Solid heterogeneous catalyst for olefin hydroformylation reaction and production method and use thereof

Abstract

A solid heterogeneous catalyst consisting of a metal component and an organic ligand polymer, wherein the metal component is one or more of Rh, Ir or Co, the organic ligand polymer is a polymer having a large specific surface area and hierarchical porosity formed by polymerizing an organic ligand monomer containing P and alkenyl group and optional N via a solvothermal polymerization process, the metal component forms coordinated bond with the P atom or N in backbone of the organic ligand polymer and exists in a monoatomic dispersion state; when the catalyst is used in an olefin hydroformylation reaction, the metal component and the P and/or N atom form in situ an intermediate active species similar to homogeneous catalyst due to the coordination effect, and the catalyst has an excellent catalytic property, can be easily separated, and has a relatively high stability.

Claims

1. A solid heterogeneous catalyst for olefin hydroformylation reaction, wherein the solid heterogeneous catalyst consists of a metal component and an organic ligand polymer, wherein the metal component is one or more of Rh, Ir or Co, the organic ligand polymer is a polymer having a large specific surface area and hierarchical porosity formed by polymerizing an organic ligand monomer containing P and alkenyl group and optional N via a solvothermal polymerization process, the metal component forms coordinated bonds with the P atom or N in backbone of the organic ligand polymer and exists in a monoatomic dispersion state.

2. The solid heterogeneous catalyst according to claim 1, wherein the metal component accounts for 0.005 to 5.0% based on the total weight of the solid heterogeneous catalyst.

3. The solid heterogeneous catalyst according to claim 1, wherein the organic ligand monomer is an organic phosphine ligand monomer containing P and vinyl group and optional N.

4. The solid heterogeneous catalyst according to claim 1, wherein the organic ligand polymer has a specific surface area of 100 to 3000 m.sup.2/g, a pore volume of 0.1 to 5.0 cm.sup.3/g, and a pore size distribution of 0.2 to 50.0 nm.

5. A method for producing the solid heterogeneous catalyst of claim 1, comprising: a) adding a radical initiator into an organic solvent containing an organic ligand monomer in an autoclave for synthesis at 273 to 473 K and under the protection of inert gas, and stirring it for 0.5 to 100 h; b) keeping the solution of step a) in an autoclave for synthesis for 0.5 to 100 h at 273 to 473 K and under the protection of inert gas to perform a solvothermal polymerization reaction; c) drawing off the solvent under vacuum at room temperature after the completion of step b), thereby obtaining the organic ligand polymer; d) placing the organic ligand polymer in an organic solvent containing an active metal component, stirring it at 273 to 473 K and under the protection of inert gas for 0.5 to 100 h, and then drawing off the solvent under vacuum at room temperature, thereby obtaining the solid heterogeneous catalyst, in which the metal component is supported by the organic ligand polymer itself.

6. The method according to claim 5, wherein the organic solvent used in steps a) and d) is one or more of benzene, toluene, tetrahydrofuran, methanol, ethanol, or trichloromethane; the radical initiator used in step a) is one or more of cyclohexanone peroxide, dibenzoyl peroxide, tert-butyl hydroperoxide, azodiisobutyronitrile, or azodiisoheptonitrile.

7. The method according to claim 6, wherein the organic ligand monomer is an organic phosphine ligand monomer containing vinyl, and the organic solvent is benzene, toluene, or tetrahydrofuran.

8. The method according to claim 5, wherein the weight ratio of the radical initiator to the organic ligand monomer is 1:500 to 1:5.

9. An olefin hydroformylation method comprising conducting an olefin hydroformylation reaction in the presence of the solid heterogeneous catalyst according to claim 1, olefins, and CO/H.sub.2 mixed gas in a fixed bed, a trickle bed, a slurry bed, or an autoclave reactor, at a reaction temperature of 323 to 573K, a reaction pressure of 0.05 to 20.0 MPa, and a volume space velocity of the gas of 100 to 20000 h.sup.1.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 shows the result of the reaction stability of a catalyst of the invention in ethylene hydroformylation after more than 1000 h.

(2) FIG. 2 is an HRTEM image of a catalyst sample after reacting continuously in ethylene hydroformylation for more than 1000 h according to a catalyst of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

(3) On the basis of research of various homogeneous immobilization methods, the invention forms an organic ligand polymer having a large specific surface area and hierarchical porosity by polymerization in an autoclave, in which an organic phosphine ligand having alkenyl group (e.g. vinyl) introduced by the aromatic ring is used as the monomer for the polymerization and the solvothermal polymerization synthesis process is used, and new sites having catalytic activity is formed by the function of coordinated bonds between P and/or N atom having lone pair electrons and the empty orbital of the active transition metal ion, wherein a large amount of the P and/or N atoms are exposed out of the organic ligand polymer present in the backbone of the polymer. Herein, such a catalyst is referred to as a catalyst in which the active metal component is supported by the organic ligand polymer itself. On one hand, the organic ligand polymer acts as the ligand for the active metal component, and on the other hand, it acts as a support having a high specific surface area for supporting a highly dispersed active metal component. It is shown by research through modern characterization technologies, such as EXAFS, .sup.31P NMR, HRTEM, FT-IR, and the like, that in this kind of catalysts in which the metal is supported by the organic ligand polymer itself, the active metal component exists in a monoatomic dispersion state, and the metal ion forms chemical bonds with P and/or N in the organic ligand polymer, and further, the metal in the catalyst, which has run for a long time, still remains in the monoatomic dispersion state, which means that the active site of homogeneous catalysis plays a role in the olefin hydroformylation reaction, and can exist in the organic ligand polymer stably, so that the chemical coordinated bonds formed of the metal component with the P and/or N in the organic ligand polymer solves the problem that the ions of active atoms intend to be lost. Thus, it enables the catalyst of the invention in which the active metal component is supported by the organic ligand polymer itself to solve the problems present in the immobilization of homogeneous catalysis so far, such as the decrease of reactivity, loss of active components, and the like. That is to say, it has a prospect in solving the problem of poor reaction stability.

(4) More specifically, the solid heterogeneous catalyst provided by the invention consists of an organic ligand polymer and an active metal component supported by the organic ligand polymer itself, wherein the metal component is one or more of Rh, Ir or Co, the organic ligand polymer is a polymer having a large specific surface area and hierarchical porosity formed by a polymerization reaction, in which an organic ligand monomer containing P and alkenyl group and optional N is subjected to a solvothermal polymerization process in an autoclave, and the metal component forms coordinated bonds with the P atom or N in the backbone of the organic ligand polymer and exists in a monoatomic dispersion state. The organic ligand monomer is preferably an organic phosphine ligand monomer containing P and vinyl aromatic hydrocarbon and optional N. Additionally or preferably, the metal component accounts for 0.005 to 5.0 wt. % based on the total weight of the catalyst, and more preferably, the metal component accounts for 0.01 to 5.0 wt. % based on the total weight of the catalyst

(5) Preferably, in the catalyst mentioned above, the organic ligand polymer has a specific surface area of 200 to 2000 m.sup.2/g, a pore volume of 0.5 to 5.0 cm.sup.3/g, and a pore size distribution of 0.5 to 50.0 nm.

(6) The catalyst provided by the invention, in which a metal is supported by an organic ligand polymer itself, can be produced by the following method, for example:

(7) a) adding a radical initiator into an organic solvent containing an above-mentioned organic ligand monomer (such as a vinyl-functionalizing triphenylphosphine ligand, or a vinyl-functionalizing diphenylpyridylphosphine ligand) in an autoclave for synthesis at 273 to 473 K and under the protection of inert gas (such as nitrogen or argon), and stirring it for 0.5 to 100 h. Here, preferably, the solvent may be one or more of benzene, toluene, tetrahydrofuran, methanol, ethanol, or trichloromethane, the radical initiator may be one or more of cyclohexanone peroxide, dibenzoyl peroxide, tert-butyl hydroperoxide, azodiisobutyronitrile, or azodiisoheptonitrile. Preferably, the weight ratio of the radical initiator to the organic ligand monomer is 1:500 to 1:5.

(8) b) keeping the above-mentioned solution in an autoclave for synthesis for 0.5 to 100 h at 273 to 473 K and under the protection of inert gas, to perform a solvothermal polymerization reaction by using a solvothermal polymerization method;

(9) c) drawing off the solvent under vacuum at room temperature from the solution after polymerization mentioned above, so as to obtain an organic phosphine polymer support containing P and vinyl group and optional N and having a large specific surface area and hierarchical porosity;

(10) d) placing the organic phosphine polymer support into an organic solvent (which may be the same solvent as that in the above step a)) containing a metal component, stirring it at 273 to 473 K and under the protection of inert gas (such as nitrogen or argon) for 0.5 to 100 h, cooling it down to the room temperature after the stirring, and drawing off the solvent under vacuum at room temperature, so as to obtain a solid heterogeneous catalyst consisting of the organic ligand polymer and an active metal component supported by the organic ligand polymer itself.

(11) The catalyst can be used for catalyzing olefin hydroformylation reactions, which can be carried out in a fixed bed or a trickle bed, a slurry bed or an autoclave reactor. The typical operation conditions of the reactions are as follows: the reaction temperature of 323 to 573 K, the reaction pressure of 0.5 to 20.0 MPa, and the space velocity of the gas of 10020000 h.sup.1. After evaluating the catalyst in the reaction, the results show that the solid heterogeneous catalyst of the invention, which consists of the organic ligand polymer and an active metal component supported by the organic ligand polymer itself, has an excellent catalytic activity, selectivity and stability. Furthermore, the catalyst can be separated from the products easily and recycled.

(12) In production of the catalyst of the invention, the organic ligand monomer used can include, but not limited to, one or more of the followings:

(13) ##STR00001## ##STR00002## ##STR00003##

(14) In order to describe the production method of the catalyst and the use thereof in the olefin hydroformylation reaction better, examples for the production of some catalyst samples (in which only tri(4-vinylphenyl)phosphine monomer (i.e. the monomer L-2 mentioned above) and di(4-vinylphenyl)-2-pyridylphosphine (i.e. the monomer L-6 mentioned above) are used as the exemplary organic ligand monomers for explanation) and use thereof in reaction process are provided below. However, the invention is not limited to the Examples listed. Unless otherwise indicated, the percent used in this application is by weight.

(15) In the following Examples, all raw materials are as follows.

(16) H.sub.2/CO mixed gas (containing 50 vol. % H.sub.2 and 50 vol. % CO): Zhonghao Guangming Chemical Industry Research & Design Institute Ltd.

(17) ethylene: Zhonghao Guangming Chemical Industry Research & Design Institute Ltd., purity99.999 vol. %

(18) tri(4-vinylphenyl)phosphine: synthesized by Zhejiang University, chemical pure

(19) di(4-vinylphenyl)-2-pyridylphosphine monomer: synthesized by Zhejiang University, chemical pure

(20) The measurement for the specific surface area and the pore size distribution of samples was performed on an Autosorb-1 adsorption analyzer of Quantachrome Instruments Co. Before test, the samples were pretreated at 373 K for 20 hours. A N.sub.2 adsorption-desorption test was carried out at a liquid nitrogen temperature of 77 K.

Example 1

Production of an Organic Ligand Polymer

(21) 10.0 g tri(4-vinylphenyl)phosphine was dissolved in 100.0 ml tetrahydrofuran at 298 K under a protective atmosphere of nitrogen gas. 1.0 g radical initiator azodiisobutyronitrile was added into the above solution, and stirred for 2 hours. The stirred solution was kept standing at 373 K under a protective atmosphere of nitrogen gas for 24 h. Then it was cooled to room temperature, the solvent was drawn off at room temperature (about 298 K) under vacuum, and thereby a P-containing ligand polymer with hierarchical porosity was formed by polymerization from tri(4-vinylphenyl)phosphine via a solvothermal method. The technical route for the polymerization of the tri(4-vinylphenyl)phosphine ligand polymer support in this example was shown as follows:

(22) ##STR00004##
wherein the polymerization degree n was 450-550, the hierarchical porosity comprising macropores, mesopores, and micropores was contained, the BET specific surface area measured was 981 m.sup.2/g, the pore volume was 1.45 cm.sup.3/g, and the pore size distribution was 0.5 to 100.0 nm.

Example 2

Production of an Organic Ligand Polymer

(23) The production procedure was same as in Example 1, except that the monomer di(4-vinylphenyl)-2-pyridylphosphine is used instead of the monomer tri(4-vinylphenyl)phosphine.

Example 3

Production of a Solid Heterogeneous Catalyst Containing 2 wt % Rh

(24) 50.10 mg of dicarbonylacetylacetonato rhodium (I) was added into a three-necked flask charged with 100.0 ml of tetrahydrofuran at 298 K under a protective atmosphere of nitrogen gas, stirred, and dissolved. 1.0 g of the P-containing ligand polymer with hierarchical porosity of Example 1 was added thereto. This mixture was stirred at 298 K under a protective atmosphere of nitrogen gas for 24 hours, then the solvent was drawn off at room temperature under vacuum, and thereby a solid heterogeneous catalyst, which has a metal Rh supported by the P-containing ligand polymer with hierarchical porosity itself, was obtained. The solid heterogeneous catalyst prepared above, which has an metal component supported by the tri(4-vinylphenyl)phosphine ligand polymer itself and hierarchical porosity, was charged into a fixed bed reactor. Ethylene gas as olefins and CO/H.sub.2 mixed gas (in which the volume ratio of H.sub.2:CO=1:1) in molar ratio of 1:2 were charged thereto. The reaction was started under the following conditions: at 393K, under 1.0 MPa, at a volume space velocity of the olefin gas of 1000 h.sup.1, at a volume space velocity of the CO/H.sub.2 mixed gas of 2000 h.sup.1. The resultant liquid product propylaldehyde was collected in a cold trap collecting tank. The liquid product was analyzed by an HP-7890N gas chromatograph equipped with an HP-5 capillary column and a FID detector, using ethanol as the internal standard. The tail gas of the reaction was on-line analyzed by a HP-7890N gas chromatograph equipped with a Porapak-QS column and a TCD detector. The results of the reaction were shown in Table 1.

Example 4

Production of a Solid Heterogeneous Catalyst Containing 2 wt % Rh

(25) In Example 4, the production steps and the conditions of the hydroformylation reaction were same as those in Example 3, except taking 0.5 mg of dicarbonylacetylacetonato rhodium (I) instead of 50.10 mg of dicarbonylacetylacetonato rhodium (I), which was dissolved in 100.0 ml of tetrahydrofuran. The results of the reaction were listed in Table 1.

Example 5

Production of a Solid Heterogeneous Catalyst Containing 10 wt % Co

(26) In Example 5, the production steps for the catalyst and the conditions of the hydroformylation reaction are same as those in Example 3, except taking 398.25 mg of cobalt chloride instead of 50.10 mg of dicarbonylacetylacetonato rhodium (I). The results of the reaction were listed in Table 1.

Example 6

Production of a Solid Heterogeneous Catalyst Containing 0.4 wt % Rh-5 wt % Co

(27) In Example 6, the production steps for the catalyst and the conditions of the hydroformylation reaction were the same as those in Example 3, except taking 10.40 mg of dicarbonylacetylacetonato rhodium (I) and 199.13 mg of cobalt chloride instead of 50.10 mg of dicarbonylacetylacetonato rhodium (I). The results of the reaction were listed in Table 1.

Example 7

Production of a Solid Heterogeneous Catalyst Containing 0.125 wt % Rh

(28) In Example 7, the production steps for the catalyst and the conditions of the hydroformylation reaction were same as those in Example 3, except weighing 3.13 mg of dicarbonylacetylacetonato rhodium (I) instead of 50.10 mg of dicarbonylacetylacetonato rhodium (I). The reaction was carried out continuously. The results of the reaction, which was carried out for 432 h, were listed in Table 1.

Example 8

Reaction Stability of the Catalyst Containing 0.125 wt % Rh

(29) In Example 8, the production steps for the catalyst and the conditions of the hydroformylation reaction were same as those in Example 7. The reaction was carried out continuously. The results of the reaction, which was carried out for 1008 h, were listed in Table 1.

Comparative Example 1

Production of the Catalyst Containing 2 wt % Rh

(30) In Comparative Example 1, the production steps for the catalyst and the conditions of the hydroformylation reaction were same as those in Example 3, except taking 1.0 g of SiO.sub.2 instead of the organic ligand polymer formed by polymerizing tri(4-vinylphenyl)phosphine produced in Example 1. The results of the reaction were listed in Table 1.

(31) TABLE-US-00001 TABLE 1 the ethylene hydroformylation reaction properties of the novel heterogeneous catalyst Ethylene Selectivity (wt %) Example conversion, (%) ethane propylaldehyde Example 3 98.0 3.5 96.5 Example 4 42.3 0.9 99.1 Example 5 15.1 4.9 95.1 Example 6 89.5 2.9 97.1 Example 7 96.9 5.1 94.9 Example 8 97.1 5.2 94.8 Comparative 38.9 0.8 99.2 Example 1

(32) As can be known from the above-mentioned results, the heterogeneous catalyst containing an insoluble ligand of the invention, such as the polymer formed by self-polymerization of tri(4-vinylphenyl)phosphine, has an excellent catalytic activity and the catalyst can be easily separated, when it is used in the ethylene hydroformylation reaction in a fixed bed reactor. Meanwhile, as found by comparing Example 7 with Example 8, the catalyst has a very good stability. FIG. 1 shows that this kind of catalyst always has a stable activity during the long reaction process. At the same time, FIG. 2 shows that the active component Rh still remains in the monoatomic dispersion state on the surface of the polymer formed by polymerizing tri(4-vinylphenyl)phosphine, after a reaction lasting more than 1000 h.

(33) The invention has been described in details above, but it is not limited to the particular embodiments described herein. Those skilled in the art will understand that other modifications and variations may be made, without departing the scope of the invention. The scope of the invention is defined by the appended claims.