FREMGANGSMAATE FOR ISOMERISERING AV ALKYLBENZENER, SAERLIG XYLENER

PCT No. PCT/NO83/00036 Sec. 371 Date May 31, 1984 Sec. 102(e) Date May 31, 1984 PCT Filed Sep. 26, 1983 PCT Pub. No. WO84/01375 PCT Pub. Date Apr. 12, 1984.A method of isomerizing alkylbenzenes, in particular xylenes. The method is based on the application of a catalyst which comprises an inorganic oxide support containing at least one mixed oxide compound of SiO2 and Al2O3 in any proportion, and performing the isomerization at a temperature between 150 DEG and 300 DEG C. under a pressure ranging from about atmospheric to a few atmospheres. The catalyst is produced by reaction of the support with an aluminum alkyl compound of the type AlRyX3-y, wherein R=CH3, C2H5 or C3H7, y=1 or 2 and X=Cl, preferably Al(C2H5)Cl2. The support may be impregnated with platinum and/or rhenium. Characteristic features of this method are that the isomerization process can be run without any promotor, and that isomerization of xylene under moderate conditions yields a high degree of conversion and high selectivity. The process can be run with from 0 to 30% ethylbenzene in the feed stock and with or without dilution of the feed with toluene. The method is particularly applicable to converting meta-xylene to ortho- and para-xylene.