A method for purification of a styrene-containing feedstock includes steps of introducing the styrene-containing feedstock into the middle of an extractive distillation column, and a solvent for the extractive distillation into the upper part of the column; discharging a raffinate oil from the top of the column, and a rich solvent rich in styrene from the bottom of the column. The rich solvent is then introduced into the middle of the solvent recovery column for vacuum distillation to obtain a crude styrene from the top of the solvent recovery column, and a lean solvent is discharged from the bottom of the solvent recovery column and recycled to the upper part of the extractive distillation column. A portion of the rich solvent is sent to a solvent purification zone for a liquid-liquid extraction using water to obtain a mixture of a styrene polymer and styrene.

A method for purification of a styrene-containing feedstock includes steps of introducing the styrene-containing feedstock into the middle of an extractive distillation column, and a solvent for the extractive distillation into the upper part of the column; discharging a raffinate oil from the top of the column, and a rich solvent rich in styrene from the bottom of the column. The rich solvent is then introduced into the middle of the solvent recovery column for vacuum distillation to obtain a crude styrene from the top of the solvent recovery column, and a lean solvent is discharged from the bottom of the solvent recovery column and recycled to the upper part of the extractive distillation column. A portion of the rich solvent is sent to a solvent purification zone for a liquid-liquid extraction using water to obtain a mixture of a styrene polymer and styrene.

An apparatus and method for extraction of oils from botanical material using high-pressure hydrocarbons such as propane, or butane, or mixtures thereof are described. A high-pressure propane or butane saturated liquid/vapor mixture formed by pressure reduction through a valve placed before an extraction column, thereby serving as an expansion port was employed. The apparatus is capable of both continuous liquid extraction or batch-style liquid operation through the use of a manifold valve, which directs the solvent liquid/vapor in the system to either a supply tank or an extraction column.

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.

The present invention provides a process for separating unsaturated hydrocarbons from a mixture of saturated and unsaturated hydrocarbons, which process comprises the steps of (a) contacting the mixture with a solvent;(b) allowing to form two phases in equilibrium, a first phase comprising solvent and unsaturated hydrocarbons and a second phase comprising the remainder of the mixture; (c) removing the phases separately; and (d) removing from at least one of the phases the hydrocarbons to obtain at least one product stream and regenerated solvent for use in step (a),wherein the solvent comprises dihydrolevoglucosenone or a derivative of dihydrolevoglucosenone.

The present invention provides a process for separating unsaturated hydrocarbons from a mixture of saturated and unsaturated hydrocarbons, which process comprises the steps of (a) contacting the mixture with a solvent;(b) allowing to form two phases in equilibrium, a first phase comprising solvent and unsaturated hydrocarbons and a second phase comprising the remainder of the mixture; (c) removing the phases separately; and (d) removing from at least one of the phases the hydrocarbons to obtain at least one product stream and regenerated solvent for use in step (a),wherein the solvent comprises dihydrolevoglucosenone or a derivative of dihydrolevoglucosenone.

The present invention relates to a plant and a process for producing propylene at least one oxygenate, comprising a reactor for converting the reactant mixture into a product mixture which comprises propylene and also aliphatic and aromatic C.sub.5+ hydrocarbons, at least one distillation column for removing a C.sub.5+ stream, the C.sub.5+ stream comprising at least 90 wt % of the aliphatic and aromatic C.sub.5+ hydrocarbons of the product mixture, an extractive distillation column for separating the C.sub.5+ stream into an aromatics stream and an aliphatics stream, the aliphatics stream comprising at least 90 wt % of the aliphatics of the C.sub.5+ stream, and the aromatics stream comprising at least 90 wt % of the aromatics of the C.sub.5+ stream, and an aliphatics recycle line for at least partial recycling of the aliphatics stream to the reactor. According to the invention, an aromatics recycle line is provided which returns the aromatics stream at least partially as extractant into the extractive distillation column.

The present invention relates to a plant and a process for producing propylene at least one oxygenate, comprising a reactor for converting the reactant mixture into a product mixture which comprises propylene and also aliphatic and aromatic C.sub.5+ hydrocarbons, at least one distillation column for removing a C.sub.5+ stream, the C.sub.5+ stream comprising at least 90 wt % of the aliphatic and aromatic C.sub.5+ hydrocarbons of the product mixture, an extractive distillation column for separating the C.sub.5+ stream into an aromatics stream and an aliphatics stream, the aliphatics stream comprising at least 90 wt % of the aliphatics of the C.sub.5+ stream, and the aromatics stream comprising at least 90 wt % of the aromatics of the C.sub.5+ stream, and an aliphatics recycle line for at least partial recycling of the aliphatics stream to the reactor. According to the invention, an aromatics recycle line is provided which returns the aromatics stream at least partially as extractant into the extractive distillation column.

A method for preparing a purified styrene composition is provided. The method includes providing a crude composition and subjecting the crude composition to at least one crystallization step. The crude composition contains 70% by weight or more styrene based on the total weight of the crude composition. The at least one crystallization step comprises at least one of a static crystallization stage and a dynamic crystallization stage. The crude composition contains at least one impurity selected from the group consisting of: color inducing species, oxygenates, sulfur species, alpha-methylstyrene, and mixtures thereof.