An extractive distillation column system contains a combination column and a side rectification column. A process can be used for separation of butenes from C4-hydrocarbon streams using the extractive distillation column system.

An extractive distillation column system contains a combination column and a side rectification column. A process can be used for separation of butenes from C4-hydrocarbon streams using the extractive distillation column system.

An extractive distillation column system contains a combination column and a side rectification column. A process can be used for separation of butenes from C4-hydrocarbon streams using the extractive distillation column system.

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.

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.

The invention relates to a hydrogel product comprising glycosaminoglycan molecules as the swellable polymer, wherein the glycosaminoglycan molecules are covalently crosslinked via crosslinks comprising a spacer group selected from the group consisting of di-, tri-, tetra-, and oligosaccharides.

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.