Abstract: A catalyst composition with a high halogenated aromatics isomerization activity, a halogenated aromatic isomerization method using said catalyst composition, and a halogenated aromatics isomerization method capable of prolonging the life or regeneration period of the catalyst. The invention also includes a catalyst composition characterized in that the maximum diameter of secondary particles of the zeolite in the formed catalyst is 5 microns or less is used to improve the halogenated aromatics isomerization activity. Furthermore, if dissolved oxygen is decreased, the life or regeneration period of the catalyst can be prolonged.

Abstract: The present invention provides a catalyst composition with a high halogenated aromatics isomerization activity, a halogenated aromatic isomerization method using said catalyst composition, and a halogenated aromatics isomerization method capable of prolonging the life or regeneration period of the catalyst.

Abstract: An adsorbing and separating agent for halogenated aromatic compounds and an adsorbing and separating method for the compounds, using an adsorbent which has a porosity of from 0.20 cc/cc to 0.37 cc/cc, a packing density of from 0.50 g/ml to 0.70 g/ml, and a grain size of from 0.1 mm to 1.0 mm.

Abstract: The invention provides an adsorbing and separating agent for halogenated aromatic compounds, and an adsorbing and separating method for the compounds. Using the adsorbing and separating agent of the invention gives a high-purity, halogenated aromatic compound isomer. In the adsorbing and separating method of the invention, the adsorbent used is prevented from being deteriorated and its life can be prolonged. The adsorbent for separating halogenated aromatic compounds of the invention has a porosity o from 0.20 cc/cc to 0.37 cc/cc, a packing density of from 0.50 g/ml to 0.70 g/ml, and a grain size of from 0.1 mm to 1.0 mm. With the adsorbent, a halogenated aromatic compound isomer is separated and recovered; or a halogenated aromatic compound having a dissolved oxygen content of at most 15 ppm by weight is separated and recovered with an adsorbent. In the method, at least one, high-purity isomer can be efficiently separated and recovered from a mixture of halogenated aromatic compound isomers.

Abstract: Aromatic hydrocarbons are efficiently converted by bringing feedstock containing from 5 to 50% by weight of an aromatic hydrocarbon having an ethyl group and a C.sub.9 alkyl aromatic hydrocarbon into contact with a catalyst capable of disproportionation, trans-alkylation and dealkylation, a secondary particle diameter of a zeolite in the catalyst being 10 .mu.m or less.

Abstract: An improved process for producing xylene from feedstock containing C.sub.9 alkyl aromatic hydrocarbons with the aid of a catalyst capable of disproportionation, rearrangement, and dealkylation, wherein said improvement comprises performing the reaction in the presence of an aromatic hydrocarbon having one or more ethyl groups in an amount of 5 to 50 wt %.