Catalyst comprising at least one zeolite with structure type NES and ...
Catalyst comprising at least one zeolite with structure type NES and rhenium, and its use for transalkylation of alkylaromatic hydrocarbons
US Patènt # 6864400
| Invèntors: | Merlen; Elisabeth (Rueil-Malmaison, FR); Alario; Fabio (Neuilly sur Seine, FR); Ferrer; Nathalie (Montesson, FR); Martin; Olivia (Nanterre, FR) |
| Assignee: | Institut Francais DuPetrole (Rueil-Malmaison Cedex, FR) |
| Appl. No.: | 428033 |
| Filed: | May 2, 2003 |
ABSTRACT
The present invention concerns a catalyst which contain at least one zeolite with structure type NES, preferably NU-87, comprising silicon and at least one element T selected from the group formed by aluminium, iron, gallium and boron. Preferably, element T has been extracted so that the overall Si/T atomic ratio is more than 20. This zeolite is at least partially in its acid form. The binder is preferably alumina. The catalyst also contains at least one metal selected from the group formed by group VIIB, group VIB and iridium, preferably rhenium. Finally, the catalyst optionally also contains at least one metal selected from the group formed by elements from groups III and IV of the periodic table, preferably indium or tin. The present invention also concerns the use of the catalyst in a process for transalkylating alkylaromatic hydrocarbons such as toluene and alkylaromatic compounds containing at least 9 carbon atoms. In particular, this catalyst is highly effective in treating C9+ aromatic feeds containing more than 5% by weight of aromatic olefins containing 10 carbon atoms and more, this feed possibly also containing benzene.
FIELD OF THE INVÈNTION
The present invèntion relates to a catalyst which can, for example, be used in aromatic hydrocarbon transformation reactions. More precisely, it concerns a catalyst for alkylaromatic hydrocarbon transalkylation, preferably transalkylation of toluene and aromatic compounds containing at least 9 carbon atoms, to produce xylenes. The present invèntion also relates to the preparation of said catalyst and to its use in an alkylaromatic hydrocarbon transalkylation process.
PRIOR ART
A number of catalysts for dismutation and/or transalkylation have already been described in the prior art, and are based on mordenite (United States patènts U.S. Pat. No. 3,506,731, U.S. Pat. No. 4,151,120, U.S. Pat. No. 4,180,693, U.S. Pat. No. 4,210,770, U.S. Pat. No. 3,281,483, U.S. Pat. No. 3,780,121 and U.S. Pat. No. 3,629,351) or based on omega zeolite (U.S. Pat. No. 5,210,356, U.S. Pat. No. 5,371,311).
European patènt EP-B1-0 378 916 describes NU-87 zeolite, a zeolite with structure type NES, and a method for its preparation in the presence of a salt of a polymethylene diammonium cation, for example decamethonium bromide. In that patènt, rhenium is cited among numerous other elements for its hydrodehydrogenating properties.
U.S. Pat. No. 5,641,393 concerns SSZ-37 zeolite with a SiO.sub.2 /Al.sub.2 O.sub.3 ratio for the as synthesised zeolite of more than 400. The synthesis of that zeolite is different from that of NU-87 in that the template is the N,N-dimethyl-4-azoniatricyclo[5.2.2.0.sup.(2,6) ]undec-8-ene for the SSZ-37 zeolite. The importance of NU-87 zeolite with structure type NES for dismutation and/or transalkylation of alkylaromatic hydrocarbons has been demonstrated in the Applicant's French patènt FR-A-2 752 568. That patènt also mentions the importance of adding a metal such as nickel.
In EP-A1-0 731 071, the use of a catalyst based on mordenite zeolite and rhenium is described for transalkylation of aromatic C9 cuts comprising an aromatic compound containing at least one ethyl group. While rhenium is the preferred metal, other metals (Ni, Co, Mo, Cr and W) are cited as being suitable.
