2,2-Dimethylpentane

Last updated
2,2-Dimethylpentane
2-Dimethylpentane.png
Names
Preferred IUPAC name
2,2-Dimethylpentane
Other names
  • Neoheptane
  • 2,2-DMP
Identifiers
3D model (JSmol)
1730757
ChemSpider
ECHA InfoCard 100.008.801 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 209-680-5
PubChem CID
UNII
  • InChI=1/C7H16/c1-5-6-7(2,3)4/h5-6H2,1-4H Yes check.svgY
    Key: CXOWYJMDMMMMJO-UHFFFAOYSA-N Yes check.svgY
  • CCCC(C)(C)C
Properties
C7H16
Molar mass 100.205 g·mol−1
AppearanceColorless liquid
Odor Odorless
Density 0.67385 g cm−3 (liquid, 20 °C, 1 atm)
0.6695 g cm−3 (liquid, 25 °C, 1 atm) [1]
Melting point −123.7 °C; −190.8 °F; 149.4 K
Boiling point 79.2 °C; 174.5 °F; 352.3 K
Structure
0.0 D
Thermochemistry
221.12 J K−1 mol−1 [2]
Std molar
entropy (S⦵298)
300.3 J K−1 mol−1 [2]
-238.5 kJ mol−1 [2]
-4802.94 kJ mol−1 [2]
Hazards [3]
GHS labelling:
GHS-pictogram-flamme.svg GHS-pictogram-exclam.svg GHS-pictogram-silhouette.svg GHS-pictogram-pollu.svg
Danger
H225, H304, H315, H335, H336, H410
P210, P233, P240, P241, P242, P243, P261, P264, P271, P273, P280, P301+P310, P302+P352, P303+P361+P353, P304+P340, P312, P321, P331, P332+P313, P362, P370+P378, P391, P403+P233, P403+P235, P405, P501
Flash point 15 [4]  °C (59 °F; 288 K)
Safety data sheet (SDS) [5]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

2,2-Dimethylpentane is one of the isomers of heptane. It is also called neoheptane as it contains the (CH3)3C grouping. It has the most extreme properties of the isomers of heptane.

Contents

Preparation

A method to produce high purity 2,2-dimethylpentane is to react the grignard reagent of n-propyl bromide (CH3CH2CH2MgBr) with tert-butyl chloride ((CH3)3CCl). [6] n-PrMgCl can be used instead of the bromide. [7]

2,2-Dimethylpentane synthesis01.svg

Properties

In 1929 Graham Edgar and George Calingaert made 2,2-dimethylpentane and measured its physical characteristics for the first time. The measurements were at 20 °C, not the standard conditions used in later times. [8]

For 2,2-dimethylpentane they measured a density of 0.6737 at 20 °C with a rate of change Δd/ΔT of 0.000855. The density and boiling are the lowest of the isomers of heptane. The dielectric constant is 1.915, the lowest of the heptane isomers. The critical temperature is 247.7 °C and critical pressure 28.4 atmospheres. The refractive index at 20° is 1.38233, the same as for 2,4-dimethylpentane, equal lowest for the heptane isomers. The adiabatic compressibility is 0.0001289 and isothermal compressibility is 0.00016279 atmospheres, highest for the heptanes. The velocity of sound is 1.080 km/s which is lowest of the heptanes. Coefficient of thermal expansion is 0.001268/°, highest of the heptanes. Surface tension is 17.80 dynes/cm. Viscosity is 0.00385. The heat of combustion is 11470 cal/g which is very similar to other heptanes. [8]

Reactions

2,2-Dimethylpentane can form a clathrate hydrate with helper gas molecules. The type of clathrate formed is called "clathrate H". 2,2-Dimethylpentane was the first compound for which the structure was determined. The clathrate has 34 molecules of water per molecule, and also has xenon and hydrogen sulfide as helper molecules. The crystals are hexagonal in form and melt at 0.6 °C. This substance is important as clathrate hydrates form problems by blocking natural gas pipelines. [9]

2,2-Dimethylpentane does not react with bromine, iodine, nitric acid or chlorosulfonic acid because there are no tertiary carbon atoms (a carbon atom with only one hydrogen attached). [10]

Heating alkanes over an aluminium trichloride is used to reform to make different isomers. 2,2-Dimethylpentane does not participate in this process and so cannot be reformed, or created by reforming other heptanes. [11] [12]

Natural occurrence

2,2-Dimethylpentane exists in some crude oils at low levels [10] of about 0.01%. [13]

Related Research Articles

<span class="mw-page-title-main">Heptane</span> Chemical compound

Heptane or n-heptane is the straight-chain alkane with the chemical formula H3C(CH2)5CH3 or C7H16. When used as a test fuel component in anti-knock test engines, a 100% heptane fuel is the zero point of the octane rating scale (the 100 point is 100% iso-octane). Octane number equates to the anti-knock qualities of a comparison mixture of heptane and iso-octane which is expressed as the percentage of iso-octane in heptane, and is listed on pumps for gasoline (petrol) dispensed globally.

<span class="mw-page-title-main">3,3-Dimethylpentane</span> Chemical compound

3,3-Dimethylpentane is one of the isomers of heptane. 3,3-Dimethylpentane has a boiling point of 86.0 °C and melting point of −134.9 °C. Its density is 0.6934. The refractive index is 1.39092 at 20 °C.

<span class="mw-page-title-main">2,3-Dimethylpentane</span> Chemical compound

2,3-Dimethylpentane is an organic compound of carbon and hydrogen with formula C
7H
16, more precisely CH
3–CH(CH
3)–CH(CH
3)–CH
2–CH
3: a molecule of pentane with methyl groups –CH
3 replacing hydrogen atoms on carbon atoms 2 and 3. It is an alkane, a fully saturated hydrocarbon; specifically, one of the isomers of heptane.

Thorium(IV) hydroxide is an inorganic compound with a chemical formula Th(OH)4.

Gadolinium(III) fluoride is an inorganic compound with a chemical formula GdF3.

<span class="mw-page-title-main">Cerium(IV) hydroxide</span> Chemical compound

Cerium(IV) hydroxide, also known as ceric hydroxide, is an inorganic compound with the chemical formula Ce(OH)4. It is a yellowish powder that is insoluble in water but soluble in concentrated acids.

Nickel dicyanide is the inorganic compound with a chemical formula Ni(CN)2. It is a gray-green solid that is insoluble in most solvents.

<span class="mw-page-title-main">Praseodymium(III) hydroxide</span> Chemical compound

Praseodymium(III) hydroxide is an inorganic compound with a chemical formula Pr(OH)3.

<span class="mw-page-title-main">Neodymium(III) hydroxide</span> Chemical compound

Neodymium(III) hydroxide is an insoluble inorganic compound with the chemical formula Nd(OH)3.

<span class="mw-page-title-main">Dysprosium(III) hydroxide</span> Chemical compound

Dysprosium(III) hydroxide is an inorganic compound with the chemical formula Dy(OH)3.

<span class="mw-page-title-main">TMSR-LF1</span> Molten salt reactor prototype

TMSR-LF1 is a 2 MWt molten salt reactor (MSR) pilot plant located in northwest China.

<span class="mw-page-title-main">Neodymium compounds</span> Chemical compounds with at least one neodymium atom

Neodymium compounds are compounds formed by the lanthanide metal neodymium (Nd). In these compounds, neodymium generally exhibits the +3 oxidation state, such as NdCl3, Nd2(SO4)3 and Nd(CH3COO)3. Compounds with neodymium in the +2 oxidation state are also known, such as NdCl2 and NdI2. Some neodymium compounds have colors that vary based upon the type of lighting.

Praseodymium(III) carbonate is an inorganic compound, with a chemical formula of Pr2(CO3)3. The anhydrous form is olive green, and many of its hydrates such as heptahydrate and octahydrate are known. They are all insoluble in water.

<span class="mw-page-title-main">Europium compounds</span> Compounds with at least one europium atom

Europium compounds are compounds formed by the lanthanide metal europium (Eu). In these compounds, europium generally exhibits the +3 oxidation state, such as EuCl3, Eu(NO3)3 and Eu(CH3COO)3. Compounds with europium in the +2 oxidation state are also known. The +2 ion of europium is the most stable divalent ion of lanthanide metals in aqueous solution. Many europium compounds fluoresce under ultraviolet light due to the excitation of electrons to higher energy levels. Lipophilic europium complexes often feature acetylacetonate-like ligands, e.g., Eufod.

<span class="mw-page-title-main">Terbium compounds</span> Chemical compounds with at least one terbium atom

Terbium compounds are compounds formed by the lanthanide metal terbium (Tb). Terbium generally exhibits the +3 oxidation state in these compounds, such as in TbCl3, Tb(NO3)3 and Tb(CH3COO)3. Compounds with terbium in the +4 oxidation state are also known, such as TbO2 and BaTbF6. Terbium can also form compounds in the 0, +1 and +2 oxidation states.

<span class="mw-page-title-main">Cerium(III) acetate</span> Chemical compound

Cerium acetate is an inorganic compound with the chemical formula of Ce(CH3COO)3. It is a white powder that is soluble in water. Its 1.5 hydrate loses water at 133°C to obtain an amorphous anhydrous form, and the amorphous phase changes to crystal at 212°C, and phase changes again at 286°C.

A niobate is an oxo-acid salt formed by niobium(V), and the common forms are metaniobate (NbO3−) and orthoniobate (NbO43−). The most common niobates are lithium niobate (LiNbO3) and potassium niobate (KNbO3).

Actinium oxyfluoride is an inorganic compound, with the chemical formula AcOF. It is radioactive. It crystallises in a calcium fluoride structure. It can be obtained by reacting actinium fluoride with ammonia and water:

<span class="mw-page-title-main">Holmium(III) hydroxide</span> Chemical compound

Holmium(III) hydroxide is an inorganic compound with the chemical formula Ho(OH)3.

Cerium(III) selenate is an inorganic compound with the chemical formula Ce2(SeO4)3. It can be obtained by reacting selenic acid and cerium(III) carbonate, and the solvent is evaporated to precipitate crystals. The double salt CsCe(SeO4)2·4H2O can be obtained from mixing cerium(III) selenate and cesium selenate in an aqueous solution, and then evaporating and crystallizing the solution.

References

  1. ↑ 马沛生. 有机化合物实验物性数据手册--含碳氢氧卤部分[M]. 化学工业出版社, 2006：170.
  2. 1 2 3 4 马沛生. 有机化合物实验物性数据手册--含碳氢氧卤部分[M]. 化学工业出版社, 2006：466.
  3. ↑ "2,2-Dimethylpentane". pubchem.ncbi.nlm.nih.gov.
  4. ↑ 戈克尔. 有机化学手册[M]. 化学工业出版社, 2006：174.
  5. ↑ "Material Safety Data Sheet 2,2-Dimethylpentane, 99+%". fscimage.fishersci.com.
  6. ↑ Edgar, Graham; Calingaert, George; Marker, R. E. (May 1929). "The Preparation And Properties Of The Isomeric Heptanes. Part I. Preparation". Journal of the American Chemical Society. 51 (5): 1483–1491. doi:10.1021/ja01380a027.
  7. ↑ Soroos, Harold; Willis, H. B. (March 1941). "The Preparation of 2,2- and 3,3-Dimethylpentane". Journal of the American Chemical Society. 63 (3): 881. doi:10.1021/ja01848a515.
  8. 1 2 Edgar, Graham; Calingaert, George (May 1929). "The Preparation And Properties Of The Isomeric Heptanes. Part II. Physical Properties". Journal of the American Chemical Society. 51 (5): 1540–1550. doi:10.1021/ja01380a035.
  9. ↑ Udachin, K. A.; Ratcliffe, C. I.; Enright, G. D.; Ripmeester, J. A. (May 1997). "Structure H Hydrate: A Single Crystal Diffraction Study of 2,2-dimethylpentane·5(Xe, H2S)·34H2O". Supramolecular Chemistry. 8 (3): 173–176. doi:10.1080/10610279708034933.
  10. 1 2 Bruun, J.H.; Bruun, M.M.H. (July 1932). "Note on the probable presence of 2,2-dimethylpentane in a midcontinent petroleum". Bureau of Standards Journal of Research. 9 (1): 53. doi: 10.6028/jres.009.008 .
  11. ↑ van Eijk van Voorthuijsen, J. J. B. (3 September 2010). "The isomerization equilibria of the butanes, pentanes, hexanes and heptanes". Recueil des Travaux Chimiques des Pays-Bas. 66 (5): 323–334. doi:10.1002/recl.19470660508.
  12. ↑ Anderson, Hazel C. (1954). Bibliography of the Fischer-Tropsch Synthesis and Related Processes: Review and compilation of the literature on the production of synthetic liquid fuels and chemicals by the hydrogenation of carbon monoxide. U.S. Government Printing Office. p. 462.
  13. ↑ Atarshchikov, S. V.; Mirimanyan, A. A.; Mkrtychev, A. A. (September 2005). "Moderate-Temperature Isomerizate — A High-Octane Component of Automotive Gasoline". Chemistry and Technology of Fuels and Oils. 41 (5): 362–369. doi:10.1007/s10553-005-0081-9. S2CID   96819836.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.