Abstract: The present invention relates to a novel anthracene derivative, a method for preparation thereof, and an organic electronic device using the same. The anthracene derivative according to the present invention can function as a hole injecting, hole transporting, electron injecting, electron transporting, or light emitting in an organic electronic device including an organic light emitting device, and in particular, used alone as a light emitting, or as a host or dopant in a host/dopant system. The organic electronic device according to the present invention exhibits excellent characteristics in terms of efficiency, drive voltage, life time, and stability.

Abstract: The invention includes an enantioselective indicator-displacement assay useful to determine enantiomeric excess (ee) enantiomeric samples colorimetrically. Determination may be by inspection of color with the naked eye, spectrographic measurement, or mathematical calculation. Concentration may also be determined. The assay may involve two independent absorption measurements. On suitable group of enantiomeric molecules to be assayed include ?-hydroxy acids. The inherent relationship between the absorbance of the indicator-displacement ensemble and the overall concentration and ee of the analyte is established through solution equilibria. The invention also includes use of the assay in drug screening and manufacturing, high throughput screening of catalysts and kits for use in conducting assays of the invention.

Abstract: The present invention relates to a method of preparing optically active amines and chiral amines prepared thereby. The method includes reacting an amine compound, a metal catalyst, a biocatalyst including a lipase, and an acyl donor compound in an organic solvent to obtain a chiral amide compound, and then hydrolyzing the chiral amide compound to obtain a chiral amine.

Abstract: The invention concerns a method for the isolation of a stereoisomer from a mixture comprising the two stereoisomers of the general formulae (I-A) and (I-A?) and/or the two stereoisomers of the general formulae (I-B) and (I-B?) in which R1, R2 and R3, identical or different, are selected from the group consisting of —H, —F, —Cl, —C1-C6-alkyl, —S—C1-C6-alkyl, —OH, —O—C1-C6-alkyl, —O—C1-C6-alkylenephenyl, —OCO—C1-C6-alkyl, —OCON(C1-C6-alkyl)2 and —O—SiR8R9R10 (in which R8, R9 and R10, identical or different, are —C1-C6-alkyl or -phenyl); R4 is —H or —C1-C6-alkyl; R5 is —C1-C6-alkyl; and R6 and R7, identical or different, are —H or —C1-C6-alkyl; or their salts with organic or inorganic acids; comprising the step (a) manipulating the mixture ratio of the stereoisomers in the mixture so that at least one of the stereoisomers is present in an enantiomeric excess.

Abstract: The present invention is directed to Form II of sertraline hydrochloride and novel methods for its preparation. According to the present invention, sertraline hydrochloride Form II may be produced directly form sertraline base or sertraline mandelate. It may also be produced from sertraline hydrochloride solvate and hydrate forms, and crystallized from new solvent systems. Pharmaceutical compositions containing sertraline hydrochloride Form II and methods of treatment using such pharmaceutical compositions are also disclosed.

Abstract: The present invention provides a process for the optical resolution of racemic tomoxetine under reaction conditions that improve reaction yields and optical purity. The invention also provides an epimerization process for the (S)-(+) enantiomer. The invention further provides the conversion of the enantiomer obtained from the optical resolution into atomoxetine or a pharmaceutically acceptable salt thereof.

Abstract: Provided is a recycling process for preparing sertraline, which may be carried out on an industrial scale.

Abstract: This invention relates to crystalline polymorphs of sertraline hydrocloride, i.e. (1S-cis)-4-(3,4-dichlorophenyl)-1,2,3,4-tetrahydro-N-methyl-1-naphtalenamine hydrochloride, denominated form I, II and V, and methods for their preparation.

Abstract: This invention relates to a method for the preparation of sertraline hydrochloride, (1S-cis)-4-(3,4-dichlorophenyl)-1,2,3,4-tetrahydro-N-methyl-1-naphtalenamine hydrochloride, in its crystalline form II.

Abstract: A method for bisformylation an arylamine compound by reacting an arylamine compound with an alkyleneamine in a reaction mixture while refluxing an acid in the reaction mixture.

Abstract: A process for preparing optically active amines, a process for preparing racemic amines which can be resolved using optically active carboxylic acids or enzymes, and racemic and optically active amines and optically active amides are described.

Abstract: Sertraline hydrochloride, (1Scis)-4-(3,4-dichlorophenyl)-1,2,3,4-tetrahydro-N-methyl-1-naphtalenaminehydrochloride, polymorph II is prepared by extracting or dissolving the sertraline base into ethyl acetate, adding isopropanol as a solvent, adding hydrogen chloride dissolved in ethyl acetate or in gaseous form, and finally isolating and drying sertraline hydrochloride polymorphic form II.

Abstract: A process for preparing 2-[(dimethylamino)methyl]-1-(3-methoxyphenyl)cyclohexanol with high stereoselectivity and high yield by reacting 2-[(dimethylamino)methyl]-cyclohexanone in a Grignard reaction with a Grignard compound of 3-bromoanisole in a suitable solvent and in the presence of an inorganic lithium salt and an ?,?-dialkoxyalkane.

Abstract: Crystalline forms of Venlafaxine hydrochloride were found, referred to hereinafter as polymorphic Forms A, B and D. Furthermore, the present invention is directed to processes for the preparation of these crystalline forms and pharmaceutical compositions comprising the crystalline forms.

Abstract: Provided are processes for preparation of crystalline sertraline hydrochloride Form II substantilly free of other polymorphic forms of sertraline hydrochloride, preferably on an industrial scale.

Abstract: A method of obtaining an enantioenriched organic compound comprising the steps of: 1) generating from a starting racemic, non-enantiopure or achiral compound a first mixture comprising at least one fluorous-tagged compound and at least one other non-fluorous tagged compound, at least one of these two compounds being enantioenriched relative to the starting compound; 2) contacting a first non-fluorous phase including the first mixture with a fluorous phase at a first phase interface, the fluorous-tagged compound distributing between the first non-fluorous phase and the fluorous phase; and 3) contacting the fluorous phase with a second non-fluorous phase at a second phase interface. The method further includes the step of having a third compound in the second non-fluorous phase that reacts with the fluorous-tagged compound to produce a second compound and the step of generating the first mixture by chemical or enzymatic kinetic resolution of a racemic or non-enantiopure compound.

Abstract: Process for the preparation of (1S,2R)-1-amino-2-indanol-(R,R)-tartrate methanol solvate, in which in a solvent a mixture of enantiomers of cis-1-amino-2-indanol reacts at an elevated temperature with (R,R)-tartaric acid and methanol and in which optically enriched (1S,2R)-1-amino-2-indanol-(R,R)-tartrate methanol solvate crystallizes out, after which the crystals are recovered, the recovery taking place at a temperature between 10 and 50° C. in the presence of 0-20 wt. % water relative to the amount of methanol plus solvent, on the understanding that if the reaction mixture is essentially free from water the recovery substantially takes place at a temperature between 30 and 50° C. Preferably the reactants are at least in part contacted with each other at an elevated temperature and only methanol is used as solvent. Preferably the amount of (1S,2R)-1-amino-2-indanol applied is between 0.02 and 0.1 g per ml of solvent.

Abstract: A process for the purification of a mixture of aromatic polyamines obtained by hydrogenation of the corresponding aromatic polynitro compounds, said mixture including the various isomers of the said amines as well as reaction by-products, including the steps of carrying out a distillation of the mixture in a distillation column, wherein a first stream, corresponding to a fraction or to all of the stream recovered at the bottom of the distillation column, is separated and is used in a chemical reaction and a second stream is separated corresponding (i) to a stream drawn off from the side in the gas phase, in the lower third of the said column, this stream representing at most 20% or more than 80% of the total volume (first and second stream); or (ii) to a fraction of the first stream, this fraction representing 2 to 50% of the volume of the first stream; in order to treat it subsequently.

Abstract: The invention relates to &agr;-sulfin- and &agr;-sulfonamino acid amides of the general formula I including the optical isomers thereof and mixtures of such isomers, wherein n is a number zero or one; R1 is C1-C12alkyl, C1-C12alkyl substituted with C1-C4alkoxy, C1-C4alkylthio, C1-C4alkylsulfonyl, C3-C8cycloalkyl, cyano, C1-C6alkoxycarbonyl, C3-C6alkenyloxycarbonyl or C3-C6alkenyloxycarbonyl; C3-C8cycloalkyl; C2-C12alkenyl; C2-C12alkynyl; C1-C12haloalkyl; or a group NR12R13 wherein R12 and R13 are each independently of the other hydrogen or C1-C6-alkyl, or together are tetra- or penta-methylene; R2 and R3 are each independently hydrogen; C1-C8alkyl; C1-C8alkyl substituted with hydroxy, mercapto, C1-C4alkoxy or C1-C4alkylthio; C3-C8alkenyl; C3-C8alkynyl; C3-C8cycloalkyl; C3-C8cycloalkyl-C1-C4alkyl; or the two groups R2 and R3 together with the carbon atom to which they are bonded form a three- to eight-membered hydrocarbon ring; R4, R5, R6 and R7 are each independently hydrogen or C1-C4alk

Abstract: A method for separating the diastereomer bases of 2-[(dimethylamino)methyl]-1-(3-methoxyphenyl)-cyclohexanol in which the separation of the diastereomer bases takes place through formation of a base hydrate.

Abstract: A mixture comprised of about 60-85% of 2,4-toluenediamine (2,4-TDA) and about 15-40% of 2,6-toluenediamine (2,6-TDA) is melted, the temperature of the mixture is lowered to a 2,4-TDA nucleation temperature, and the temperature of the mixture is gradually reduced from the nucleation temperature to about 65 to about 70° C. The resultant mixture is in the form of a solids phase enriched in 2,4-TDA, and a novel and useful liquid phase enriched in 2,6-TDA. These phases are separated. Preferably the solids are further purified by “sweating” them and removing the sweated liquid impurities. The sweated liquid can be recycled together with another charge of a mixture comprised of 2,4-TDA and 2,6-TDA. 2,4-TDA can be produced with a purity of 96-99%.

Abstract: A method for separating the diastereomer bases of 2-[(dimethylamino)methyl]-1-(3-methoxyphenyl)-cyclohexanol in which the separation of the diastereomer bases takes place through formation of a base hydrate.

Abstract: (R*,R*)-2-[(dimethylamino)methyl]-1-(3-methoxyphenyl)cyclohexanol (Tramadol) is synthesized in a Grignard reaction in the presence of an additive resulting in a higher trans:cis ratio of product than is obtained in the absence of the additive. The Grignard reaction between 3 bromoanisole and the appropriate Mannich base in the presence of an amine or ether additive gives the amine product in an improved trans/cis ratio. The base is converted to its hydrochloride and recrystallized from a low molecular weight nitrile such as acetonitrile until a greater than 98% trans/cis ratio is obtained. Recrystallization from isopropanol gives (R*,R*)2-[(dimethylamino)methyl]-1-(3-metboxyphenyl)cyclohexanol hydrochloride free of the nitrile solvent. A hydrochloride of Tramadol can be synthesized without increasing a ratio of trans:cis by including a step in which HCl is added to Tramadol base in the presence of toluene.

Abstract: A mixture of materials having different boiling points is separated into fractions having different boiling points. The separated fraction containing the desired product is stripped using the vapors of a lower boiling fraction. The process of the present invention is particularly useful for recovering a desired isomer or isomer mixture from a technical mixture obtained during production of an aromatic amine such as toluenediamine. Little or no unwanted isomer or by-product is present in the isomer or isomer mixture product of this process.

Abstract: A new polymeric material, a process for forming the material and method of using the material to separate enantiomers of chiral compounds, particularly amino acids and pharmaceuticals are disclosed. A polymeric material can be formed from polyaniline doped with a chiral acid and then extracted with a suitable base. This leaves behind a polymeric material which preferentially traps, and then selectively releases, one enantiomer of a chiral mixture brought in contact with the surface of the polymeric material. In particular, when polyaniline is doped with either R- or S-camphorsulfonic acid (CSA) it takes on a chiral structure. Removing the chiral acid dopant leads to a new chiral polyaniline. The dedoped chiral polyanilines have the ability to discriminate among enantiomers of many compounds which exist in chiral mixtures.

Abstract: The invention concerns a method for preparing an optically active alcohol of formula (I) in which the carbon atom indicated by the symbol * can have the configuration (R) or (S) and X represents a non-substituted amino group or a mono- or di-(C.sub.1 -C.sub.4)alkylamino group optionally salified from corresponding ketones by catalytic hydrogenation in the presence of a rhodium complex.

Abstract: A process for the alkoxylation of a polyetheramine to form an etheramine alkoxylate. In the process, a polyetheramine is reacted with an alkylene oxide in the presence of an alcohol to form the etheramine alkoxylate. The alcohol serves as a catalyst to allow the reaction proceed at a heightened temperature as compared to the reaction in the absence of alcohol, while at the same time limiting the amount of glycol by-product production which would otherwise typically form when higher polyetheramines are to be alkoxylated. The alcohol may be, for instance, ethanol or methanol.

Abstract: The present invention provides a process for effectively racemizing an amine compound in which an asymmetric carbon is located at the .beta.-position of the amino group or more distant therefrom, which comprises reacting the amine compound with a complex of an alkali metal and a polycyclic aromatic hydrocarbon.

Abstract: The present invention relates to a process for cleaving optically active amides to carboxylic acids and optically active amines with retention of the center of chirality, wherein the amides are hydrolyzed in the presence of a polyol or of an amino alcohol and of an alkali metal or alkaline earth metal hydroxide.

Abstract: The invention provides a process for the separation of (RR,SS) 2-dimethylaminomethyl-1-(3-methoxyphenyl) cyclohexanol hydrochloride ?(RR,SS)-Tramadol!, from a mixture consisting of (RR,SS) Tramadol and (RS,SR)-2-dimethylaminomethyl-1-(3-methoxyphenyl) cyclohexanol ?(RS,SR)-Tramadol!, which process includes combining the mixture with an electrophilic reagent, the reagent selectively reacting with the hydroxyl group of (RS,SR)-Tramadol, leaving most of the (RR,SS) Tramadol intact, and precipitating the remaining, practically pure (RR,SS) Tramadol from the mixture.

Abstract: Amine mixtures generated during the production of diaminotoluene by hydrogenating dinitrated aromatic compounds are treated to separate high boiling materials from the desired amine products. In this process, any water of reaction and any solvent are first removed from the diaminotoluene isomer mixture (TDA mixture). The low-boiling TDA isomers are then separated using a TDA isomer distillation column. In the process of the present invention, the bottom phase remaining after the initial distillation contains a mixture of m-TDA and high-boiling materials. This bottom phase is separated and concentrated until the high-boiling material content is from approximately 25 to 60 wt. %. This concentrated bottom phase is then mixed with o-TDA in a ratio of 1:1 to 1:5 and a m-/o-TDA mixture is removed by distillation. The m-/o-TDA mixture thus recovered is then returned to the TDA isomer distillation column.

Abstract: A process for racemization of an optically active 1-phenylethylamine derivative represented by formula (I): ##STR1## wherein R.sup.1 represents a phenyl group substituted at least at the ortho-position, which comprises reacting the optically active 1-phenylethylamine derivative (1) with an aldehyde compound represented by formula (2):R.sup.2 --CHO (2)where R.sup.2 represents an optionally substituted alkyl group or an optionally substituted phenyl group to form an optically active imine represented by formula (3): ##STR2## reacting the imine with an alkaline metal tert-alkoxide in an aprotic solvent, and then hydrolyzing the resultant racemic imine.

Abstract: L-amino acid amides are converted to the corresponding D-amino acid amides. An amide formed from an L-amino acid and an optically active (S)-.alpha.-alkylbenzylamine is subjected to dehydration condensation with an aryl aldehyde to form a Schiff's base, which is racemized at the amino acid moiety in the presence of a base to yield an N-allylidene-D-amino acid-(S)-amide. The less-soluble diastereomer N-allylidene-D-amino acid-(S)-amide is crystallized from the reaction mixture and recovered by means of solid/liquid separation. The N-allylidene form is readily hydrolyzed into the amino acid-(S)-amide and the starting aldehyde.

Abstract: The invention provides a process for the purification and isolation of (RR,SS)-2-dimethylaminomethyl-1-(3-methoxyphenyl)cyclohexanol from mixtures also containing the (RS,SR) isomer comprising reacting the above mixture in a solvent at elevated temperature under acidic conditions, whereby the (RS,SR) isomer is selectively converted to the (RR,SS) isomer, 1-(3-methoxyphenyl)-2-dimethylaminomethylcyclohex-6-ene, 1-(3-methoxyphenyl)-2-dimethyl-aminomethylcyclohex-1-ene or a mixture thereof, selectively precipitating the desired (RR,SS) isomer as an amine acid salt, and recrystallizing the purified product.

Abstract: Etheramine alkoxylates are described which have the formula: ##STR1## where R.sup.1 is a straight or branched alkyl, aryl or alkylaryl group of 6 to 22 carbon atoms; R.sup.3 are independently hydrogen or C.sub.1 to C.sub.3 alkyl; m averages from about 1 to about 20; and x and y each independently average from about 0 to 30, where x+y averages from about 2 to about 60. These etheramine alkoxylates have surfactant properties. Further, they may be quaternized to make other compounds which will have useful surfactant properties.

Abstract: A two-step process for the conversion of a trans-1-amino-2-hydroxycycloalkane stereoselectively to a cis-1-amino-2-hydroxycycloalkane is disclosed. The novel step, a one-step hydrolysis with formal inversion, can be used to convert an amide of a trans-1-amino-2-hydroxycycloalkane to a cis-1-amino-2-hydroxycycloalkane. Methods for obtaining the trans-1-amino-2-hydroxycycloalkanes and their amides from alkenes are also disclosed. A preferred process converts indene to cis-1-amino-2-indanol.

Abstract: The present invention relates to a process for the synthesis of chiral enantiomerically pure .beta.-amino alcohols which are extraordinarily important as therapeutic agents for the treatment of a variety of human disorders and as chiral auxiliaries in organic synthesis. The hydroboration of enamines is a versatile and convenient method for the synthesis of both racemic and enantiomerically pure .beta.-amino alcohols in high yields. This methodology enables the synthesis of virtually any .beta.-amino alcohol. Hydroboration of these enamines with chiral organic borohydrides, e.g. either mono- or diisopinocampheylborane, followed by oxidation with aqueous or solid NaOH/30% H.sub.2 O.sub.2 or Me.sub.3 NO, gives the corresponding chiral .beta.-amino alcohol. Enantiomeric excesses ranged from 60% for reactions run at 25.degree. C. to greater than 99% for reactions run at -25.degree. C.

Abstract: One chiral form of a 1-aryl-2-aminopropane is produced in preference to its enantiomer by allowing a 1-arylpropan-2-one to react with a 1-amino-1-phenylethane of predominantly one chiral form and reducing the resultant 1-(1-arylprop-2-ylideneimino)-1-phenylethane to yield phenylethane and a mixture of 1-aryl-2-aminopropanes in which one chiral form thereof is present in preference to its enantiomer. The mixture of 1-aryl-2-aminopropanes then is subjected to the action of an omega-amino acid transaminase which converts one of the two chiral forms of 1-aryl-2-aminopropane into the corresponding arylpropanone which can be separated from the remaining chiral form of the 1-aryl-2-aminopropane.

Abstract: The present invention relates to a process for the preparation of optically active amino acid amide. L-amino and D-amino acid amides are mixed in the presence of 0.5-4 equivalents of an aldehyde, relative to the quantity of amino acid amide, in the presence of a solvent and water. The mixture is converted in whole or in part by means of an optically active carboxylic acid into a salt of the amino acid amide and the carboxylic acid. A portion mainly consisting of one of the diastereoisomers of that salt is separated from the reaction mixture obtained. Instead of a mixture of L-amino and D-amino acid amides, it is also possible to use a mixture of the Schiff bases of an amino acid amide and an aldehyde, in which case it is not necessary to add extra aldehyde, and the required quantity of water amounts to at least 1 equivalent relative to the quantity of Schiff base. With this process, a high yield of optically active amino acid amide or the corresponding amino acid is rapidly obtained.

Abstract: This invention is concerned with a process for separating isomers of disubstituted benzenes, wherein a mixture of isomers of disubstituted benzenes is contacted with a substituted cyclodextrin to form inclusion complexes, and desired isomers are recovered therefrom in a highly selective manner. The invention also provides substituted cyclodextrins suited for use in the process. Substituted cyclodextrins used in the process can be recovered and used repeatedly.

Abstract: A novel process for converting trans-isomeric N-methyl-4-(3,4-dichlorophenyl)-1,2,3,4-tetrahydro-1-naphthaleneamine to cis-isomeric N-methyl-4-(3,4-dichlorophenyl)-1,2,3,4-tetrahydro-1-naphthaleneamine is disclosed. The process involves contacting trans-isomeric N-methyl-4-(3,4-dichlorophenyl)-1,2,3,4-tetrahydro-1-naphthaleneamine, or a mixture of same with up to about an equal part by weight of the corresponding cis-isomer, with a basic equilibration agent like potassium tert.-butoxide in a reaction-inert polar organic solvent to ultimately afford a cis/trans-mixture wherein the amount of cis-amine present in said mixture achieves a constant value of about 2:1 on a weight-by-weight basis. The aforesaid resultant mixture is useful as an intermediate product that ultimately leads to pure cis-(1S) (4S)-N-methyl-4-(3,4-dichlorophenyl)-1,2,3,4-tetrahydro-1-naphthaleneamine (sertraline), which is a known antidepressant agent.

Abstract: The invention relates to a process for the isomerization of o-, m- or p-toluidine, or of a mixture of them, on a zirconium-containing zeolite catalyst of the pentasil type. Catalysts of this type are distinguished by particularly high activity and a long useful life. The invention particularly relates to the preparation of m-toluidine by isomerization of o- and/or p-toluidine on zirconium-containing zeolite catalysts of the pentasil type.

Abstract: A racemate may be resolved into its enantiomers by stereoselective adsorption on a crystalline molecular sieve having an assymetric crystal structure for example zeolite ZSM11. The resolution may be assisted by the presence of an enantiomer of a compound separable from that of the racemate either preadsorbed on the molecular sieve or included in a polar solvent solution of the racemate to be treated. Resolution of an alkyl aryl sulphoxide racemate is exemplified.

Abstract: This invention comprises a process for separating 2,4-toluenediamine from a feed mixture comprising 2,4-toluenediamine and at least one isomer thereof, which process comprises contacting the mixture at adsorption conditions with an adsorbent comprising a Y type zeolite cation-exchanged with a Ni or Ca cation or an X type zeolite cation-exchanged with a cation from the group Na, Ni and K, thereby selectively adsorbing the 2,4-toluenediamine or an L type zeolite cation-exchanged with a K cation, or an X type zeolite cation exchanged with a Ba cation, thereby selectively adsorbing the 2,6-toluenediamine. The remainder of the feed mixture is removed from the adsorbent and the adsorbed toluenediamine isomer is recovered by desorption at desorption conditions with a desorbent material comprising a lower alcohol or an amine.

Abstract: The invention provides a process for the manufacture of o-toluidine and/or m-toluidine and/or p-toluidine, which comprises the two following steps (a) and (b):(a) treatment of a toluidine isomer mixture or of the not intended toluidine isomer or of one of the not intended toluidine isomers with an isomerization catalyst selected from the group of synthetic zeolites of the pentasil type,(b) isolation of the intended isomer or one of the intended isomers from the isomer mixture formed in step (a) by selective adsorption to a medium-pore or large-pore zeolite and subsequent desorption, furthermore discharge of the isolated isomer and recycling of the remaining isomer mixture to step (a).

Abstract: Separate isomers via supercritical gas extraction.

Abstract: This invention comprises a process for separating p-toluidine from a feed mixture comprising p-toluidine and o- or m-toluidine, which process comprises contacting the mixture at adsorption conditions with an adsorbent comprising an X or Y-type zeolite cation exchanged with a cation in the group Fe, Mn, Co, Ni or Zn, thereby selectively adsorbing the p-toluidine. The remainder of the feed mixture is removed from the adsorbent and the p-toluidine is recovered by desorption at desorption conditions with a desorbent material comprising aniline or an alkyl amine excluding alkyl amines having eight or more carbon atoms per molecule when the adsorbent comprises an X-type zeolite.

Abstract: The invention provides a process for the manufacture of o-toluidine and/or m-toluidine and/or p-toluidine, which comprises the two following steps (a) and (b):(a) treatment of a toluidine isomer mixture or of the not intended toluidine isomer or of one of the not intended toluidine isomers with an isomerization catalyst selected from the group of synthetic zeolites of the pentasil type,(b) isolation of the intended isomer or one of the intended isomers from the isomer mixture formed in step (a) by selective adsorption to a medium-pore or large-pore zeolite and subsequent desorption, furthermore discharge of the isolated isomer and recycling of the remaining isomer mixture to step (a).

Abstract: An adsorptive separation process for separating the para-isomers of a di-substituted benzene from a feed mixture comprising the para-isomer and at least one other isomer. One substituted group is NO.sub.2 -- and the other group is a normal hydrocarbon having less than 6 carbon atoms per molecule, the halogens, NH.sub.2 --, NO.sub.2 -- or C.tbd.N--. The process comprises contacting the feed mixture with an adsorbent comprising crystalline silica having a silica/alumina mole ratio of at least 12, selectively adsorbing substantially all of the para-isomer to the substantial exclusion of the remaining isomers and thereafter recovering high-purity para-isomer by means of desorption with an appropriate desorbent material.

Abstract: A process for selective cracking of 1,4-disubstituted benzene compounds having at least one polar substituent. Mixtures containing isomers of such a compound are brought into contact with a specified type of shape selective crystalline zeolite catalyst under conditions of temperature and pressure conducive to reaction of said benzene compound, thereby selectively reacting the 1,4-disubstituted isomer in preference to the 1,2- and 1,3-disubstituted isomers of said polar benzene compound. The shape selective zeolite catalysts employed herein are crystalline zeolites characterized by a silica to alumina ratio of at least about 12 and a constraint index within the approximate range of 1 to 12.