Dimethylacetamide (DMAc or DMA) is the
organic compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...
with the
formula
In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwee ...
CH
3C(O)N(CH
3)
2. This colorless, water-miscible, high-boiling liquid is commonly used as a polar
solvent
A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...
in
organic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...
. DMA is miscible with most other solvents, although it is poorly soluble in
aliphatic
In organic chemistry, hydrocarbons ( compounds composed solely of carbon and hydrogen) are divided into two classes: aromatic compounds and aliphatic compounds (; G. ''aleiphar'', fat, oil). Aliphatic compounds can be saturated, like hexane, or ...
hydrocarbon
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, and their odors are usually weak or ex ...
s.
Synthesis and production
DMA is prepared commercially by the reaction of
dimethylamine
Dimethylamine is an organic compound with the formula (CH3)2NH. This secondary amine is a colorless, flammable gas with an ammonia-like odor. Dimethylamine is commonly encountered commercially as a solution in water at concentrations up to aroun ...
with
acetic anhydride
Acetic anhydride, or ethanoic anhydride, is the chemical compound with the formula (CH3CO)2O. Commonly abbreviated Ac2O, it is the simplest isolable anhydride of a carboxylic acid and is widely used as a reagent in organic synthesis. It is a col ...
or
acetic acid
Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main component ...
. Dehydration of the salt of dimethylamine and acetic acid also furnishes this compound:
: CH
3CO
2H·HN(CH
3)
2 → H
2O + CH
3CON(CH
3)
2
Dimethylacetamide can also be produced by the reaction of
dimethylamine
Dimethylamine is an organic compound with the formula (CH3)2NH. This secondary amine is a colorless, flammable gas with an ammonia-like odor. Dimethylamine is commonly encountered commercially as a solution in water at concentrations up to aroun ...
with
methyl acetate
Methyl acetate, also known as MeOAc, acetic acid methyl ester or methyl ethanoate, is a carboxylate ester with the formula CH3COOCH3. It is a flammable liquid with a characteristically pleasant smell reminiscent of some glues and nail polish remo ...
.
:
The separation and purification of the product is carried out by multistage
distillation
Distillation, or classical distillation, is the process of separation process, separating the components or substances from a liquid mixture by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distilla ...
in rectification columns. DMA is obtained with essentially quantitive (99%)
yield referred to methyl acetate.
[
]
Reactions and applications
The chemical reactions of dimethylacetamide are typical of ''N'',''N''-disubstituted amide
In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a compound with the general formula , where R, R', and R″ represent organic groups or hydrogen atoms. The amide group is called a peptide bond when it is ...
s. 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 ...
of the acyl-N bond occurs in the presence of acid
In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...
s:
: CH3CON(CH3)2 + H2O + HCl → CH3COOH + (CH3)2NH2+Cl−
However, it is resistant to bases. For this reason DMA is a useful solvent for reactions involving strong bases such as sodium hydroxide
Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions .
Sodium hydroxide is a highly caustic base and alkali ...
.
Dimethylacetamide is commonly used as a solvent for fibers (e.g., polyacrylonitrile
Polyacrylonitrile (PAN), also known as polyvinyl cyanide and Creslan 61, is a synthetic, semicrystalline organic polymer resin, with the linear formula (C3H3N)n. Though it is thermoplastic, it does not melt under normal conditions. It degrades bef ...
, spandex
Spandex, Lycra, or elastane is a synthetic fiber known for its exceptional elasticity. It is a polyether-polyurea copolymer that was invented in 1958 by chemist Joseph Shivers at DuPont's Benger Laboratory in Waynesboro, Virginia, US.
The ge ...
) or in the adhesive
Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation.
The use of adhesives offers certain advant ...
industry.[ It is also employed in the production of ]pharmaceuticals
A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and rel ...
and plasticizer
A plasticizer ( UK: plasticiser) is a substance that is added to a material to make it softer and more flexible, to increase its plasticity, to decrease its viscosity, and/or to decrease friction during its handling in manufacture.
Plasticiz ...
s as a reaction medium.
A solution of lithium chloride
Lithium chloride is a chemical compound with the formula Li Cl. The salt is a typical ionic compound (with certain covalent characteristics), although the small size of the Li+ ion gives rise to properties not seen for other alkali metal chlor ...
in DMAc (LiCl/DMAc) can dissolve cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall ...
. Unlike many other cellulose solvents, LiCl/DMAc gives a molecular dispersion, i.e. a "true solution". For this reason, it is used in gel permeation chromatography Gel permeation chromatography (GPC) is a type of size-exclusion chromatography (SEC), that separates analytes on the basis of size, typically in organic solvents. The technique is often used for the analysis of polymers. As a technique, SEC was firs ...
to determine the molar mass distribution The molar mass distribution (or molecular weight distribution) describes the relationship between the number of moles of each polymer species (Ni) and the molar mass (Mi) of that species. In linear polymers, the individual polymer chains rarely have ...
of cellulose samples.
Dimethylacetamide is also used as an excipient
An excipient is a substance formulated alongside the active ingredient of a medication, included for the purpose of long-term stabilization, bulking up solid formulations that contain potent active ingredients in small amounts (thus often referred ...
in drugs, e.g. in Vumon (teniposide
Teniposide (trade name Vumon) is a chemotherapeutic medication used in the treatment of childhood acute lymphocytic leukemia (ALL), Hodgkin's lymphoma, certain brain tumours, and other types of cancer. It is in a class of drugs known as podophyllot ...
), Busulfex (busulfan
Busulfan (Myleran, GlaxoSmithKline, Busulfex IV, Otsuka America Pharmaceutical, Inc.) is a chemotherapy drug in use since 1959. It is a cell cycle non-specific alkylating antineoplastic agent, in the class of alkyl sulfonates. Its chemical ...
) or Amsidine ( amsacrine).
Toxicity
Dimethylacetamide, like most simple alkyl amides, is of low acute toxicity. Chronic exposure can cause hepatotoxicity
Hepatotoxicity (from ''hepatic toxicity'') implies chemical-driven liver damage. Drug-induced liver injury is a cause of acute and chronic liver disease caused specifically by medications and the most common reason for a drug to be withdrawn fro ...
.[U.S. Department of Health and Human Services & U.S. Department of Labor (1978]
Occupational Health Guideline for Dimethyl Acetamide
Now: Occupational Health Guideline for Chemical Hazards
DHHS (NIOSH) Publication Number 81-123
January 1981. The National Institute for Occupational Safety and Health (NIOSH). At high doses (400 mg/kg body mass daily), dimethylacetamide causes effects on the central nervous system
The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all par ...
(e.g. depression, hallucination
A hallucination is a perception in the absence of an external stimulus that has the qualities of a real perception. Hallucinations are vivid, substantial, and are perceived to be located in external objective space. Hallucination is a combinatio ...
s and delusion
A delusion is a false fixed belief that is not amenable to change in light of conflicting evidence. As a pathology, it is distinct from a belief based on false or incomplete information, confabulation, dogma, illusion, hallucination, or some o ...
).
Dimethylacetamide may be incompatible with polycarbonate
Polycarbonates (PC) are a group of thermoplastic polymers containing carbonate groups in their chemical structures. Polycarbonates used in engineering are strong, tough materials, and some grades are optically transparent. They are easily work ...
or ABS. Devices (e.g. syringes) that contain polycarbonate or ABS can dissolve when coming into contact with dimethylacetamide.
Regulation
In 2011, dimethylacetamide was identified in the EU as a Substance of very high concern
A substance of very high concern (SVHC) is a chemical substance (or part of a group of chemical substances) concerning which it has been proposed that use within the European Union be subject to authorisation under the REACH Regulation. Indeed, l ...
(SVHC) because of its reproductive toxicity
Reproductive toxicity refers to the potential risk from a given chemical, physical or biologic agent to adversely affect both male and female fertility as well as offspring development. Reproductive toxicants may adversely affect sexual function ...
. In 2014, the European Commission has started an investigation to restrict the use of dimethylacetamide in the EU according to REACH.
In 2015, the CNESST (Committee on Standards, Equity, Health and Safety at Work in Quebec
Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...
) has adopted a tightened classification of dimethylacetamide:[Commission des normes, de l'équité, de la santé et de la sécurité du travail (CNESST), Quebec, Canada]
WHMIS 2015 classification of N,N-Dimethylacetamide
References
{{Reflist
External links
Process flowsheet of Dimethylacetamide Production from Acetic Acid and Dimethylamine
Amide solvents
Acetamides