cyclopentadiene

Cyclopentadiene

1,3-Cyclopentadiene;R-Pentine;Pentole;Pyropentylene;Cyclopentadiene;26912-33-4;2351150-22-4

542-92-7

C5H6

InChIKey=ZSWFCLXCOIISFI-UHFFFAOYSA-N

66.10114

66.10

208-835-4

5DFH9434HF

0857

1993

DTXSID0027191

Colorless liquid

Pesticide Intermediates

0

1.79

Cyclopentadiene is a colorless liquid with an irritating, terpene-like odor. Bp: 42.5°C; Flash point: 77°F. Density: 0.805 g cm-3.

0.8021 g/cm³ @ Temp: 20 °C

-85 °C

41.5-42.1 °C @ Press: 760 Torr

-32.2±13.0 °C

1.503

10.3 mM at 25 °C (shake flask-UV spectrophotometry, Streitwieser and Nebenzahl, 1976)

Monomer may largely be prevented from dimerizing by storage at -80 deg C or below.

381 at 20.6 °C, 735 at 40.6 °C, 1,380 at 60.9 °C (Stoeck and Roscher, 1977)

Relative vapour density (air = 1): 2.3

Oral-rat LD50: 113 mg/kg; Oral-Mouse LD50: 800 mg/kg

It is flammable in case of open flame, high temperature, oxidant; strong decomposition at high temperature; burning produces irritating smoke

The substance can readily form explosive peroxides on contact with air. The substance will readily polymerize to dimer with fire or explosion hazard. The reaction is accelerated by peroxides or trichloroacetic acid.

MONOMERIC FORM HAS TERPENE ODOR IN VAPOR STATE

Henry's Law constant = 2.12X10-2 atm-cu m/mol at 25 °C (est)

MP: -85 °C. Density: 0.8235 at 0 °C/4 °C; 0.8131 at 10 °C/4 °C; 0.7966 at 25 °C/4 °C; 0.7914 at 30 °C/4 °C|Cyclopentadiene polymerizes to dicyclopentadiene on standing; accelerated by peroxides or trichloroacetic acid.|Dimer has camphor-like odor. /dicyclopentadiene/|Cyclopentadiene undergoes self-condensation in a Diels-Alder reaction. /Cyclopentadiene/|Hydroxyl radical reaction rate constant = 1.4X10-10 cu cm/molec-sec at 25 °C (est)|Ozone radical reaction rate constant = 3.2X10-16 cu cm/molec-sec at 25 °C (est)

No rapid reaction with air No rapid reaction with water

Hydrocarbons, Aliphatic Unsaturated

Highly Flammable

CYCLOPENTADIENE is incompatible with strong oxidizing agents. Ignites on contact with oxygen (O2) and ozone (O3). Explodes on contact with fuming nitric acid or a mixture of sulfuric acid and nitrogen tetroxide. Reacts vigorously on contact with potassium hydroxide and other strong bases. Mixtures with air are explosive. Presents a moderate explosion hazard when exposed to heat or flame. Decomposes violently at high temperature and pressure. May form explosive peroxides in storage. Undergoes a spontaneous dimerization at room temperature to give DICYCLOPENTADIENE (C10H12, CAS No: 77-73-6), which is a low-melting solid (melting point: 32.5° C). The reaction is strongly exothermic (Hazardous Chemicals Desk Reference, p. 360 (1987)), but occurs sufficiently slowly that cyclopentadiene can be said to be stable at room temperature. The dimerization accounts for the partial or complete solidification of liquid cyclopentadiene in storage. Polymerization occurs more rapidly and extensively at higher temperatures. When heated to 180-200° C, cyclopentadiene gives polycyclopentadiene, a white waxy solid. Stronger heating breaks down polycyclopentadiene and re-generates the monomeric cyclopentadiene as a vapor. The vapor decomposes violently at higher temperatures and pressures.

640 °C

8.56 eV

Class IC Flammable Liquid: Fl.P. at or above 73°F and below 100°F.

The vapour is heavier than air.