Abstract: Processes for obtaining aromatic hydrocarbons from a hydrocarbon mixture a1. Mixture a1 is extractively distilled with extractive solvent a2 producing mixture bl comprising solvent a2, aromatic hydrocarbons and high boilers, and nonaromatic hydrocarbon mixture b2. Mixture b1 is distilled to aromatic hydrocarbon c1 and solvent comprising high boilers c2. Substream dl is removed from c2 and c2 is recycled to extractive distillation. Substream d1 is extracted with water producing aqueous phase e1 and organic phase e2. Aqueous phase e1 is distilled and purified solvent a2 is recovered and recycled into extractive distillation of mixture b1. Substream e2? is removed from organic phase e2 and recycled into extractive distillation of mixture b1. The amount of organic phase e2? is such that when d1 comprising solvent, high boilers, water and circulated stream e2? is dispersed, aqueous extract phase e1, forms a disperse phase and organic phase e2 a continuous phase.

Abstract: A process is proposed for distillatively obtaining pure 1,3-butadiene from crude 1,3-butadiene in a plant comprising one or more distillation columns, comprising supply of a feed stream of crude 1,3-butadiene to the one distillation column or the first of the plurality of distillation columns, the one distillation column or the plurality of distillation columns having a flange with an internal diameter of ?80 mm, comprising two mutually opposite plane-parallel surfaces (1) with an intermediate seal (2) which seals the interior of the one distillation column or of the first of the plurality of distillation columns from an intermediate space (3) on the atmosphere side between the two mutually opposite plane-parallel surfaces (1), and the intermediate space (3) on the atmosphere side between the two mutually opposite plane-parallel surfaces (1) being closed off from the atmosphere to form a chamber, wherein the chamber is purged continuously during the operation of the plant with a low-oxygen gas or a low-oxygen

Abstract: Processes for obtaining aromatic hydrocarbons from a hydrocarbon mixture comprising aromatic and nonaromatic hydrocarbons and high boilers comprising: (A) providing a hydrocarbon mixture a1 and an extractive solvent a2, (B) extractively distilling the mixture a1 with the extractive solvent to obtain a mixture b1 of extractive solvent, the aromatic hydrocarbons, and high boilers, (C) distilling the mixture b1 to one or more fractions c1 comprising aromatic hydrocarbons and the extractive solvent c2 comprising high boilers, (D) removing a substream d1 from the extractive solvent c2, (E) extracting the substream d1 of the extractive solvent with water to obtain an aqueous extract phase e1 essentially free of high boilers and an organic phase e2 comprising the high boilers, (F) distilling the aqueous extract phase e1 and recovering the extractive solvent a2. Step (E) is preceded by a distillation in which a fraction of very high-boiling hydrocarbons is removed from substream d1.

Abstract: Process for regenerating a ruthenium-containing supported hydrogenation catalyst. wherein the catalyst is treated with steam and then dried. Integrated process for hydrogenating benzene to cyclohexane in the presence of a ruthenium-containing supported catalyst, comprising, as well as the hydrogenation step. the catalyst regeneration steps.

Abstract: The invention relates to a process for obtaining aromatic hydrocarbons selected from benzene, toluene, xylene and ethylbenzene mixtures thereof from a hydrocarbon mixture which additionally comprises nonaromatic hydrocarbons and high boilers, comprising the steps of (A) providing a hydrocarbon mixture a1 and an extractive solvent a2 composed of N-formylmorpholine, (B) extractively distilling the hydrocarbon mixture a1 with the extractive solvent to obtain a mixture b1 of extractive solvent and the aromatic hydrocarbons, said mixture comprising high boilers, and a mixture b2 comprising nonaromatic hydrocarbons, (C) distilling the mixture b1 of extractive solvent and aromatic hydrocarbons obtained in step (B) to obtain one or more fractions c1 composed of aromatic hydrocarbons and the extractive solvent c2 which comprises high boilers, (D) removing a substream d1 from the extractive solvent c2 and recycling the extractive solvent c2 into the extractive distillation (B), (E) extracting the substream d1 of the ex

Abstract: The invention relates to a process for obtaining aromatic hydrocarbons selected from benzene, toluene, xylene and ethylbenzene and mixtures thereof from a hydrocarbon mixture which additionally comprises nonaromatic hydrocarbons and high boilers, comprising the steps of (A) providing a hydrocarbon mixture a1 and an extractive solvent a2 composed of N-formylmorpholine, (B) extractively distilling the hydrocarbon mixture a1 with the extractive solvent to obtain a mixture b1 of extractive solvent and the aromatic hydrocarbons, said mixture comprising high boilers, and a mixture b2 comprising nonaromatic hydrocarbons, (C) distilling the mixture b1 of extractive solvent and aromatic hydrocarbons obtained in step (B) to obtain one or more fractions c1 composed of aromatic hydrocarbons and the extractive solvent c2 which comprises high boilers, (D) removing a substream d1 from the extractive solvent c2 and recycling the extractive solvent c2 into the extractive distillation (B), (E) extracting the substream d1 of th

Abstract: A process is proposed for distillatively obtaining pure 1,3-butadiene from crude 1,3-butadiene in a plant comprising one or more distillation columns, comprising supply of a feed stream of crude 1,3-butadiene to the one distillation column or the first of the plurality of distillation columns, the one distillation column or the plurality of distillation columns having a flange with an internal diameter of ?80 mm, comprising two mutually opposite plane-parallel surfaces (1) with an intermediate seal (2) which seals the interior of the one distillation column or of the first of the plurality of distillation columns from an intermediate space (3) on the atmosphere side between the two mutually opposite plane-parallel surfaces (1), and the intermediate space (3) on the atmosphere side between the two mutually opposite plane-parallel surfaces (1) being closed off from the atmosphere to form a chamber, wherein the chamber is purged continuously during the operation of the plant with a low-oxygen gas or a low-oxygen

Abstract: A process for the continuous gas-phase oxidation of C3- and C4-precursors to (meth)acrolein and/or (meth)acrylic acid in the presence of a catalyst in a reactor which has a feed for the reaction mixture at one reactor end and removal of the reaction mixture at the opposite reactor end and which is equipped with means, arranged in the interior of the reactor, for removing the heat of reaction, through which means a heat exchange composition flows and which means are in the form of heat exchanger plates, is proposed.

Abstract: Catalysts having a bimodal pore radius distribution comprise a) from 10 to 99.9% by weight of zirconium dioxide and b) from 0 to 60% by weight of aluminum oxide, silicon dioxide and/or titanium dioxide and c) from 0.1 to 10% by weight of at least one element of main group I or II, an element of transition group III, an element of transition group VIII, of the Periodic Table of the Elements, lanthanum and/or tin, with the proviso that the sum of the percentages by weight is 100.

Abstract: A process for the preparation of maleic anhydride by heterogeneously catalyzed gas-phase oxidation in a reactor with feed for the reaction mixture at one end of the reactor and discharge of the product mixture at the opposite end of the reactor, and with devices for dissipating the heat of reaction which are arranged in the reactor interior and through which a heat-exchange medium flows and which are designed as heat-exchanger plates.

Abstract: A process for the preparation of maleic anhydride by heterogeneously catalyzed gas-phase oxidation in a reactor with feed for the reaction mixture at one end of the reactor and discharge of the product mixture at the opposite end of the reactor, and with devices for dissipating the heat of reaction which are arranged in the reactor interior and through which a heat-exchange medium flows and which are designed as heat-exchanger plates.

Abstract: A process for hydrolyzing alkyl monohalides comprises using activated carbon impregnated with alkali metal hydroxide or alkaline earth metal hydroxide in the presence of water and converting the alkyl monohalides virtually quantitatively into the corresponding alcohols. Apparatus for carrying out the process comprises at least one, preferably two, especially three, reactors (2), especially tubular reactors. The process is also particularly useful for preparing alcohols.

Abstract: A process for recycling plastic waste in a steam cracker, wherein a melt obtained from plastic waste is converted into products at from 400.degree. 550.degree. C., and a distillate fraction is separated off from the products at from 180.degree. to 280.degree. C. and is fed as feed material to a steam cracker.

Abstract: In a process for the recovery of a polymerizable useful fraction, consisting of styrene, methylstyrenes, vinyltoluenes, indene, methylindenes and fractions whose boiling points are between styrene and methylindenes, from the crack gases of a steam cracker, the sidestream of the crack gas column is divided, by means of a distillation unit, into the useful fraction and into fractions which are recycled to the crack gas column.

Abstract: A process for the preparation of 1,4-butanediol by catalytically hydrogenating maleic anhydride in the presence of an alcohol, at elevated temperature and elevated pressure and with the aid of a cobalt-containing catalyst comprises partially hydrogenating the reaction mixture in a first hydrogenation step at from 100.degree. to 200.degree. C. and at from 30 to 200 bar and subsequently post-hydrogenating the product of this first hydrogenation step, without further work-up at higher temperature and pressure than in the first hydrogenation step, in a second hydrogenation step at from 200.degree. to 300.degree. C. and at from 200 to 350 bar.