Tetramethylammonium chloride

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Tetramethylammonium chloride
Tetramethylammonium-3D-balls.png Tetramethylammonium-chloride-ion-pair-2D.png
Tetramethylammonium chloride.jpg
CAS number 75-57-0 YesY
PubChem 6379
ChemSpider 6139 N
Jmol-3D images Image 1
Molecular formula C4H12NCl
Molar mass 109.60 g/mol
Appearance White crystals
Density 1.17 g/cm3
Melting point 425 °C (797 °F; 698 K) (decomposes)
Solubility in water Soluble
MSDS External MSDS
Related compounds
Other anions tetramethylammonium hydroxide
Other cations tetraethylammonium chloride
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
Infobox references

Tetramethylammonium chloride is one of the simplest quaternary ammonium salts, bearing only 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 very hygroscopic colourless solid that is soluble in water and polar organic solvents. Tetramethylammonium chloride is a major industrial chemical,[1] being used in such processes as hydrofracking.[2] 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.

Preparation and laboratory uses[edit]

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.[3] The overall reaction is:

NH4+Cl + 2 (CH3O)2CO → N(CH3)4+Cl + 2 H2O + 2 CO2

It is used in organic synthesis for methylation and occasionally as a precipitating agent.[4]

In low concentrations, it is used in polymerase chain reactions to increase yield and specificity. It has been shown to enhance yield 5–10 fold at 60mM by stabilizing the AT base pairs.[5]


LD50 = 25 mg/kg (mouse, i.p.); 40 mg/kg (mouse, s.c.); 50 mg/kg (rat, p.o.). Very toxic to aquatic organisms.[6]

Diverse data on human exposure, environmental toxicology and environmentally-related chemistry is available through the NIH Toxnet database.[1]

See also[edit]


  1. ^ a b http://toxnet.nlm.nih.gov/cgi-bin/sis/search/a?dbs+hsdb:@term+@DOCNO+7987
  2. ^ http://fracfocus.org/chemical-use/what-chemicals-are-used
  3. ^ Zheng, Z. et al.; Wang, Jie; Wu, Ting Hua; Zhou, Xiao Ping (2007). "Alkylation of Ammonium Salts Catalyzed by Imidazolium-Based Ionic Liquid Catalysts". Advanced Synthesis & Catalysis 349 (7): 1095–1101. doi:10.1002/adsc.200600451. 
  4. ^ W. J. Middleton and D. W. Wiley (1973), "tetramethylammonium 1-Propene-1,1,2,3,3-pentacarbonitrile", Org. Synth. ; Coll. Vol. 5: 1013 
  5. ^ Chevet E. et al (1995). "Low concentrations of tetramethylammonium chloride increase yield and specificity of PCR". Nucleic Acids Research 23 (16) 3343–344.
  6. ^ http://datasheets.scbt.com/sc-251199.pdf