2-methylpentane

Structural formula
General
Surname	2-methylpentane
other names	Isohexane; i -hexane;
Molecular formula	C 6 H 14
Brief description	colorless liquid with a faint, gasoline-like odor
External identifiers / databases
EC number	203-523-4
ECHA InfoCard	100.003.204
PubChem	7892
Wikidata	Q209445
properties
Molar mass	86.18 g mol −1
Physical state	liquid
density	0.65 g cm −3
Melting point	−154 ° C
boiling point	60 ° C
Vapor pressure	227 hPa (20 ° C); 344 hPa (30 ° C); 504 hPa (40 ° C); 719 hPa (50 ° C);
solubility	very sparingly soluble in water (0.014 g l −1 at 25 ° C); soluble in ethanol;
Refractive index	1.3715 (at 20 ° C, 589 nm)
safety instructions
H and P phrases	H: 225-304-315-336-411
	P: 210-261-273-301 + 310-331
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

2-Methylpentane is a chemical compound from the group of the aliphatic , saturated hydrocarbons , more precisely the hexanes .

Extraction and presentation

2-methylpentane occurs in petroleum . The compound can also be obtained by the isomerization of n -hexane .

properties

Physical Properties

2-methylpentane is a highly flammable, volatile, colorless liquid with a faint, peculiar gasoline-like odor. According to Antoine, the vapor pressure function results from log ₁₀ (P) = A− (B / (T + C)) (P in bar, T in K) with A = 3.9640, B = 1135.41 and C = −46.578 in the temperature range from 286 to 334 K. The temperature dependence of the enthalpy of vaporization can be ^calculated according to the equation Δ _V H ⁰ = A · e ^(−βT^_r⁾ (1 − T _r ) ^β (Δ _V H ⁰ in kJ / mol, T _r = (T / T _c ) reduced temperature) with A = 45.25 kJ / mol, β = 0.2739 and T _c = 497.5 K in the temperature range between 298 K and 333 K.

The most important thermodynamic properties are listed in the following table:

property	Type	Value [unit]
Standard enthalpy of formation	Δ _f H ⁰_gas	−174.3 kJ mol ⁻¹
Enthalpy of combustion	Δ _c H ⁰_gas	−4157.7 kJ mol ⁻¹
Heat capacity	c _p	194.19 J mol ⁻¹ K ⁻¹ (25 ° C) as a liquid
Enthalpy of fusion	Δ _f H ⁰	6.27 kJ mol ⁻¹ at the melting point
Entropy of fusion	Δ _f S ⁰	53.43 kJ mol ⁻¹ at the melting point
Enthalpy of evaporation	Δ _V H ⁰	27.79 kJ mol ⁻¹ at the normal pressure boiling point of 30.1 kJ mol ⁻¹ at 25 ° C
Critical temperature	T _C	224.5 ° C
Critical pressure	P _C	30.4 bar
Critical volume	V _C	0.368 l mol ⁻¹
Critical density	ρ _C	2.72 mol·l ⁻¹

Vapor pressure function of 2-methylpentane

Temperature dependence of the heat of vaporization of 2-methylpentane

Safety-related parameters

2-methylpentane forms highly flammable vapor-air mixtures. The compound has a flash point of <−7 ° C. The explosion range is between 1.2% by volume (40 g / m ³ ) as the lower explosion limit (LEL) and 7% by volume (250 g / m ³ ) as the upper explosion limit (UEL). The ignition temperature is 300 ° C. The substance therefore falls into temperature class T3.

use

2-methylpentane is used as a solvent and is contained in cleaning agents. The compound is also used as a reference substance in spectroscopy and chromatography .

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ Entry on 2-methylpentane in the GESTIS substance database of the IFA , accessed on April 11, 2018(JavaScript required) .
↑ ^a ^b Data sheet 2-methylpentane (PDF) from Merck , accessed on October 8, 2010.
↑ Entry on 2-methylpentane in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on August 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
↑ ^a ^b entry on methylpentane. In: Römpp Online . Georg Thieme Verlag, accessed on June 16, 2014.
↑ Williamham, CB; Taylor, WJ; Pignocco, JM; Rossini, FD: Vapor Pressures and Boiling Points of Some Paraffin, Alkylcyclopentane, Alkylcyclohexane, and Alkylbenzene Hydrocarbons in J. Res. Natl. Bur. Stand. (US) 35 (1945) 219-244.
↑ ^a ^b ^c Majer, V .; Svoboda, V .: Enthalpies of Vaporization of Organic Compounds: A Critical Review and Data Compilation , Blackwell Scientific Publications, Oxford, 1985, p. 300.
↑ ^a ^b Prosen, EJ; Rossini, FD: Heats of combustion and formation of the paraffin hydrocarbons at 25 ° C in: J. Res. Natl. Bur. Stand. (US) 35 (1945) 263-267.
↑ Ohnishi, K .; Fujihara, I .; Murakami, S .: Thermodynamic properties of decalins mixed with hexane isomers at 298.15K. 1. Excess enthalpies and excess isobaric heat capacities in Fluid Phase Equilib. 46 (1989) 59-72, doi : 10.1016 / 0378-3812 (89) 80275-4 .
↑ ^a ^b Douslin, DR; Huffman, HM: Low-temperature thermal data on the five isometric hexanes in J. Am. Chem. Soc. 68 (1946) 1704-1708, doi : 10.1021 / ja01213a006 .
↑ ^a ^b ^c ^d Daubert, TE: Vapor-Liquid Critical Properties of Elements and Compounds. 5. Branched Alkanes and Cycloalkanes in J. Chem. Eng. Data 41 (1996) 365-372, doi : 10.1021 / je9501548 .
^ ^A ^b E. Brandes, W. Möller: Safety-related parameters - Volume 1: Flammable liquids and gases , Wirtschaftsverlag NW - Verlag für neue Wissenschaft GmbH, Bremerhaven 2003.

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ Entry on 2-methylpentane in the GESTIS substance database of the IFA , accessed on April 11, 2018(JavaScript required) .

[Merck-2] Data sheet 2-methylpentane (PDF) from Merck , accessed on October 8, 2010.

[CLP_100.003.204-3] Entry on 2-methylpentane in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on August 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .

[Römpp-4] try on methylpentane. In: Römpp Online . Georg Thieme Verlag, accessed on June 16, 2014.

[Williamham-5] Williamham, CB; Taylor, WJ; Pignocco, JM; Rossini, FD: Vapor Pressures and Boiling Points of Some Paraffin, Alkylcyclopentane, Alkylcyclohexane, and Alkylbenzene Hydrocarbons in J. Res. Natl. Bur. Stand. (US) 35 (1945) 219-244.

[Majer_Svoboda-6] Majer, V .; Svoboda, V .: Enthalpies of Vaporization of Organic Compounds: A Critical Review and Data Compilation , Blackwell Scientific Publications, Oxford, 1985, p. 300.

[Prosen-7] Prosen, EJ; Rossini, FD: Heats of combustion and formation of the paraffin hydrocarbons at 25 ° C in: J. Res. Natl. Bur. Stand. (US) 35 (1945) 263-267.

[8] Ohnishi, K .; Fujihara, I .; Murakami, S .: Thermodynamic properties of decalins mixed with hexane isomers at 298.15K. 1. Excess enthalpies and excess isobaric heat capacities in Fluid Phase Equilib. 46 (1989) 59-72, doi : 10.1016 / 0378-3812 (89) 80275-4 .

[Douslin-9] Douslin, DR; Huffman, HM: Low-temperature thermal data on the five isometric hexanes in J. Am. Chem. Soc. 68 (1946) 1704-1708, doi : 10.1021 / ja01213a006 .

[Daubert-10] Daubert, TE: Vapor-Liquid Critical Properties of Elements and Compounds. 5. Branched Alkanes and Cycloalkanes in J. Chem. Eng. Data 41 (1996) 365-372, doi : 10.1021 / je9501548 .

[Brandes-11] A ^b E. Brandes, W. Möller: Safety-related parameters - Volume 1: Flammable liquids and gases , Wirtschaftsverlag NW - Verlag für neue Wissenschaft GmbH, Bremerhaven 2003.