Molar mass 109.6 g/mol Density 1.17 g/cm³ Appearance White crystals | Formula C4H12NCl Melting point 425 °C | |
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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.
Contents
Preparation and laboratory uses
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
Although it can be induced to serve as a methylation reagent, it is typically employed as a source of the inert counter cation Me4N+. Similarly it serves as a lipophilic precipitating agent.
In low concentrations, it is used in polymerase chain reactions to increase yields and specificity. It has been shown to enhance yields 5–10 fold at 60mM by stabilizing the AT base pairs.
Toxicity
LD50 = 25 mg/kg (mouse, i.p.); 40 mg/kg (mouse, s.c.); 50 mg/kg (rat, p.o.). Very toxic to aquatic organisms.
Diverse data on human exposure, environmental toxicology and environmentally-related chemistry is available through the NIH Toxnet database.