A method for preparing normal aldehydes by hydroformylation of α-olefins

Abstract

The present invention provides a method for preparing n-aldehydes by hydroformylation of α-olefins, a method for preparing a heterogeneous catalyst, a heterogeneous catalyst composition, and its use in preparing n-aldehydes by hydroformylation of α-olefins, as well as a use for increasing the normal-to-isomer ratio of n-aldehydes to isomers in an aldehyde product prepared by hydroformylation of α-olefins to 70 or more. The n-aldehyde preparation method of the present invention mixes a ligand for modifying the catalyst with a solvent, a catalyst, and reaction raw materials, and simultaneously performs catalyst modification and catalytic reaction during the reaction process, thereby avoiding the drawback of easy detachment of the catalytic ligand in conventional processes, and can simultaneously achieve a high normal-to-isomer ratio product distribution and a high linear n-aldehyde yield.

Description

Technical Field

[0001] The present invention belongs to the field of fine chemical preparation and relates to a method for preparing normal aldehydes by using α-olefins, and specifically relates to a method for preparing normal aldehydes by using a hydroformylation reaction of α-olefins, a method for preparing a heterogeneous catalyst, a heterogeneous catalyst composition prepared thereby, and use of the heterogeneous catalyst composition in preparing normal aldehydes by using a hydroformylation reaction of α-olefins, as well as use of the heterogeneous catalyst composition in increasing the normal-to-isomer ratio of normal aldehydes to isomerized aldehydes in an aldehyde product prepared by hydroformylation of α-olefins to above 70. Background Art

[0002] Olefin hydroformylation is currently the world's largest homogeneous catalytic reaction system, with an annual production capacity of tens of millions of tons. The aldehyde compounds produced by hydroformylation are highly valuable fine chemicals. They can also be converted into bulk chemicals such as alcohols, esters, and amines, which are then used to synthesize a variety of high-value-added fine chemicals such as detergents, surfactants, pharmaceuticals, and fragrances. Hydroformylation reactions typically produce linear n-aldehydes and branched-chain aldehydes. Of these, n-aldehydes have greater industrial economic value, leading to a current demand for more linear n-aldehydes in both academic research and industry.

[0003] The hydroformylation reaction is generally catalyzed by transition metals, and the catalytic activity of metals is in the order of Rh>>Co>>Ir, Ru>Os>Pt>Pd>Fe>Ni from high to low. Among them, only rhodium-based and cobalt-based catalysts are used in industrial production, while other metals remain at the stage of academic research. The industrial system is mainly aimed at the hydroformylation process of short-chain olefins (such as ethylene, propylene and butene), while the hydroformylation of medium and long-chain olefins is less common. The catalysts commonly used in hydroformylation reactions are still mainly homogeneous catalysts, which inevitably lead to the problem of difficulty in separating the product and the catalyst. At the same time, homogeneous catalysts perform relatively average in terms of activity and selectivity when catalyzing the hydroformylation of α-olefins with more than five carbon atoms. Therefore, it is necessary to develop catalysts with high catalytic activity and high selectivity for linear aldehyde products.

[0004] At present, in the heterogeneous catalyst aspect of catalyzing alpha-olefin hydroformylation, some research progress has been achieved, but overall progress is still relatively slow, mainly homogeneous catalyst immobilization or utilizing organic ligand to modify heterogeneous catalyst, and then be applied to catalyzing alpha-olefin hydroformylation reaction.In 2013, Alexis T.Bell (ACS Catalysis, 2013, 3:348-357) reported the supported heterogeneous catalyst Rh / SiO2 for the first time, and modified it with phosphine ligand, realized the heterogeneous transformation of homogeneous hydroformylation reaction, but the ratio of normal aldehyde to isomeric aldehyde in the product is still lower, and simultaneously, organic ligand is combined with heterogeneous catalyst modification, and its ligand easily comes off in the reaction process, thereby affecting the performance stability and recycling of catalyst.Patent CN108579740A reports the method utilizing step-by-step impregnation-calcination, and nano metal rhodium is loaded on titanium dioxide nanotube, and the heterogeneous catalyst obtained has preferably catalytic performance to hexene hydroformylation, but linear aldehyde product selectivity is also not good. The technical solution disclosed in CN109876847A successfully encapsulated Rh in S-1 zeolite molecular sieve via epitaxial growth and applied it to a hydroformylation reaction. While both olefin conversion and aldehyde selectivity exceeded 95%, the ratio of normal- to iso-aldehydes in the hydroformylation product was only 1-2.

[0005] In summary, the recyclability of heterogeneous catalysts overcomes the drawbacks of homogeneous catalysts, which are difficult to separate. However, this also presents new challenges. First, heterogeneous catalysts are generally less active than homogeneous catalysts. Second, the local environment of heterogeneous catalysts is difficult to adjust, posing further challenges to enhancing selectivity. Furthermore, both surface ligand modification of heterogeneous catalysts and immobilization of homogeneous catalysts present difficulties in overcoming the problem of detachment. Summary of the Invention

[0006] The present invention provides a method for preparing normal-aldehydes by hydroformylating α-olefins. The method modifies the catalyst during the reaction, resulting in high selectivity for aldehyde products and a very high normal-to-iso ratio distribution. The yield of linear normal-aldehydes can reach 95%, resolving the difficulty in achieving both a high normal-to-iso ratio distribution and a high linear normal-aldehyde yield in the prior art. Furthermore, the method is characterized by simplicity, high operability, and excellent economic efficiency.

[0007] In a first aspect, the present invention provides a method for preparing normal aldehydes by hydroformylation of α-olefins, wherein the method comprises the following steps:

[0008] (1) mixing a heterogeneous catalyst, α-olefin, synthesis gas, solvent, and organic ligand in a reactor according to a predetermined ratio;

[0009] (2) performing a hydroformylation reaction of α-olefins at a predetermined temperature and pressure to obtain normal aldehydes;

[0010] Wherein, the heterogeneous catalyst is an encapsulated heterogeneous catalyst in which a noble metal element is encapsulated in a molecular sieve, and the noble metal element is one or more of Rh, Ir, and Au;

[0011] The organic ligand is one or more of a N-containing organic ligand, a P-containing organic ligand, and a S-containing organic ligand;

[0012] Preferably, the noble metal element is in the form of particles with an average particle size of 0.8 to 1.8 nm.

[0013] In a second aspect, the present invention provides a method for preparing a heterogeneous catalyst for preparing normal aldehydes by hydroformylation of α-olefins, wherein the method comprises the following steps:

[0014] (i) mixing molecular sieve template agent tetrapropylammonium hydroxide, tetraethyl orthosilicate, potassium hydroxide and water in a hydrothermal kettle and reacting under stirring;

[0015] (ii) adding an inorganic salt of a noble metal element and ethylenediamine to the hydrothermal reactor, centrifuging, washing, drying, and calcining after hydrothermal treatment to obtain a sample powder;

[0016] (iii) reducing in a H2 / N2 atmosphere to obtain the heterogeneous catalyst as noble metal element clusters encapsulated by molecular sieves.

[0017] In a third aspect, the present invention provides a heterogeneous catalyst composition for preparing normal aldehydes by hydroformylation of α-olefins, wherein the heterogeneous catalyst composition comprises the above-mentioned heterogeneous catalyst and an organic ligand.

[0018] In a fourth aspect, the present invention provides use of the catalyst composition for catalyzing the hydroformylation of α-olefins to prepare normal aldehydes.

[0019] The method for preparing normal aldehydes by hydroformylation of α-olefins, the method for preparing a heterogeneous catalyst, and the heterogeneous catalyst composition prepared thereby provided by the present invention have the following beneficial effects:

[0020] 1. The present invention innovatively utilizes molecular sieves to encapsulate noble metal active components to obtain sub-nanometer-sized (0.8-1.8 nm) noble metal particles, thereby significantly increasing the active centers on the active components and thus improving the catalytic activity of the catalyst.

[0021] 2. The ligand used to modify the catalyst is mixed with the solvent, catalyst, and reaction raw materials. During the reaction process, the catalyst modification and catalytic reaction are carried out simultaneously, thereby avoiding the disadvantage of easy detachment of the catalytic ligand in conventional processes and giving the catalyst higher stability and reusability.

[0022] 3. During the reaction process of this process, the organic ligand is complexed with the precious metal clusters on the surface of the catalyst, so that the raw materials can only enter the pores of the molecular sieve to undergo catalytic reaction, thereby utilizing the confinement effect of the molecular sieve pore space to achieve shape selection of the product, significantly improving the selectivity of linear normal-aldehydes, and thus obtaining a very high product normal-to-isomer ratio, which can reach more than 75, or even more than 100, or even more than 150. This solves the problems of low product normal-to-isomer ratio and / or low normal-aldehyde yield in existing methods, and has extremely high industrial application value.

[0023] 4. The catalyst provided by this process utilizes the technology of encapsulating precious metal active components with molecular sieves to obtain sub-nanometer-sized precious metal particles, thereby significantly increasing the active centers on the active components, making the catalyst have very high catalytic activity.

[0024] 5. This process has the characteristics of strong operability and good economy. DETAILED DESCRIPTION

[0025] The specific embodiments of the present invention are described in detail below. The specific embodiments described herein are only used to illustrate and explain the present invention, but are not used to limit the present invention.

[0026] In some embodiments, the present invention provides a method for preparing normal aldehydes by hydroformylation of α-olefins, wherein the method comprises the following steps:

[0027] (1) mixing a heterogeneous catalyst, α-olefin, synthesis gas, solvent, and organic ligand in a reactor according to a predetermined ratio;

[0028] (2) performing a hydroformylation reaction of α-olefins at a predetermined temperature and pressure to obtain normal aldehydes;

[0029] Wherein, the heterogeneous catalyst is an encapsulated heterogeneous catalyst in which a noble metal element is encapsulated in a molecular sieve, and the noble metal element is one or more of Rh, Ir, and Au;

[0030] The organic ligand is one or more of a N-containing organic ligand, a P-containing organic ligand, and a S-containing organic ligand;

[0031] Preferably, the noble metal element is in the form of particles with an average particle size of 0.8 to 1.8 nm.

[0032] In the present invention, the heterogeneous catalyst is an encapsulated heterogeneous catalyst, which is a catalyst formed by encapsulating noble metal sub-nanoclusters with molecular sieves having different topological structures.

[0033] In some embodiments, the molecular sieves with different topological structures are one or more of MFI, MWW, and MEL molecular sieves with all-silicon composition.

[0034] In some embodiments, the mass content of the noble metal elements in the active component sub-nanoclusters accounts for 0.01 to 1 wt %, preferably 0.02 to 0.6 wt %, of the molecular sieve carrier.

[0035] In some embodiments, the organic ligand is one or more of a N-containing organic ligand, a P-containing organic ligand, and a S-containing organic ligand having different degrees of noble metal coordination properties. The N-containing organic ligand of the modified component is one or more of L1, L2, L3, and L4. The P-containing organic ligand of the modified component is one or more of L5, L6, L7, and L8. The S-containing organic ligand of the modified component is one or more of L9, L10, L11, L12, and L13. Among them, the S-containing organic ligand is preferred. The structure of the organic ligand is as follows:

[0036]

[0037]

[0038] In some embodiments, in step (1), the α-olefin is one or more of C3 to C15 normal olefins; preferably, the α-olefin is one or more of 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, and 1-pentadecene.

[0039] In some embodiments, in step (1), the solvent is one or more of toluene, ethylbenzene, cyclohexane, acetonitrile, and p-xylene.

[0040] In some embodiments, in step (1), the volume ratio of CO to H2 in the synthesis gas is 1:(0.5-3).

[0041] In some embodiments, in step (1), the mixed molar ratio of the heterogeneous catalyst, α-olefin, synthesis gas, solvent and organic ligand is (0.015-0.0001):1:(20-140):(10-200):(0.15-3).

[0042] In some embodiments, in step (2), the hydroformylation reaction temperature is 60-140° C., the pressure is 3-6 MPa, and the reaction time is 3-10 h.

[0043] In some embodiments, the method for preparing normal aldehyde further comprises a distillation step (3), and the operating conditions of the distillation are: temperature 50-150° C., and pressure 1-100 mbar.

[0044] In some embodiments, the present invention provides a method for preparing a heterogeneous catalyst for preparing normal aldehydes by hydroformylation of α-olefins, wherein the method comprises the following steps:

[0045] (i) mixing molecular sieve template agent tetrapropylammonium hydroxide, tetraethyl orthosilicate, potassium hydroxide and water in a hydrothermal kettle and reacting under stirring;

[0046] (ii) adding an inorganic salt of a noble metal element and ethylenediamine to the hydrothermal reactor, allowing the mixture to stand, centrifuging, washing, drying, and calcining to obtain a sample powder;

[0047] (iii) reducing in a H2 / N2 atmosphere to obtain the heterogeneous catalyst as noble metal element clusters encapsulated by molecular sieves.

[0048] In some embodiments, in step (i), the molar stoichiometric ratio of the molecular sieve template agent tetrapropylammonium hydroxide, tetraethyl orthosilicate, potassium hydroxide and water is (0.3-0.4):1:(0.025-0.06):(13-35).

[0049] In some embodiments, in step (i), the reaction is carried out at 30-35° C. for 6-10 h.

[0050] In some embodiments, in step (ii), the inorganic salt of the noble metal element is one or more of chloroiridic acid, chloroauric acid, and rhodium trichloride.

[0051] In some embodiments, in step (ii), the molar ratio of the inorganic salt of the noble metal element to ethylenediamine is 1:50.

[0052] In some embodiments, in step (ii), the standing is performed at 90-130° C. for 12-24 hours.

[0053] In some embodiments, in step (ii), the drying is performed at 95-100° C. for 11-12 hours.

[0054] In some embodiments, in step (ii), the calcination is performed at 400-600° C. for 4-5 hours in an air atmosphere.

[0055] In some embodiments, in step (iii), the H2 / N2 atmosphere is an atmosphere of 10% H2 / 90% N2.

[0056] In some embodiments, in step (iii), the reduction is performed at 400-450° C. for 4-5 h.

[0057] In some embodiments, the present invention provides a heterogeneous catalyst composition for preparing normal aldehydes by hydroformylation of α-olefins, wherein the heterogeneous catalyst composition comprises the above-mentioned heterogeneous catalyst and an organic ligand.

[0058] In some embodiments, the present invention provides the use of the above-mentioned heterogeneous catalyst composition for catalyzing the hydroformylation of α-olefins to produce normal aldehydes, or for increasing the normal-to-isomer ratio of normal aldehydes to isomers in the aldehyde product prepared by the hydroformylation of α-olefins to 70 or more.

[0059] In some embodiments, the positive iso-ratio is greater than 80, greater than 90, greater than 100, greater than 110, greater than 120, greater than 130, greater than 140, or greater than 150.

[0060] Next, exemplary embodiments of the present invention are described in the following numbered paragraphs:

[0061] 1. A method for preparing normal aldehydes by hydroformylation of α-olefins, wherein the method comprises the following steps:

[0062] (1) mixing a heterogeneous catalyst, α-olefin, synthesis gas, solvent, and organic ligand in a reactor according to a predetermined ratio;

[0063] (2) performing a hydroformylation reaction of α-olefins at a predetermined temperature and pressure to obtain normal aldehydes;

[0064] Wherein, the heterogeneous catalyst is an encapsulated heterogeneous catalyst in which a noble metal element is encapsulated in a molecular sieve, and the noble metal element is one or more of Rh, Ir, and Au;

[0065] The organic ligand is one or more of a N-containing organic ligand, a P-containing organic ligand, and a S-containing organic ligand.

[0066] 2. The method according to paragraph 1, wherein the noble metal element is in the form of particles with an average particle size of 0.8 to 1.8 nm.

[0067] 3. The method according to paragraph 1 or 2, wherein the molecular sieve is one or more of MFI, MWW, and MEL molecular sieves having an all-silicon composition.

[0068] 4. The method as described in any one of paragraphs 1 to 3, wherein the mass content of the noble metal element accounts for 0.01 to 1 wt% of the molecular sieve carrier.

[0069] 5. The method as described in any one of paragraphs 1 to 4, wherein the mass content of the precious metal element accounts for 0.02 to 0.6 wt% of the molecular sieve carrier.

[0070] 6. The method according to any one of paragraphs 1 to 5, wherein the organic ligand is one or more selected from the following:

[0071]

[0072]

[0073] 7. The method as described in any one of paragraphs 1 to 6, wherein in step (1), the α-olefin is one or more C3 to C15 normal olefins.

[0074] 8. The method of any one of paragraphs 1 to 7, wherein in step (1), the α-olefin is one or more of 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, and 1-pentadecene.

[0075] 9. The method according to any one of paragraphs 1 to 8, wherein in step (1), the solvent is one or more of toluene, ethylbenzene, cyclohexane, acetonitrile, and p-xylene.

[0076] 10. The method of any one of paragraphs 1 to 9, wherein in step (1), the volume ratio of CO to H2 in the synthesis gas is 1:(0.5 to 3).

[0077] 11. The method of any one of paragraphs 1 to 10, wherein in step (1), the mixed molar ratio of the heterogeneous catalyst, α-olefin, synthesis gas, solvent and organic ligand is (0.015 to 0.0001):1:(20 to 140):(10 to 200):(0.15 to 3).

[0078] 12. The method of any one of paragraphs 1 to 11, wherein in step (2), the hydroformylation reaction temperature is 60 to 140° C., the pressure is 3 to 6 MPa, and the reaction time is 3 to 10 h.

[0079] 13. The method according to any one of paragraphs 1 to 12, further comprising a distillation step (3), wherein the distillation is carried out under the following operating conditions: a temperature of 50-150° C. and a pressure of 1-100 mbar.

[0080] 14. A method for preparing a heterogeneous catalyst for preparing normal aldehydes by hydroformylation of α-olefins, wherein the method comprises the following steps:

[0081] (i) mixing molecular sieve template agent tetrapropylammonium hydroxide, tetraethyl orthosilicate, potassium hydroxide and water in a hydrothermal kettle and reacting under stirring;

[0082] (ii) adding an inorganic salt of a noble metal element and ethylenediamine to the hydrothermal reactor, allowing the mixture to stand, centrifuging, washing, drying, and calcining to obtain a sample powder;

[0083] (iii) reducing the sample powder in a H2 / N2 atmosphere to obtain the heterogeneous catalyst as noble metal element particles encapsulated by molecular sieves.

[0084] 15. The method of paragraph 14, wherein in step (i), the molar stoichiometric ratio of the molecular sieve template agent tetrapropylammonium hydroxide, tetraethyl orthosilicate, potassium hydroxide and water is (0.3-0.4):1:(0.025-0.06):(13-35).

[0085] 16. The method of paragraph 14 or 15, wherein in step (i), the reaction is carried out at 30-35°C for 6-10 hours.

[0086] 17. The method of any one of paragraphs 14 to 16, wherein in step (ii), the inorganic salt of the noble metal element is one or more of chloroiridic acid, chloroauric acid, and rhodium trichloride.

[0087] 18. The method of any one of paragraphs 14 to 17, wherein in step (ii), the molar ratio of the inorganic salt of the noble metal element to ethylenediamine is 1:50.

[0088] 19. The method of any one of paragraphs 14 to 18, wherein in step (ii), the standing is performed at 90-130° C. for 12-24 hours.

[0089] 20. The method of any of paragraphs 14-19, wherein in step (ii), the drying is performed at 95-100° C. for 11-12 hours.

[0090] 21. The method of any one of paragraphs 14 to 20, wherein in step (ii), the calcination is performed at 400-600° C. for 4-5 hours in an air atmosphere.

[0091] 22. The method of any of paragraphs 14 to 21, wherein in step (iii), the H2 / N2 atmosphere is a 10% H2 / 90% N2 atmosphere.

[0092] 23. The method of any of paragraphs 14 to 22, wherein in step (iii), the reduction is performed at 400-450° C. for 4-5 hours.

[0093] 24. A heterogeneous catalyst composition for preparing normal aldehydes by hydroformylation of α-olefins, wherein the heterogeneous catalyst composition comprises: (1) the organic ligand described in any of the methods described in paragraphs 1-13; and (2) the heterogeneous catalyst described in any of the methods described in paragraphs 1-13 or the heterogeneous catalyst prepared by the method described in any of claims 14-23.

[0094] 25. Use of the heterogeneous catalyst composition described in paragraph 24 for catalyzing the hydroformylation of α-olefins to produce normal aldehydes.

[0095] 26. Use of the heterogeneous catalyst composition described in paragraph 24 for increasing the normal-to-iso ratio of normal aldehyde to isoaldehyde in an aldehyde product prepared by hydroformylation of α-olefins to 70 or more.

[0096] 27. The use of paragraph 26, wherein the normal-to-normal ratio is 80 or greater, 90 or greater, 100 or greater, 110 or greater, 120 or greater, 130 or greater, 140 or greater, or 150 or greater.

[0097] The present invention is described below by means of specific examples, but the present invention is not limited thereto.

[0098] Example

[0099] In order to further illustrate the technical features, objectives and beneficial effects of the present invention, the following series of embodiments are provided for detailed description, but are not limited to these embodiments.

[0100] Note: The product analysis method in the examples was Agilent chromatography analysis, and the specific detection method for normal aldehyde and isomeric aldehyde was as follows:

[0101] Injection volume: 0.5 μL; column temperature: 30°C for 6 min, then increase to 100°C at 5°C / min, then maintain for 2 min, then increase to 220°C at 10°C / min, then maintain for 2 min; injection port temperature: 270°C; detector temperature: 270°C.

[0102] Septum purge gas flow rate: 3 ml / min; chromatographic column flow rate (N2): 1 ml / min; split injection, split ratio is 50:1; hydrogen flow rate: 40 ml / min; air flow rate: 350 ml / min; tail gas purge flow rate: 25 ml / min.

[0103] Comparative Example

[0104] Comparative Example 1

[0105] Catalyst preparation: 0.2 wt% Ir / MFI catalyst was prepared by the following steps:

[0106] The molecular sieve template tetrapropylammonium hydroxide, tetraethyl orthosilicate, potassium hydroxide, and water were mixed in a hydrothermal autoclave at a molar ratio of 0.4:1:0.06:35 and stirred at 30°C for 6 hours. Chloroiridic acid and ethylenediamine were then added to the hydrothermal autoclave at a molar ratio of 1:50, allowed to stand at 100°C for 12 hours, and then centrifuged and washed. The resulting sample powder was dried at 100°C for 12 hours. It was then calcined at 600°C for 4 hours in an air atmosphere. Finally, it was reduced at 400°C for 5 hours in a 10% H2 / 90% N2 atmosphere to obtain molecular sieve-encapsulated iridium clusters (average particle size of 0.8-1.3 nm), i.e., a 0.2wt% Ir / MFI catalyst.

[0107] Hydroformylation: An autoclave was charged with 1 mmol of the reaction substrate, 1-hexene, 10 ml of the cyclohexane reaction solvent, and 0.02 g of a 0.2 wt% Ir / MFI catalyst. The air in the autoclave was repeatedly displaced with CO. After the displacement was complete, the autoclave was filled with CO and H2 at a total pressure of 4 MPa and a 1:1 volume ratio. The reaction was allowed to proceed at 100°C for 10 hours. After the autoclave was cooled to room temperature, the mixture was analyzed by chromatography. The results of the catalyst-catalyzed olefin hydroformylation are shown in Table 1.

[0108] Comparative Example 2

[0109] Catalyst preparation: 0.3 wt% Au / MFI catalyst was prepared by the following steps:

[0110] Molecular sieve templates tetrapropylammonium hydroxide, tetraethyl orthosilicate, potassium hydroxide, and water were mixed in a hydrothermal autoclave at a molar ratio of 0.4:1:0.06:35 and stirred at 30°C for 6 hours. Chloroauric acid and ethylenediamine were then added to the autoclave at a molar ratio of 1:50, allowed to stand at 100°C for 12 hours, and then centrifuged and washed. The resulting sample powder was dried at 100°C for 12 hours. The mixture was then calcined at 600°C for 4 hours in an air atmosphere. Finally, the mixture was reduced at 400°C in a 10% H2 / 90% N2 atmosphere for 5 hours to obtain molecular sieve-encapsulated gold clusters (average particle size 0.8-1.6 nm), namely the 0.3wt% Au / IMF catalyst.

[0111] Hydroformylation: An autoclave was charged with 1 mmol of the reaction substrate, 1-octene, 12 ml of the reaction solvent, xylene, and 0.01 g of a 0.3 wt% Au / MFI catalyst. The air in the autoclave was repeatedly displaced with CO. After the air was displaced, CO and H₂ were introduced at a total pressure of 4 MPa and a 1:1 volume ratio. The reaction was continued at 80°C for 5 h. After the autoclave was cooled to room temperature, the mixture was analyzed by chromatography. The results of the catalyst-catalyzed olefin hydroformylation are shown in Table 1.

[0112] Example 1

[0113] Catalyst preparation: 0.05 wt% Rh / MFI catalyst was prepared by the following steps:

[0114] The molecular sieve template tetrapropylammonium hydroxide, tetraethyl orthosilicate, potassium hydroxide, and water were mixed in a hydrothermal kettle at a molar ratio of 0.4:1:0.06:35 and stirred at 30°C for 6 hours. Rhodium trichloride and ethylenediamine were then added to the hydrothermal kettle at a molar ratio of 1:50, allowed to stand at 100°C for 24 hours, then centrifuged and washed, and the resulting sample powder was dried at 100°C for 12 hours. It was then calcined at 600°C for 4 hours in an air atmosphere. Finally, it was reduced at 400°C for 5 hours in a 10% H2 / 90% N2 atmosphere to obtain molecular sieve-encapsulated rhodium clusters (average particle size of 0.9 nm), i.e., 0.05wt% Rh / MFI catalyst.

[0115] Hydroformylation: An autoclave was charged with 1 mmol of the reaction substrate 1-pentene, 8 ml of toluene as the reaction solvent, 3 μl of the N-containing organic ligand L2, and 0.06 g of a 0.05% Rh / MFI catalyst. The air in the autoclave was repeatedly displaced with CO. After the displacement was complete, the autoclave was filled with CO and H2 at a total pressure of 4 MPa and a volume ratio of 1:0.5. The reaction was continued at 80°C for 5 h. After the autoclave was cooled to room temperature, the mixture was analyzed by chromatography. The results of the catalyst-catalyzed olefin hydroformylation are shown in Table 1.

[0116] Example 2

[0117] Catalyst preparation: 0.1 wt% Rh / MFI catalyst was prepared by the following steps:

[0118] The molecular sieve template tetrapropylammonium hydroxide, tetraethyl orthosilicate, potassium hydroxide, and water were mixed in a hydrothermal kettle at a molar ratio of 0.4:1:0.06:35 and stirred at 30°C for 6 hours. Rhodium trichloride and ethylenediamine were then added to the hydrothermal kettle at a molar ratio of 1:50, allowed to stand at 100°C for 24 hours, then centrifuged and washed, and the resulting sample powder was dried at 100°C for 12 hours. It was then calcined at 400°C for 4 hours in an air atmosphere. Finally, it was reduced at 400°C for 5 hours in a 10% H2 / 90% N2 atmosphere to obtain molecular sieve-encapsulated rhodium clusters (average particle size of 1.2 nm), i.e., 0.1wt% Rh / MFI catalyst.

[0119] Hydroformylation: An autoclave was charged with 1 mmol of the reaction substrate, 1-hexene, 8 ml of ethylbenzene as the reaction solvent, 8 μl of the P-containing organic ligand L7, and 0.04 g of a 0.1% Rh / MFI catalyst. The air in the autoclave was repeatedly displaced with CO. After the displacement was complete, the autoclave was filled with CO and H2 at a total pressure of 3 MPa and a volume ratio of 1:2. The reaction was continued at 100°C for 3 hours. After the autoclave was cooled to room temperature, the mixture was analyzed by chromatography. The results of the catalyst-catalyzed olefin hydroformylation are shown in Table 1.

[0120] Example 3

[0121] Catalyst preparation: 0.15 wt% Rh / MFI catalyst was prepared by the following steps:

[0122] The molecular sieve template tetrapropylammonium hydroxide, tetraethyl orthosilicate, potassium hydroxide, and water were mixed in a hydrothermal kettle at a molar ratio of 0.4:1:0.06:35 and stirred at 30°C for 6 hours. Rhodium trichloride and ethylenediamine were then added to the hydrothermal kettle at a molar ratio of 1:50, allowed to stand at 90°C for 12 hours, then centrifuged and washed, and the resulting sample powder was dried at 100°C for 12 hours. It was then calcined at 400°C for 4 hours in an air atmosphere. Finally, it was reduced at 400°C for 5 hours in a 10% H2 / 90% N2 atmosphere to obtain molecular sieve-encapsulated rhodium clusters (average particle size of 1.3 nm), i.e., 0.15wt% Rh / MFI catalyst.

[0123] Hydroformylation: An autoclave was charged with 1 mmol of the reaction substrate 1-heptene, 8 ml of the cyclohexane reaction solvent, 10 μl of the sulfur-containing organic ligand L11, and 0.02 g of a 0.15% Rh / MFI catalyst. The air in the autoclave was repeatedly displaced with CO. After the displacement was complete, the autoclave was filled with CO and H2 at a total pressure of 5 MPa and a volume ratio of 1:3. The reaction was carried out at 120°C for 5 h. After the autoclave was cooled to room temperature, the mixture was analyzed by chromatography. The results of the catalyst-catalyzed olefin hydroformylation are shown in Table 1.

[0124] Example 4

[0125] Catalyst preparation: 0.3 wt% Rh / MFI catalyst was prepared by the following steps:

[0126] The molecular sieve template tetrapropylammonium hydroxide, tetraethyl orthosilicate, potassium hydroxide, and water were mixed in a hydrothermal kettle at a molar ratio of 0.4:1:0.06:35 and stirred at 30°C for 6 hours. Rhodium trichloride and ethylenediamine were then added to the hydrothermal kettle at a molar ratio of 1:50, allowed to stand at 100°C for 24 hours, then centrifuged and washed, and the resulting sample powder was dried at 100°C for 12 hours. It was then calcined at 600°C for 4 hours in an air atmosphere. Finally, it was reduced at 400°C for 5 hours in a 10% H2 / 90% N2 atmosphere to obtain molecular sieve-encapsulated rhodium clusters (average particle size of 1.2 nm), i.e., 0.3wt% Rh / MFI catalyst.

[0127] Hydroformylation: An autoclave was charged with 1 mmol of the reaction substrate, 1-decene, 15 ml of the reaction solvent, p-xylene, and 0.02 g of the 0.3% Rh / MFI catalyst. Then, 15 μl of the sulfur-containing organic ligand L13 was added. The air in the autoclave was repeatedly displaced with CO. After the displacement was complete, the autoclave was filled with CO and H2 at a total pressure of 6 MPa and a 1:1 volume ratio. The reaction was continued at 130°C for 4 hours. After the autoclave was cooled to room temperature, the mixture was analyzed by chromatography. The results of the catalyst-catalyzed olefin hydroformylation are shown in Table 1.

[0128] Example 5

[0129] Catalyst preparation: 0.6 wt% Rh / MFI catalyst was prepared by the following steps:

[0130] The molecular sieve template tetrapropylammonium hydroxide, tetraethyl orthosilicate, potassium hydroxide, and water were mixed in a hydrothermal kettle at a molar ratio of 0.4:1:0.06:35 and stirred at 30°C for 6 hours. Rhodium trichloride and ethylenediamine were then added to the hydrothermal kettle at a molar ratio of 1:50, allowed to stand at 100°C for 24 hours, then centrifuged and washed, and the resulting sample powder was dried at 100°C for 12 hours. It was then calcined at 600°C for 4 hours in an air atmosphere. Finally, it was reduced at 400°C for 5 hours in a 10% H2 / 90% N2 atmosphere to obtain molecular sieve-encapsulated rhodium clusters (average particle size of 1.2 nm), i.e., 0.6wt% Rh / MFI catalyst.

[0131] Hydroformylation: An autoclave was charged with 1 mmol of the reaction substrate, 1-octene, 15 ml of cyclohexane as the reaction solvent, and 0.02 g of 0.6% Rh / MFI catalyst. Then, 5 μl of the sulfur-containing organic ligand L10 was added. The air in the autoclave was repeatedly displaced with CO. After the displacement was complete, the autoclave was filled with CO and H2 at a total pressure of 5 MPa and a 1:1 volume ratio. The reaction was continued at 90°C for 4 hours. After the autoclave was cooled to room temperature, the mixture was analyzed by chromatography. The results of the catalyst-catalyzed olefin hydroformylation are shown in Table 1.

[0132] Example 6

[0133] Catalyst preparation: 0.3 wt% Rh / MEL catalyst was prepared by the following steps:

[0134] The molecular sieve template tetrabutylammonium hydroxide, tetraethyl orthosilicate, potassium hydroxide, and water were mixed in a hydrothermal kettle at a molar ratio of 0.3:1:0.025:13 and stirred at 30°C for 10 hours. Rhodium trichloride and ethylenediamine were then added to the hydrothermal kettle at a molar ratio of 1:50, allowed to stand at 130°C for 24 hours, then centrifuged and washed, and the resulting sample powder was dried at 100°C for 12 hours. It was then calcined at 600°C for 4 hours in an air atmosphere. Finally, it was reduced at 400°C for 5 hours in a 10% H2 / 90% N2 atmosphere to obtain molecular sieve-encapsulated rhodium clusters (average particle size of 1.0 nm), i.e., 0.3wt% Rh / MEL catalyst.

[0135] Hydroformylation: An autoclave was charged with 1 mmol of the reaction substrate 1-decene, 10 ml of p-xylene as the reaction solvent, 3 μl of the P-containing organic ligand L5, and 0.02 g of a 0.3% Rh / MEL catalyst. The air in the autoclave was repeatedly displaced with CO. After the displacement was complete, the autoclave was filled with CO and H2 at a total pressure of 4 MPa and a 1:1 volume ratio. The reaction was carried out at 110°C for 4 hours. After the autoclave was cooled to room temperature, the mixture was analyzed by chromatography. The results of the catalyst-catalyzed olefin hydroformylation are shown in Table 1.

[0136] Example 7

[0137] Catalyst preparation: 0.6 wt% Rh / MEL catalyst was prepared by the following steps:

[0138] The molecular sieve template tetrabutylammonium hydroxide, tetraethyl orthosilicate, potassium hydroxide, and water were mixed in a hydrothermal kettle at a molar ratio of 0.3:1:0.025:13 and stirred at 30°C for 10 hours. Rhodium trichloride and ethylenediamine were then added to the hydrothermal kettle at a molar ratio of 1:50, allowed to stand at 100°C for 24 hours, then centrifuged and washed, and the resulting sample powder was dried at 100°C for 12 hours. It was then calcined at 600°C for 4 hours in an air atmosphere. Finally, it was reduced at 400°C for 5 hours in a 10% H2 / 90% N2 atmosphere to obtain rhodium clusters of molecular sieve (average particle size of 1.0 nm), i.e., 0.6wt% Rh / MEL catalyst.

[0139] Hydroformylation: An autoclave was charged with 1 mmol of the reaction substrate, 1-dodecene, 15 ml of cyclohexane as the reaction solvent, and 0.02 g of a 0.6 wt% Rh / MEL catalyst. Then, 3 μl of the sulfur-containing organic ligand L9 was added. The air in the autoclave was repeatedly displaced with CO. After the displacement was complete, CO and H₂ were introduced at a total pressure of 3 MPa and a 1:1 volume ratio. The reaction was continued at 90°C for 4 hours. After the autoclave was cooled to room temperature, the mixture was analyzed by chromatography. The results of the catalyst-catalyzed olefin hydroformylation are shown in Table 1.

[0140] Example 8

[0141] 3 μl of S-containing organic ligand L12 was added to the reactor under evaluation, and the other conditions were the same as those in Comparative Example 1.

[0142] Example 9

[0143] 3 μl of S-containing organic ligand L13 was added to the reactor under evaluation, and the other conditions were the same as those in Comparative Example 2.

[0144] Table 1 Reaction results of olefin hydroformylation catalyzed by various catalysts

[0145]

[0146] As can be seen from the above table, the heterogeneous catalyst provided by the present invention is suitable for the hydroformylation reaction of C3-C17 α-olefins, has the characteristics of high catalytic activity, high selectivity and very high product normal-to-iso ratio, and has important industrial application value.

Claims

1. A method for preparing normal aldehydes by hydroformylation of α-olefins, wherein: The method comprises the following steps: (1) mixing a heterogeneous catalyst, α-olefin, synthesis gas, solvent, and organic ligand in a reactor according to a predetermined ratio; (2) performing a hydroformylation reaction of α-olefins at a predetermined temperature and pressure to obtain normal aldehydes; The heterogeneous catalyst is an encapsulated heterogeneous catalyst in which a noble metal element is encapsulated in a molecular sieve, and the noble metal element is one or more of Rh, Ir, and Au; and the organic ligand is one or more selected from the following:

2. The method according to claim 1, wherein The noble metal element is in the form of particles and has an average particle size of 0.8 to 1.8 nm.

3. The method according to claim 1 or 2, wherein The molecular sieve is one or more of MFI, MWW and MEL molecular sieves having an all-silicon composition.

4. The method according to claim 1 or 2, wherein The mass content of the noble metal element accounts for 0.01 to 1 wt% of the molecular sieve carrier.

5. The method according to claim 1 or 2, wherein: The mass content of the noble metal element accounts for 0.02 to 0.6 wt % of the molecular sieve carrier.

6. The method according to claim 1 or 2, wherein: In step (1), the α-olefin is one or more C3 to C15 normal olefins.

7. The method according to claim 1 or 2, wherein: In step (1), the α-olefin is one or more of 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, and 1-pentadecene.

8. The method according to claim 1 or 2, wherein: In step (1), the solvent is one or more of toluene, ethylbenzene, cyclohexane, acetonitrile, and p-xylene.

9. The method according to claim 1 or 2, wherein: In step (1), the volume ratio of CO to H2 in the synthesis gas is 1:(0.5-3).

10. The method according to claim 1 or 2, wherein: In step (1), the mixed molar ratio of the heterogeneous catalyst, α-olefin, synthesis gas, solvent and organic ligand is (0.015-0.0001):1:(20-140):(10-200):(0.15-3).

11. The method according to claim 1 or 2, wherein: In step (2), the hydroformylation reaction temperature is 60-140° C., the pressure is 3-6 MPa, and the reaction time is 3-10 h.

12. The method according to claim 1 or 2, wherein: The method further comprises a distillation step (3), wherein the operating conditions of the distillation are: temperature 50-150° C. and pressure 1-100 mbar.

13. A method for preparing a heterogeneous catalyst for preparing normal aldehydes by hydroformylation of α-olefins, wherein: The method comprises the following steps: (i) mixing molecular sieve template agent tetrapropylammonium hydroxide, tetraethyl orthosilicate, potassium hydroxide and water in a hydrothermal kettle, and reacting at 30-35° C. for 6-10 hours under stirring; (ii) adding an inorganic salt of a noble metal element and ethylenediamine to the hydrothermal reactor, allowing the mixture to stand, centrifuging, washing, drying, and calcining to obtain a sample powder, wherein the molar ratio of the inorganic salt of the noble metal element to the ethylenediamine is 1:50; (iii) reducing the sample powder in a H2 / N2 atmosphere to obtain the heterogeneous catalyst as noble metal element particles encapsulated by molecular sieves; In step (i), the molar stoichiometric ratio of the molecular sieve template agent tetrapropylammonium hydroxide, tetraethyl orthosilicate, potassium hydroxide and water is (0.3-0.4):1:(0.025-0.06):(13-35); In the process of preparing normal aldehydes by hydroformylation of α-olefins, the organic ligand is complexed with the surface noble metal clusters of the heterogeneous catalyst; The organic ligand is one or more selected from the following:

14. The method of claim 13, wherein: In step (ii), the inorganic salt of the noble metal element is one or more of chloroiridic acid, chloroauric acid, and rhodium trichloride.

15. The method according to claim 13 or 14, wherein: In step (ii), the standing is performed at 90-130° C. for 12-24 hours.

16. The method according to claim 13 or 14, wherein In step (ii), the drying is performed at 95-100° C. for 11-12 h.

17. The method according to claim 13 or 14, wherein: In step (ii), the calcination is carried out at 400-600° C. for 4-5 hours in an air atmosphere.

18. The method according to claim 13 or 14, wherein In step (iii), the H2 / N2 atmosphere is an atmosphere of 10% H2 / 90% N2.

19. The method according to claim 13 or 14, wherein: In step (iii), the reduction is carried out at 400-450° C. for 4-5 h.

20. A heterogeneous catalyst composition for preparing normal aldehydes by hydroformylation of α-olefins, wherein: The heterogeneous catalyst composition comprises: (1) the organic ligand described in the method of any one of claims 1-12; and (2) the heterogeneous catalyst described in the method of any one of claims 1-12 or the heterogeneous catalyst prepared by the method of any one of claims 13-19.

21. Use of the heterogeneous catalyst composition according to claim 20 for catalyzing the hydroformylation of α-olefins to prepare normal aldehydes.

22. Use of the heterogeneous catalyst composition according to claim 20 for increasing the normal-to-iso ratio of normal aldehyde to isoaldehyde in an aldehyde product prepared by hydroformylation of α-olefin to 70 or more.

23. The use according to claim 22, wherein The positive-to-different ratio is 80 or more, 90 or more, 100 or more, 110 or more, 120 or more, 130 or more, 140 or more, or 150 or more.

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