1,3-Cyclopentadiene(CAS#542-92-7)
nature
Colorless, flowing, flammable liquid, highly volatile, with a terpene like odor
Melting point -85 ℃,
boiling point 41.5 ℃
Relative density 0.8024,
refractive index 1.4429
Spontaneous combustion point 640 ℃ (in air)
Insoluble in water, easily soluble in organic solvents such as ethanol, ether, benzene, acetone, carbon tetrachloride, etc
Due to the presence of two double bonds and one active methylene group, the property is very lively
It is also easy to polymerize into dicyclopentadiene at room temperature, but it can still be converted into cyclopentadiene when heated (176.6-190 ℃)
The heat of evaporation of monomer cyclopentadiene is 354 719 5J/mol
Preparation method
Recovering cyclopentadiene from industrial by-products.
(1) Starting from the crude benzene fraction of coal tar, dimeric cyclopentadiene is obtained by polymerization, distillation, and separation, followed by thermal cracking at 350-370 ℃.
(2) Cracking natural gas and petroleum hydrocarbons at high temperatures produces cyclopentadiene under appropriate conditions.
The synthesis method uses cyclopentene or cyclopentane as raw materials, activated alumina, chromium oxide, and potassium oxide as catalysts, and dehydrogenation is carried out at a reaction temperature of 600 ℃ and a pressure of 2666-3333Pa to produce cyclopentadiene. In addition, 1,4-pentadiene and 1,3-pentadiene can be used as raw materials to produce cyclopentadiene.
purpose
Mainly used for manufacturing diene pesticides, plastics, coatings, Used for medications, fragrances, synthetic rubber, petroleum resins, high-energy fuels, etc.
