| 摘要 |
A process for the preparation and separation of paraxylene from mixtures of C8 aromatic hydrocarbons comprising: a) the separation by adsorption of the feed mixture into a mixture (I) of para-xylene and ethylbenzene and a mixture (II) of ortho-xylene and meta-xylene; b) the separation of para-xylene by crystallization of (I) with subsequent distillation in order to obtain ethylbenzene with recirculation of the residue to the crystallization step; c) the isomerization of (II) after its distillation; d) the separation of para-xylene from the isomerizate by isomerization; e) the recirculation of the components, not adsorbed in step d), to the isomerization step. A crystalline silicate with the composition (in moles of oxides) (1,0+/-0,3) (R)2/nO (aFe2O3.bAl2O3.cGa2O3) .y(d.SiO2.eGeO2), wherein R: one or more mono- or bivalent cations, a >/= 0,1 - preferably = 1 b >/= 0 c >/= 0 -preferably = 0 a + b + c = 1 y >/= 10 -preferably less than 300 d >/= 0,1 e >/= 0 -preferably = 0 d + e = 1 n: valency of R is used as well as adsorbent or as isomerization catalyst. |
