Acenaphthylene

Not to be confused with Acenaphthene.

Acenaphthylene, a polycyclic aromatic hydrocarbon is an ortho- and peri-fused tricyclic hydrocarbon. The molecule resembles naphthalene with positions 1 and 8 connected by a -CH=CH- unit. It is a yellow solid.^[3] Unlike many polycyclic aromatic hydrocarbons, it has no fluorescence.

Acenaphthylene

Names
Preferred IUPAC name Acenaphthylene[1]
Other names Cyclopenta[de]naphthalene Acenaphthalene Tricyclo[6.3.1.04,12]dodeca-1(12),2,4,6,8,10-hexaene[citation needed] Tricyclo[6.3.1.04,12]dodecahexaene[citation needed]
Identifiers
CAS Number	208-96-8 Y
3D model (JSmol)	Interactive image Interactive image
ChEBI	CHEBI:33081 Y
ChemSpider	8807 Y
ECHA InfoCard	100.005.380
PubChem CID	9161
UNII	1Z25C36811 Y
CompTox Dashboard (EPA)	DTXSID3023845
InChI InChI=1S/C12H8/c1-3-9-4-2-6-11-8-7-10(5-1)12(9)11/h1-8H Y Key: HXGDTGSAIMULJN-UHFFFAOYSA-N Y InChI=1/C12H8/c1-3-9-4-2-6-11-8-7-10(5-1)12(9)11/h1-8H Key: HXGDTGSAIMULJN-UHFFFAOYAQ
SMILES c3cc1cccc2\C=C/c(c12)c3 c1cc2cccc3c2c(c1)C=C3
Properties
Chemical formula	C12H8
Molar mass	152.196 g·mol−1
Appearance	Yellow crystals
Density	0.8987 g cm−3
Melting point	91.8 °C (197.2 °F; 364.9 K)
Boiling point	280 °C (536 °F; 553 K)
Solubility in water	Insoluble
Solubility in ethanol	very soluble
Solubility in diethyl ether	very soluble
Solubility in benzene	very soluble
Solubility in chloroform	soluble
Thermochemistry[2]
Heat capacity (C)	166.4 J mol−1 K−1
Enthalpy of fusion (ΔfH⦵fus)	186.7 kJ/mol
Enthalpy of vaporization (ΔfHvap)	69 kJ/mol
Enthalpy of sublimation (ΔfHsublim)	71.06 kJ/mol
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H310, H315, H319, H330, H335
Precautionary statements	P260, P261, P262, P264, P270, P271, P280, P284, P301+P312, P302+P350, P302+P352, P304+P340, P305+P351+P338, P310, P312, P320, P321, P322, P330, P332+P313, P337+P313, P361, P362, P363, P403+P233, P405, P501
Flash point	122 °C (252 °F; 395 K)
Related compounds
Related compounds	acenaphthene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Occurrence

Acenaphthylene occurs as about 2% of coal tar. It is produced industrially by gas phase dehydrogenation of acenaphthene.^[3]

Reactions

Hydrogenation gives the more saturated compound acenaphthene. Chemical reduction affords the radical anion sodium or potassium acenaphthalenide, which is used as a strong reductant (E = -2.26 V vs FC).^[4]

It functions as a ligand for some organometallic compounds.^[5]

Uses

Polymerisation of acenaphthylene with acetylene in the presence of a Lewis acid catalyst gives electrically conductive polymers. Acenaphthylene possesses excellent properties as an antioxidant in cross-linked polyethylene and ethylene-propylene rubber. Thermal trimerization of acenaphthylene leads to decacyclene, which can be further processed to sulfur dyes.^[6]

Toxicity

The no-observed-adverse-effect-level of acenaphthylene after repeated 28-day oral administration to both male and female rats was found to be 4 mg/kg/day.^[7]