1,1,3,3-Tetramethylguanidine

Tetramethylguanidine is an organic compound with the formula HNC(N(CH3)2)2. This colourless liquid is a strong base, as judged by the high pKa of it conjugate acid.[2]

1,1,3,3-Tetramethylguanidine
Skeletal formula of 1,1,3,3-tetramethylguanidine
Ball and stick model of 1,1,3,3-tetramethylguanidine
Spacefill model of 1,1,3,3-tetramethylguanidine
Names
IUPAC name
1,1,3,3-Tetramethylguanidine
Identifiers
3D model (JSmol)
969608
ChemSpider
ECHA InfoCard 100.001.185
EC Number
  • 201-302-7
MeSH 1,1,3,3-tetramethylguanidine
UN number 2920
Properties
C5H13N3
Molar mass 115.180 g·mol−1
Appearance Colourless liquid
Density 918 mg mL−1
Melting point −30 °C (−22 °F; 243 K)
Boiling point 160 to 162 °C (320 to 324 °F; 433 to 435 K)
Miscible
Vapor pressure 30 Pa (at 20 °C)
Acidity (pKa) 13.0±1.0[1] (pKa of conjugate acid in water)
1.469
Hazards
GHS pictograms GHS02: Flammable GHS05: Corrosive GHS07: Harmful
GHS Signal word Danger
H226, H302, H314
P280, P305+351+338, P310
Flash point 60 °C (140 °F; 333 K)
Explosive limits 1–7.5%
Related compounds
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

It was originally prepared from tetramethylthiourea via S-methylation and amination, but alternative methods start from cyanogen iodide.[3]

UsesEdit

TMG is mainly used as a strong, non-nucleophilic base for alkylations, often as a substitute for the more expensive bases DBU and DBN.[3] Since it is highly water-soluble, it is easily removed from mixtures in organic solvents. It is also used as a base-catalyst in the production of polyurethane.[4]

ReferencesEdit

  1. ^ Kaupmees, K.; Trummal, A.; Leito, I. (2014). "Basicities of Strong Bases in Water: A Computational Study". Croat. Chem. Acta. 87 (4): 385–395. doi:10.5562/cca2472.
  2. ^ Rodima, Toomas; Leito, I. (2002). "Acid-Base Equilibria in Nonpolar Media. 2. Self-Consistent Basicity Scale in THF Solution Ranging from 2-Methoxypyridine to EtP1(pyrr) Phosphazene". J. Org. Chem. 67 (6): 1873–1881. doi:10.1021/jo016185p.
  3. ^ a b Ishikawa, T.; Kumamoto, T. (2006). "Guanidines in Organic Synthesis". Synthesis. 2006 (5): 737–752. doi:10.1055/s-2006-926325.
  4. ^ Geoghegan, J. T.; Roth, R. W. (2003). "Catalytic Effects of 1,1,3,3-Tetramethylguanidine for Isocyanate Reactions". J. Appl. Polym. Sci. 9 (3): 1089–1093. doi:10.1002/app.1965.070090325.