Olefin metathesis method using a catalyst containing aluminium and molybdenum incorporated by means of at least two precursors

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 two precursors of which at least one precursor contains molybdenum and at least one precursor contains aluminum.

Claims

1. A process for the metathesis of olefins, comprising 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 two precursors of which at least one precursor contains molybdenum and at least one precursor contains aluminium, in which the catalyst is prepared by dry impregnation according to a process comprising: a) solubilizing of the molybdenum-containing precursor and the aluminium-containing precursor in a volume of solution corresponding to the pore volume of a preformed mesoporous matrix based on oxide, b) impregnating the preformed mesoporous matrix based on oxide with the solution obtained in a), optionally maturating a solid thus obtained, c) optionally drying, calcining and/or steam treating a solid obtained at the end of b), at a pressure greater than or equal to 0.1 MPa at a temperature of 50 C. to 1000 C., and d) thermally activating a solid obtained at the end of c), at a pressure greater than or equal to 0.1 MPa and a temperature of 100 C. to 1000 C.

2. The process according to claim 1 in which the molybdenum-containing precursor is a coordination complex based on molybdenum and/or polyoxometallate based on molybdenum and/or a (thio)molybdate.

3. The process according to claim 1 in which the molybdenum-containing precursor of the coordination complex type based on molybdenum has formula (I)
Mo.sub.m(Y).sub.n(N).sub.n(X).sub.o(CR.sub.2).sub.r(I) in which, the Y groups, identical to or different from each other, are O, S and or NR, the X groups, identical to or different from each other, are halides, chlorate, bromate, iodate, nitrate, sulphate, hydrogen sulphate, alkylsulphate, thiosulphate, carbonate, hydrogen carbonate, phosphate, hydrogen phosphate, dihydrogen phosphate, substituted or unsubstituted alkyl, cycloalkyl or aryl groups, substituted or unsubstituted cyclopentadienyl groups, alkoxy, aryloxy, siloxy, amide, hydrido, nitro, carboxylate, acetylacetonate, sulphonate, -diketiminate, iminopyrrolure, amidinate, borate, cyanide, cyanate, thiocyanate or NR.sub.2CS.sub.2.sup. groups, the R and R groups, identical to or different from each other, are alkyl, aryl alkoxy or aryloxy groups, m is equal to 1 or 2, n is 0 to 4, n is 0 to 2, o is 0 to 10, r is 0 to 2, and n+n+o+r is greater than or equal to 1.

4. The process according to claim 1 in which the molybdenum-containing precursor is a polyoxometallate based on molybdenum of formula (II)
(X.sub.xMo.sub.mM.sub.bO.sub.yH.sub.h).sup.q.nH.sub.2O(II) in which, x is greater than or equal to 0, m is greater than or equal to 2, b is greater than or equal to 0, y is greater than or equal to 7, h is 0 to 12, q is 1 to 20, n is 0 to 200, and x, m, b, y, h, n and q being integers, X being phosphorus, silicon or boron, M being aluminium, zinc, nickel, cobalt, tungsten, vanadium, niobium, tantalum, iron or copper.

5. The process according to claim 4 in which the polyoxometallate is an isopolyanion based on molybdenum in which the subscript x of the element X is equal to 0.

6. The process according to claim 4 in which the polyoxometallate is a heteropolyanion that is a Strandberg heteropolyanion of formula X.sub.2Mo.sub.5O.sub.23H.sub.h.sup.q.nH.sub.2O, an Anderson heteropolyanion of formula XMo.sub.6O.sub.24H.sub.h.sup.q.nH.sub.2O, a Keggin heteropolyanion of formula XMo.sub.12O.sub.40H.sub.h.sup.q.nH.sub.2O, a lacunary Keggin heteropolyanion of formula XMo.sub.11O.sub.39H.sub.h.sup.q.nH.sub.2O, a lacunary Keggin heteropolyanion of formula XMo.sub.9O.sub.34H.sub.h.sup.q.nH.sub.2O, a Dawson heteropolyanion of formula X.sub.2Mo.sub.18O.sub.62H.sub.h.sup.q.nH.sub.2O, or a Preyssler heteropolyanion of formula X.sub.5Mo.sub.30O.sub.110H.sub.h.sup.q.nH.sub.2O.

7. The process according to claim 4 in which the polyoxometallate is a heteropolyanion that is a Strandberg heteropolyanion of formula X.sub.2Mo.sub.4CoO.sub.23H.sub.h.sup.q.nH.sub.2O, an Anderson heteropolyanion of formula XMo.sub.5CoO.sub.24H.sub.h.sup.q.nH.sub.2O, a Keggin heteropolyanion of formula XMo.sub.11CoO.sub.40H.sub.h.sup.q.nH.sub.2O, a lacunary Keggin heteropolyanion of formula XMo.sub.10CoO.sub.39H.sub.h.sup.q.nH.sub.2O, a lacunary Keggin heteropolyanion of formula XMo.sub.8CoO.sub.34H.sub.h.sup.q.nH.sub.2O, a Dawson heteropolyanion of formula X.sub.2Mo.sub.17CoO.sub.62H.sub.h.sup.q.nH.sub.2O, or a Preyssler heteropolyanion of formula X.sub.5Mo.sub.29CoO.sub.110H.sub.h.sup.q.nH.sub.2O.

8. The process according to claim 1 in which the molybdenum-containing precursor is a (thio)molybdate of formula (III)
C.sub.c(MoY.sub.4).sub.z(III) in which C represents an organic or inorganic cation, the Y groups, identical to or different from each other, are O and or S, c is 1 to 4, and z is 1 to 10.

9. The process according to claim 1 in which the aluminium-containing precursor is a coordination complex based on aluminium and/or an aluminium salt and/or a heteropolyanion salt based on aluminium and/or a colloidal solution of alumina.

10. The process according to claim 1 in which the aluminium-containing precursor is a coordination complex based on aluminium of formula (IV)
Al.sub.nR.sub.m.xH.sub.2O(IV) in which, n is 1 to 3, m is 1 to 3, x is 0 to 200, and the R groups are identical or different from each other, and are hydrogen, a halides, chlorate, bromate, iodate, nitrate, sulphate, hydrogen sulphate, alkylsulphate, thiosulphate, carbonate, hydrogen carbonate, phosphate, hydrogen phosphate, dihydrogen phosphate, a substituted or unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl or aryl group, a substituted or unsubstituted cyclopentadienyl group, or a hydroxy, alkoxy, aryloxy, carboxylate, nitrate, acetylacetonate, sulphonate, or perchlorate group.

11. The process according to claim 1 in which the aluminium-containing precursor is an aluminium salt of formula (V)
[Al.sub.nR.sub.m].sup.[C].sup.+.nH.sub.2O(V) in which, n is 1 to 3, m is 1 to 3, x is 0 to 200, the R groups are identical to or different from each other, and are hydrogen, an oxo group, a halides, a substituted or unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl or aryl group, a substituted or unsubstituted cyclopentadienyl group, or a hydroxy, alkoxy, aryloxy, carboxylate, sulphonate, nitrate, acetylacetonate, or perchlorate group, and C is hydrogen, an alkali, an alkaline-earth element, a transition metal, a post-transition metal, a rare earth, or an ammonium or phosphonium cation.

12. The process according to claim 1 in which the aluminium-containing precursor is a heteropolyanion salt based on aluminium of formula (VI)
(Al.sub.aM1.sub.mM2.sub.bX.sub.xO.sub.yH.sub.h).sup.q(C.sup.r+).sub.c.nH.sub.2O(VI) 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 0 to 12, q is 0 to 20, r is 0 to 20, c is 0 to 20, n is 0 to 200, x, m, y, h, n and q being integers, X being phosphorus, silicon or boron, M1 and M2, identical to or different from each other, being aluminium, zinc, nickel, cobalt, molybdenum, tungsten, vanadium, niobium, tantalum, iron or copper, and C represents one or more atoms, identical or different, hydrated or non-hydrated, capable of existing in the cationic form, 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.

13. 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.

14. A process according to claim 1 in which the metathesis reaction is carried out at a temperature of 0 to 500 C.

15. The process according to claim 14 in which the olefins are linear olefins of formula R.sup.1R.sup.2CCR.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 having 3 to 20 carbon atoms.

16. 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.

17. A process for the metathesis of olefins, comprising 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 two precursors of which at least one precursor contains molybdenum and at least one precursor contains aluminium, in which the catalyst is prepared by a process comprising the following stages: a) solubilizing of the molybdenum-containing precursor in a volume of solution corresponding to the pore volume of a preformed mesoporous matrix based on oxide, b) impregnating of the preformed mesoporous matrix based on oxide with the solution obtained in a), optionally maturing a solid thus obtained, c) drying to remove impregnation solvent from solution a), d) solubilizing aluminium-containing precursor in a volume of solution corresponding to the pore volume of solid obtained in c), e) impregnating a solid obtained in c) with a solution obtained in d), optionally maturing a solid thus obtained, f) optionally drying, calcining and/or steam treating a solid obtained at the end of stage e), at a pressure greater than or equal to 0.1 MPa at a temperature of 50 C. to 1000 C., and g) thermally activating a solid obtained at the end of f), at a pressure greater than or equal to 0.1 MPa, in a temperature of 100 C. to 1000 C.

18. A process for the metathesis of olefins, comprising 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 two precursors of which at least one precursor contains molybdenum and at least one precursor contains aluminium, in which the catalyst is prepared by impregnation in excess solution according to a process comprising: a) solubilizing the molybdenum-containing precursor and the aluminium-containing precursor 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) impregnating the preformed mesoporous matrix based on oxide, with the solution obtained in a), filtration and recovery of the solid, optionally maturing of a solid thus obtained, c) optionally drying, calcining and/or steam treating of a solid obtained at the end of b) at a pressure greater than or equal to 0.1 MPa at a temperature of 50 C. to 1000 C., and d) thermally activating of a solid obtained at the end of c) at a pressure greater than or equal to 0.1 MPa at a temperature of 100 C. to 1000 C.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The FIGURE represents productivity of catalyst of the Examples

EXAMPLES

(2) In the examples, the molybdenum-containing precursor of the heteropolyanion type PMo.sub.12O.sub.40H.sub.3 and the precursors containing aluminium of the coordination complex type Al.sub.2(SO.sub.4).sub.3 are commercially available.

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 11.7 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 6.4% Mo+1% Al/SiO2 by Dry Impregnation with a Solution of PMo12O403.3H+.30H2O_and Al2(SO4)3.18H2O

(4) 1.5 g of PMo.sub.12O.sub.40.sup.3.3H.sup.+.30H.sub.2O and 1.83 g of Al.sub.2(SO.sub.4).sub.3.18H.sub.2O are dissolved at 60 C. in 11.7 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 a molybdenum-containing precursor and an aluminium-containing precursor is greater than the activity of catalyst 1A not according to the invention and prepared by impregnation with a single molybdenum-containing precursor.

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