1,3-Dimethyl-2-imidazolidinone explained

1,3-Dimethyl-2-imidazolidinone (DMI) is a cyclic urea used as a high-boiling polar aprotic solvent.^[1] This colourless, highly polar solvent has high thermal and chemical stability. Together with homologous solvent DMPU, since the 1970s it serves as an analog of tetramethylurea.^{[2] [3]} It can be prepared from 1,2-dimethylethylenediamine by reaction with phosgene.

History

In 1940 Du Pont applied for a patent on acetylene storage in many polar organic solvents, one of which was 1,3-dimethyl-2-imid azolidone. The company filed another patent on a method of synthesizing the same compound, albeit called s-dimethylethyleneurea, in 1944.

Soon thereafter William Boon from the Imperial Chemical Industries published a different synthesis method of what he called 1:3-dimethyliminazolid-2-one.^[4] The compound was more closely studied in the 1960s,^{[5] [6]} with its adoption as a solvent starting in the 1970s.

Solvent

DMI has excellent solvating ability for both inorganic and organic compounds. In many applications, DMI (as well as DMPU) can be used as a substitute or replacement for the carcinogenic solvent HMPA.^[7] Compared to the 6-atom ring analog, it has an advantage of lower viscosity (1.9 vs. 2.9 cP at 25°C).

DMI is used in a variety of applications including detergents, dyestuffs, electronic materials and in the manufacture of polymers.

DMI is toxic in contact with skin.^[8]

References

1. Leahy, Ellen M. "1,3-Dimethyl-2-imidazolidinone"e-EROS Encyclopedia of Reagents for Organic Synthesis (2001),
2. Rosenfarb . Joseph . Huffman . Hugh L. Jr. . Caruso . Joseph A. . 1976 . Dielectric constants, viscosities, and related physical properties of several substituted liquid ureas at various temperatures . Journal of Chemical & Engineering Data . 21 . 2 . 150–153 . 10.1021/je60069a034 . 0021-9568.
3. Barker . Barbara J. . Rosenfarb . Joseph . Caruso . Joseph A. . 1979 . Ureas as Solvents for Chemical Investigations . Angewandte Chemie International Edition in English . en . 18 . 7 . 503–507 . 10.1002/anie.197905031 . 1521-3773.
4. Boon . W. R. . 1947 . Respiratory stimulants. Part I. Fully-substituted ureas derived from αω-alkylenediamines . Journal of the Chemical Society (Resumed) . en . 0 . 307–318 . 10.1039/JR9470000307 . 0368-1769.
5. Web site: Zaugg . Harold E. . 1960 . Specific Solvent Effects in the Alkylation of Enolate Anions. IV. Kinetic Order of Solvent Participation . 2025-01-18 . ACS Publications . EN . 10.1021/ja01465a025.
6. Book: Lien, Eric J. . Dipole Moment, Structure and Activity of Cyclic Ureas, Thioureas and Related Compounds . 1966 . University of California, San Francisco . en.
7. Lo, C.-C. . Chao, P.-M. . Replacement of carcinogenic solvent HMPA by DMI in insect sex pheromone synthesis . Journal of Chemical Ecology . 1990 . 16 . 12 . 3245–3253 . 10.1007/BF00982095 . 24263426. 9859086 .
8. https://www.tcichemicals.com/eshop/en/us/commodity/D1477/ DMI