Hydroformylation catalyst and method for preparing isobutyraldehyde

Abstract

The invention provides a hydroformylation catalyst and a method for preparing isobutyraldehyde. The hydroformylation catalyst contains a metal compound and a phosphine-containing ligand containing a specific sulfur. The method comprises the following steps: adding a substrate and a hydroformylation catalyst into a high-pressure reaction kettle, introducing synthesis gas into the high-pressure reaction kettle, and heating for reaction to prepare a corresponding formylation product. The catalyst has high regioselectivity, can reduce the normal-isomerization ratio of an olefin hydroformylation reaction product aldehyde, realizes the low normal-isomerization ratio in the process of preparing butyraldehyde through propylene hydroformylation, and has the characteristic of high stability in the reaction.

Description

Technical Field

[0001] The invention belongs to the technical field of organic chemical synthesis, and particularly relates to a hydroformylation catalyst and a method for preparing isobutyraldehyde. Background Art

[0002] Olefin hydroformylation technology is a green and efficient olefin utilization technology that can achieve efficient conversion and utilization of olefins. The products are oxygen-containing chemicals such as organic alcohols, acids, and esters with high added value. Among them, the propylene hydroformylation reaction has important industrial significance, and n-butyraldehyde and iso-butyraldehyde are produced during the reaction.

[0003] Among them, n-butyraldehyde is usually further converted into n-butanol and 2-ethylhexanol, both of which are important basic chemical principles for the production of bulk daily necessities such as plasticizers, detergents, coatings, and medicines. As a by-product of the reaction, isobutyraldehyde has received less attention in industrialization. In recent years, the production capacity and demand of isobutyraldehyde downstream products such as neopentyl glycol and dodecyl alcohol ester have increased, and there is a gap between supply and demand, and supply is limited. Therefore, it is particularly important to significantly increase the yield of isobutyraldehyde through innovation of the catalytic system.

[0004] Currently available industrial hydroformylation devices mostly use the second-generation low-pressure rhodium carbonyl synthesis process, and the product iso-ratio is 6-10. For such devices, the iso-ratio of butyraldehyde can be changed by adjusting the type of ligand and the reaction conditions. For example, CN102741210B reported that the iso-ratio was reduced by adding phosphite ligands and reducing the transition metal concentration in the first reaction zone. CN101657407B reported that the product iso-ratio was controlled and reduced by changing the concentration of organic polyphosphite ligands relative to transition metals in the reaction. However, such methods are difficult to operate stably for a long period of time, and there is still a lot of room for improvement in the catalytic system.

[0005] Therefore, in view of the existing propylene hydroformylation reaction system, it is of great significance to develop a hydroformylation catalyst that can increase the production of isobutyraldehyde. Summary of the invention

[0006] In order to make up for the deficiencies in the prior art, the present invention provides a catalyst for hydroformylation reaction and a method for preparing isobutyraldehyde by hydroformylation. The catalyst has high regioselectivity, can reduce the normal isomer ratio of aldehydes in the olefin hydroformylation reaction product, achieves a low normal isomer ratio in the process of preparing butyraldehyde by propylene hydroformylation, and has the characteristics of high stability in the reaction.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] A phosphine ligand for a hydroformylation catalyst, wherein the phosphine ligand has a structure shown in Formula I:

[0009]

[0010] Among them, R1, R2, and R3 are each independently selected from electron donating groups and / or electron withdrawing groups, and are preferably independently any one of hydrogen, chlorine, methyl, methoxy, isopropoxy, and trifluoromethyl.

[0011] In one embodiment of the present invention, the phosphine ligand is any one or more of the following ligands L1-L8:

[0012]

[0013] Another object of the present invention is to provide a hydroformylation catalyst.

[0014] A hydroformylation catalyst, the catalyst adopts the above-mentioned phosphine ligand, the hydroformylation catalyst comprises a metal compound and a phosphine-containing ligand; preferably, the molar ratio of the metal compound to the phosphine-containing ligand is 1:(1-10), preferably 1:(2-5), wherein the molar amount of the metal compound is calculated based on the amount of metal atomic substance.

[0015] In one embodiment of the present invention, the metal compound is selected from rhodium metal compounds and / or cobalt metal compounds, preferably rhodium metal compounds, more preferably one or more of rhodium halides, complexes of rhodium and acetyl compounds, further preferably one or more of rhodium chloride (RhCl3), acetylacetonato dicarbonyl rhodium (Rh(CO)2acac), and acetylacetonato triphenylphosphine carbonyl rhodium (ROPAC).

[0016] The molar ratio of the metal compound to the phosphine-containing ligand is 1:(1-10), for example, the molar ratio is 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, preferably 1:(2-5), wherein the molar amount of the metal compound is calculated based on the amount of rhodium atom substance.

[0017] The catalyst system of the present invention has high catalytic activity and regional selectivity. Based on the existing hydroformylation technology, the present invention designs a catalyst composition of a novel multidentate phosphine ligand to adjust the selectivity of propylene hydroformylation, for example, the normal-isobutyraldehyde ratio of the butyraldehyde product can reach 0.1:0.8-1.0, greatly improving the production capacity of isobutyraldehyde.

[0018] In the hydroformylation catalyst of the present invention, by introducing an atomic five-membered heterocyclic compound into a multidentate phosphine ligand, the 6π electron system of the thiophene ring can change the coordination strength with the metal active site, and the coordinated catalyst system has better reaction activity and better stability, and can significantly improve the conversion rate and selectivity of the hydroformylation reaction, promote the generation of isomer products, and thus achieve a low positive-to-isomer ratio.

[0019] In one embodiment of the present invention, the phosphine ligand has a structure as shown in Formula I;

[0020]

[0021] Among them, R1, R2, and R3 are each independently selected from electron donating groups and / or electron withdrawing groups, and are preferably independently any one of hydrogen, chlorine, methyl, methoxy, isopropoxy, and trifluoromethyl.

[0022] Another object of the present invention is to provide a use of a hydroformylation catalyst.

[0023] A use of a hydroformylation catalyst, wherein the catalyst adopts the above-mentioned phosphine ligand, or is the above-mentioned catalyst, and the catalyst is used for catalyzing a hydroformylation reaction between a reaction substrate and synthesis gas CO / H2.

[0024] Another object of the present invention is to provide a hydroformylation synthesis method.

[0025] A hydroformylation synthesis method, wherein the catalyst of the method adopts the above-mentioned phosphine ligand or the above-mentioned catalyst, and the method comprises the following steps: adding a substrate and a hydroformylation catalyst into a high-pressure reactor, then introducing synthesis gas CO / H2 into the high-pressure reactor, heating the reactor for reaction, and preparing a corresponding formylation product.

[0026] In one embodiment of the present invention, the substrate in the synthesis method is propylene;

[0027] In one embodiment of the present invention, the product in the synthesis method is butyraldehyde;

[0028] In one embodiment of the present invention, the synthesis process wherein the synthesis gas comprises CO and H2.

[0029] In one embodiment of the present invention, in the synthesis method, the mass concentration of rhodium in the catalyst solution is 50-400 ppm, preferably the rhodium concentration is 100-200 ppm.

[0030] In one embodiment of the present invention, in the synthesis method, the molar ratio of CO and H2 is (0.7-1.3):1.

[0031] In one embodiment of the present invention, in the synthesis method, the reaction temperature is 60-100° C., the reaction time is 2-6 h; and the synthesis gas pressure is 1.0-3.0 MPaG.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The catalyst for propylene hydroformylation provided by the present invention has high catalytic activity and stability, a conversion rate of more than 99%, and a selectivity of isomeric aldehyde products of more than 90%, which can effectively improve regional selectivity and effectively inhibit the generation of by-products, greatly changing the regulation of the catalyst on the product positive-to-isomer ratio in the hydroformylation reaction, and is more conducive to the generation of isomers of the hydroformylation product. DETAILED DESCRIPTION

[0034] The present invention is further described below by means of specific examples. The examples described in the present invention are only used to illustrate the present invention and do not limit the scope of the present invention.

[0035] Unless otherwise specified, the raw materials used in the following specific embodiments of the present invention are purchased through commercial channels.

[0036] Table 1 Raw material information

[0037]

[0038] Table 2 Equipment information

[0039]

[0040] Gas chromatography analysis: carrier gas: high-purity nitrogen; injection mode: automatic injector; nitrogen flow rate: 68.1 ml / min; vaporization chamber temperature: 270°C; split injection, split ratio: 30:1; injection volume: 0.2 μl; column temperature: first-order programmed temperature rise, initial value 35°C, maintained for 5 minutes, then increased to 260°C at a rate of 15°C / min, maintained for 15 minutes; the total running time was 25 minutes.

[0041] Preparation Example 1

[0042]

[0043] 2,8-Dibromodibenzothiophene (1 mol) and aqueous ammonia solution (2.4 mol) were mixed, coupled with 10 mol % Cu2O and N-methylpyrrolidone (NMP) at 100° C., and reacted for 24 hours to obtain substance A.

[0044] Substance A was dissolved in tetrahydrofuran, the reaction system was placed in a low temperature cold bath, and n-butyl lithium solution (1.3 mol) was added dropwise to the solution. After reacting for 30 minutes, diphenylphosphine chloride (6 mol) was added, and the reaction was continued for 12 hours, and then the reaction was quenched with an ammonium chloride aqueous solution, and then separated and dried to obtain ligand L1.

[0045] Spectral characterization:

[0046] 1H NMR (500MHz, DMSO-d6) δ7.77(s,2H),7.65–7.58(m,16H),7.51(s,2H),7.44–7.36(m,8H),7.35–7.27(m,19H).

[0047] 13 C NMR (125MHz, Chloroform-d) δ142.05,139.49,137.72,131.20,129.00,127.35,126.28,123.39,123.34,115.92.

[0048] Preparation Example 2

[0049] 2,8-Dibromodibenzothiophene (1 mol) and aqueous ammonia solution (2.4 mol) were mixed, coupled with 10 mol % Cu2O and N-methylpyrrolidone (NMP) at 100° C., and reacted for 24 hours to obtain substance A.

[0050] Substance A was dissolved in tetrahydrofuran, the reaction system was placed in a low temperature cold bath, and n-butyl lithium solution (1.3 mol) was added dropwise to the solution. After reacting for 30 minutes, di(p-tolyl)phosphine chloride (6 mol) was added, and the reaction was continued for 12 hours, and then the reaction was quenched with an aqueous ammonium chloride solution, and then separated and dried to obtain ligand L3.

[0051] Preparation Example 3

[0052] 2,8-Dibromodibenzothiophene (1 mol) and aqueous ammonia solution (2.4 mol) were mixed, coupled with 10 mol % Cu2O and N-methylpyrrolidone (NMP) at 100° C., and reacted for 24 hours to obtain substance A.

[0053] Substance A was dissolved in tetrahydrofuran, the reaction system was placed in a low temperature cold bath, and n-butyl lithium solution (1.3 mol) was added dropwise to the solution. After reacting for 30 minutes, chlorodi[4-(trifluoromethyl)phenyl]phosphine (6 mol) was added, and the reaction was continued for 12 hours. The reaction was quenched with an aqueous ammonium chloride solution, and then separated and dried to obtain ligand L8.

[0054] Example 1

[0055] 0.03g Rh(CO)2acac and 0.3g L1 phosphine ligand were added to the autoclave in sequence, and the nitrogen and synthesis gas were replaced three times and then emptied, and 100g propylene was added, and then 2.0MPaG synthesis gas was introduced, and the temperature was raised to 80°C for 4 hours to obtain butyraldehyde. The synthesis gas is CO and H2 with a molar ratio of 1:1.

[0056] Example 2

[0057] 0.10g Rh(CO)2acac and 0.22g L3 phosphine ligand were added to the autoclave in sequence, and the autoclave was emptied after replacing nitrogen three times and synthesis gas three times, and then 100g propylene was added, and then 2.0MPaG synthesis gas was introduced, and the temperature was raised to 80°C for 4 hours to obtain butyraldehyde. The synthesis gas is CO and H2 with a molar ratio of 1:1.

[0058] Example 3

[0059] 0.06g Rh(CO)2acac and 0.76g L8 phosphine ligand were added to the autoclave in sequence, and the autoclave was emptied after replacing nitrogen three times and synthesis gas three times, and then 100g propylene was added, and then 1.0MPaG synthesis gas was introduced, and the temperature was raised to 80°C for 4 hours to obtain butyraldehyde. The synthesis gas is CO and H2 with a molar ratio of 1:1.

[0060] Example 4

[0061] 0.01g Rh(CO)2acac and 0.10g L8 phosphine ligand were added to the autoclave in sequence, and the autoclave was emptied after replacing nitrogen three times and synthesis gas three times, and then 100g propylene was added, and then 3.0MPaG synthesis gas was introduced, and the temperature was raised to 100°C for reaction for 2 hours to obtain butyraldehyde. The synthesis gas was CO and H2 with a molar ratio of 0.8:1.

[0062] Example 5

[0063] 0.19g Rh(CO)2acac and 0.89g L8 phosphine ligand were added to the autoclave in sequence, and the autoclave was emptied after replacing nitrogen three times and synthesis gas three times, and then 100g propylene was added, and then 1.0MPaG synthesis gas was introduced, and the temperature was raised to 60°C for reaction for 6 hours to obtain butyraldehyde. The synthesis gas was CO and H2 with a molar ratio of 1.2:1.

[0064] Example 6

[0065] 0.03g Rh(CO)2acac and 1.00g L8 phosphine ligand were added to the autoclave in sequence, and the autoclave was emptied after replacing nitrogen three times and synthesis gas three times, and then 100g propylene was added, and then 2.0MPaG synthesis gas was introduced, and the temperature was raised to 90°C for reaction for 5 hours to obtain butyraldehyde. The synthesis gas is CO and H2 with a molar ratio of 1:1.

[0066] Comparative Example 1

[0067] Compared with Example 1, the only difference is that a triphenylphosphine ligand other than that of the present application is used instead.

[0068] Comparative Example 2

[0069] Compared with Example 1, the only difference is that the (2,7-di-tert-butyl-9,9-dimethyl-9H-anthracene-4,5-diyl)bis(diphenylphosphine) (CAS: 221462-97-1) ligand which is not in the solution of the present application is used instead.

[0070] The reaction selectivity, conversion rate and product iso-ratio in the above examples and comparative examples were tested, and the test results are shown in Table 3:

[0071] Table 3 Performance test results

[0072] Serial number Conversion rate / % Isoaldehyde selectivity / % Positive difference ratio Example 1 99.7 90.1 0.10 Example 2 99.5 89.8 0.12 Example 3 99.2 88.5 0.11 Example 4 99.1 89.6 0.12 Example 5 99.8 88.6 0.11 Example 6 99.4 87.3 0.10 Comparative Example 1 99.0 9.8 9.06 Comparative Example 2 98.6 17.1 4.76

[0073] In Table 1, the normal-isomer ratio refers to the mass ratio of the normal isomer to the isomer in the hydroformylation product.

[0074] It can be seen from Table 1 that the catalyst for propylene hydroformylation prepared by the present invention can efficiently catalyze the synthesis of isobutyraldehyde from propylene, the raw material conversion rate can be as high as 99.8%, the selectivity of the isomeric aldehyde product can reach 90%, and the product butyraldehyde is relatively low.

[0075] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. A phosphine ligand for a hydroformylation catalyst, characterized in that: The phosphine ligand has a structure shown in Formula I: Among them, R1, R2, and R3 are each independently selected from electron donating groups and / or electron withdrawing groups, and are preferably independently any one of hydrogen, chlorine, methyl, methoxy, isopropoxy, and trifluoromethyl.

2. The phosphine ligand according to claim 1, characterized in that The phosphine ligand is any one or more of the following ligands L1-L8:

3. A hydroformylation catalyst, wherein the catalyst uses the phosphine ligand according to claim 1 or 2, characterized in that: The hydroformylation catalyst comprises a metal compound and a phosphine-containing ligand; Preferably, the molar ratio of the metal compound to the phosphine-containing ligand is 1:(1-10), preferably 1:(2-5), wherein the molar amount of the metal compound is calculated as the amount of metal atomic substance.

4. The catalyst according to claim 3, characterized in that The metal compound is selected from rhodium metal compounds and / or cobalt metal compounds, preferably rhodium metal compounds, more preferably one or more of rhodium halides, complexes of rhodium and acetyl compounds, further preferably one or more of rhodium chloride (RhCl3), acetylacetonato dicarbonyl rhodium (Rh(CO)2acac), and acetylacetonato triphenylphosphine carbonyl rhodium (ROPAC).

5. The catalyst according to claim 3 or 4, characterized in that The phosphine ligand has a structure as shown in Formula I; Among them, R1, R2, and R3 are each independently selected from electron donating groups and / or electron withdrawing groups, and are preferably independently any one of hydrogen, chlorine, methyl, methoxy, isopropoxy, and trifluoromethyl.

6. Use of a hydroformylation catalyst, wherein the catalyst adopts the phosphine ligand according to claim 1 or 2, or is the catalyst according to any one of claims 3 to 5, and the catalyst is used to catalyze the hydroformylation reaction of a reaction substrate and synthesis gas CO / H2.

7. A hydroformylation synthesis method, wherein the catalyst of the method is the phosphine ligand according to claim 1 or 2, or the catalyst according to any one of claims 3 to 5, and the method comprises the following steps: adding a substrate and a hydroformylation catalyst into a high-pressure reactor, then introducing synthesis gas CO / H2 into the high-pressure reactor, heating the reactor for reaction, and preparing a corresponding formylation product.

8. The synthesis method according to claim 7, characterized in that The substrate is propylene; and / or, the product is butyraldehyde; And / or, the syngas comprises CO and H2.

9. The synthesis method according to claim 7 or 8, characterized in that: In the synthesis method, the mass concentration of rhodium in the catalyst solution is 50-400 ppm, preferably the rhodium concentration is 100-200 ppm; And / or, in the synthesis method, the molar ratio of CO to H2 is (0.7-1.3):1; And / or, in the synthesis method, the reaction temperature is 60-100° C., the reaction time is 2-6 h; and the synthesis gas pressure is 1.0-3.0 MPaG.

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