PEP Review 95-1-5
Norbornene from Dicyclopentadiene and Ethylene
Published: July 1997
Norbornene, or bicyclo[2.2.1]-2-heptene, has been used to make polymers in a number of elastomer applications in the past. In recent commercial applications, norbornene has been used to make cyclic olefin copolymers—a new class of engineering polymers with a unique balance of properties, including low density; high transparency; and resistance to heat, water, and chemicals.
Norbornene is produced from the reaction of ethylene and cyclopentadiene (CPD) via the Diels-Alder condensation process. because CPD dimerizes spontaneously at ambient temperature, in commercial practice it is always shipped and handled as the dimer, dicyclopentadiene (DCPD). However, DCPD readily dissociates into CPD when heated to temperatures at which norbornene synthesis generally takes place.
The patent literature indicates that norbornene can be produced at elevated temperatures and pressures with a wide range of conversions and selectivities. We have based our PEP evaluation on a relatively recent patent by DuPont Canada that describes a process for producing norbornene in which high DCPD conversions and high selectivities to norbornene can be obtained. In this process, ethylene and DCPD are reacted in the presence of an inert hydrocarbon solvent at elevated temperatures and pressures, high ethylene to DCPD feed ratios, and relatively short residence times.
This review presents the economics for producing 5,000 t/yr (11 million lb/yr) of norbornene, based on the DuPont Canada process. This capacity represents a reasonable commercial scale for a specialty monomer facility.