The disclosure provides methodology for the synthesis of mono-alkylated cyclopentadiene structures, which can be obtained via fulvene intermediates. In one embodiment, the cyclopentadiene ring is substituted with a trialkylsilyl moiety, which enables the further reaction with certain metal halides to form metal adducts. For example, the monoalkyl cyclopentadienes substituted with a trimethylsilyl group can be reacted with TiCl.sub.4 to provide R*CpTiCl.sub.3 complexes, wherein R* is a group of the formula ##STR00001##
wherein R.sup.1 and R.sup.2 are as defined herein.

The disclosure provides methodology for the synthesis of mono-alkylated cyclopentadiene structures, which can be obtained via fulvene intermediates. In one embodiment, the cyclopentadiene ring is substituted with a trialkylsilyl moiety, which enables the further reaction with certain metal halides to form metal adducts. For example, the monoalkyl cyclopentadienes substituted with a trimethylsilyl group can be reacted with TiCl.sub.4 to provide R*CpTiCl.sub.3 complexes, wherein R* is a group of the formula ##STR00001##
wherein R.sup.1 and R.sup.2 are as defined herein.

A system and a process for dimerizing cyclopentadiene (CPD) including producing a C.sub.6+C.sub.7 rich bottoms stream and a C.sub.5 rich side draw from a debutanizer, where the C.sub.5 rich side draw and at least a portion of the C.sub.6+C.sub.7 rich bottoms stream are directed to a dimerizer where the CPD is thermally dimerized to dicyclopentadiene (DCPD). DCPD is more stable than CPD and thus safer to handle.

A system and a process for dimerizing cyclopentadiene (CPD) including producing a C.sub.6+C.sub.7 rich bottoms stream and a C.sub.5 rich side draw from a debutanizer, where the C.sub.5 rich side draw and at least a portion of the C.sub.6+C.sub.7 rich bottoms stream are directed to a dimerizer where the CPD is thermally dimerized to dicyclopentadiene (DCPD). DCPD is more stable than CPD and thus safer to handle.

A preparation process of 5-ethylidene-2-norbornene, including: introducing dicyclopentadiene into a dicyclopentadiene decomposition reactor to thermally decompose the dicyclopentadiene; introducing a product of the above step into a cyclopentadiene purification tower; introducing 1,3-butadiene, a solvent, and cyclopentadiene separated from the top of the cyclopentadiene purification tower into a Diels-Alder reactor to react the same; introducing a product of the immediate above step into a 1,3-butadiene removal tower to recover 1,3-butadiene from the top; introducing a mixture at the bottom of the 1,3-butadiene removal tower into a desolvation tower, and recycling a solvent and unreacted raw materials recovered from the top of the desolvation tower to the dicyclopentadiene decomposition reactor; introducing a mixture at the bottom of the desolvation tower into a 5-vinyl-2-norbornene separation tower to separate 5-vinyl-2-norbornene; and introducing the 5-vinyl-2-norbornene into an isomerization reactor to react the same.

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.

The disclosure provides methodology for the synthesis of mono-alkylated cyclopentadiene structures, which can be obtained via fulvene intermediates. In one embodiment, the cyclopentadiene ring is substituted with a trialkylsilyl moiety, which enables the further reaction with certain metal halides to form metal adducts. For example, the monoalkyl cyclopentadienes substituted with a trimethylsilyl group can be reacted with TiCl.sub.4 to provide R*CpTiCl.sub.3 complexes, wherein R* is a group of the formula

##STR00001##

wherein R.sup.1 and R.sup.2 are as defined herein.

A system and a process for dimerizing cyclopentadiene (CPD) including producing a C.sub.6+C.sub.7 rich bottoms stream and a C.sub.5 rich side draw from a debutanizer, where the C.sub.5 rich side draw and at least a portion of the C.sub.6+C.sub.7 rich bottoms stream are directed to a dimerizer where the CPD is thermally dimerized to dicyclopentadiene (DCPD). DCPD is more stable than CPD and thus safer to handle.

A system and a process for dimerizing cyclopentadiene (CPD) including producing a C.sub.6+C.sub.7 rich bottoms stream and a C.sub.5 rich side draw from a debutanizer, where the C.sub.5 rich side draw and at least a portion of the C.sub.6+C.sub.7 rich bottoms stream are directed to a dimerizer where the CPD is thermally dimerized to dicyclopentadiene (DCPD). DCPD is more stable than CPD and thus safer to handle.