Abstract: The invention relates to a process for selectively adsorbing ethylbenzene from a stream containing one or more isomeric xylenes. The ethylbenzene is adsorbed on a Beta zeolite. Certain desorbents, of which paradiethylbenzene is preferred, give the zeolite good ethylbenzene selectively over the xylenes.

Abstract: There is provided a method for the selective sorption of n-alkylbenzene, such as n-propylbenzene, from an alkylbenzene mixture, such as a mixture of n-propylbenzene and isopropylbenzene, with an oxide impregnated ZSM-5 sorbent. This method may be particularly useful in the purification of cumene product streams.

Abstract: A process for separating a C.sub.9 aromatic isomer from a feed stream containing a mixture of C.sub.9 aromatic isomers by contacting the feed stream with a bed of the adsorbent zeolite beta. The adsorbed C.sub.9 aromatic isomer is removed from the adsorbent by desorption.

Abstract: There is provided a process for the separation of aromatic hydrocarbons mixtures into single components, in which the mixtures in vapor phase pass onto an adsorption bed formed by a potassium-exchanged Y zeolite, which is preventively saturated with desorbent vapors. According to the invention the desorbent used is isopropylbenzene in vapor phase. This facilitates the quick separation of the pure components, with the exception of the presence of desorbent. The process according to this invention is quicker in comparison to traditional ones. It requires the use of lower charges of desorbent and allows the separation of single pure components of the mixtures. It especially improves the paraxylene separation in higher concentrations with respect to the desorbent.

Abstract: A process able to separate ortho-xylene from the other C.sub.8 aromatics. In the process the ortho-xylene-containing feed mixture is contacted with an X-type zeolite having silver cations at exchangeable cationic sites which has been subjected to a reduction step. The ortho-xylene is selectively adsorbed onto the adsorbent. The feed is then removed from the absorbent and the ortho-xylene recovered by desorption with para-diethylbenzene. The process is particularly amenable to the simulated moving bed flow scheme.

Abstract: A process for separating ethylbenzene from a feed mixture comprising ethylbenzene and at least one xylene isomer. The mixture is contacted with an adsorbent comprising a barium cation exchanged type-X zeolite containing from about 3.0 to about 6.0 wt. % H.sub.2 O. The unadsorbed portion of the feed mixture is removed from the adsorbent and the ethylbenzene recovered by desorption with benzene.

Abstract: An improved process for separating ortho aromatic isomers from a feed stream containing a mixture of aromatics by contacting the feed stream with a bed of the crystalline aluminophosphate adsorbent AlPO.sub.4 -5. The adsorbed ortho aromatic isomers is removed from the adsorbent by desorption.

Abstract: A process for separating the ortho-isomer from a feed mixture comprising at least two bi-alkyl substituted monocyclic aromatic isomers, including the ortho-isomers, the isomers having from 9 to about 18 carbon atoms per molecule. The process comprises contacting, at adsorption conditions, the feed with an adsorbent comprising a crystalline aluminosilicate consisting essentially of a sodium or calcium Y-type zeolite or sodium X-type zeolite which selectively adsorbs the ortho-isomers. The feed is removed from the adsorbent, and the ortho-isomers recovered by desorption at desorption conditions with a desorbent material comprising a C.sub.8 or heavier monocyclic aromatic with a boiling point at least 5.degree. C. different than that of the feed mixture when the adsorbent is the sodium Y-type zeolite, or a C.sub.8 or lighter monocyclic aromatic when the adsorbent is a sodium X or calcium Y-type zeolite.The process is particularly amenable to the employment of a simulated moving bed flow scheme.

Abstract: An adsorptive separation method capable of effectively separating the desired component from a mixture containing the same at a high purity and a high recovery ratio, and easily coping with scale-up of the apparatus is disclosed.

Abstract: An improved technique for sorption of certain members of a ZSM-5 type of zeolites is provided. The class of zeolites is characterized by a silica to alumina mole ratio greater than 12 and a Constraint Index within the approximate range of greater than about 2 to about 12. The process of this invention involves sorption and/or selective separation of bicyclic fused-ring aromatic compounds, having a critical dimension less than 6.8 Angstrom units.

Abstract: A process for separating a normal paraffin hydrocarbon from a mixture of the same with a cyclic and/or branched chain paraffin hydrocarbon. The process comprises contacting the mixture at a temperature of from about 120.degree. C. to about 140.degree. C. with a zeolite free molecular sieve comprising silicalite. The normal paraffin hydrocarbon is selectively retained and will preferably be recovered from the molecular sieve by displacement with a displacement material.

Abstract: An improved adsorptive separation process by the selective sorption properties of certain members of a novel class of zeolites is provided. The zeolites are characterized by a silica to alumina mole ratio greater than 12 and a Constraint Index within the approximate range of greater than 2 to about 12. The process of this invention involves selective separation of aromatic compounds selected from the group consisting of mono-substituted and para-disubstituted benzene ring compounds and mono-substituted pyridine ring compounds in admixture with aromatic compounds selected from the group consisting of ortho-disubstituted, meta-disubstituted and more highly substituted benzene ring compounds and poly-substituted pyridine ring compounds by contacting the mixture with said zeolite to effect the selective sorption of said aromatic compounds selected from the group consisting of mono-substituted and para-disubstituted benzene ring compounds and mono-substituted pyridine ring compounds by said zeolite.

Abstract: An improved hydrocarbon separation process by the selective sorption properties of certain members of a novel class of zeolites is provided. The novel class of zeolites is characterized by a silica to alumina mole ratio greater than 12 and a Constraint Index within the approximate range of greater than about 2 to about 12. The process of this invention involves selective separation of higher molecular weight hydrocarbon compounds in admixture with lower molecular weight hydrocarbon compounds within a homolgous series by contacting the respective mixture with a zeolite having a SiO.sub.2 /Al.sub.2 O.sub.3 mole ratio of at least about 12 and a Constraint Index with the approximate range of greater than 2 to about 12, to effect the selective sorption of said higher molecular weight hydrocarbon compounds by said zeolite.

Abstract: A process for the separation of the para-isomer from a hydrocarbon feed mixture comprising at least two bi-alkyl substituted monocyclic aromatic isomers, including the para-isomer, said isomers having from 8 to about 18 carbon atoms per molecule, which process employs an adsorbent comprising a zeolite which has been contacted at pyrolyzing conditions with a pyrolyzing agent to preferentially adsorb the para-isomer. The para-isomer thereafter is removed from the adsorbent by contacting it with a desorbent material and is recovered as a product stream. In a preferred embodiment the process uses a simulated moving-bed countercurrent flow system.

Abstract: Para-xylene may be separated as front-end product in high purity by contacting charge C-8 aromatic hydrocarbon mixture with certain NaY-type zeolites in the presence of a pyridine.

Abstract: An improved adsorption-desorption separation process is disclosed for separating close boiling fractions or isomers of a hydrocarbon feedstream containing mixed hydrocarbon fractions or isomers.

Abstract: An improved process for separating ortho aromatic isomers from a feed stream containing a mixture of aromatics by contacting the feed stream with a bed of the crystalline aluminosilicate adsorbent CSZ-1. The adsorbed ortho aromatic isomer is removed from the adsorbent by desorption.

Abstract: A process for the separation of metaxylene from aromatic C.sub.8 hydrocarbons, particularly from ethylbenzene and paraxylene, wherein a first phase is provided in which the mixture of aromatic hydrocarbons is selectively adsorbed, in vapor phase, into a catalytic bed consisting of zeolite of the Y type, preliminarily exchanged with potassium, and in a second phase a desorption is effected with a suitable solvent. The process, carried out at a temperature of 150.degree. to 200.degree. C. and preferably at atmospherical pressure, permits the recovery of metaxylene, substantially pure and at a concentration much higher than that of the starting mixture.

Abstract: A process for separating a normal paraffin from a mixture of the same with another structural class of hydrocarbon selected from the cyclic hydrocarbons having greater than six carbons per molecule and the branched chain hydrocarbons. The process comprises contacting the mixture at adsorption conditions with an adsorbent comprising silicalite. The normal paraffin is selectively adsorbed and will preferably be recovered from the adsorbent by desorption with a desorbent material.

Abstract: Para-xylene may be separated as front-end product in high purity by contacting charge C-8 aromatic hydrocarbon mixture with NaX-type or LiX-type zeolite in the presence of a pyridine.

Abstract: An adsorptive separation process for separating meta-xylene from a feed mixture comprising meta-xylene and the other C.sub.8 aromatics, which process comprises contacting the feed mixture with an adsorbent comprising type Y zeolite containing sodium at the exchangeable cationic sites and having a silica to alumina mole ratio of from about 4.5 to about 5.0, selectively adsorbing substantially all of the meta-xylene isomers to the substantial exclusion of the remaining C.sub.8 aromatics and thereafter recovering high-purity meta-xylene. A desorption step may be used to desorb the adsorbed meta-xylene. The process is carried out preferably in the liquid phase.

Abstract: A process for preparing a stream enriched in para-xylene from a mixture of para-xylene with other aromatic hydrocarbons which comprises contacting the mixture with a particular modified crystalline silicate and subsequently desorbing the para-xylene enriched stream from the silicate.

Abstract: A process for separating three components from a feedstream employing an adsorbent and desorbent material which in combination have selectivities for the components in descending order of magnitude. The process uses a simulated-moving bed counter current flow system with an intermediate raffinate stream taken off the column at about the midpoint of the adsorption zone in addition to the usual extract and raffinate product streams. In a preferred embodiment the first component is para-xylene, the second component is ethyl benzene, and the third component is a mixture of meta and ortho-xylene.

Abstract: A process for separating a first component comprising meta-xylene, a second component comprising a mixture of para-xylene and ortho-xylene and a third component comprising ethyl benzene from a feedstream employing an adsorbent comprising a Y-zeolite containing sodium ions at exchangeable cationic sites and a desorbent material comprising toluene which in combination have selectivities for the first, second and third components, respectively, in descending order of magnitude. The process uses a simulated-moving bed counter current flow system with an intermediate raffinate stream taken off the column at about the midpoint of the adsorption zone in addition to the usual extract and raffinate product streams.

Abstract: An adsorptive separation process is disclosed for separating para-aromatic isomers from a hydrocarbon feed containing a mixture of aromatic isomers, using a crystalline aluminosilicate adsorbent which has been treated with an alkyl amine preferably an alkyl amine hydrochloride. The alkyl amine treatment substantially increases the selectivity of the adsorbent for the para-xylene isomer, relative to the heavy desorbent p-DEB, thereby improving the efficiency of the separation process.

Abstract: .alpha.-Alkylstyrene impurities, such as isopropenylstyrene, are removed from styrene and nuclear alkyl derivatives of styrene, such as t-butylstyrene, containing the same by treatment with a strong acid cation exchange resin.

Abstract: Planar organic molecules, such as divinylbenzene or para-dioxin molecules, are adsorbed from mixtures of planar and non-planar molecules, such as commercial divinylbenzenes containing non-planar ethylvinylbenzene, or commercial 2,4,5-T herbicide containing non-planar 2,4,5-trichlorophenoxyacetic acid, by partially pyrolyzed, macroporous, resinous polymer particles.

Abstract: An adsorbent for separating para-xylene from C.sub.8 aromatic hydrocarbons, specifically a faujasite zeolite which contains potassium, zirconium and proton or ammonium as cation, process for separating para-xylene, and process for making the adsorbent.