Efficient catalyst for producing isononanoic acid through dehydrogenation of isononyl alcohol as well as preparation method and application of efficient catalyst

Abstract

The invention discloses an efficient catalyst for producing isononanoic acid through dehydrogenation of isononanol and a preparation method and application of the efficient catalyst, the catalyst comprises a ZnO-MgO composite carrier and active components Cu and Co loaded on the ZnO-MgO composite carrier, and the loading capacity of the active components Cu and Co is 0.5-5% of the mass of the ZnO-MgO composite carrier; the molar ratio of ZnO to MgO in the ZnO-MgO composite carrier is (1-5): 1; the preparation method comprises the following steps: (1) dissolving precursors Zn salt and Mg salt in water, dropwise adding a sodium carbonate solution until the pH value is 10, stirring for 20-40 minutes, carrying out suction filtration, and drying the obtained powder for later use; (2) adding the powder in the step (1) into water, stirring, adding precursor Cu salt and Co salt, stirring at 60-90 DEG C, taking out a solid after the solvent is completely evaporated, and drying for later use; and (3) roasting the solid in the step (2) in an air atmosphere to obtain the Cu-Co / ZnO-MgO catalyst. The catalyst prepared by the invention has very high catalytic property for preparing isononanoic acid by dehydrogenation of isononyl alcohol, the reaction efficiency is high, and the possibility of continuous production of isononanoic acid is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of isononanoic acid preparation, and particularly relates to a high-efficiency catalyst for dehydrogenating isononanol to produce isononanoic acid, a preparation method thereof, and an application thereof. Background Art

[0002] Isononanoic acid is a transparent liquid with a slightly peculiar odor and appears light yellow. It can be used as a raw material for synthesizing lubricants, a pharmaceutical intermediate, a raw material for metal soaps and metal working fluids; it is also suitable for modifying alkyd resins, which can improve yellowing resistance and impact resistance; it can also be used to produce various isononanoic acid esters for modifying alkyd resins, significantly improving the oxidation resistance and impact resistance of resin materials.

[0003] Common methods for synthesizing isononanoic acid include: (1) a synthesis method for preparing isononanoic acid from diisobutene, mainly including two combined paths: hydroformylation reaction and oxidation reaction to synthesize isononanoic acid, and hydroesterification reaction and hydrolysis reaction to synthesize isononanoic acid; (2) a method for preparing isononanoic acid by oxidizing isononanal, which mostly uses metal salts as homogeneous catalysts for catalytic oxidation reactions; (3) a method for preparing isononanoic acid by dehydrogenating isononanol. Compared with the first two methods, the method of dehydrogenating isononanol to produce isononanoic acid is simpler and has a high selectivity for isononanoic acid. Therefore, the method of dehydrogenating isononanol to produce isononanoic acid has received increasing attention. Chinese Patent Application CN114874089A discloses a preparation method of isononanoic acid, which uses a method of mixing isononanol and sodium hydroxide to remove hydrogen at high temperature to obtain isononanoate, and then obtains isononanoic acid through acidification treatment. This method reacts at 260 - 300 °C for 2 - 5 h and needs to be maintained at 2 - 5 MPa for 2 - 3 h, obtaining relatively high reaction performance. However, this method has a long reaction time and low reaction efficiency, and it is difficult to achieve continuous production of isononanoic acid.

[0004] Based on this, the present invention develops a high-efficiency catalyst for dehydrogenating isononanol to produce isononanoic acid to optimize the reaction conditions, improve the reaction rate, and thus facilitate the continuous production of isononanoic acid. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a high-efficiency catalyst for dehydrogenating isononanol to produce isononanoic acid, which has high catalytic activity for dehydrogenating isononanol to produce isononanoic acid and improves the reaction efficiency.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is:

[0007] In the first aspect, the present invention provides a high-efficiency catalyst for dehydrogenating isononanol to produce isononanoic acid, which includes a ZnO-MgO composite support and active components Cu and Co supported on the ZnO-MgO composite support.

[0008] Furthermore, the loadings of the active components Cu and Co are respectively 0.5-5% of the mass of the ZnO-MgO composite support.

[0009] Furthermore, the molar ratio of ZnO to MgO in the ZnO-MgO composite support is 1-5:1.

[0010] In a second aspect, the present invention provides a method for preparing a highly efficient catalyst for the dehydrogenation of isononyl alcohol to produce isononanoic acid, comprising the steps of:

[0011] (1) Dissolve the precursor Zn salt and Mg salt in water, add sodium carbonate solution dropwise until the pH = 10, stir for 20-40 min and then perform suction filtration, and dry the obtained powder for later use;

[0012] (2) Add the powder from step (1) to water and stir, and add the precursor Cu salt and Co salt, stir at 60-90 °C, and take out the solid and dry it for later use after the solvent has completely evaporated;

[0013] (3) Calcinate the solid in step (2) in an air atmosphere to obtain a Cu-Co / ZnO-MgO catalyst.

[0014] Furthermore, in step (3), the calcination temperature is 550-650 °C and the calcination time is 2-5 h.

[0015] In a third aspect, the present invention provides an application of a catalyst in a reaction system for the dehydrogenation of isononyl alcohol to produce isononanoic acid.

[0016] Furthermore, the steps for the dehydrogenation of isononyl alcohol to produce isononanoic acid are as follows:

[0017] S1. Put isononyl alcohol, sodium hydroxide and the catalyst into a dehydrogenation reaction kettle in proportion and heat up for dehydrogenation reaction under a nitrogen atmosphere, and obtain isononanoate after the reaction is completed;

[0018] S2. Acidify the isononanoate to obtain crude isononanoic acid, and obtain a high-purity isononanoic acid product after purification.

[0019] Furthermore, in step S1, the mass ratio of isononyl alcohol to sodium hydroxide is 0.8-4:1, and the addition amount of the catalyst is 0.5-2% of the mass of isononyl alcohol.

[0020] Furthermore, in step S1, the dehydrogenation reaction temperature is 200-400 °C and the dehydrogenation reaction time is 60-80 min.

[0021] Furthermore, in step S1, the dehydrogenation reaction kettle is provided with at least two stages, multiple dehydrogenation reaction kettles are connected in series, and the total reaction time of the multiple series-connected dehydrogenation reaction kettles is 60-80 min.

[0022] The beneficial effects of the present invention are as follows:

[0023] The high-efficiency catalyst for the dehydrogenation of isononyl alcohol to produce isononanoic acid provided by the present invention has strong catalytic performance for the dehydrogenation of isononyl alcohol to prepare isononanoic acid. The reaction can be completed in about 1 h, with a fast reaction rate, high conversion rate of isononyl alcohol, and high selectivity of isononanoic acid, improving the feasibility of continuous production of isononanoic acid. Detailed implementation mode

[0024] The present invention provides a high-efficiency catalyst for the dehydrogenation of isononyl alcohol to produce isononanoic acid, its preparation method and application. To make the purpose, technical solution and effect of the present invention clearer and more definite, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] Among them, the present invention does not have special restrictions on the sources of all raw materials, and they can be commercially available.

[0026] The present invention provides a high-efficiency catalyst for the dehydrogenation of isononyl alcohol to produce isononanoic acid, which includes a ZnO-MgO composite support and active components Cu and Co supported on the ZnO-MgO composite support. Among them, the loading amounts of the active components Cu and Co are respectively 0.5-5% of the mass of the ZnO-MgO composite support, and the molar ratio of ZnO to MgO in the ZnO-MgO composite support is 1-5:1.

[0027] In the preferred implementation mode of the present invention, the loading amounts of the active components Cu and Co are both respectively 1-3% of the mass of the ZnO-MgO composite support, and the molar ratio of ZnO to MgO in the ZnO-MgO composite support is 3.5-4.5:1, more preferably 4:1.

[0028] The preparation method of the above-mentioned high-efficiency catalyst for the dehydrogenation of isononyl alcohol to produce isononanoic acid includes the steps:

[0029] (1) Dissolve the precursor Zn salt and Mg salt in water, dropwise add sodium carbonate solution until pH = 10, stir for 20-40 min and then carry out suction filtration, and dry the obtained powder for later use;

[0030] (2) Add the powder in step (1) to water and stir, and add the precursor Cu salt and Co salt, stir at 60-90 °C, and take out the solid and dry it for later use after the solvent is completely evaporated;

[0031] (3) Calcinate the solid in step (2) in an air atmosphere, the calcination temperature is 550-650 °C, the calcination time is 2-5 h, and the heating rate is 3 °C / min to obtain the Cu-Co / ZnO-MgO catalyst.

[0032] In a preferred embodiment of the present invention, the above-mentioned precursor salt is a soluble salt such as nitrate, chloride, acetate, sulfate or carbonate, and preferably acetate is used.

[0033] The present invention also provides an application of a catalyst in the reaction system for preparing isononanoic acid by dehydrogenation of isononanol. The specific process is as follows:

[0034] S1. Charge isononanol, sodium hydroxide and the catalyst into a dehydrogenation reaction kettle in proportion and heat up for dehydrogenation reaction under a nitrogen atmosphere. After the reaction is completed, isononanoate is obtained.

[0035] S2. Acidify the isononanoate to obtain crude isononanoic acid. After standing and separating layers, the lower aqueous phase is discharged, and the upper organic phase enters a rectification system for purification. After purification, a high-purity isononanoic acid product is obtained.

[0036] Specifically, in the above step S1, the mass ratio of isononanol to sodium hydroxide is 0.8 - 4:1, and the addition amount of the catalyst is 0.5 - 2% of the mass of isononanol. Preferably, the mass ratio of isononanol to sodium hydroxide is 1 - 1.5:1, and the addition amount of the catalyst is 1 - 1.5% of the mass of isononanol.

[0037] Specifically, the above dehydrogenation reaction temperature is 200 - 400 °C, and the dehydrogenation reaction time is 60 - 80 min. Preferably, the dehydrogenation reaction temperature is 220 - 260 °C, and more preferably 240 °C.

[0038] Specifically, in the above step S1, the dehydrogenation reaction kettle is provided with at least two stages, multiple dehydrogenation reaction kettles are connected in series, and the total reaction time of the multiple series-connected dehydrogenation reaction kettles is 60 - 80 min.

[0039] Specifically, in the above step S1, the dehydrogenation reaction kettle is provided with 2 - 6 stages, and the reaction time of each stage of the dehydrogenation reaction kettle is 10 - 40 min.

[0040] Based on the Cu-Co / ZnO-MgO catalyst of the present invention, continuous production of isononanoic acid can be realized. The continuous production system of isononanoic acid: includes a first-stage dehydrogenation reaction kettle and an Nth-stage dehydrogenation reaction kettle connected in series in sequence, N ranges from 2 to 6, and the inlet end of the first-stage dehydrogenation reaction kettle is connected with a pretreatment kettle, and the outlet end of the Nth-stage dehydrogenation reaction kettle is connected with a buffer kettle and an acidification kettle in sequence; and the gas outlets of the above first-stage dehydrogenation reaction kettle and the Nth-stage dehydrogenation reaction kettle are connected to a storage tank through pipelines for collecting hydrogen generated by the reaction. In addition, detection ports are provided on both the first-stage dehydrogenation reaction kettle and the Nth-stage dehydrogenation reaction kettle, and the detection ports are connected with pressure gauges. When the gas pressure detected by the pressure gauge of a certain stage of the dehydrogenation reaction kettle does not change for a long time, it is regarded that the reaction terminates.

[0041] Based on the above continuous production system of isononanoic acid, the continuous production process of isononanoic acid is as follows: Isooctanol, sodium hydroxide and a catalyst are proportionally put into a pretreatment kettle, heated to 120 - 180 °C, and stirred until evenly mixed, and then transported to the first - stage dehydrogenation reaction kettle through a pipeline and a transfer pump, and reacted at 200 - 400 °C for a set time; then the mixture in the first - stage dehydrogenation reaction kettle is successively transported to the second - stage to the N - th stage dehydrogenation reaction kettles through a pipeline and a transfer pump, and the reaction temperature and reaction time of the second - stage to the N - th stage dehydrogenation reaction kettles are the same as those of the first - stage dehydrogenation reaction kettle; then the product sodium isononanoate from the N - th stage dehydrogenation reaction kettle is transported into a buffer kettle for cooling, water is added for dilution, and the solid catalyst is removed by filtration. The filtered sodium isononanoate solution enters an acidification kettle, is acidified with sulfuric acid to obtain crude isononanoic acid, then stands for stratification, and the lower aqueous phase is discharged, and the upper organic phase enters a rectification system for purification, and high - purity isononanoic acid product is obtained after purification.

[0042] Example 1

[0043] This example provides an efficient catalyst for the dehydrogenation of isooctanol to produce isononanoic acid, and its preparation method includes the steps:

[0044] (1) Weigh 4.315 g of zinc acetate dihydrate and 2.128 g of magnesium acetate tetrahydrate, add them to 50 mL of water to prepare a mixed solution, and continuously stir the solution until the solids are completely dissolved. Add sodium carbonate to the solution to adjust the pH value to pH = 10, stir for 30 min, then perform suction filtration, and dry the obtained powder for later use;

[0045] (2) Weigh 0.062 g of copper acetate monohydrate and 0.085 g of cobalt acetate tetrahydrate, add them to 5 mL of water to prepare a mixed solution. Add the powder from step (1) to 50 mL of water and stir, and add the above - mentioned mixed solution of copper salt and cobalt salt, then continuously stir in a water bath at 70 °C. After the solvent is completely evaporated, take out the solid and dry it for later use;

[0046] (3) Calcine the solid in step (2) in an air atmosphere at 600 °C for 3 h, with a heating rate of 3 °C / min to obtain the Cu - Co / ZnO - MgO catalyst.

[0047] In the Cu - Co / ZnO - MgO catalyst prepared in this example, the loadings of the active components Cu and Co are both 1% of the mass of the ZnO - MgO composite support, and the molar ratio of ZnO to MgO in the ZnO - MgO composite support is 4:1, that is, Cu - Co(1) / ZnO 4 -MgO 1 。

[0048] Example 2

[0049] This example provides an efficient catalyst for the dehydrogenation of isononyl alcohol to produce isononanoic acid. The difference from Example 1 is that the addition amounts of zinc acetate dihydrate and magnesium acetate tetrahydrate in this example are different from those in Example 1. The addition amounts of zinc acetate dihydrate and magnesium acetate tetrahydrate in this example are 4.494 g and 1.773 g, 4.045 g and 2.660 g, 2.696 g and 5.320 g respectively, and the molar ratio of ZnO to MgO in the obtained catalyst is 5:1, 3:1, 1:1, which are denoted as Cu-Co(1) / ZnO 5 -MgO 1 、Cu-Co(1) / ZnO 3 -MgO 1 、Cu-Co(1) / ZnO 1 -MgO 1 。

[0050] Example 3

[0051] This example provides an efficient catalyst for the dehydrogenation of isononyl alcohol to produce isononanoic acid. The difference from Example 1 is that the active components in this example are separate Fe, Cu, Mn, Co, and the addition amounts of iron nitrate, copper acetate, manganese acetate, and cobalt acetate are 0.141 g, 0.062 g, 0.098 g, 0.085 g respectively. The finally obtained catalysts are Fe / ZnO 4 -MgO 1 、Cu / ZnO 4 -MgO 1 、Mn / ZnO 4 -MgO 1 、Co / ZnO 4 -MgO 1 ,and the loadings of Fe, Cu, Mn, Co are all 1% of the mass of the ZnO-MgO composite support.

[0052] Example 4

[0053] This example provides an efficient catalyst for the dehydrogenation of isononyl alcohol to produce isononanoic acid. The difference from Example 1 is that the addition amounts of copper acetate monohydrate and cobalt acetate tetrahydrate in this example are different from those in Example 1. The addition amounts of copper acetate monohydrate and cobalt acetate tetrahydrate in this example are 0.031 g and 0.0425 g, 0.186 g and 0.255 g, 0.310 g and 0.425 g respectively, and the loadings of Cu and Co in the obtained catalyst are 0.5%, 3%, 5% respectively, which are denoted as Cu-Co(0.5) / ZnO 4 -MgO 1 、Cu-Co(3) / ZnO 4 -MgO 1 、Cu-Co(5) / ZnO 4 -MgO1 .

[0054] Example 5

[0055] In this example, the catalyst prepared in Example 1 and Example 2 was used to catalyze the dehydrogenation of isononyl alcohol to prepare isononanoic acid. This example was carried out in a single-stage reaction kettle. The specific steps are as follows:

[0056] S1. 19.8 g of isononyl alcohol, 5 g of sodium hydroxide and 0.2 g of catalyst were added to the dehydrogenation reaction kettle in proportion, and 1 Mpa of nitrogen was filled into the reaction kettle. The temperature was raised to 240 °C for dehydrogenation reaction. The rotation speed of the stirring shaft in the dehydrogenation reaction kettle was set to 500 r / min. After reacting for 1 h, heating and stirring were stopped to obtain isononanoate;

[0057] S2. 20 mL of water was added to the isononanoate obtained in step S1, and sulfuric acid with a mass content of 30% was added to adjust the pH to 2. After standing for 1 h, the upper layer was the crude product of isononanoic acid. The upper organic phase was fed into the rectification system for purification, and a high-purity isononanoic acid product was obtained after purification.

[0058] The crude isononanoic acid product was analyzed by chromatography, and the conversion rate of isononyl alcohol and the selectivity of isononanoic acid were calculated to obtain the dehydrogenation reaction results of catalysts with different carrier molar ratios, as shown in Table 1 below.

[0059] Table 1 Dehydrogenation reaction results of catalysts with different carrier mass ratios

[0060] Catalyst Reaction time / min Conversion rate of isononyl alcohol / % Selectivity of isononanoic acid / % <![CDATA[Cu-Co(1) / ZnO 5 -MgO 1 > 60 93.37 78.18 <![CDATA[Cu-Co(1) / ZnO 4 -MgO 1 > 60 94.16 98.31 <![CDATA[Cu-Co(1) / ZnO 3 -MgO 1 > 60 85.57 89.62 <![CDATA[Cu-Co(1) / ZnO 1 -MgO 1 > 60 73.25 91.97 ZnO 60 65.86 91.75

[0061] According to the dehydrogenation reaction results of catalysts with different carrier mass ratios in Table 1, it can be seen that the molar ratio of ZnO to MgO in different carriers has a great influence on the catalytic effect of the catalyst. When the molar ratio of ZnO to MgO is 4:1, the conversion rate of isononyl alcohol and the selectivity of isononanoic acid are the highest.

[0062] Example 6

[0063] The difference between this example and Example 5 is that in this example, the catalyst prepared in Example 1 and Example 3 was used, and other parameters were the same as those in Example 5.

[0064] The crude isononanoic acid product prepared in this example was analyzed by chromatography, and the conversion rate of isononyl alcohol and the selectivity of isononanoic acid were calculated to obtain the dehydrogenation reaction results of different catalysts, as shown in Table 2 below.

[0065] Table 2 Dehydrogenation reaction results of catalysts with different active components

[0066]

[0067]

[0068] According to the detection results in Table 2, when Cu and Co are used as the active components of the catalyst, the reaction process has a high conversion rate of isononanol and maintains a high selectivity for isononanoic acid.

[0069] In addition, it should be noted that the other catalysts in Table 2 can also exhibit high reaction performance when the reaction time reaches 2 - 4 h, but their reaction rates are too slow to meet the requirements of large-scale continuous production of isononanoic acid. In addition, when the active components are combinations of Fe, Cu, Mn, and Co in pairs (except for the Cu-Co combination), their catalytic effects are not much different from those when Fe, Cu, Mn, and Co are used as active components alone. The conversion rate of isononanol at 60 min is about 60 - 80%, and when the reaction time reaches 2 - 4 h, the conversion rate of isononanol can reach more than 90%. Compared with the Cu-Co combination, their reaction rates are too slow and it is also difficult to meet the requirements of large-scale continuous production of isononanoic acid.

[0070] Example 7

[0071] The difference between this example and Example 5 is that in this example, the catalyst used is the catalyst prepared in Example 1 and Example 4, and other parameters are the same as those in Example 5.

[0072] The crude isononanoic acid product prepared in this example was subjected to chromatographic analysis, and the conversion rate of isononanol and the selectivity of isononanoic acid were calculated to obtain the dehydrogenation reaction results of different catalysts, as shown in Table 3 below.

[0073] Table 3 Dehydrogenation reaction results of catalysts with different active component masses

[0074] Catalyst Reaction time / min Conversion rate of isononyl alcohol / % Selectivity of isononanoic acid / % <![CDATA[Cu-Co(0.5) / ZnO 4 -MgO 1 > 60 81.4 98.13 <![CDATA[Cu-Co(1) / ZnO 4 -MgO 1 > 60 94.16 98.31 <![CDATA[Cu-Co(3) / ZnO 4 -MgO 1 > 60 90.22 98.36 <![CDATA[Cu-Co(5) / ZnO 4 -MgO 1 > 60 85.67 98.64

[0075] According to the detection results in Table 3, when the loadings of Cu and Co are 1 - 3%, the reaction process has a high conversion rate of isononanol and maintains a high selectivity for isononanoic acid.

[0076] Example 8

[0077] In this example, a multi-stage series dehydrogenation reactor was used for the continuous production of isononanoic acid, and the number of reaction stages was adjusted to be different, and each stage of the reactor reacted for different times.

[0078] In this example, the mass ratio of isononanol to sodium hydroxide is 1.1:1, and the catalyst Cu-Co(1) / ZnO 4 -MgO 1 The catalyst addition amount is 1% of the mass of isononanol, the reaction temperature of each stage of the reactor is 240 °C, and 1 MPa of nitrogen is charged.

[0079] The crude isononanoic acid product prepared in this example was subjected to chromatographic analysis, and the conversion rate of isononanol and the selectivity of isononanoic acid were calculated to obtain the dehydrogenation reaction results of different catalysts, as shown in Table 4 below.

[0080] Table 4 Catalytic reaction results of the tandem process of isononanol multi-stage dehydrogenation reactors

[0081]

[0082]

[0083] According to the detection results in Table 4, the Cu-Co / ZnO-MgO catalyst has high catalytic activity for the dehydrogenation of isononanol to prepare isononanoic acid. It is feasible to apply it to the continuous reaction of isononanoic acid in a series of multi-stage reactors, enabling the scaled-up production of isononanoic acid.

[0084] It should be noted that the parts not described in this invention can be realized by adopting or referring to existing technologies.

[0085] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions, or substitutions made by those skilled in the art within the scope of the essence of the present invention should also fall within the protection scope of the present invention.

Claims

1. An efficient catalyst for dehydrogenating isononanol to produce isononanoic acid, characterized in that: The invention comprises a ZnO-MgO composite carrier and active components Cu and Co loaded on the ZnO-MgO composite carrier.

2. The highly efficient catalyst for dehydrogenating isononanol to produce isononanoic acid according to claim 1, characterized in that: The loading amounts of active components Cu and Co are respectively 0.5-5% of the mass of the ZnO-MgO composite carrier.

3. The high-efficiency catalyst for dehydrogenating isononanol to produce isononanoic acid according to claim 1, characterized in that: It is characterized in that The molar ratio of ZnO to MgO in the ZnO-MgO composite carrier is 1 to 5:

1.

4. The method for preparing a highly efficient catalyst for producing isononanoic acid by dehydrogenation of isononanol according to any one of claims 1 to 3, characterized in that: Includes steps: (1) Dissolve the precursors Zn salt and Mg salt in water, add sodium carbonate solution until pH = 10, stir for 20 to 40 minutes, filter, and dry the obtained powder for later use; (2) adding the powder of step (1) into water and stirring, and adding the precursors Cu salt and Co salt, stirring at 60-90° C., after the solvent is completely evaporated, taking out the solid and drying it for later use; (3) calcining the solid in step (2) under air atmosphere to obtain a Cu-Co / ZnO-MgO catalyst.

5. The method for preparing a highly efficient catalyst for dehydrogenating isononanol to produce isononanoic acid according to claim 4, characterized in that: In the step (3), the calcination temperature is 550-650° C. and the calcination time is 2-5 hours.

6. Use of the catalyst according to any one of claims 1 to 3 in a reaction system for dehydrogenating isononanol to prepare isononanoic acid.

7. The application according to claim 6, characterized in that: The steps of dehydrogenating isononanol to prepare isononanoic acid are: S1, adding isononanol, sodium hydroxide and a catalyst into a dehydrogenation reaction kettle in proportion and heating the kettle under a nitrogen atmosphere to carry out a dehydrogenation reaction, and obtaining isononanoate after the reaction is completed; S2. Acidifying the isononanoate to obtain crude isononanoic acid, and purifying to obtain a high-purity isononanoic acid product.

8. The use according to claim 7, characterized in that: In the step S1, the mass ratio of isononanol to sodium hydroxide is 0.8-4:1, and the amount of catalyst added is 0.5-2% of the mass of isononanol.

9. The use according to claim 7, characterized in that: In step S1, the dehydrogenation reaction temperature is 200-400° C., and the dehydrogenation reaction time is 60-80 min.

10. The use according to claim 7, characterized in that: In the step S1, at least two stages of dehydrogenation reactors are arranged, and the multiple stages of dehydrogenation reactors are connected in series, and the total reaction time of the multiple stages of dehydrogenation reactors connected in series is 60 to 80 minutes.

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