A system and method for preparing iso-nonyl acid from iso-nonyl aldehyde

Abstract

The application discloses a system and a method for preparing iso-nonyl acid by taking iso-nonyl aldehyde as raw material, and belongs to the field of chemical industry. The method for preparing iso-nonyl acid by taking iso-nonyl aldehyde as raw material is designed through a segmented oxidation process, so that the selectivity of iso-nonyl acid is preferably improved, and meanwhile, based on series connection type double rectification separation treatment and adsorption treatment, the prepared iso-nonyl acid is high in purity and does not need further purification treatment.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, specifically to a system and method for preparing isononanoic acid from isononal as a raw material. Background Technology

[0002] Isonononic acid is an important organic chemical raw material with excellent wettability, penetrability, and emulsifying properties, and is therefore widely used in lubricants, industrial detergents, cosmetics, and pharmaceuticals. The direct oxidation of isonononal as a raw material to prepare isonononic acid is currently the main production process for isonononoic acid, which has advantages such as a simple process route, mild process conditions, and a single type of raw material.

[0003] The process of oxidizing isononaldehyde to prepare isononanoic acid mainly uses transition metal salts such as manganese, cobalt, and copper as homogeneous catalysts. These catalysts often have advantages such as mild reaction conditions and high catalytic efficiency. However, these catalysts also have problems such as difficulty in recycling and reuse. At the same time, the process of oxidizing isononaldehyde to prepare isononanoic acid also has some other problems, such as (1) the selectivity of isononanoic acid is not high. The reason is that the process is highly exothermic. As the exothermic oxidation reaction proceeds rapidly, the reaction is difficult to control, so the selectivity of isononanoic acid also decreases; (2) there are many process by-products, which require further purification of semi-finished products, resulting in high production costs.

[0004] Due to these technical challenges, the process of oxidizing isononaldehyde to prepare isonononic acid is still difficult to industrialize on a large scale. Summary of the Invention

[0005] Based on the deficiencies of the existing technology, the purpose of this invention is to provide a system and method for preparing isononanoic acid from isononal as raw material. Through the design of a segmented oxidation process, the selectivity of isononanoic acid is optimized. At the same time, based on the series double distillation separation and adsorption treatment, the prepared isononanoic acid has high purity and does not require further purification treatment.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A system for preparing isononanoic acid from isononal as a raw material still includes a series-connected oxidation reactor, a filter, a series-connected double distillation column, and an adsorption column;

[0008] The series-connected oxidation reactor consists of two oxidation reactors, A1 and A2, connected in series, with a transition heat sink between the two oxidation reactors.

[0009] The series-connected dual distillation column consists of a light-light-removal column and a refining column connected in series.

[0010] The number of trays in the light-weight removal tower is 8 to 18;

[0011] The number of trays in the refining column is 25 to 45;

[0012] The adsorption tower is equipped with adsorption packing material.

[0013] Another object of the present invention is to provide a method for preparing isononanoic acid from isononanal, comprising the following steps:

[0014] (1) Isonononaldehyde is preheated and then fed into the system described in this invention. An oxidation reaction is carried out in the oxidation reactor A1 at 40-60°C to obtain reactant I.

[0015] (2) Reactant I is sent to a transition radiator to cool down, and then sent to an oxidation reactor A2 at 40-60°C for a two-stage oxidation treatment to obtain reactant II; the first-stage oxidation treatment and the second-stage oxidation treatment are provided with a heterogeneous catalyst;

[0016] (3) Reactant II was sent to a filter for catalyst separation to obtain reactant III;

[0017] (4) Reactant III was sent to a light-light-removal tower for a first-stage impurity separation process, and then sent to a purification tower for a second-stage impurity separation process to obtain reactant IV.

[0018] (5) The reactant IV is sent to the adsorption tower for adsorption and impurity removal to obtain isononanoic acid.

[0019] Existing conventional processes for the oxidation of isononanaldehyde to prepare isononanoic acid often suffer from low reproducibility of materials (especially oxidation catalysts), low yields of isononanoic acid, and low purity. Therefore, the system and scheme described in this invention improve upon the traditional isonononanaldehyde oxidation reaction for isononanoic acid by setting up a series reactor configuration and a transition heat sink between the two reactors. After preheating, isonononanaldehyde enters the first reactor for a preliminary reaction, then cools down using the transition heat sink before proceeding to the second reactor for a second-stage reaction. This segmented oxidation design improves heat dissipation throughout the isonononanaldehyde oxidation process, thus increasing the yield of isononanoic acid. Furthermore, due to the simplified system circuit design, the transition heat sink can also be used for the initial preheating of isonononanaldehyde. Once crude isononanoic acid is generated, this scheme uses a filter to recover the heterogeneous catalyst, effectively improving catalyst utilization.

[0020] After catalyst recovery, the product is processed using a series of two distillation columns. A light component separation column is used for light component separation, followed by a purification column for heavy component separation. Finally, an adsorption column is used for final adsorption separation of remaining impurities. This process achieves higher purification efficiency compared to traditional separation methods. However, the number of trays in both distillation columns must be strictly limited. Too many trays increase energy consumption, while insufficient trays in either column will prevent the desired purification effect from being achieved.

[0021] Preferably, the pressure during the first-stage oxidation reaction and the second-stage oxidation reaction is 0.1 to 2 MPa.

[0022] More preferably, the pressure during the first-stage oxidation reaction and the second-stage oxidation reaction is 0.4 to 0.8 MPa.

[0023] Under the aforementioned pressure, the oxidation reaction of isononaldehyde can be effectively controlled within an appropriate rate, avoiding the generation of excessive heat and thus preventing the reaction from becoming difficult to control.

[0024] Preferably, the heterogeneous catalyst is a solid acid catalyst supported on a transition metal element.

[0025] More preferably, the transition metal element is at least one of Fe, Mn, Co, and Cr.

[0026] Preferably, the filter is at least one of a bag filter, a basket filter, a plate filter, and a tubular filter.

[0027] Preferably, the temperature at the top of the light-weight removal tower is 45–95°C, and the pressure at the top of the tower is 1–45 kPa.

[0028] More preferably, when reactant II is fed into the light-weight removal tower, the separated material is collected from the top of the tower.

[0029] Under the light component separation method of the specific number of trays described in this invention, the light components in reactant II can be effectively separated from the bulk, and when the top temperature and pressure are set within the above-mentioned preferred range, these light component impurities can be efficiently extracted from the top of the column.

[0030] Preferably, the top temperature of the refining column is 110–180°C, and the top pressure is 1–45 kPa.

[0031] More preferably, the reactant IV is drawn from the top of the purification column.

[0032] Unlike the light components, the heavy components have a larger molecular weight than isononanoic acid in the bulk, so they tend to aggregate at the bottom during separation. Therefore, unlike the light component removal column, the target component after separation needs to be collected at the top of the column. When the specific top temperature and pressure settings mentioned above are selected, the product has a higher isononanoic acid content.

[0033] Preferably, the adsorption packing material in the adsorption tower is at least one of white clay, diatomaceous earth, molecular sieve, and activated carbon fiber.

[0034] The beneficial effects of this invention are that it provides a system and method for preparing isononanoic acid from isononal as a raw material. Through the segmented oxidation process design, the selectivity of isononanoic acid is optimized (reaching more than 95%). At the same time, based on the series double distillation separation and adsorption treatment, the prepared isononanoic acid has high purity (purity reaches more than 99%), and no further purification treatment is required. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the purification system for isononanoic acid described in this article, including a series-connected oxidation reactor, a filter C, a series-connected double distillation column, and an adsorption column E; the series-connected oxidation reactor consists of two oxidation reactors, A1 and A2, connected in series, with a transition heat sink B between the two oxidation reactors; the series-connected double distillation column consists of a light-removal column D1 and a purification column D2 connected in series. Detailed Implementation

[0036] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments and comparative examples. The purpose of this description is to provide a detailed understanding of the invention, not to limit its scope. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this invention. Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this invention are all commonly used reagents and instruments. The isononanal used in all embodiments and comparative examples is of the same mass, and preheating is performed using a transitional heat sink B.

[0037] Example 1

[0038] An embodiment of the system and method for preparing isononanoic acid from isononal as a raw material according to the present invention, wherein the system is as follows: Figure 1 As shown, the system includes an isononanaldehyde oxidation unit and an isononanaldehyde purification unit. Specifically, it includes a series-connected oxidation reactor, a filter C, a series-connected double distillation column, and an adsorption column E. The series-connected oxidation reactor consists of two oxidation reactors, A1 and A2, connected in series, with a transition radiator B between them. Oxidation reactors A1 and A2 contain a heterogeneous catalyst, which is a solid acid catalyst loaded with Mn, and the catalyst dosage is 1% of isononanaldehyde. The filter C is a bag filter. The series-connected double distillation column consists of a light-removal column D1 and a purification column D2 connected in series. The adsorption column E is filled entirely with kaolin.

[0039] The method for preparing isononanoic acid from isononalaldehyde includes the following steps:

[0040] (1) Isononaldehyde was preheated to 45°C and then sent to the system described in this embodiment. An oxidation reaction was carried out in the oxidation reactor A1 at 50°C (fluctuation range of 48-52°C) and 0.5MPa for 2 hours to obtain reactant I.

[0041] (2) Reactant I was sent to the transition radiator B to cool down to 50°C, and then sent to the oxidation reactor A2 to be set at 50°C (fluctuation within 1°C) and 0.5MPa for two-stage oxidation treatment for 2 hours to obtain reactant II.

[0042] (3) Reactant II is sent to filter C for catalyst separation treatment to obtain reactant III;

[0043] (4) Reactant III is fed into the light-light product removal tower D1 for a first-stage impurity separation process. The product is collected from the bottom of the tower, and the separated substance is collected from the top of the tower. The product is then fed into the purification tower D2 for a second-stage impurity separation process to obtain reactant IV. Reactant IV is collected from the top of the tower, and the separated substance is collected from the bottom of the tower. The light-light product removal tower D1 has 12 trays, a top temperature of 60°C, and a top pressure of 5 kPa. The purification tower D2 has 30 trays, a top temperature of 140°C, and a top pressure of 3 kPa.

[0044] (5) The reactant IV is sent to the adsorption tower E for adsorption and impurity removal to obtain isononanoic acid.

[0045] Example 2

[0046] This invention provides an embodiment of a purification method and system for isononanoic acid. The purification system for isononanoic acid is the same as in Embodiment 1, but a plate filter is used for filter C, and the packing material in adsorption tower E is entirely diatomaceous earth.

[0047] The method for preparing isononanoic acid from isononalaldehyde includes the following steps:

[0048] (1) Isonononaldehyde was preheated to 45°C and then sent to the system described in this embodiment. An oxidation reaction was carried out in the oxidation reactor A1 at 50°C (fluctuation range 48-52°C) and 0.6MPa for 2 hours to obtain reactant I.

[0049] (2) Reactant I was sent to the transition radiator B to cool down to 50°C, and then sent to the oxidation reactor A2 to be set at 50°C (fluctuation within 1°C) and 0.6MPa for two-stage oxidation treatment for 2 hours to obtain reactant II;

[0050] (3) Reactant II is sent to filter C for catalyst separation treatment to obtain reactant III;

[0051] (4) Reactant III is fed into the light-light-removal tower D1 for a first-stage impurity separation process. The product is collected from the bottom of the tower, and the separated substance is collected from the top of the tower. Then, the product is fed into the purification tower D2 for a second-stage impurity separation process to obtain reactant IV. Reactant IV is collected from the top of the tower, and the separated substance is collected from the bottom of the tower. The light-light-removal tower D1 has 15 trays, a top temperature of 60°C, and a top pressure of 4 kPa. The purification tower D2 has 30 trays, a top temperature of 140°C, and a top pressure of 3 kPa.

[0052] (5) The reactant IV is sent to the adsorption tower E for adsorption and impurity removal to obtain isononanoic acid.

[0053] Comparative Example 1

[0054] A system and method for preparing isononanoic acid from isononal as raw material, the system comprising an oxidation reactor A, a filter C, a series-connected double distillation column and an adsorption column E connected in sequence; the series-connected double distillation column consists of a light-light removal column D1 and a purification column D2 connected in series; the rest are the same as the corresponding components of the system described in Example 1.

[0055] The method for preparing isononanoic acid from isononalaldehyde includes the following steps:

[0056] (1) Isononaldehyde was preheated to 45°C and then sent into the system. The oxidation reaction was carried out in the oxidation reactor A at 50°C (fluctuation range of 46-54°C) and 0.5MPa for 4 hours to obtain reactant I.

[0057] (2) Reactant I is fed into filter C for catalyst separation treatment to obtain reactant II;

[0058] (3) Reactant II is fed into the light-light-removal tower D1 for a first-stage impurity separation process. The product is collected from the bottom of the tower, and the separated substance is collected from the top of the tower. Then, the product is fed into the purification tower D2 for a second-stage impurity separation process to obtain reactant III. Reactant III is collected from the top of the tower, and the separated substance is collected from the bottom of the tower. The light-light-removal tower D1 has 12 trays, a top temperature of 60°C, and a top pressure of 5 kPa. The purification tower D2 has 30 trays, a top temperature of 140°C, and a top pressure of 3 kPa.

[0059] (4) The reactant III is sent to the adsorption tower E for adsorption and impurity removal treatment to obtain isononanoic acid.

[0060] Comparative Example 2

[0061] A system and method for preparing isononanoic acid from isononal as a raw material, the system comprising a series-connected oxidation reactor, a filter C, and a series-connected double distillation column; unless otherwise specified, the configuration of the corresponding components is the same as that of the system described in Example 1.

[0062] The method for preparing isononanoic acid from isononalaldehyde includes the following steps:

[0063] (1) Isononaldehyde was preheated to 45°C and then sent to the system described in this embodiment. An oxidation reaction was carried out in the oxidation reactor A1 at 50°C (fluctuation range of 48-52°C) and 0.5MPa for 2 hours to obtain reactant I.

[0064] (2) Reactant I was sent to the transition radiator B to cool down to 50°C, and then sent to the oxidation reactor A2 to be set at 50°C (fluctuation within 1°C) and 0.5MPa for two-stage oxidation treatment for 2 hours to obtain reactant II.

[0065] (3) Reactant II is sent to filter C for catalyst separation treatment to obtain reactant III;

[0066] (4) Reactant III is fed into the light-light removal tower D1 for a first-stage impurity separation process. The product is collected from the bottom of the tower, and the separated substance is collected from the top of the tower. Then the product is fed into the purification tower D2 for a second-stage impurity separation process to obtain isononanoic acid. The isononanoic acid is collected from the top of the tower, and the separated substance is collected from the bottom of the tower. The light-light removal tower D1 has 12 trays, a top temperature of 60°C, and a top pressure of 5 kPa. The purification tower D2 has 30 trays, a top temperature of 140°C, and a top pressure of 3 kPa.

[0067] Comparative Example 3

[0068] A system and method for preparing isononanoic acid from isononal as a raw material, the system comprising a series-connected oxidation reactor, a filter C, a single distillation column D, and an adsorption column E; unless otherwise specified, the configuration of the corresponding components is the same as that of the system described in Example 1.

[0069] The method for preparing isononanoic acid from isononalaldehyde includes the following steps:

[0070] (1) Isononaldehyde was preheated to 45°C and then sent to the system described in this embodiment. An oxidation reaction was carried out in the oxidation reactor A1 at 50°C (fluctuation range of 48-52°C) and 0.5MPa for 2 hours to obtain reactant I.

[0071] (2) Reactant I was sent to the transition radiator B to cool down to 50°C, and then sent to the oxidation reactor A2 to be set at 50°C (fluctuation within 1°C) and 0.5MPa for two-stage oxidation treatment for 2 hours to obtain reactant II.

[0072] (3) Reactant II is sent to filter C for catalyst separation treatment to obtain reactant III;

[0073] (4) Reactant III is fed into a single distillation column D for intermittent light component removal and heavy component removal. First, light component removal and heavy component removal are performed, and the light component is collected from the top of the column. Then, heavy component removal and heavy component removal are performed to obtain reactant IV, which is collected from the top of the column. The heavy component is collected from the bottom of the column. The single distillation column has 32 trays. During the light component removal stage, the top temperature is 61°C. During the heavy component removal stage, the top temperature is 142°C.

[0074] (5) The reactant IV is sent to the adsorption tower E for adsorption and impurity removal to obtain isononanoic acid.

[0075] Comparative Example 4

[0076] A purification method and system for isononanoic acid, differing from Example 1 only in that the number of trays in the light removal tower D1 is 5.

[0077] Comparative Example 5

[0078] A purification method and system for isononanoic acid, differing from Example 1 only in that the purification column D2 has 20 trays.

[0079] The purity of isononanoic acid purified in each embodiment and comparative example was determined by gas chromatography. Simultaneously, the conversion rate of isononal and the selectivity of isononanoic acid were statistically analyzed using the following formulas:

[0080] Isononal conversion rate (%) = (molar amount of isononal before reaction - molar amount of isononal after reaction) / molar amount of isononal before reaction × 100%;

[0081] Isonononanoic acid selectivity (%) = (molar amount of isonononanoic acid after reaction / molar amount of isononal before reaction) × 100%;

[0082] The results are shown in Table 1.

[0083] Table 1

[0084]

[0085]

[0086] As can be seen from Table 1, the system and method for preparing isononanoic acid from isononanal as described in this invention can effectively improve the conversion rate of isononanal and the selectivity of isononanoic acid, and can ensure that the purity of the prepared product reaches more than 99%. In contrast, the scheme described in Comparative Example 1 did not adopt a step-by-step oxidation process, and the temperature stability of the isononanal oxidation process was low. Although the purity of the prepared product was high, the selectivity of isononanoic acid was not high, and the product yield was not high. The scheme described in Comparative Example 2 did not design a final adsorption tower, so the purity of the prepared product could not reach 99%. The product of Comparative Example 3 used a single distillation column for impurity separation, and the purity of the product was only 98%. Although the schemes of Comparative Examples 4 and 5 used a series double distillation column to separate impurities, due to the insufficient number of trays, it was also difficult to achieve high product purity.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing isononanoic acid from isonononal as a raw material, characterized in that, The method is carried out in a system for preparing isononanoic acid; The system includes a series-connected oxidation reactor, a filter, a series-connected double distillation column, and an adsorption column; The series-connected oxidation reactor consists of two oxidation reactors, A1 and A2, connected in series, with a transition heat sink between the two oxidation reactors. The series-connected dual distillation column consists of a light-light-removal column and a refining column connected in series. The number of trays in the light-weight removal tower is 8 to 18; The number of trays in the refining column is 25 to 45; The adsorption tower is equipped with adsorption packing material; The method includes the following steps: (1) Isonononaldehyde is preheated and then fed into the system. It undergoes an oxidation reaction at 40-60°C in the oxidation reactor A1 to obtain reactant I. (2) Reactant I is sent to the transition radiator to cool down, and then sent to the oxidation reactor A2 at 40~60℃ for a two-stage oxidation reaction to obtain reactant II; the first-stage oxidation reaction and the second-stage oxidation reaction are provided with heterogeneous catalysts; (3) Reactant II is sent to a filter for catalyst separation to obtain reactant III; (4) Reactant III was sent to a light-light-removal tower for a first-stage impurity separation process, and then sent to a purification tower for a second-stage impurity separation process to obtain reactant IV; (5) The reactant IV is sent to the adsorption tower for adsorption and impurity removal treatment to obtain isononanoic acid.

2. The method for preparing isononanoic acid from isononal as a raw material as described in claim 1, characterized in that, The filter is at least one of bag filter, basket filter, plate filter, and tubular filter.

3. The method for preparing isononanoic acid from isononal as described in claim 1, characterized in that, The temperature at the top of the light-weight removal tower is 45~95℃, and the pressure at the top of the tower is 1~45kPa.

4. The method for preparing isononanoic acid from isononal as a raw material as described in claim 1, characterized in that, The temperature at the top of the refining column is 110~180℃, and the pressure at the top of the column is 1~45kPa.

5. The method for preparing isononanoic acid from isononal as a raw material as described in claim 1, characterized in that, The adsorption packing material in the adsorption tower is at least one of white clay, diatomaceous earth, molecular sieve, and activated carbon fiber.

6. The method for preparing isononanoic acid from isononal as a raw material as described in claim 1, characterized in that, The pressure during the first and second stage oxidation reactions is 0.1~2 MPa.

7. The method for preparing isononanoic acid from isononal as a raw material as described in claim 1, characterized in that, The heterogeneous catalyst is a solid acid catalyst supported on a transition metal element.

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