Tetramethylbutane

Tetramethylbutane

Names
IUPAC name 2,2,3,3-Tetramethylbutane[1]
Identifiers
CAS Number	594-82-1
3D model (Jmol)	Interactive image
ChemSpider	11185
ECHA InfoCard	100.008.961
EC Number	209-855-6
PubChem	11675
UN number	1325
InChI InChI=1S/C8H18/c1-7(2,3)8(4,5)6/h1-6H3 Key: OMMLUKLXGSRPHK-UHFFFAOYSA-N
SMILES CC(C)(C)C(C)(C)C
Properties
Chemical formula	C8H18
Molar mass	114.23 g·mol^−1
Appearance	White, opaque, waxy crystals
Odor	Odorless
Melting point	98 to 104 °C; 208 to 219 °F; 371 to 377 K
Boiling point	106.0 to 107.0 °C; 222.7 to 224.5 °F; 379.1 to 380.1 K
Henry's law constant (kH)	2.9 nmol Pa^−1 kg^−1
Thermochemistry
Specific heat capacity (C)	232.2 J K^−1 mol^−1 (at 2.8 °C)
Std molar entropy (S^o298)	273.76 J K^−1 mol^−1
Std enthalpy of formation (ΔfH^o298)	−270.3 – −267.9 kJ mol^−1
Std enthalpy of combustion (ΔcH^o298)	−5.4526 – −5.4504 MJ mol^−1
Hazards
EU classification (DSD)	F Xn N
R-phrases	R11, R38, R65, R67, R50/53
S-phrases	(S2), S16, S29, S33
Flash point	4 °C (39 °F; 277 K)
Explosive limits	1–?%
Related compounds
Related alkanes	Neopentane 2,2-Dimethylbutane 2,3-Dimethylbutane Triptane Tetraethylmethane 2,2,4-Trimethylpentane 2,3,3-Trimethylpentane 2,3,4-Trimethylpentane Tetra-tert-butylmethane
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

Tetramethylbutane, sometimes called hexamethylethane, is a hydrocarbon with formula C₈H₁₈ or (H₃C-)₃C-C(-CH₃)₃. It is the most heavily branched and most compact of the many octane isomers, the only one with a butane (C4) backbone. Because of its highly symmetrical structure, it has a very high melting point and a short liquid range; in fact, it is the smallest saturated acyclic hydrocarbon that appears as a solid at a room temperature of 25 °C. (Among cyclic hydrocarbons, cubane, C₈H₈ is even smaller and is also solid at room temperature.)

The compound can be obtained by reaction of Grignard reagent tert-butylmagnesium bromide with ethyl bromide, or of ethylmagnesium bromide with tert-butyl bromide in the presence of manganese(II) ions.^[2] This transformation is believed to go through the dimerization of two tert-butyl radicals, which are generated by decomposition of the organomanganese compounds generated in situ.

The full IUPAC name of the compound is 2,2,3,3-tetramethylbutane, but the numbers are superfluous in this case because there is no other possible arrangement of "tetramethylbutane".

References

1. "Hexamethylethane - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 26 March 2005. Identification and Related Information. Retrieved 11 March 2012.
2. M. S. KHARASCH; J. W. HANCOCK; W. NUDENBERG; P. O. TAWNEY (1956). "Factors Influencing the Course and Mechanism of Grignard Reactions. XXII. The Reaction of Grignard Reagents with Alkyl Halides and Ketones in the Presence of Manganous Salts". Journal of Organic Chemistry. 21 (3): 322–327. doi:10.1021/jo01109a016.