Cyclopentane

Structural formula
General
Surname	Cyclopentane
other names	Pentamethylene
Molecular formula	C 5 H 10
Brief description	colorless liquid with a gasoline-like odor
External identifiers / databases
EC number	206-016-6
ECHA InfoCard	100.005.470
PubChem	9253
ChemSpider	8896
Wikidata	Q80260
properties
Molar mass	70.13 g mol −1
Physical state	liquid
density	0.74 g cm −3 (20 ° C)
Melting point	−94 ° C
boiling point	49 ° C
Vapor pressure	346 hPa (20 ° C); 513 hPa (30 ° C); 739 hPa (40 ° C); 1040 hPa (50 ° C);
solubility	practically insoluble in water (156 mg l −1 at 25 ° C); miscible with many organic solvents;
Refractive index	1.4065 (20 ° C)
safety instructions
GHS hazard labeling from Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger
H and P phrases	H: 225-412
	P: 210-233-240-273-403 + 235
MAK	Switzerland: 600 ml m −3 or 1720 mg m −3
Toxicological data	11400 mg kg −1 ( LD 50 , rat , oral )
	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

Cyclopentane is a colorless liquid belonging to the cycloalkane group .

properties

The skeletal formula shown in the info box does not reflect the “real” molecular structure. The five carbon atoms are not in one plane. In addition, the molecule is "flexible"; that is, its atoms are in constant motion in the molecular association (see article pseudorotation ). The energetically favorable conformations are the so-called envelope conformation (Engl. Envelope conformation ) and the half-chair conformation ( half-chair conformation ).

Envelope conformation of cyclopentane
Half-chair conformation of cyclopentane

Cyclopentane melts at −94 ° C and boils at 49 ° C. Cyclopentane is practically insoluble in water, but it is miscible with many organic solvents . The vapor pressure is 346 hPa at 20 ° C, the liquid is highly volatile. The density is 0.75 g / ml at 20 ° C. Cyclopentane smells like gasoline. The flash point is −51 ° C, the ignition temperature is 320 ° C.

Use and occurrence

Cyclopentane occurs in petroleum . It is used, among other things, as a solvent for organic substances. Since the 1990s, cyclopentane (possibly mixed with its other isomers or C4 hydrocarbons) has also been used as a (physical) blowing agent in the manufacture of rigid polyurethane foams. Most of the newer household refrigerators in Germany contain the hydrocarbon isobutane as a refrigerant and the hydrocarbon cyclopentane as a foaming agent.

By the oxidation of cyclopentane can be cyclopentanone synthesize.

safety instructions

Cyclopentane is highly flammable and slightly hazardous to water (WGK 1). Due to its low boiling point of 49 ° C and its flash point of −51 ° C, it forms easily flammable vapor-air mixtures. The explosion range is between 1.5 vol.% As the lower explosion limit (LEL) and 8.7 vol.% As the upper explosion limit (UEL). With a minimum ignition energy of 0.24 mJ, vapor-air mixtures are extremely ignitable. High concentrations of cyclopentane can cause unconsciousness.

Web links

Commons : Cyclopentane - Collection of pictures, videos and audio files

Wiktionary: Cyclopentane - explanations of meanings, word origins, synonyms, translations

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m Entry on cyclopentane in the GESTIS substance database of the IFA , accessed on January 8, 2018(JavaScript required) .

↑ Entry on cyclopentane. In: Römpp Online . Georg Thieme Verlag, accessed on November 10, 2014.

↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-130.

↑ Entry on Cyclopentane in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .

↑ Swiss Accident Insurance Fund (Suva): Limit values - current MAK and BAT values (search for 287-92-3 or cyclopentane ), accessed on November 2, 2015.

↑ Cyclopentane data sheet (PDF) from Merck , accessed on January 19, 2011.

↑ Shell Devel. Co., Patent, US 2391740 1944 .

↑ Fenn, JB: Lean flammability limit and minimum spark ignition energy in Ind. Eng. Chem. 43 (1951), pp. 2865-2869.

↑ Calcote, HF; Gregory, CA; Barnett, CM; Gilmer, RB: Spark Ignition - Effect of Molecular Structure in Ind. Eng. Chem. 44 (1952), pp. 2656-2662.

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m Entry on cyclopentane in the GESTIS substance database of the IFA , accessed on January 8, 2018(JavaScript required) .

[2] Entry on cyclopentane. In: Römpp Online . Georg Thieme Verlag, accessed on November 10, 2014.

[CRC90_3_130-3] David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-130.

[CLP_100.005.470-4] Entry on Cyclopentane in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .

[5] Swiss Accident Insurance Fund (Suva): Limit values - current MAK and BAT values (search for 287-92-3 or cyclopentane ), accessed on November 2, 2015.