Tetramethylethylene

Tetramethylethylene is a hydrocarbon with the formula Me₂C=CMe₂ (Me = methyl). A colorless liquid, it is the simplest tetrasubstituted alkene.

Tetramethylethylene

Names
Preferred IUPAC name 2,3-Dimethylbut-2-ene
Identifiers
CAS Number	563-79-1
3D model (JSmol)	Interactive image
ChemSpider	10776
ECHA InfoCard	100.008.422
EC Number	209-263-8
PubChem CID	11250
UNII	7UQ4B3F5JC Y
CompTox Dashboard (EPA)	DTXSID2060339
InChI InChI=1S/C6H12/c1-5(2)6(3)4/h1-4H3 Key: WGLLSSPDPJPLOR-UHFFFAOYSA-N
SMILES CC(=C(C)C)C
Properties
Chemical formula	C6H12
Molar mass	84.162 g·mol−1
Appearance	colorless liquid
Density	0.7075 g/cm3 (20 °C)
Melting point	−74.6 °C (−102.3 °F; 198.6 K)
Boiling point	73.3 °C (163.9 °F; 346.4 K)
Critical point (T, P)	521.0(9) K, 3.4(1) MPa[1]
Solubility in water	insoluble
Solubility	soluble in ethanol, ether, acetone, chloroform[1]
Magnetic susceptibility (χ)	−65.9×10−6 cm3·mol−1[1]
Refractive index (nD)	1.4122 (20 °C)[1]
Thermochemistry[1]
Heat capacity (C)	174.7 J·mol−1·K−1
Std molar entropy (S⦵298)	270.2 J·mol−1·K−1
Std enthalpy of formation (ΔfH⦵298)	−101.4 kJ·mol−1 (liquid) −68.1 kJ·mol−1 (gas)
Enthalpy of fusion (ΔfH⦵fus)	6.45 kJ·mol−1 (at melting point)
Enthalpy of vaporization (ΔfHvap)	32.51 kJ·mol−1 (25 °C) 29.64 kJ·mol−1 (at boiling point)
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H225, H304
Precautionary statements	P210, P233, P240, P241, P242, P243, P280, P301+P310, P303+P361+P353, P331, P370+P378, P403+P235, P405, P501
Flash point	−8 °C
Autoignition temperature	401 °C[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthesis

It can be prepared by base-catalyzed isomerization of 2,3-dimethyl-1-butene.^[2] Another route involves direct dimerization of propylene.^[3] It can also be produced by photolysis of tetramethylcyclobutane-1,3-dione.^[4]

Reactions

Tetramethylethylene forms metal-alkene complexes with low-valent metals and reacts with diborane to give the monoalkyborane known as thexylborane.^[5][6]

Oxidation gives pinacol.

It is a precursor to the herbicide fenpropathrin.^[3]

References

1. CRC handbook of chemistry and physics : a ready-reference book of chemical and physical data. William M. Haynes, David R. Lide, Thomas J. Bruno (2016-2017, 97th ed.). Boca Raton, Florida. 2016. ISBN 978-1-4987-5428-6. OCLC 930681942.{{cite book}}: CS1 maint: location missing publisher (link) CS1 maint: others (link)
2. Hattori, Hideshi (2001). "Solid base catalysts: Generation of basic sites and application to organic synthesis". Applied Catalysis A: General. 222 (1–2): 247–259. doi:10.1016/S0926-860X(01)00839-0.
3. Olivier-Bourbigou, H.; Breuil, P. A. R.; Magna, L.; Michel, T.; Espada Pastor, M. Fernandez; Delcroix, D. (2020). "Nickel Catalyzed Olefin Oligomerization and Dimerization" (PDF). Chemical Reviews. 120 (15): 7919–7983. doi:10.1021/acs.chemrev.0c00076. PMID 32786672. S2CID 221124789.
4. Nicholas J. Turro, Peter A. Leermakers, George F. Vesley (1967). "Cyclohexylidenecyclohexane". Organic Syntheses. 47: 34. doi:10.15227/orgsyn.047.0034.{{cite journal}}: CS1 maint: multiple names: authors list (link)
5. Negishi, Ei-Ichi; Brown, Herbert C. (1974). "Thexylborane-A Highly Versatile Reagent for Organic Synthesis via Hydroboration". Synthesis. 1974 (2): 77–89. doi:10.1055/s-1974-23248. S2CID 96012955.
6. Giordano, G.; Crabtree, R. H. (1990). "Di-μ-Chloro-Bis(η ⁴ -1,5-Cyclooctadiene)-Dirhodium(I)". Di-μ-Chloro-Bis(η⁴-1,5-Cyclooctadiene)-Dirhodium(I). Inorganic Syntheses. Vol. 28. pp. 88–90. doi:10.1002/9780470132593.ch22. ISBN 9780471526193.