Heptane

Heptane
n-Heptane
Identifiers
CAS number 142-82-5 YesY
PubChem 8900
ChemSpider 8560 YesY
UNII 456148SDMJ YesY
ChEBI CHEBI:43098 YesY
ChEMBL CHEMBL134658 YesY
RTECS number MI7700000
Jmol-3D images Image 1
Properties
Molecular formula C7H16
Molar mass 100.21 g/mol
Appearance colourless liquid
Density 0.684 g/ml, liquid
Melting point

−90.61 °C (182.55 K)

Boiling point

98.42 °C (371.58 K)

Solubility in water Immiscible
Viscosity 0.386 cP at 25 °C
Hazards
EU classification Flammable (F)
Harmful (Xn)
Dangerous for
the environment (N)
R-phrases R11, R38, R50/53,
R65, R67
S-phrases (S2), S9, S16, S29, S33,
S60, S61, S62
NFPA 704
NFPA 704.svg
3
1
0
Flash point −4 °C
Autoignition
temperature
220 °C
Related compounds
Related alkanes Hexane
Octane
Related compounds Methylcyclohexane
Cycloheptane
 YesY (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

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 a 100% iso-octane). Octane number equates to the anti-knock qualities of a comparison mixture of heptane and isooctane which is expressed as the percentage of isooctane in heptane and is listed on pumps for gasoline dispensed in the United States and internationally.

Contents

Uses

Heptane (and its many isomers) is widely applied in laboratories as a totally non-polar solvent. As a liquid, it is ideal for transport and storage. In the grease spot test, heptane is used to dissolve the oil spot to show the previous presence of organic compounds on a stained paper. This is done by shaking the stained paper in a heptane solution for about half a minute.[citation needed]

Aqueous bromine may be distinguished from aqueous iodine by its appearance after extraction into heptane. In water, both bromine and iodine appear brown. However, iodine turns purple when dissolved in heptane, whereas the bromine solution remains brown.

Heptane is commercially available as mixed isomers for use in paints and coatings, as the rubber cement solvent "Bestine", the outdoor stove fuel "Powerfuel" by Primus, as pure n-Heptane for research and development and pharmaceutical manufacturing and as a minor component of gasoline.

Octane rating scale

n-Heptane is the zero point of the octane rating scale. It is undesirable in petrol, because it burns explosively, causing engine knocking, as opposed to branched-chain octane isomers, which burn more slowly and give better performance. It was chosen as the zero point of the scale because of the availability of very high purity n-heptane, unmixed with other isomers of heptane or other alkanes, distilled from the resin of Jeffrey Pine and from the fruit of Pittosporum resiniferum. Other sources of heptane and octane, produced from crude oil, contain a mixture of different isomers with greatly differing ratings and do not give as precise a zero point. ChevronPhillips Specialty Chemical produces a specialized grade of high purity n-Heptane (>99.0%) from crude oil through precision refining and distillation that is used in the measurement of octane rating for fuels.

Isomers and enantiomers

Heptane has nine isomers, or eleven if enantiomers are counted:

  • Heptane (n-heptane), H3C–CH2–CH2–CH2–CH2–CH2–CH3,
  • 2-Methylhexane (isoheptane), H3C–CH(CH3)–CH2–CH2–CH2–CH3,
  • 3-Methylhexane, H3C–CH2–C*H(CH3)–CH2–CH2–CH3 (chiral),
  • 2,2-Dimethylpentane (neoheptane), (H3C)3–C–CH2–CH2–CH3,
  • 2,3-Dimethylpentane, (H3C)2–CH–C*H(CH3)–CH2–CH3 (chiral),
  • 2,4-Dimethylpentane, (H3C)2–CH–CH2–CH–(CH3)2,
  • 3,3-Dimethylpentane, H3C–CH2–C(CH3)2–CH2–CH3,
  • 3-Ethylpentane, H3C–CH2–CH(CH2CH3)–CH2–CH3,
  • 2,2,3-Trimethylbutane, CH3–C(CH3)2–CH(CH3)–CH3, this isomer is also known as pentamethylethane and triptane.[1]

References

  1. ^ [1]

External links


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Look at other dictionaries:

  • Heptane — Formule brute et représentation 3D de l heptane …   Wikipédia en Français

  • heptane — [ ɛptan ] n. m. • 1890; de hept(a) et ane ♦ Chim. Hydrocarbure saturé (C7H16 ) de la série des alcanes. L heptane, point zéro sur l échelle des indices d octane. ● heptane nom masculin Hydrocarbure saturé C7H16, utilisé comme étalon pour la… …   Encyclopédie Universelle

  • Heptane — sind zu den Alkanen zählende Kohlenwasserstoffen mit der Summenformel C7H16. Es existieren neun Konstitutionsisomere: n Heptan 2 Methylhexan 3 Methylhexan 2,2 Dimethylpentan 2,3 Dimethylpentan 2,4 Dimethylpentan 3,3 Dimethylpentan 3 Ethylpentan 2 …   Deutsch Wikipedia

  • Heptane — Heptane,   Singular Heptan das, s, zu den Alkanen zählende aliphatische Kohlenwasserstoffe mit der Summenformel C7H16, die in neun Strukturisomeren auftreten können. Die Heptane sind farblose Flüssigkeiten, die mit stark rußender Flamme brennen;… …   Universal-Lexikon

  • Heptane — Hep tane, n. [Gr. epta seven.] (Chem.) Any one of several isometric hydrocarbons, {C7H16}, of the paraffin series (nine are possible, four are known); so called because the molecule has seven carbon atoms. Specifically, a colorless liquid, found… …   The Collaborative International Dictionary of English

  • Heptāne — Heptāne, Kohlenwasserstoffe von der Formel C7H16. Normales Heptan CH3.(CH2)5.CH3 findet sich im Erdöl und im Harz der Fichte Pinus Sabiniana. Aus letzterm durch Destillation gewonnen, bildet es eine farblose Flüssigkeit vom spez. Gew. 0,7, riecht …   Meyers Großes Konversations-Lexikon

  • Heptane — Heptāne, Kohlenwasserstoffe mit 7 Atomen Kohlenstoff, kommen im Petroleum, das normale H. als bei 98° siedende, nach Orangen riechende Flüssigkeit im ätherischen Öl von Pinus sabineāna Dougl. vor …   Kleines Konversations-Lexikon

  • heptane — [hep′tān΄] n. [ HEPT(A) + ANE] an alkane, C7H16, existing in several isomeric forms: the normal isomer is used in standard mixtures to test octane ratings …   English World dictionary

  • heptane — noun Any of the nine isomers of the saturated aliphatic hydrocarbon CH, obtained from petroleum, especially n heptane (CH(CH)CH) See Also: heptyl …   Wiktionary

  • heptane — heptanas statusas T sritis chemija formulė H(CH₂)₇H atitikmenys: angl. heptane rus. гептан …   Chemijos terminų aiškinamasis žodynas

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