Tetramethylammonium Hydroxide

Me4N+OH-

[75-59-2]  · C4H13NO  · Tetramethylammonium Hydroxide  · (MW 91.18)

(conversion of hydroperoxyoxiranes to hydroxyalkyl-1,2-dioxetanes; catalyst for transesterification of carboxylic acids; synthesis of phosphorylating agent)

Physical Data: dependent on form supplied in, e.g. 10% aqueous solution has n20D 1.3521 and d 1.006 g cm-3.

Solubility: sol MeOH, H2O.

Form Supplied in: commercially available as a solution in water or methanol, or in solid form as the pentahydrate.

Preparative Methods: 1. By heating trimethylacetonylammonium bromide (MeCOCH2+NMe3 Br-) to 195-200 °C. The free base is obtained by treating the bromide with warm water.1 2. Prepared as a solution in water by electrolysis of tetramethylammonium iodide (at anode), ammonium hydroxide (at cathode), and water (central compartment) in a three-compartment cell.2 3. By an ion-exchange method using AV-17 and Me4NX (X = Cl, Br, I).3 4. By treatment of tetramethylammonium iodide with freshly prepared silver(I) oxide in water at 50 °C.4

Handling, Storage, and Precautions: decomposes on distillation; stored as solution. It is a very strong base, readily absorbing carbon dioxide from the air. Keep container well closed. Solution is flammable and causes burns.

General Discussion.

Hydroperoxyoxiranes (2) are converted to the 3a-hydroxyalkyl-1,2-dioxetanes (3) by treatment with tetramethylammonium hydroxide in a two-phase water/diethyl ether medium (eq 1).5

Tetramethylammonium hydroxide in methanol is used to catalyze the transesterification of carboxylic acids. The methyl esters are formed on pyrolysis of the corresponding tetramethylammonium salt when injected into a gas chromatographic unit6 (methyl esters are popular derivatives for the gas chromatogaphic analysis of fatty acids7).

Aqueous solutions of quaternary ammonium hydroxides were used as initiators for the anionic homogeneous polymerization of acrylonitrile and methylacrylonitrile in DMF.8

Aqueous tetramethylammonium hydroxide reacts with di-t-butyl phosphite to give tetramethylammonium t-butyl hydrogen phosphite (4). This is a convenient phosphorylating agent for organic halides. It reacts easily with alkyl iodides and some alkyl bromides in boiling acetone, affording the corresponding alkyl t-butyl phosphites (5). Treatment with Trifluoroacetic Acid at room temperature yields monoalkyl hydrogen phosphites (6).9


1. Schmidt, E. LA 1891, 267, 267.
2. Krokhv, V. V. Zh. Prikl. Khim. 1964, 37, 2321.
3. Kreshkov, A. P.; Sayushkina, E. N.; Drozdov, V. A. Zh. Prikl. Khim. 1965, 38, 2398.
4. Zwierzak, A.; Kuba, M. T 1971, 27, 3163.
5. Leclercq, D.; Bats, J. P.; Picard, P.; Moulines, J. S 1982, 778.
6. Robb, E. W.; Westbrook III, J. J. Analyt. Chem. 1963, 35, 1644.
7. Metcalfe, L. D.; Wang, C. N. J. Chromatogr. Sci. 1981, 19, 530.
8. Zilkha, A.; Feit, B.-A.; Frankel, M. J. Polym. Sci. 1961, 49, 231.
9. Zwierzak, A.; Kuba, M. T 1973, 29, 1089.

Jonathan Knight

University of Bristol, UK



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