Olefin metathesis method using a catalyst containing aluminum and molybdenum

Abstract

The invention relates to a process for the metathesis of olefins implemented with a catalyst comprising a mesoporous matrix and at least the elements molybdenum and aluminum, said elements being incorporated into said matrix by means of at least one precursor comprising molybdenum and aluminum.

Claims

1. A process for the metathesis of olefins carried out by bringing the olefins into contact with a catalyst comprising a mesoporous matrix and at least the elements molybdenum and aluminium, said elements being incorporated into said matrix using at least one precursor comprising molybdenum and aluminium, in which the catalyst is prepared by dry impregnation according to the process comprising the following stages: a) solubilization of the precursor comprising molybdenum and aluminium in a volume of solution corresponding to the pore volume of a preformed mesoporous matrix based on oxide, b) impregnation of the preformed mesoporous matrix based on oxide with the solution obtained in stage a), optional maturation of the solid thus obtained, c) optional stage of drying, calcination and/or steam treatment of the solid obtained at the end of stage b), in a temperature range from 50? C. to 1000? C., and d) stage of thermal activation of the solid obtained at the end of stage c), in a temperature range from 100? C. to 1000? C.

2. The process according to claim 1 in which the precursor is a precursor of a heteropolyanion salt, corresponding to formula (I):
(Al.sub.aMo.sub.mM.sub.bX.sub.xO.sub.yH.sub.h).sup.q?(C.sup.r+).sub.c.nH.sub.2O(I) in which, a is greater than 0, m is greater than or equal to 1, b is greater than or equal to 0, x is greater than or equal to 0, y is greater than or equal to 10, h is comprised between 0 and 12, q is comprised between 1 and 20, r is comprised between 1 and 20, c is comprised between 1 and 20, n is comprised between 0 and 200, x, m, y, h, n and q being integers, M being a metallic element selected from zinc, nickel, cobalt, tungsten, vanadium, niobium, tantalum, iron and copper, and X being phosphorus, silicon or boron, and C represents one or more atoms, identical or different, hydrated or non-hydrated, from the elements of the periodic table capable of existing in cationic form.

3. The process according to claim 2 in which the metallic element M is cobalt, tungsten, or vanadium.

4. The process according to claim 2 in which the precursor of the heteropolyanion salt is an Anderson heteropolyanion salt of formula AlMo.sub.6O.sub.24H.sub.6.sup.3?(C.sup.r+).sub.c.nH.sub.2O that can also be written as the formula Al(OH).sub.6Mo.sub.6O.sub.18.sup.3?(C.sup.r+).sub.c.nH.sub.2O.

5. The process according to claim 4 in which the precursor of the Anderson heteropolyanion salt is [Al(OH).sub.6Mo.sub.6O.sub.18].sup.3?[(C.sub.6H.sub.10N.sub.3O.sub.2).sub.2Na(H.sub.2O).sub.2].sup.3+6H.sub.2O(C.sub.6H.sub.10N.sub.3O.sub.2=histidinium); [Al(OH).sub.6Mo.sub.6O.sub.18].sup.3?.sub.2{Na.sub.2[Me.sub.3N(CH.sub.2).sub.2OH].sub.4}.sup.6+.8NH.sub.2CONH.sub.2. 4H.sub.2O; [Al(OH).sub.6Mo.sub.6O.sub.18].sup.3?.(H.sub.3O.sup.+)[Cu(C.sub.6NO.sub.2H.sub.4)(phenantroline)(H.sub.2O)].sup.+.sub.2.5H.sub.2O; [Al(OH).sub.6Mo.sub.6O.sub.18].sup.3?[Al(H.sub.2O).sub.6].sup.3+.10H.sub.2O, or [Al(OH).sub.6Mo.sub.6O.sub.18].sup.3?[(NH.sub.4).sup.+].sub.3.7H.sub.2O.

6. The process according to claim 2 wherein C is hydrogen, an alkali, or alkaline-earth element, transition metal, a post-transition metal or a rare earth, in hydrated or non-hydrated form, that is an oxygen-containing and/or nitrogen-containing and/or phosphorus-containing organic cation.

7. The process according to claim 6 wherein the cation is an ammonium or phosphonium cation.

8. The process according to claim 1 in which the mesoporous matrix is a matrix based on the oxide of at least one element X that is silicon, titanium, zirconium, magnesium, lanthanum, cerium or mixtures thereof.

9. The process according to claim 1 in which the metathesis reaction is carried out at a temperature comprised between 0 and 500? C.

10. The process according to claim 9 in which the olefins are linear olefins corresponding to formula R.sup.1R.sup.2C?CR.sup.3R.sup.4, where R.sup.1, R.sup.2, R.sup.3 and R.sup.4, identical or different, are hydrogen or a hydrocarbyl radical of 1 to 20 carbon atoms, or olefins with a cyclic structure, the ring comprising from 3 to 20 carbon atoms.

11. The process according to claim 1 in which the metathesis reaction is the cross-metathesis reaction of ethylene with 2-butene, or the reverse reaction converting propylene to a mixture of ethylene and 2-butene.

12. The process according to claim 1 wherein the pressure in (c) is ?0.1 MPa.

13. The process according to claim 1 wherein the pressure in (c) is ?0.1 MPa.

14. The process according to claim 1 wherein the pressure in (d) is ?0.1 MPa.

15. The process according to claim 1 wherein the pressure in (d) is ?0.1 MPa.

16. A process for the metathesis of olefins carried out by bringing the olefins into contact with a catalyst comprising a mesoporous matrix and at least the elements molybdenum and aluminium, said elements being incorporated into said matrix using at least one precursor comprising molybdenum and aluminium, in which the catalyst is prepared by impregnation in excess according to the process comprising the following stages: a) solubilization of the precursor comprising molybdenum and aluminium in a volume of solution corresponding to between 1.5 and 20 times the pore volume of the preformed mesoporous matrix based on oxide, b) impregnation of the preformed mesoporous matrix based on oxide, with the solution obtained in stage a), filtration and recovery of the solid, optional maturation of the solid thus obtained, c) optional stage of drying, calcination and/or steam treatment of the solid obtained at the end of stage b) in a temperature range from 50? C. to 1000? C., and d) stage of thermal activation of the solid obtained at the end of stage c) in a temperature range from 100? C. to 1000? C.

17. The process according to claim 16 wherein the pressure in (c) is ?0.1 MPa.

18. The process according to claim 16 wherein the pressure in (c) is ?0.1 MPa.

19. The process according to claim 16 wherein the pressure in (d) is ?0.1 MPa.

20. The process according to claim 16 wherein the pressure in (d) is ?0.1 MPa.

21. A process for the metathesis of olefins carried out by bringing the olefins into contact with a catalyst comprising a mesoporous matrix and at least the elements molybdenum and aluminium, said elements being incorporated into said matrix using at least one precursor comprising molybdenum and aluminium, in which the catalyst is prepared according to the process comprising the following stages: a1) solubilization of the precursor comprising molybdenum and aluminium and of the precursors of the mesoporous matrix based on oxide of at least one element X in an aqueous or hydro-organic solution in the presence of a pore-forming agent so as to form a colloidal solution, b1) spray-drying said colloidal solution so as to obtain spherical solid elemental particles incorporating the mesostructured matrix based on oxide and the precursor comprising molybdenum and aluminium, c1) optional stage of drying, calcination and/or steam treatment of the solid particles obtained at the end of stage b1) and d1) stage of thermal activation of the dry solid particles at the end of stage c1), in a temperature range from 100 to 1000? C.

22. The process according to claim 21 wherein the pressure in (c) is ?0.1 MPa.

23. The process according to claim 21 wherein the pressure in (c) is ?0.1 MPa.

24. The process according to claim 21 wherein the pressure in (d) is ?0.1 MPa.

25. The process according to claim 21 wherein the pressure in (d) is ?0.1 MPa.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The FIGURE represents productivity of the catalyst as a function of time.

EXAMPLES

(2) In the examples, the precursor of the phosphomolybdic acid heteropolyanion type PMo.sub.12O.sub.40.sup.3?.3H.sup.+ is commercially available and the molybdenum- and aluminium-containing precursor of the heteropolyanion salt type ammonium aluminium molybdate [Al(OH).sub.6Mo.sub.6O.sub.18].sup.3?.[(NH.sub.4).sup.+].sub.3.7H.sub.2O is prepared according to the method described in G. Wiese and J. Fuchs, Z. Naturforsch, 1967, 469, 73.

Example 1A (Not According to the Invention): Preparation of 6.7% Mo/SiO2 by Dry Impregnation with a Solution of PMo12O403?.3H+.30H2O

(3) 1.5 g of PMo.sub.12O.sub.40.sup.3?.3H.sup.+.30H.sub.2O is dissolved at 60? C. in 7.3 ml of distilled water. On complete dissolution, a silica (S.sub.BET=462 m.sup.2/g, V.sub.p=0.75 ml/g) is impregnated with this solution. The solid obtained is matured for 24 h at 25? C. under air. The resulting solid is dried in an oven at 120? C. for 24 h then activated under nitrogen at 550? C. for 2 h.

Example 1B (According to the Invention): Preparation of 6.7% Mo+0.3% Al/SiO2 by Dry Impregnation with a Solution of Al(OH)6Mo6O183?.(NH4+)3

(4) 2.3 g of [Al(OH).sub.6Mo.sub.6O.sub.18].sup.3?.[(NH.sub.4.sup.+)].sub.3.7H.sub.2O is dissolved at 60? C. in 7.3 ml of distilled water. On complete dissolution, a silica (S.sub.BET=462 m.sup.2/g, V.sub.p=0.75 ml/g) is impregnated with this solution. The solid obtained is matured for 24 h at 25? C. under air. The resulting solid is dried in an oven at 120? C. for 24 h then activated under nitrogen at 550? C. for 2 h.

Example 2: Metathesis of Propylene to Ethylene and 2-Butene

(5) 2 g of catalyst prepared in Example 1A and 1B is mixed in a proportion of 50% by weight with silicon carbide (SiC) in a double-jacketed fixed bed reactor. The heat transfer fluid of the double jacket is heated to 70? C. Pure propylene is conveyed to the reactor by means of a Gilson pump and the pressure is set at 4.5 MPa. The productivity of the catalysts expressed in millimole of propylene consumed per gram of catalyst and per hour is quantified as a function of time denoted t (in hours denoted h) in the FIGURE.

(6) The activity of the catalyst 1B according to the invention prepared by impregnation with precursors comprising aluminium and molybdenum is greater than the activity of catalyst 1A not according to the invention and prepared by impregnation with a precursor based on molybdenum.

(7) The stability of catalyst 1B according to the invention is better than the stability of catalyst 1A not according to the invention.