1,1,3,3-Tetramethylguanidine

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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[1]
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 115.18 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[2] (pKa of conjugate acid in water)
1.469
Hazards
GHS pictograms The flame pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The corrosion pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
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

Tetramethylguanidine is an organic compound with the formula HNC(N(CH3)2)2. This colourless liquid is a strong base with a higher pKa than typical amines.[3]

It was originally prepared from tetramethylthiourea via S-methylation and amination, but alternative methods start from cyanogen iodide.[4]

Uses[edit]

TMG is mainly used as a strong, non-nucleophilic base for alkylations, often as a substitute for the more expensive bases DBU and DBN.[4] 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.[5]

References[edit]

  1. ^ "1,1,3,3-tetramethylguanidine - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 26 March 2005. Identification. Retrieved 10 April 2012. 
  2. ^ Kaupmees, K.; Trummal, A.; Leito, I. (2014). "Basicities of Strong Bases in Water: A Computational Study". Croat. Chem. Acta. 87: 385–395. doi:10.5562/cca2472. 
  3. ^ 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. 
  4. ^ a b Ishikawa, T.; Kumamoto, T. (2006). "Guanidines in Organic Synthesis". Synthesis. 2006 (5): 737–752. doi:10.1055/s-2006-926325. 
  5. ^ Geoghegan, J. T.; Roth, R. W. (2003). "Catalytic effects of 1,1,3,3-tetramethylguanidine for isocyanate reactions". J. Appl. Polymer Sci. 9 (3): 1089–1093. doi:10.1002/app.1965.070090325.