METHOD FOR PREPARING A MULTI-METAL CATALYST HAVING AN OPTIMIZED SITE PROXIMITY

Abstract

The invention concerns a process for preparing a catalyst comprising at least one metal M from the platinum group, tin, a phosphorus promoter, a halogenated compound, a porous support and at least one promoter X1 selected from the group constituted by gallium, indium, thallium, arsenic, antimony and bismuth. The promoter or promoters X1 and the phosphorus are introduced during one or more sub-steps a1) or a2), the sub-step a1) corresponding to synthesis of the precursor of the main oxide and sub-step a2) corresponding to shaping the support. The tin is introduced during at least one of sub-steps a1) and a2). The product is dried and calcined before depositing at least one metal M from the platinum group. The ensemble is then dried in a stream of neutral gas or a stream of gas containing oxygen, and then is dried. The invention also concerns the use of a catalyst obtained by said process in catalytic reforming or aromatics production reactions.

Claims

1. A process for preparing a catalyst comprising at least one metal M from the platinum group, tin, a phosphorus promoter, a halogenated compound, a porous support and at least one promoter X1 selected from the group constituted by gallium, indium, thallium, arsenic, antimony and bismuth, said process comprising the following steps: a) introducing the promoter or promoters X1 and phosphorus during one of sub-steps a1) or a2), said sub-step a1) corresponding to synthesis of a precursor of the main oxide, said sub-step a2) corresponding to shaping the support; b) introducing tin during at least one of the sub-steps a1) and a2), the steps a) and b) possibly being consecutive or simultaneous; c) drying the product obtained at the end of step b); d) calcining the product obtained in step c) at a temperature in the range 350° C. to 650° C.; e) depositing at least one metal M from the platinum group; f) drying in a stream of neutral gas or a stream of gas containing oxygen, at a moderate temperature not exceeding 150° C.; g) calcining the product obtained in step f) at a temperature in the range 350° C. to 650° C.

2. A process for preparing a catalyst according to claim 1, in which the atomic ratio Sn/M is in the range 0.5 to 4.0.

3. A process for preparing a catalyst according to claim 1, in which the ratio X1/M is in the range 0.1 to 5.0.

4. A process for preparing a catalyst according to claim 1, in which the ratio P/M is in the range 0.2 to 30.0.

5. A process for preparing a catalyst according to claim 1, in which the quantity of metal M is in the range 0.01% to 5% by weight.

6. A process for preparing a catalyst according to claim 1, in which the metal M is platinum or palladium.

7. A process for preparing a catalyst according to claim 1, in which the halogenated compound is selected from the group constituted by fluorine, chlorine, bromine and iodine.

8. A process for preparing a catalyst according to claim 1, in which the quantity of halogenated compound is in the range 0.1% to 15.0% by weight.

9. A process for preparing a catalyst according to claim 1, in which the halogenated compound is chlorine and the chlorine content is in the range 0.1% to 5.0% by weight.

10. A process for preparing a catalyst according to claim 1, in which the support comprises at least one oxide selected from the group constituted by oxides of magnesium, titanium, zirconium, aluminium and silicon.

11. A process for preparing a catalyst according to claim 1, in which the tin is only introduced in part during synthesis or shaping of the support, the process then comprising a supplemental step for depositing a complementary fraction of the tin onto the support, either between steps d) and e), followed or not followed by drying and calcining, or between steps e) and f), or after step g), followed by drying and calcining.

12. A process using a catalyst prepared in accordance with claim 1 in a reaction for catalytic reforming or aromatics production by bringing said catalyst into contact with a hydrocarbon feed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0101] FIG. 1 shows the change in yield of aromatics compounds as a function of displacement of the vibration frequency of the C—O bond, illustrating the gain in yield of aromatics products obtained when the electron density of the platinum particles is reduced under the conditions for recording the IR spectra.