2,2-Dimethylbutane - Wikipedia

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2,2-Dimethylbutane, trivially known as neohexane at William Odling's 1876 suggestion,[4] is an organic compound with formula C6H14 or (H3C-)3-C-CH2-CH3. It is therefore an alkane, indeed the most compact and branched of the hexane isomers — the only one with a quaternary carbon and a butane (C4) backbone.

2,2-Dimethylbutane

Names
Preferred IUPAC name 2,2-Dimethylbutane[2]
Other names Neohexane,[1] 22DMB
Identifiers
CAS Number	75-83-2 Y
3D model (JSmol)	Interactive image
Beilstein Reference	1730736
ChEMBL	ChEMBL142735 Y
ChemSpider	6163 Y
ECHA InfoCard	100.000.825
EC Number	200-906-8
PubChem CID	6403
RTECS number	EJ9300000
UNII	07L56L3MP2 N
UN number	1208
CompTox Dashboard (EPA)	DTXSID4025111
InChI InChI=1S/C6H14/c1-5-6(2,3)4/h5H2,1-4H3 YKey: HNRMPXKDFBEGFZ-UHFFFAOYSA-N Y
SMILES CCC(C)(C)C
Properties
Chemical formula	C6H14
Molar mass	86.178 g·mol−1
Appearance	Colorless liquid
Odor	Odorless
Density	649 mg mL−1
Melting point	−102 to −98 °C; −152 to −145 °F; 171 to 175 K
Boiling point	49.7 to 49.9 °C; 121.4 to 121.7 °F; 322.8 to 323.0 K
log P	3.51
Vapor pressure	36.88 kPa (at 20 °C)
Henry's lawconstant (kH)	6.5 nmol Pa−1 kg−1
Magnetic susceptibility (χ)	−76.24·10−6 cm3/mol
Refractive index (nD)	1.369
Thermochemistry
Heat capacity (C)	189.67 J K−1 mol−1
Std molarentropy (S⦵298)	272.00 J K−1 mol−1
Std enthalpy offormation (ΔfH⦵298)	−214.4 – −212.4 kJ mol−1
Std enthalpy ofcombustion (ΔcH⦵298)	−4.1494 – −4.1476 MJ mol−1
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H225, H304, H315, H336, H411
Precautionary statements	P210, P261, P273, P301+P310, P331
NFPA 704 (fire diamond)	1 3 0
Flash point	−29 °C (−20 °F; 244 K)
Autoignitiontemperature	425 °C (797 °F; 698 K)
Explosive limits	1.2–7.7%
NIOSH (US health exposure limits):
PEL (Permissible)	none[3]
Related compounds
Related alkanes	Neopentane 2,3-Dimethylbutane Triptane Tetramethylbutane 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). N verify (what is YN ?) Infobox references

Contents

• 1 Synthesis
• 2 Uses
• 3 See also
• 4 References

Synthesis

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Butlerov's student V. Goryainov originally discovered neohexane in 1872 by cross-coupling of zinc ethyl with tert-butyl iodide.[5]

2,2-Dimethylbutane can be synthesised by the hydroisomerisation of 2,3-dimethylbutane using an acid catalyst.[6]

It can also be synthesised by isomerization of n-pentane in the presence of a catalyst containing combinations of one or more of palladium, platinum, rhodium and rhenium on a matrix of zeolite, alumina, silicon dioxide or other materials. Such reactions create a mixture of final products including isopentane, n-hexane, 3-methylpentane, 2-methylpentane, 2,3-dimethylbutane and 2,2-dimethylbutane. Since the composition of the final mixture is temperature dependant the desired final component can be obtained choice of catalyst and by combinations of temperature control and distillations.[7][8][9]

Uses

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Neohexane is used as a high-octane anti-knock additive in gasoline and in the manufacture of agricultural chemicals.[10] It is also used in a number of commercial, automobile and home maintenance products, such as adhesives, electronic contact cleaners and upholstery polish sprays.[11]

In laboratory settings, it is commonly used as a probe molecule in techniques which study the active sites of metal catalysts. Such catalysts are used in hydrogen-deuterium exchange, hydrogenolysis, and isomerization reactions. It is well suited to this purpose as 2,2-dimethylbutane contains both an isobutyl and an ethyl group.[12]

See also

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• Methylbutane (isopentane)
• 2-Methylpentane (isohexane)

References

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1. ^ Haynes, William M. (2010). Handbook of Chemistry and Physics (91 ed.). Boca Raton, Florida, USA: CRC Press. p. 3-194. ISBN 978-1-43982077-3.
2. ^ "2,2-DIMETHYLBUTANE - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 26 March 2005. Identification and Related Records. Retrieved 9 March 2012.
3. ^ NIOSH Pocket Guide to Chemical Hazards. "#0323". National Institute for Occupational Safety and Health (NIOSH).
4. ^ Philosophical Magazine. Taylor & Francis. 1876.
5. ^ Журнал Русского физико-химического общества (in Russian). Тип-ія Б. Демакова. 1872.
6. ^ "2,2-dimethylbutane". National Center for Biotechnology Information. 18 July 2015. Retrieved 20 July 2015.
7. ^ Rabo, J. A.; Pickert, P. E.; Mays, R. L. (1961). "Pentane and Hexane Isomerization". Industrial & Engineering Chemistry. 53 (9). American Chemical Society (ACS): 733–736. doi:10.1021/ie50621a029. ISSN 0019-7866.
8. ^ Den Hartog, A. J.; Rek, P. J. M.; Botman, M. J. P.; De Vreugd, C.; Ponec, V. (1988). "Reactions of 2,2-dimethylbutane on platinum-rhenium/alumina catalysts. Effect of sulfur and chlorine on the selectivity". Langmuir. 4 (5). American Chemical Society (ACS): 1100–1103. doi:10.1021/la00083a006. ISSN 0743-7463.
9. ^ Brown, Ronald; Kemball, Charles; McDougall, Gordon S. (1995). "Exchange reactions of 2,2-dimethylpentane, 2,2-dimethylbutane and 2,2-dimethylpropane over Pt/SiO2 and Rh/SiO2". Journal of the Chemical Society, Faraday Transactions. 91 (7). Royal Society of Chemistry (RSC): 1131. doi:10.1039/ft9959101131. ISSN 0956-5000.
10. ^ "Hazardous Substance Fact Sheet - 2,2-Dimethylbutane" (PDF). New Jersey Department of Health. June 2008. Retrieved 2 July 2021.
11. ^ "2,2-Dimethylbutane". Consumer Products Information Database. 2021. Retrieved 2 July 2021.
12. ^ Burch, R.; Paál, Z. (1994). "The use of 2,2-dimethylbutane (neohexane) as a probe molecule of metal catalysts". Applied Catalysis A: General. 114 (1). Elsevier BV: 9–33. Bibcode:1994AppCA.114....9B. doi:10.1016/0926-860x(94)85106-9. ISSN 0926-860X.

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