpholine

Morpholine

Morpholine is an organic chemical compound having the chemical formula O2NH. This heterocycle, pictured at right, features both amine and ether functional groups. Because of the amine, morpholine is a base; its conjugate acid is called morpholinium...

 derivative is used in organic chemistry

Organic chemistry

Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, composition, reactions, and preparation of carbon-based compounds, hydrocarbons, and their derivatives...

 as a co-oxidant and sacrificial catalyst in oxidation reactions for instance in osmium tetroxide oxidations and the Sharpless asymmetric dihydroxylation

Sharpless asymmetric dihydroxylation

Sharpless asymmetric dihydroxylation is the chemical reaction of an alkene with osmium tetroxide in the presence of a chiral quinine ligand to form a vicinal diol....

 or oxidations with TPAP. NMO is commercially supplied both as a monohydrate C₅H₁₁NO₂.H₂O and as the anhydrous compound. The monohydrate is used as a solvent

Solvent

A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...

 for cellulose

Cellulose

Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....

 in the Lyocell

Lyocell

Lyocell is a regenerated cellulose fiber made from dissolving pulp . It was first manufactured in 1987 by Courtaulds Fibres UK at their pilot plant S25...

 process to produce cellulose fiber

Cellulose fiber

Cellulose fibers are fibres of cellulose from any source, either natural or manufactured.-Textile:In the textile industry regenerated cellulose is used as fibers such as rayon, . Cellulose fibers are manufactured from dissolving pulp...

s.

Solvent of cellulose

NMMO monohydrate is used as a solvent

Solvent

A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...

 in the Lyocell

Lyocell

Lyocell is a regenerated cellulose fiber made from dissolving pulp . It was first manufactured in 1987 by Courtaulds Fibres UK at their pilot plant S25...

 process to produce Tencel fiber. It dissolves cellulose to form a solution called dope, and the cellulose is reprecipitated in a water bath to produce a fiber. The process is similar but not analogous to the viscose

Viscose

Viscose is a viscous organic liquid used to make rayon and cellophane. Viscose is becoming synonymous with rayon, a soft material commonly used in shirts, shorts, coats, jackets, and other outer wear.-Manufacture:...

 process. In the viscose process, cellulose is made soluble by conversion to its xanthate

Xanthate

Xanthate usually refers to a salt with the formula ROCS2-M+ . The name xanthates is derived from Greek ξανθός , meaning “yellowish, golden”, and indeed most xanthate salts are yellow...

 derivatives. With NMMO, cellulose is not derivatized but dissolves to give a homogeneous polymer solution. The resulting fiber is similar to viscose

Viscose

Viscose is a viscous organic liquid used to make rayon and cellophane. Viscose is becoming synonymous with rayon, a soft material commonly used in shirts, shorts, coats, jackets, and other outer wear.-Manufacture:...

; this was observed, for example, for Valonia cellulose microfibrils. Dilution with water causes the cellulose to reprecipitate, i.e. the solvation of cellulose with NMMO is a water sensitive process.

Cellulose remains insoluble to most solvents since it has a strong and highly structured intermolecular hydrogen bonding network, which resists common solvents. NMMO is able to break the hydrogen bonding network that keeps cellulose insoluble to water and other solvents. Similar solubility has been obtained in a few solvents, particularly a mix of lithium chloride

Lithium chloride

Lithium chloride is a chemical compound with the formula LiCl. The salt is a typical ionic compound, although the small size of the Li+ ion gives rise to properties not seen for other alkali metal chlorides, such as extraordinary solubility in polar solvents and its hygroscopic...

 in dimethyl acetamide and some hydrophilic ionic liquid

Ionic liquid

An ionic liquid is a salt in the liquid state. In some contexts, the term has been restricted to salts whose melting point is below some arbitrary temperature, such as . While ordinary liquids such as water and gasoline are predominantly made of electrically neutral molecules, ILs are largely made...

s.

Dissolution of scleroproteins

Another use of NMO is in the dissolution of scleroprotein (found in animal tissue). This dissolution occurs in the crystal areas which are more homogeneous and contain glycine

Glycine

Glycine is an organic compound with the formula NH2CH2COOH. Having a hydrogen substituent as its 'side chain', glycine is the smallest of the 20 amino acids commonly found in proteins. Its codons are GGU, GGC, GGA, GGG cf. the genetic code.Glycine is a colourless, sweet-tasting crystalline solid...

 and alanine

Alanine

Alanine is an α-amino acid with the chemical formula CH3CHCOOH. The L-isomer is one of the 20 amino acids encoded by the genetic code. Its codons are GCU, GCC, GCA, and GCG. It is classified as a nonpolar amino acid...

 residues with a small number of other residues. How NMO dissolves these proteins is scarcely studied. Other studies, however, have been done in similar amide

Amide

In chemistry, an amide is an organic compound that contains the functional group consisting of a carbonyl group linked to a nitrogen atom . The term refers both to a class of compounds and a functional group within those compounds. The term amide also refers to deprotonated form of ammonia or an...

 systems (i.e. hexapeptide). The hydrogen bonds of the amides can be broken by NMO.

Oxidant

NMO, as a N-oxide, is an oxidant. It is used as a stoichiometric oxidant to regenerate the main catalyst after the main catalyst has been reduced by the substrate. For example, the toxic and volatile osmium tetroxide needs to be added in stoichiometric amounts to effect dihydroxylation, but if continuously regenerated with NMO, the amount can be reduced to catalytic quantities.