Abstract: A process for separating the para and ortho isomers of a halogen substituted toluene from a feed mixture of the same. Separation of the isomers is effected by selective adsorption and desorption and is susceptible to various flow schemes for performing continuous adsorptive separations. The process uses an X type zeolite adsorbent having calcium, barium, potassium, or combinations thereof as cations and a mixed desorbent containing chlorobenzene and/or bromobenzene and alicyclic hydrocarbons.

Abstract: This invention comprises a process for separating the minor dinitrotoluene isomers, 2,3-dinitrotoluene and 3,4-dinitrotoluene from a feed mixture comprising 2,4- and 2,6-dinitrotoluene, and the minor isomers, which process comprises contacting the mixtures at adsorption conditions with an adsorbent comprising a Y type, or dealuminated Y type, zeolite, cation exchanged with Na, Ca or H, thereby selectively adsorbing the 2,3- and 3,4- isomers or 2,4- and 2-6 isomers, respectively. The remainder of the feed mixture is removed from the adsorbent and the minor isomers are recovered by desorption at desorption conditions with a desorbent material comprising an alcohol, ketone or an ester.

Abstract: A process for separating ortho- or meta-nitrobenzaldehyde from a feed mixture comprising ortho-nitrobenzaldehyde or metal-nitrobenzaldehyde and at least one other isomer from which the ortho- or metal-isomer is to be separated. The feed mixture is contacted at adsorption conditions with meta-selective adsorbent comprising a type X zeolite having sodium or lithium cations at exchangeable cationic sites or with an ortho-selective adsorbent comprising a type Y zeolite having alkali metal or alkaline earth metal cations at exchangeable cationic sites or a phosphate-substituted crystalline, aluminum silicate zeolite. Preferred desorbents are lower alkyl acetates and formates, acetonitrile and benzaldehyde.

Abstract: This invention comprises a process for separating 2,4-dinitrotoluene from a feed mixture comprising 2,4-dinitrotoluene and at least one isomer thereof, 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 K, Na, Ca, Ba, Li or Mg, thereby selectively adsorbing the 2,4-dinitrotoluene. The remainder of the feed mixture is removed from the adsorbent and the 2,4-dinitrotoluene is recovered by desorption at desorption conditions with a desorbent material comprising a C.sub.3 to C.sub.5 alcohol, a ketone, toluene, an ester or a nitrocompound.