Amides
DETAIL
Synthesis and production
DMA is prepared commercially by the reaction of dimethylamine with acetic anhydride or acetic acid. Dehydration of the salt of dimethylamine and acetic acid also furnishes this compound:
Dimethylacetamide can also be produced by the reaction of dimethylamine with methyl acetate.
One route to dimethylacetamide
The separation and purification of the product is carried out by multistage distillation 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 amides. Hydrolysis of the acyl-N bond occurs in the presence of acids:
However, it is resistant to bases. For this reason DMA is useful solvent for reactions involving strong bases such as sodium hydroxide.
Dimethylacetamide is commonly used as a solvent for fibers (e.g., polyacrylonitrile, spandex) or in the adhesive industry. It is also employed in the production of pharmaceuticals and plasticizers as a reaction medium.
A solution of lithium chloride in DMAc (LiCl/DMAc) can dissolve cellulose. 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 to determine the molar mass distribution of cellulose samples.
Dimethylacetamide is also used as an excipient in drugs, e.g. in Vumon (teniposide), Busulfex (busulfan) or Amsidine (amsacrine).