A first method for refining dicyclopentadiene of the present invention is characterized in that the method separates and recovers dicyclopentadiene by distilling the crude dicyclopentadiene that contains dicyclopentadiene and is obtained by removing a C5 fraction and a BTX fraction from the reaction product obtained by dimerization reaction of the cracked gasoline by-produced in an ethylene plant that uses as feed stock a C2 fraction, a C3 fraction and a C4 fraction. A second method for refining dicyclopentadiene of the present invention is characterized in that the dicyclopentadiene-containing fraction refined by distillation is brought into contact with an inert gas or a hydrocarbon gas having 1 to 3 carbon atoms.

A first method for refining dicyclopentadiene of the present invention is characterized in that the method separates and recovers dicyclopentadiene by distilling the crude dicyclopentadiene that contains dicyclopentadiene and is obtained by removing a C5 fraction and a BTX fraction from the reaction product obtained by dimerization reaction of the cracked gasoline by-produced in an ethylene plant that uses as feed stock a C2 fraction, a C3 fraction and a C4 fraction. A second method for refining dicyclopentadiene of the present invention is characterized in that the dicyclopentadiene-containing fraction refined by distillation is brought into contact with an inert gas or a hydrocarbon gas having 1 to 3 carbon atoms.

Systems and methods for recovering cyclopentadiene and/or isoprene from a mixture comprising C.sub.5 hydrocarbons are disclosed. A C.sub.5 mixture comprising cyclopentadiene and/or isoprene is flowed into a dimerization unit to form dimers. The dimers are then separated from the unreacted C.sub.5 hydrocarbons. The separated dimers are monomerized to form a stream comprising cyclopentadiene and/or isoprene, which is subsequently separated to form a first product stream comprising primarily isoprene and a second product stream comprising primarily cyclopentadiene.

Systems and methods for recovering cyclopentadiene and/or isoprene from a mixture comprising C.sub.5 hydrocarbons are disclosed. A C.sub.5 mixture comprising cyclopentadiene and/or isoprene is flowed into a dimerization unit to form dimers. The dimers are then separated from the unreacted C.sub.5 hydrocarbons. The separated dimers are monomerized to form a stream comprising cyclopentadiene and/or isoprene, which is subsequently separated to form a first product stream comprising primarily isoprene and a second product stream comprising primarily cyclopentadiene.

Systems and methods for producing dicyclopentadiene from cyclopentadiene using reactive jet mixing are disclosed. A C.sub.5 hydrocarbon mixture that comprises cyclopentadiene (C.sub.5H.sub.6) is injected as a jet stream into C.sub.5 hydrocarbon liquid in a reactor tank. Under appropriate reaction conditions, cyclopentadiene is dimerized to form dicyclopentadiene.

Systems and methods for producing dicyclopentadiene from cyclopentadiene using reactive jet mixing are disclosed. A C.sub.5 hydrocarbon mixture that comprises cyclopentadiene (C.sub.5H.sub.6) is injected as a jet stream into C.sub.5 hydrocarbon liquid in a reactor tank. Under appropriate reaction conditions, cyclopentadiene is dimerized to form dicyclopentadiene.

A hydrocarbon production method for producing hydrocarbons from a hydrocarbon mixture includes: a first extractive distillation step of performing extractive distillation of an extractive distillation target to obtain a fraction (A) in which isoprene and piperylene are enriched and a fraction (B) in which a linear hydrocarbon and a branched hydrocarbon are enriched; a first distillation step of obtaining a fraction (C) in which isoprene is enriched and a fraction (D) in which piperylene is enriched from the fraction (A); a dehydrogenation step of performing dehydrogenation or oxidative dehydrogenation of either or both of the linear hydrocarbon and the branched hydrocarbon contained in the fraction (B) to obtain a dehydrogenated product; and a recovery step of supplying the dehydrogenated product to an extractive distillation column or a distillation column and obtaining isoprene and/or piperylene from the dehydrogenated product.

A hydrocarbon production method for producing hydrocarbons from a hydrocarbon mixture includes: a first extractive distillation step of performing extractive distillation of an extractive distillation target to obtain a fraction (A) in which isoprene and piperylene are enriched and a fraction (B) in which a linear hydrocarbon and a branched hydrocarbon are enriched; a first distillation step of obtaining a fraction (C) in which isoprene is enriched and a fraction (D) in which piperylene is enriched from the fraction (A); a dehydrogenation step of performing dehydrogenation or oxidative dehydrogenation of either or both of the linear hydrocarbon and the branched hydrocarbon contained in the fraction (B) to obtain a dehydrogenated product; and a recovery step of supplying the dehydrogenated product to an extractive distillation column or a distillation column and obtaining isoprene and/or piperylene from the dehydrogenated product.

Systems and methods for recovering cyclopentadiene and/or isoprene from a mixture comprising C.sub.5 hydrocarbons are disclosed. A C.sub.5 mixture comprising cyclopentadiene and/or isoprene is flowed into a dimerization unit to form dimers. The dimers are then separated from the unreacted C.sub.5 hydrocarbons. The separated dimers are monomerized to form a stream comprising cyclopentadiene and/or isoprene, which is subsequently separated to form a first product stream comprising primarily isoprene and a second product stream comprising primarily cyclopentadiene.

Systems and methods for recovering cyclopentadiene and/or isoprene from a mixture comprising C.sub.5 hydrocarbons are disclosed. A C.sub.5 mixture comprising cyclopentadiene and/or isoprene is flowed into a dimerization unit to form dimers. The dimers are then separated from the unreacted C.sub.5 hydrocarbons. The separated dimers are monomerized to form a stream comprising cyclopentadiene and/or isoprene, which is subsequently separated to form a first product stream comprising primarily isoprene and a second product stream comprising primarily cyclopentadiene.