High-carbon aldehyde and preparation method thereof

Abstract

The preparation method comprises the following steps: in the presence of a cobalt catalyst and a salicylaldehyde Schiff base ligand, carrying out carbonyl synthesis reaction on C5-C20 olefin and synthesis gas at a certain reaction temperature and pressure to generate C6-C21 aldehyde. The salicylaldehyde Schiff base coordination cobalt catalyst is introduced, the electronic structure of the catalyst is changed, the capacity of the catalyst for adsorbing and activating olefin and synthesis gas is improved, the reaction temperature and pressure can be reduced, the high-carbon aldehyde yield is greatly increased, and the method has good application prospects and industrial application potential in the field of petrochemical engineering.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical raw material preparation, and particularly relates to a higher aldehyde and a preparation method thereof. Background Art

[0002] The hydroformylation reaction of olefins is one of the homogeneous catalytic reactions with the largest application scale in current industrial production. Using this reaction, various high-value-added oxygen-containing chemicals such as plasticizer alcohols, surfactant alcohols, and carboxylic acids can be produced, and the global total output reaches 20 million tons / year. The aldehydes produced by the hydroformylation reaction of olefins have wide applications. Fatty alcohols, fatty amines, and fatty acids can be obtained by hydrogenation, amination, and oxidation respectively.

[0003] For the method of preparing higher aldehydes by the hydroformylation of higher olefins, the earliest and currently widely used industrial catalyst is cobalt catalyst, and the reaction needs to be carried out under high temperature and high pressure (140 °C - 180 °C, total pressure 20 MPa - 35 MPa), and the reaction conditions are harsh. DE59704070D1 discloses a method for preparing aldehydes having 7 - 18 carbon atoms, including the hydroformylation of higher olefins to prepare higher aldehydes at a temperature of 50 °C - 220 °C and a pressure of 10 MPa - 40 MPa in the presence of a cobalt catalyst organic phase. CN112547128B provides a rhodium catalyst composition, which can increase the selectivity of linear aldehydes in the higher aldehydes produced by the hydroformylation of higher olefins. However, the boiling point of the product higher aldehyde is relatively high, and it is difficult to separate the product from the catalyst after the reaction. The rhodium catalyst is easily decomposed and deactivated during the separation process, and continuous addition of rhodium catalyst is required, which reduces the economic efficiency of the technical route. CN111606792B provides a rhodium-phosphine water-soluble catalyst, which can catalyze the hydroformylation of higher olefins to prepare higher aldehydes in polar solvents such as water, and the product and the catalyst can be separated by extraction, but the loss of rhodium is relatively large, resulting in an increase in production cost.

[0004] It can be seen that the production process of higher aldehydes needs to be further optimized. If a non-precious metal catalytic system - namely a cobalt catalytic system - with relatively mild reaction conditions can be developed, the production cost and the requirements for production equipment will be greatly reduced, and the production process of higher aldehydes will be simplified. Summary of the Invention

[0005] The present invention is proposed to solve the problems of high catalyst cost and insufficient catalytic activity in the prior art, and its purpose is to provide a higher aldehyde and a preparation method thereof.

[0006] The present invention is achieved by the following technical solutions:

[0007] A method for preparing a high-carbon aldehyde, specifically: adding a cobalt catalyst and a salicylaldehyde Schiff base ligand into a reactor, then adding a C5-C20 olefin, and introducing syngas to carry out a hydroformylation reaction to obtain a C6-C21 aldehyde.

[0008] In the above technical solution, the cobalt catalyst is a cobalt salt and / or a cobalt oxide; the cobalt salt is any one or more of cobalt naphthenate, cobalt acetate, cobalt formate, cobalt levulinate, cobalt nitrate, cobalt carbonate, dicobalt octacarbonyl or sodium tetracarbonylcobalt; the cobalt oxide is cobalt hydroxide and / or cobalt oxide.

[0009] In the above technical solution, the structural formula of the salicylaldehyde Schiff base ligand is as follows formula (Ⅰ):

[0010]

[0011] In formula (Ⅰ): R1, R2, and R3 are independently selected from any one of hydrogen, a C1-C6 alkyl fragment, a C6-C10 aryl-containing or a C6-C10 pyridyl-containing fragment; the R1, R2, and R3 groups are the same or different; the C1-C6 alkyl fragment is methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl, tert-butyl, pentyl, tert-pentyl, neopentyl, cyclopentyl, hexyl or cyclohexyl; the C6-C10 aryl-containing fragment is phenyl, m-methylphenyl, o-methylphenyl, p-methylphenyl, p-ethylphenyl, m-ethylphenyl, p-propylphenyl, p-isopropylphenyl, p-butylphenyl, p-isobutylphenyl, p-tert-butylphenyl, benzoyl and benzamido; the C6-C10 pyridyl-containing fragment is pyridyl, m-methylpyridyl, o-methylpyridyl, p-methylpyridyl, p-ethylpyridyl, m-ethylpyridyl, p-propylpyridyl, p-isopropylpyridyl, p-butylpyridyl, p-isobutylpyridyl, p-tert-butylpyridyl, pyridinecarbonyl and pyridinecarboxamide.

[0012] In the above technical solution, the salicylaldehyde Schiff base ligand is any one of salicylaldehyde anilide, salicylaldehyde pyridylamine, salicylaldehyde phenylhydrazine, salicylaldehyde benzamide or salicylaldehyde benzoylhydrazide.

[0013] In the above technical solution, the molar ratio of cobalt in the cobalt catalyst to the salicylaldehyde Schiff base ligand is 1:(0.2-20).

[0014] In the above technical solution, the mass concentration of cobalt in the reaction solution composed of the cobalt catalyst, the salicylaldehyde Schiff base ligand and the C5-C20 olefin is 0.005%-1.000%.

[0015] In the above technical solution, the syngas is a mixture of hydrogen and carbon monoxide, and the volume ratio of hydrogen to carbon monoxide is (1-2):1.

[0016] In the above technical solution, the reaction temperature of the hydroformylation reaction is 80°C to 200°C, the reaction pressure is 3 MPa to 10 MPa, and the reaction duration is 2 h to 8 h; preferably, the reaction temperature is 80°C to 160°C, the reaction pressure is 3 MPa to 8 MPa, and the reaction duration is 8 h.

[0017] A higher aldehyde is prepared by the aforementioned method

[0018] The beneficial effects of the present invention are:

[0019] The present invention provides a preparation method for efficiently catalytically synthesizing higher aldehydes from higher olefins with low cost. The salicylaldehyde Schiff base ligand used is a class of organic compounds containing methyleneimine and hydroxybenzene (hydroxypyridine). There are lone pairs of electrons in the hybrid orbitals of the nitrogen atom in the methyleneimine group and the oxygen atom in the hydroxyl group, which endows the salicylaldehyde Schiff base with good coordination properties. Coordination with the cobalt catalyst can change the electronic effect and steric effect of the cobalt catalytic active center, thereby improving the performance of the cobalt catalyst. When catalyzing the hydroformylation of C5-C20 olefins and syngas to prepare C6-C21 aldehydes (alcohols), under medium-pressure conditions of 3-8 MPa, the reaction conversion rate can reach more than 97%, and the aldehyde (alcohol) yield can reach more than 90%. At the same time, since non-precious metal cobalt is used instead of precious metal rhodium catalyst, the catalyst cost is greatly reduced, and the economic benefits of the technology are improved. Specific Embodiments

[0020] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be further described below through specific embodiments.

[0021] Example 1

[0022] 100.0 g of 1-octene, 1.0 g of dicobalt octacarbonyl, and 0.7 g of salicylaldehyde Schiff base ligand LA (at this time, the molar ratio of cobalt to ligand is about 1:2) were added to a 250 mL high-pressure reactor. The salicylaldehyde Schiff base ligand LA has the structural formula (I), in which R1 and R2 are hydrogen, and R3 is benzamide group. After purging with nitrogen three times, 7.0 MPa of syngas was charged, and the volume ratio of hydrogen to carbon monoxide was 1:1. The reaction was started by heating, and the syngas pressure was maintained at 7.0 MPa during the reaction process. The temperature was raised to 110°C to start the reaction timing. After 8 h of reaction, the gas-phase analysis was sampled to detect the conversion rate of 1-octene, the product selectivity, and the normal / iso ratio.

[0023] Example 2

[0024] The test method of this example is the same as that of Example 1. The difference is only that: the reaction temperature is 130°C. The conversion rate, yield, and normal / iso ratio are shown in Table 1.

[0025] Example 3

[0026] The test method of this example is the same as that of Example 1. The only difference is that the reaction temperature is 90 °C. The conversion rate, yield, and normal-to-isomer ratio are shown in Table 1.

[0027] Example 4

[0028] The test method of this example is the same as that of Example 1. The only difference is that the reaction pressure is 8.0 MPa. The conversion rate, yield, and normal-to-isomer ratio are shown in Table 1.

[0029] Example 5

[0030] The test method of this example is the same as that of Example 1. The only difference is that the reaction temperature is 5.0 MPa. The conversion rate, yield, and normal-to-isomer ratio are shown in Table 1.

[0031] Example 6

[0032] The test method of this example is the same as that of Example 1. The only difference is that 0.5 g of dicobalt octacarbonyl and 0.7 g of salicylaldehyde Schiff base ligand LA (at this time, the molar ratio of cobalt to ligand is about 1:4). The conversion rate, yield, and normal-to-isomer ratio are shown in Table 1.

[0033] Example 7

[0034] The test method of this example is the same as that of Example 1. The only difference is that 1.0 g of dicobalt octacarbonyl and 2.1 g of salicylaldehyde Schiff base ligand LA (at this time, the molar ratio of cobalt to ligand is about 1:6). The conversion rate, yield, and normal-to-isomer ratio are shown in Table 1.

[0035] Example 8

[0036] The test method of this example is the same as that of Example 1. The only difference is that 1.0 g of dicobalt octacarbonyl and 2.8 g of salicylaldehyde Schiff base ligand LA (at this time, the molar ratio of cobalt to ligand is about 1:8). The conversion rate, yield, and normal-to-isomer ratio are shown in Table 1.

[0037] Example 9

[0038] The test method of this example is the same as that of Example 1. The only difference is that the salicylaldehyde Schiff base ligand LB has the structural formula (I), where R1-R2 are hydrogen and R3 are all benzoyl groups. The conversion rate, yield, and normal-to-isomer ratio are shown in Table 1.

[0039] Example 10

[0040] The test method of this example is the same as that of Example 1. The only difference is that the salicylaldehyde Schiff base ligand LC has the structural formula (I), where R1-R2 are hydrogen and R3 is anilino. The conversion rate, yield, and normal-to-isomer ratio are shown in Table 1.

[0041] Example 11

[0042] The test method of this example is the same as that of Example 1. The only difference is that the salicylaldehyde Schiff base ligand LD has the structural formula (I), where R1-R2 are hydrogen and R3 is phenyl. The conversion rate, yield and normal-to-isomer ratio are shown in Table 1.

[0043] Example 12

[0044] The test method of this example is the same as that of Example 1. The only difference is that the salicylaldehyde Schiff base ligand LE has the structural formula (I), where R1-R2 are hydrogen and R3 is pyridyl. The conversion rate, yield and normal-to-isomer ratio are shown in Table 1.

[0045] Example 13

[0046] The test method of this example is the same as that of Example 1. The only difference is that the salicylaldehyde Schiff base ligand LF has the structural formula (I), where R1-R2 are methyl and R3 is benzamido. The conversion rate, yield and normal-to-isomer ratio are shown in Table 1.

[0047] Example 14

[0048] The test method of this example is the same as that of Example 1. The only difference is that the cobalt catalyst is cobalt acetate. The conversion rate, yield and normal-to-isomer ratio are shown in Table 1.

[0049] Example 15

[0050] The test method of this example is the same as that of Example 1. The only difference is that the cobalt catalyst is cobalt acetylacetonate. The conversion rate, yield and normal-to-isomer ratio are shown in Table 1.

[0051] Example 16

[0052] The test method of this example is the same as that of Example 1. The only difference is that the cobalt catalyst is cobalt hydroxide. The conversion rate, yield and normal-to-isomer ratio are shown in Table 1.

[0053] Example 17

[0054] The test method of this example is the same as that of Example 1. The only difference is that the cobalt catalyst is cobalt formate. The conversion rate, yield and normal-to-isomer ratio are shown in Table 1.

[0055] Example 18

[0056] The test method of this example is the same as that of Example 1. The only difference is that the reactant 1-octene is replaced by 1-pentene. The conversion rate, yield and normal-to-isomer ratio are shown in Table 2.

[0057] Example 19

[0058] The test method of this example is the same as that of Example 1. The only difference is that the reactant 1-octene is replaced by 1-hexene. The conversion rate, yield and normal-to-isomer ratio are shown in Table 2.

[0059] Example 20

[0060] The test method of this example is the same as that of Example 1. The only difference is that the reactant 1-octene is replaced by 1-heptene. The conversion rate, yield and normal-to-isomer ratio are shown in Table 2.

[0061] Example 21

[0062] The test method of this example is the same as that of Example 1. The only difference is that the reactant 1-octene is replaced by 1-dodecene. The conversion rate, yield and normal-to-isomer ratio are shown in Table 2.

[0063] Comparative Example 1

[0064] The test method of this example is the same as that of Example 1. The only difference is that no ligand is added. The conversion rate and yield are shown in Table 1.

[0065] Comparative Example 2

[0066] The test method of this example is the same as that of Example 1. The only difference is that the added ligand is triphenylphosphine. The conversion rate and yield are shown in Table 1.

[0067] Comparative Example 3

[0068] The test method of this example is the same as that of Example 1. The only difference is that no cobalt catalyst is added.

[0069] The conversion rates and yields of Examples 1 to 17 and Comparative Examples 1 to 3 are shown in Table 1.

[0070] Table 1. Condition Optimization

[0071] Example Conversion rate / % Aldehyde yield / % Normal-to-isomer ratio 1 97.1 90.8 4.3 2 98.5 90.5 3.9 3 81.0 71.7 4.3 4 97.6 90.3 4.1 5 77.3 71.7 4.3 6 67.2 60.9 4.1 7 82.8 70.1 4.2 8 76.2 73.9 4.2 9 87.3 83.1 4.4 10 75.0 71.5 4.4 11 78.7 74.2 4.0 12 75.2 65.8 4.5 13 72.4 63.9 4.6 14 95.2 88.3 4.0 15 96.3 89.7 4.2 16 96.0 90.0 4.1 17 95.9 89.8 4.4 Comparative Example 1 27.4 23.8 1.2 Comparative Example 2 7.9 7.0 9.1 Comparative Example 3 0 0 /

[0072] Table 2. Reactant Evaluation

[0073]

[0074]

[0075] The applicant declares that the above description is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A method for preparing a high-carbon aldehyde, characterized in that: Specifically: A cobalt catalyst and a salicylaldehyde Schiff base ligand are added to a reactor, then C5-C20 olefins are added, and syngas is introduced to carry out a hydroformylation reaction to obtain C6-C21 aldehydes.

2. The preparation method of the high-carbon aldehyde according to claim 1, wherein: The cobalt catalyst is a cobalt salt and / or a cobalt oxide; the cobalt salt is any one or more of cobalt naphthenate, cobalt acetate, cobalt formate, cobalt acetylacetonate, cobalt nitrate, cobalt carbonate, dicobalt octacarbonyl or sodium tetracarbonylcobalt; the cobalt oxide is cobalt hydroxide and / or cobalt oxide.

3. The preparation method of the high-carbon aldehyde according to claim 1, wherein: The structural formula of the salicylaldehyde Schiff base ligand is as follows formula (Ⅰ): In formula (Ⅰ): R1, R2, and R3 are independently any one selected from hydrogen, a C1-C6 alkyl fragment, a C6-C10 aryl-containing fragment or a C6-C10 pyridyl-containing fragment.

4. The preparation method of the high-carbon aldehyde according to claim 3, characterized in that: The C1-C6 alkyl fragment is methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl, tert-butyl, pentyl, tert-pentyl, neopentyl, cyclopentyl, hexyl or cyclohexyl; the C6-C10 aryl-containing fragment is phenyl, m-methylphenyl, o-methylphenyl, p-methylphenyl, p-ethylphenyl, m-ethylphenyl, p-propylphenyl, p-isopropylphenyl, p-butylphenyl, p-isobutylphenyl, p-tert-butylphenyl, benzoyl and benzamide; the C6-C10 pyridyl-containing fragment is pyridyl, m-methylpyridyl, o-methylpyridyl, p-methylpyridyl, p-ethylpyridyl, m-ethylpyridyl, p-propylpyridyl, p-isopropylpyridyl, p-butylpyridyl, p-isobutylpyridyl, p-tert-butylpyridyl, pyridinecarbonyl and pyridinecarboxamide.

5. The preparation method of the high-carbon aldehyde according to claim 1, wherein: The salicylaldehyde Schiff base ligand is any one of salicylaldehyde aniline, salicylaldehyde pyridylamine, salicylaldehyde phenylhydrazine, salicylaldehyde benzamide or salicylaldehyde benzoylhydrazine.

6. The preparation method of the high-carbon aldehyde according to claim 1, characterized in that: The molar ratio of cobalt in the cobalt catalyst to the salicylaldehyde Schiff base ligand is 1:(0.2-20).

7. The method for preparing a high-carbon aldehyde according to claim 1, wherein: The mass concentration of cobalt in the reaction solution composed of the cobalt catalyst, the salicylaldehyde Schiff base ligand and C5-C20 olefins is 0.005%-1.000%.

8. The preparation method of the high-carbon aldehyde according to claim 1, characterized in that: The syngas is a mixture of hydrogen and carbon monoxide, and the volume ratio of hydrogen to carbon monoxide is (1-2):

1.

9. The preparation method of the high-carbon aldehyde according to claim 1, wherein: The reaction temperature of the hydroformylation reaction is 80°C-200°C, the reaction pressure is 3MPa-10MPa, and the reaction duration is 2h-8h.

10. A high-carbon aldehyde, characterized in that: Prepared by the method according to any one of claims 1-9.

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