The invention relates to C.sub.5+ hydrocarbon conversion. More particularly, the invention relates to separating a vapor phase product and a liquid phase product from a heated mixture that includes steam and C.sub.5+ hydrocarbons, catalytically cracking the liquid phase product and steam cracking the vapor phase product.

The invention relates to C.sub.5+ hydrocarbon conversion. More particularly, the invention relates to separating a vapor phase product and a liquid phase product from a heated mixture that includes steam and C.sub.5+ hydrocarbons, catalytically cracking the liquid phase product and steam cracking the vapor phase product.

A process for extracting isoprene from a pyrolysis gas mixture or a C5 fraction wherein isoprene is purified by plural extractive distillations in the presence of a polar solvent and cyclopentadiene is effectively removed and recycled as a feedstock without being converted into its dimer, dicyclopentadiene. The isoprene recovered from the process described is more than 99.5% pure.

A process for extracting isoprene from a pyrolysis gas mixture or a C5 fraction wherein isoprene is purified by plural extractive distillations in the presence of a polar solvent and cyclopentadiene is effectively removed and recycled as a feedstock without being converted into its dimer, dicyclopentadiene. The isoprene recovered from the process described is more than 99.5% pure.

A process for extracting isoprene from a pyrolysis gas mixture or a C5 fraction wherein isoprene is purified by plural extractive distillations in the presence of a polar solvent and cyclopentadiene is effectively removed and recycled as a feedstock without being converted into its dimer, dicyclopentadiene. The isoprene recovered from the process described is more than 99.5% pure.

A process for liquid-liquid extraction of an oil-blend of non-uniform oligomeric and polymeric components comprising: (a) preselecting a desired molecular weight (Mw) boundary between heavy and light components; (b) selecting an extractive solvent or an extractive mixture of solvents, which form essentially a single phase with the light components; (c) mixing the oil-blend and the extractive solvent or extractive mixture of solvents selected in step (b) at elevated temperature, which is at least at or above said fractionation temperature, and wherein the extractive solvent/mixture of solvents to oil-blend ratio is from 1:2 to 100:1; (d) allowing a phase split to form between the heavy components fraction and the light components/extractive solvent fraction at the fractionation temperature or at most 10° C. below the fractionation temperature; (e) followed by separation of said fractions.

A process for liquid-liquid extraction of an oil-blend of non-uniform oligomeric and polymeric components comprising: (a) preselecting a desired molecular weight (Mw) boundary between heavy and light components; (b) selecting an extractive solvent or an extractive mixture of solvents, which form essentially a single phase with the light components; (c) mixing the oil-blend and the extractive solvent or extractive mixture of solvents selected in step (b) at elevated temperature, which is at least at or above said fractionation temperature, and wherein the extractive solvent/mixture of solvents to oil-blend ratio is from 1:2 to 100:1; (d) allowing a phase split to form between the heavy components fraction and the light components/extractive solvent fraction at the fractionation temperature or at most 10° C. below the fractionation temperature; (e) followed by separation of said fractions.

A process for liquid-liquid extraction of an oil-blend of non-uniform oligomeric and polymeric components comprising: (a) preselecting a desired molecular weight (Mw) boundary between heavy and light components; (b) selecting an extractive solvent or an extractive mixture of solvents, which form essentially a single phase with the light components; (c) mixing the oil-blend and the extractive solvent or extractive mixture of solvents selected in step (b) at elevated temperature, which is at least at or above said fractionation temperature, and wherein the extractive solvent/mixture of solvents to oil-blend ratio is from 1:2 to 100:1; (d) allowing a phase split to form between the heavy components fraction and the light components/extractive solvent fraction at the fractionation temperature or at most 10° C. below the fractionation temperature; (e) followed by separation of said fractions.

An integrated refinery process for removing mercaptans from a hydrocarbon stream containing mercaptans and converting by-product disulfide oil to useful products. The process includes introducing the hydrocarbon stream containing mercaptans into an extraction vessel containing an alkaline solution and passing the hydrocarbon stream through an extraction section of the extraction vessel which includes one or more liquid-liquid contacting decks for reaction to convert the mercaptans to alkali metal alkanethiolates. Further, the process includes withdrawing a hydrocarbon product stream free of mercaptans from the extraction vessel and recovering spent caustic containing alkali metal alkanethiolates from the extraction vessel. Additionally, the process includes subjecting the spent caustic containing alkali metal alkanethiolates to air oxidation to produce a by-product stream containing disulfide oils (DSO) and sulfides and processing the by-product stream in a steam cracking unit to produce a DSO free product stream.

An integrated refinery process for removing mercaptans from a hydrocarbon stream containing mercaptans and converting by-product disulfide oil to useful products. The process includes introducing the hydrocarbon stream containing mercaptans into an extraction vessel containing an alkaline solution and passing the hydrocarbon stream through an extraction section of the extraction vessel which includes one or more liquid-liquid contacting decks for reaction to convert the mercaptans to alkali metal alkanethiolates. Further, the process includes withdrawing a hydrocarbon product stream free of mercaptans from the extraction vessel and recovering spent caustic containing alkali metal alkanethiolates from the extraction vessel. Additionally, the process includes subjecting the spent caustic containing alkali metal alkanethiolates to air oxidation to produce a by-product stream containing disulfide oils (DSO) and sulfides and processing the by-product stream in a steam cracking unit to produce a DSO free product stream.