In a process for producing a para-xylene enriched product from a gaseous
mixture comprising at least para-xylene, meta-xylene and ortho-xylene,
the gaseous mixture is contacted with an adsorbent capable of selectively
adsorbing para-xylene and comprising a crystalline molecular sieve having
an average crystal size between about 0.5 micron and about 20 microns.
The contacting is conducted at a temperature and pressure such that at
least part of the para-xylene in the mixture is adsorbed by the adsorbent
to produce a para-xylene-depleted effluent stream. The para-xylene is
then desorbed from said adsorbent and collected to form a para-xylene
enriched stream. The adsorption and desorption steps are repeated for a
plurality of cycles, such that the time between successive contacting
steps is no more than 10 seconds.