OLEFIN METATHESIS METHOD USING A CATALYST CONTAINING ALUMINIUM 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 aluminium, said elements being incorporated into said matrix by means of at least one precursor comprising molybdenum and aluminium.

Claims

1. 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.

2. Process according to claim 1 in which the precursor is a precursor of heteropolyanion salt type, 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 or equal to 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 an element selected from phosphorus, silicon and boron, C represents one or more atoms, identical or different, hydrated or non-hydrated, selected from the elements of the periodic table capable of existing in the cationic form, such as hydrogen, the alkali, alkaline-earth elements, transition metals, post-transition metals and rare earths, in hydrated or non-hydrated forms, selected from the oxygen-containing and/or nitrogen-containing and/or phosphorus-containing organic cations, such as the ammoniums and phosphoniums.

3. Process according to claim 2 in which the metallic element M is selected from cobalt, tungsten, vanadium.

4. Process according to claim 2 in which the precursor of the heteropolyanion salt type is selected from the group formed by the Anderson heteropolyanion salts of formula AlMo.sub.6O.sub.24H.sub.6.sup.3?(C.sup.r+).sub.c.nH.sub.2O that can also be found written as the formula Al(OH).sub.6Mo.sub.6O.sub.18.sup.3?(C.sup.r+).sub.c.nH.sub.2O, C and c corresponding to the definition according to claim 2.

5. Process according to claim 4 in which the precursor of the Anderson heteropolyanion salt type is selected from [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, [Al(OH).sub.6Mo.sub.6O.sub.18].sup.3?[(NH.sub.4)].sub.3.7H.sub.2O.

6. Process according to claim 1 in which the mesoporous matrix is a matrix based on the oxide of at least one element X selected from silicon, titanium, zirconium, magnesium, lanthanum, cerium and mixtures thereof.

7. Process according to claim 1 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), at a pressure greater than or equal to 0.1 MPa or less than or equal to 0.1 MPa, in a temperature range from 50? C. to 1000? C., d) stage of thermal activation of the solid obtained at the end of stage c), at a pressure greater than or equal to 0.1 MPa or less than or equal to 0.1 MPa, in a temperature range from 100? C. to 1000? C.

8. Process according to claim 1 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) at a pressure greater than or equal to 0.1 MPa or less than or equal to 0.1 MPa, in a temperature range from 50? C. to 1000? C., d) stage of thermal activation of the solid obtained at the end of stage c) at a pressure greater than or equal to 0.1 MPa or less than or equal to 0.1 MPa, in a temperature range from 100? C. to 1000? C.))

9. Process according to claim 1 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) at a pressure greater than or equal to 0.1 MPa or less than or equal to 0.1 MPa, d1) stage of thermal activation of the dry solid particles at the end of stage c1), at a pressure greater than or equal to 1 bar or less than or equal to 0.1 MPa, in a temperature range from 100 to 1000? C.

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

11. Process according to claim 10 in which the olefins are linear olefins corresponding to general 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.

12. 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.

Description

EXAMPLES

[0100] 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/SiO.SUB.2 .by dry impregnation with a solution of PMo.SUB.12.O.SUB.40..SUP.3?..3H.SUP.+..30H.SUB.2.O

[0101] 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/SiO.SUB.2 .by Dry Impregnation with a Solution of Al(OH).SUB.6.Mo.SUB.6.O.SUB.18..SUP.3?..(NH.SUB.4..SUP.+.).SUB.3

[0102] 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

[0103] 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 FIG. 1.

[0104] 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.

[0105] The stability of catalyst 1B according to the invention is better than the stability of catalyst 1A not according to the invention.