Tetramethylammonium chloride is one of the simplest quaternary ammonium salts, with four methyl groups tetrahedrally attached to the central N. The chemical formula (CH3)4N+Cl− is often abbreviated further as Me4N+Cl−. It is a hygroscopic colourless solid that is soluble in water and polar organic solvents. Tetramethylammonium chloride is a major industrial chemical, being used in such processes as hydrofracking. In the laboratory, it has fewer synthetic chemical applications than quaternary ammonium salts containing longer N-alkyl substituents, which are used extensively as phase-transfer catalysts.
3D model (JSmol)
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|Molar mass||109.60 g/mol|
|Melting point||425 °C (797 °F; 698 K) (decomposes)|
|Soluble in water and methanol. Slightly soluble in ethanol. Insoluble in ether, benzene, chloroform.|
|Safety data sheet||External MSDS|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Preparation and laboratory usesEdit
Tetramethylammonium chloride can be synthesized by the alkylation of ammonium chloride with dimethyl carbonate, in the presence of 1-ethyl-3-methyl imidazolium bromide ([EMIM]+Br−) as an ionic liquid catalyst. The overall reaction is:
- NH4+Cl− + 2 (CH3O)2CO → N(CH3)4+Cl− + 2 H2O + 2 CO2
LD50 = 25 mg/kg (mouse, i.p.); 40 mg/kg (mouse, s.c.); 50 mg/kg (rat, p.o.). Very toxic to aquatic organisms.
- Zheng, Z.; Wang, Jie; Wu, Ting Hua; Zhou, Xiao Ping; et al. (2007). "Alkylation of Ammonium Salts Catalyzed by Imidazolium-Based Ionic Liquid Catalysts". Advanced Synthesis & Catalysis. 349 (7): 1095–1101. doi:10.1002/adsc.200600451.
- Nenad, Maraš; Polanc, Slovenko; Kočevar, Marijan (2008). "Microwave-assisted methylation of phenols with tetramethylammonium chloride in the presence of K2CO3 or Cs2CO3". Tetrahedron. 64 (51): 11618–11624. doi:10.1016/j.tet.2008.10.024.
- W. J. Middleton and D. W. Wiley (1973). "tetramethylammonium 1-Propene-1,1,2,3,3-pentacarbonitrile". Organic Syntheses. doi:10.15227/orgsyn.041.0099.; Collective Volume, 5, p. 1013
- Chevet E. et al (1995). "Low concentrations of tetramethylammonium chloride increase yield and specificity of PCR". Nucleic Acids Research 23 (16) 3343–344.