Preparation method of 4-acetoxybutyraldehyde

Abstract

The invention discloses a preparation method of 4-acetoxybutyraldehyde, which is characterized in that under the catalytic action of a cobalt catalyst and a pyridine diphosphorus ligand, allyl acetate and synthesis gas are subjected to carbonyl synthesis reaction for 2-8 hours under the conditions that the reaction temperature is 80-200 DEG C and the pressure is 3-10 MPa, and the 4-acetoxybutyraldehyde is obtained. The catalytic system containing the cobalt catalyst and the pyridine diphosphorus ligand has the advantages of being high in catalytic activity, easy to recycle and the like, and 4-acetoxybutyraldehyde prepared through the catalytic system is high in conversion rate and yield.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of 4-acetoxybutyraldehyde, and particularly relates to a method for preparing 4-acetoxybutyraldehyde. Background Art

[0002] 1,4-Butanediol (referred to as BDO) is an important organic and fine chemical raw material, which is widely used in the fields of medicine, chemical industry, textile, paper-making, automobile and daily chemical industry, etc. BDO is used as a solvent and a humectant, and is also used in the manufacture of plasticizers, drugs, polyester resins, polyurethane resins, etc.

[0003] 4-Acetoxybutyraldehyde can be efficiently prepared into BDO through a further hydrogenation reaction. For example, Chinese Patent Application CN106518677A uses a phosphite ligand in combination with a rhodium catalyst to synthesize 4-acetoxybutyraldehyde by carbonylation of allyl acetate, and the obtained 4-acetoxybutyraldehyde is further hydrogenated to produce BDO and ethanol. Chinese Patent CN107915758A reports the use of a combination of a phosphonamide ligand and a rhodium compound as a catalyst to catalyze the preparation of 4-acetoxybutyraldehyde from allyl acetate. CN109550519A reports a method for preparing 4-acetoxybutyraldehyde by catalyzing allyl acetate with a phosphine-ruthenium functionalized ionic liquid and its combination with a rhodium catalyst. However, the above three schemes all use expensive noble metal catalysts, which greatly increases the process cost of 4-acetoxybutyraldehyde. Moreover, in such processes, due to the use of a rhodium catalyst, a side reaction of hydrogenolysis of allyl acetate to form acetic acid and propylene will occur.

[0004] Therefore, how to reduce the cost of the catalyst in the process of carbonylation of allyl acetate to prepare 4-acetoxybutyraldehyde, and improve the catalytic activity and selectivity of the catalyst, is one of the technical difficulties that need to be urgently broken through in the present technical field. Summary of the Invention

[0005] In order to solve the technical problems of high catalyst cost, insufficient catalytic activity and selectivity existing in the prior art, the present invention provides a method for preparing 4-acetoxybutyraldehyde. The method of the present invention can achieve the effect of catalytically synthesizing 4-acetoxybutyraldehyde from allyl acetate with low cost and high selectivity.

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

[0007] A method for preparing 4-acetoxybutyraldehyde, under the catalytic action of a cobalt catalyst and a pyridine bisphosphine ligand, allyl acetate reacts with syngas at a reaction temperature of 80-200 °C and a pressure of 3-10 MPa to carry out a carbonylation reaction for 2-8 h to obtain 4-acetoxybutyraldehyde.

[0008] Further, the cobalt catalyst is selected from cobalt salts, cobalt hydroxides or cobalt oxides.

[0009] Furthermore, the cobalt catalyst is selected from one or more of cobalt naphthenate, cobalt acetate, cobalt formate, cobalt levulinate, cobalt nitrate, cobalt carbonate, dicobalt octacarbonyl, sodium tetracarbonylcobaltate, cobalt hydroxide and cobalt oxide.

[0010] Further, the mass concentration of cobalt in the reaction solution is 0.005%-1.000%.

[0011] Further, the structural formula of the pyridine bisphosphine ligand is as follows:

[0012]

[0013] In the formula, the R1-R5 groups are the same or different; the R1-R5 groups are selected from hydrogen, C1-C6 alkyl segments or C6-C10 aryl-containing segments.

[0014] Furthermore, the C1-C6 alkyl segment is methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl, tert-butyl, pentyl, tert-pentyl, neopentyl, cyclopentyl, hexyl or cyclohexyl.

[0015] Furthermore, the C6-C10 aryl-containing segment is phenyl, m-tolyl, o-tolyl, p-tolyl, p-ethylphenyl, m-ethylphenyl, p-propylphenyl, p-isopropylphenyl, p-butylphenyl, p-isobutylphenyl or p-tert-butylphenyl.

[0016] Further, the phosphorus-cobalt molar ratio of the cobalt catalyst to the pyridine bisphosphine ligand is 1:(0.1-10).

[0017] Further, the syngas is a mixture of hydrogen and carbon monoxide, and the volume ratio of hydrogen to carbon monoxide is 1:1-2:1.

[0018] This application has the following beneficial effects.

[0019] The present invention adopts a catalytic system containing a cobalt catalyst and a pyridine bisphosphine ligand, and uses this catalytic system to catalyze the carbonylation of allyl acetate to produce 4-acetoxybutyraldehyde. The pyridine bisphosphine ligand in the catalytic system 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 carbonylation of allyl acetate and syngas to prepare 4-acetoxybutyraldehyde, the reaction conversion rate can reach more than 99%, and the yield of hydrogenolysis by-products <3%. At the same time, since the non-precious metal cobalt is used instead of the precious metal rhodium catalyst, the catalyst cost is greatly reduced, and the economic benefit of the technology is improved. Detailed Embodiments

[0020] The following further illustrates this patent application in conjunction with examples.

[0021] In the following examples, the materials used in the preparation process were not further processed without special instructions and were all purchased through commercial channels.

[0022] Example 1

[0023] A method for preparing 4-acetoxybutyraldehyde, comprising the following steps:

[0024] 100.0 g of allyl acetate, 1.0 g of dicobalt octacarbonyl and 1.38 g of pyridine bisphosphine ligand were added to a 250 mL high-pressure reactor. The pyridine bisphosphine ligand has the following structural formula

[0025]

[0026] In the formula: R1 is hydrogen, and R2-R5 are all phenyl. After purging with nitrogen three times, syngas was charged at 7.0 MPa, 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 hours of reaction, a gas-phase analysis sample was taken to detect the conversion rate of allyl acetate and the product selectivity.

[0027] Example 2

[0028] The test method of this example was the same as that of Example 1. The only difference was that the reaction temperature was 130 °C. The conversion rate and yield are shown in Table 1.

[0029] Example 3

[0030] The test method of this example was the same as that of Example 1. The only difference was that the reaction temperature was 90 °C. The conversion rate and yield are shown in Table 1.

[0031] Example 4

[0032] The test method of this example was the same as that of Example 1. The only difference was that the reaction pressure was 8.0 MPa. The conversion rate and yield are shown in Table 1.

[0033] Example 5

[0034] The test method of this example was the same as that of Example 1. The only difference was that the reaction pressure was 5.0 MPa. The conversion rate and yield are shown in Table 1.

[0035] Example 6

[0036] The test method of this example was the same as that of Example 1. The only difference was that 0.5 g of dicobalt octacarbonyl and 0.69 g of pyridine bisphosphine ligand were used. The conversion rate and yield are shown in Table 1.

[0037] Example 7

[0038] The test method of this example is the same as that of Example 1. The only difference is: 1.0 g of dicobalt octacarbonyl and 0.69 g of pyridine bisphosphine ligand. The conversion rate and yield are shown in Table 1.

[0039] Example 8

[0040] The test method of this example is the same as that of Example 1. The only difference is: 1.0 g of dicobalt octacarbonyl and 2.07 g of pyridine bisphosphine ligand. The conversion rate and yield are shown in Table 1.

[0041] Example 9

[0042] The test method of this example is the same as that of Example 1. The only difference is: in the structural formula of the pyridine bisphosphine ligand, R1 is hydrogen, and R2 - R5 are all tert-butyl groups. The conversion rate and yield are shown in Table 1.

[0043] Example 10

[0044] The test method of this example is the same as that of Example 1. The only difference is: in the structural formula of the pyridine bisphosphine ligand, R1 is methyl, and R2 - R5 are all phenyl groups. The conversion rate and yield are shown in Table 1.

[0045] Example 11

[0046] The test method of this example is the same as that of Example 1. The only difference is: in the structural formula of the pyridine bisphosphine ligand, R1 is hydrogen, and R2 - R5 are all methyl groups. The conversion rate and yield are shown in Table 1.

[0047] Example 12

[0048] The test method of this example is the same as that of Example 1. The only difference is: in the structural formula of the pyridine bisphosphine ligand, R1 is ethyl, and R2 - R5 are all phenyl groups. The conversion rate and yield are shown in Table 1.

[0049] Example 13

[0050] The test method of this example is the same as that of Example 1. The only difference is: in the structural formula of the pyridine bisphosphine ligand, R1 is hydrogen, and R2 - R5 are all p-methylphenyl groups. The conversion rate and yield are shown in Table 1.

[0051] Example 14

[0052] The test method of this example is the same as that of Example 1. The only difference is: the cobalt catalyst added is cobalt naphthenate. The conversion rate and yield are shown in Table 1.

[0053] Example 15

[0054] The test method of this example is the same as that of Example 1. The only difference is: the cobalt catalyst added is cobalt formate. The conversion rate and yield are shown in Table 1.

[0055] Comparative Example 1

[0056] The test method of this comparative 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.

[0057] Comparative Example 2

[0058] The test method of this comparative example is the same as that of Example 1. The only difference is that the ligand added is triphenylphosphine. The conversion rate and yield are shown in Table 1.

[0059] Comparative Example 3

[0060] The test method of this comparative example is the same as that of Example 1. The only difference is that no cobalt catalyst is added. The conversion rate and yield are shown in Table 1.

[0061] Table 1

[0062] Example Conversion rate / % Aldehyde yield / % n / i ratio 1 99.4 95.2 8.3 2 99.7 91.8 7.8 3 85.4 80.7 8.4 4 99.5 95.3 8.2 5 80.6 76.2 8.3 6 77.5 70.9 9.1 7 92.5 80.4 6.7 8 86.4 83.2 8.5 9 97.7 93.4 8.1 10 85.3 81.6 8.4 11 88.5 84.3 8.2 12 85.6 75.2 7.0 13 82.1 73.0 7.3 14 90.2 85.9 8.2 15 88.7 83.7 8.0 Comparative Example 1 32.5 25.4 3.2 Comparative Example 2 10.3 7.7 10.1 Comparative Example 3 0 0 /

[0063] It can be seen from the data analysis in Table 1 that the optimal reaction conditions are: reaction temperature 110 °C, reaction pressure 7 MPa, cobalt concentration 0.345%, and phosphorus-cobalt molar ratio 1:1. The optimal catalytic system is: the cobalt catalyst is dicobalt octacarbonyl, and the organic ligand is 1,5-bis(diphenylphosphino)pyridine. When no ligand is added, the reaction conversion rate is only 32.5%. When triphenylphosphine ligand is added, the reaction conversion rate is only 10.3%. When no cobalt catalyst is added, the reaction cannot occur. It is proved that the cobalt-pyridine bisphosphine ligand catalytic system has good catalytic activity and can catalyze the reaction of allyl acetate with syngas to prepare 4-acetoxybutyraldehyde.

[0064] The examples of this specific implementation manner are all preferred examples of the present invention, and do not limit the protection scope of the present invention accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing 4-acetoxybutyraldehyde, characterized in that: Under the catalysis of a cobalt catalyst and a pyridine bisphosphine ligand, allyl acetate reacts with syngas in a hydroformylation reaction at a reaction temperature of 80 - 200 °C and a pressure of 3 - 10 MPa for 2 - 8 h to obtain 4 - acetoxybutyraldehyde.

2. The preparation method of 4-acetoxybutyraldehyde according to claim 1, characterized in that: The cobalt catalyst is selected from cobalt salts, cobalt hydroxides or cobalt oxides.

3. The preparation method of 4-acetoxybutyraldehyde according to claim 2, characterized in that: The cobalt catalyst is selected from one or more of cobalt naphthenate, cobalt acetate, cobalt formate, cobalt levulinate, cobalt nitrate, cobalt carbonate, dicobalt octacarbonyl, sodium tetracarbonylcobaltate, cobalt hydroxide and cobalt oxide.

4. The preparation method of 4-acetoxybutyraldehyde according to claim 1, characterized in that: The mass concentration of cobalt in the reaction solution is 0.005% - 1.000%.

5. The preparation method of 4-acetoxybutyraldehyde according to claim 1, characterized in that: The structural formula of the pyridine bisphosphine ligand is as follows: In the formula, the R1 - R5 groups are the same or different; the R1 - R5 groups are selected from hydrogen, C1 - C6 alkyl fragments or C6 - C10 aryl - containing fragments.

6. The preparation method of 4-acetoxybutyraldehyde according to claim 5, 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.

7. A method for preparing 4-acetoxybutyraldehyde according to claim 5, characterized in that: 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 or p - tert - butylphenyl.

8. A method for preparing 4-acetoxybutyraldehyde according to claim 1, characterized in that: The phosphorus - cobalt molar ratio of the cobalt catalyst to the pyridine bisphosphine ligand is 1:(0.1 - 10).

9. The preparation method of 4-acetoxybutyraldehyde 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 1:1 - 2:1.

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