Abstract: Ethylbenzene can be substantially hydrode-ethylated to benzene with a minimized loss of xylene by placing a C.sub.8 aromatic hydrocarbon mixture containing ethylbenzene and xylene in the presence of hydrogen in contact with a catalyst comprising 0.6 to 20.0 parts by weight of rhenium, 100 parts by weight of an acid type of a zeolite having a main cavity inlet composed of a 10-membered oxygen ring and 100 to 900 parts by weight of alumina, which has been subjected to sulfiding.

Abstract: By using a catalyst containing an acid type zeolite and at least one component of metal selected from the group consisting of rhenium, nickel and silver and isomerizing a mixture of the isomers of dichlorotoluene in the presence of hydrogen, the concentration of at least one or more components of the isomers of dichlorotoluene can be increased. According to this method, there is provided a process for isomerization of DCT which exhibits a high isomerization capacity not degraded with reaction time.

Abstract: A specific isomer of a trisubstituted benzene is continuously separated from a mixture containing at least two isomers of the trisubstituted benzene by adsorptive separation using a simulated moving bed, wherein a faujasite type zeolite adsorbent is used as the adsorpent and the specific isomer is separated as the extract component in the presence of a substituted benzene compound. The specific isomer to be separated is, for example, 2,6-dichlorotoluene, 3,5-dichlorotoluene and 2-chloro-m-xylene. The substituted benzene compound is preferably a compound represented by the formula: ##STR1## wherein R.sup.1 is H or CH.sub.3, R.sup.2 is H, CH.sub.3 or Cl and R.sup.3 is CH.sub.3 or Cl, with the proviso that the case where R.sup.1 is CH.sub.3, R.sup.2 is Cl and R.sup.3 is Cl is excluded.

Abstract: Provided is a process for separating a halogenated toluene isomer from a feed containing a mixture of halogenated toluene isomers by adsorptive separation techniques using a Y type zeolite as an adsorbent and an alkyl aromatic hydrocarbon, 3,4-dihalotoluene or 4-haloorthoxylene as a desorbent.

Abstract: A crystalline aluminosilicate zeolite is obtained by stirring under heating an aqueous reaction mixture containing a silica source, an alumina source, an alkali source and an organic carboxylic acid.

Abstract: A crystalline aluminosilicate zeolite is obtained by stirring under heating an aqueous reaction mixture containing a silica source, an alumina source, an alkali source and an organic carboxylic acid not containing an aromatic ring preferably having 3 to 6 carbon atoms and 1 to 3 carboxyl groups.

Abstract: Provided is a process for isomerizing a halogenated toluene using an acid form of zeolite as a catalyst.