Process for continuously preparing neodecanoic acid by propylene trimerization-branched nonene hydroformylation-oxidation method

Abstract

The invention discloses a process for continuously preparing neodecanoic acid through a propylene trimerization-branched nonene hydroformylation-oxidation method, and belongs to the technical field of neodecanoic acid preparation. The process comprises the following steps: (1) continuously introducing propylene into a propylene polymerization reactor filled with a solid phosphoric acid catalyst, and carrying out polymerization reaction, so that propylene is tripolymerized into a mixed product containing branched nonene; (2) continuously introducing the mixed product containing branched nonene and synthesis gas of CO and H2 into a hydroformylation reactor filled with an Rh-Xantphos / SBA-15 catalyst, and carrying out a hydroformylation reaction to obtain a mixed product containing neocapraldehyde; (3) continuously introducing the mixed product containing neodecanal and air into an oxidation reactor filled with a TS-1 molecular sieve, and carrying out oxidation reaction to obtain a mixed product containing neodecanoic acid; and (4) rectifying and purifying the mixed product containing neodecanoic acid to obtain a high-purity neodecanoic acid product. The continuous production of neodecanoic acid can be realized by combining the process provided by the invention with a fixed bed reactor.

Description

Technical Field

[0001] This invention relates to the field of neodecanoic acid technology, specifically to a process for the continuous preparation of neodecanoic acid by propylene trimerization-branched nonene hydroformylation-oxidation. Background Technology

[0002] Neodecanoic acid (2-ethyl-2,5-dimethylhexanoic acid) plays a significant role in multiple industrial fields due to its excellent properties. For example, high-purity neodecanoic acid monomers can be used as intermediates in the synthesis of antibiotics such as ampicillin, and are also used for the efficient separation of rare earth elements (such as neodymium and praseodymium). In coatings, it can improve gloss, stability, flexibility, and heat insulation, while reducing VOC emissions. Its derivatives (glycidyl neodecanoate and vinyl neodecanoate) are important components of various coatings. Furthermore, bismuth neodecanoate, as an environmentally friendly catalyst, replaces toxic substances and extends the life of polyurethane coatings by more than 50%; cobalt neodecanoate, as a tire adhesive, has an annual demand exceeding 200,000 tons and is growing by 5%; and vinyl tert-decanoate copolymer emulsions are ideal resins for water-based coatings. The efficient, environmentally friendly, and widely applicable properties of neodecanoic acid have established its core position.

[0003] Currently, the preparation of neodecanoic acid mainly relies on the Koch reaction of propylene trimeronene with carbon monoxide and water. This reaction requires a strong acid catalyst, but traditional strong acid catalytic systems (such as boron trifluoride and concentrated sulfuric acid) have serious bottlenecks: the sulfuric acid method requires excess acid, and hydrolysis produces black waste acid containing organic matter, resulting in high treatment costs and low recycling rates; boron trifluoride corrodes equipment and produces byproducts such as bisulfite, and the production process requires high pressure and cumbersome purification. Based on this, this invention proposes a continuous process for the preparation of neodecanoic acid via propylene trimeronene-branched nonene hydroformylation-oxidation. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a process for the continuous preparation of neodecanoic acid via propylene trimerization-branched nonene hydroformylation-oxidation.

[0005] The technical solution adopted in this invention is as follows:

[0006] A process for the continuous preparation of neodecanoic acid via propylene trimerization-branched nonene hydroformylation-oxidation includes the following steps:

[0007] (1) Propylene is continuously fed into a propylene polymerization reactor filled with a solid phosphoric acid catalyst to undergo a polymerization reaction, which causes propylene to trimelinate into a mixed product containing branched nonene.

[0008] (2) The mixed product containing branched nonene and the synthesis gas of CO and H2 are continuously fed into a hydroformylation reactor packed with Rh-Xantphos / SBA-15 catalyst to undergo hydroformylation reaction and obtain a mixed product containing neodecanoic acid.

[0009] (3) The mixed product containing neodecanoic acid and air are continuously passed into an oxidation reactor filled with TS-1 molecular sieve to undergo an oxidation reaction and obtain a mixed product containing neodecanoic acid.

[0010] (4) The mixed product containing neodecanoic acid is purified by distillation to obtain high-purity neodecanoic acid product.

[0011] Furthermore, in step (1), the polymerization reaction temperature is 160–200°C and the reaction pressure is 4.0–6.0 MPa.

[0012] Further, in step (1), the solid phosphoric acid catalyst is obtained by supporting H3PO4 on a γ-Al2O3 support, and the loading of H3PO4 is 80-90 wt%. The particle size of the solid phosphoric acid catalyst is 0.5-1.0 mm, and the specific surface area is 200-250 m². 2 / g, packing density 0.8~1.0g / cm³ 3 .

[0013] Furthermore, in step (2), the CO:H2 molar ratio of the synthesis gas is 1:1 to 2, and nitrogen is used for protection during the polymerization reaction, with an oxygen content of ≤10ppm in the nitrogen.

[0014] Furthermore, in step (2), the hydroformylation reaction temperature is 80–100°C and the reaction pressure is 1.5–2.5 MPa.

[0015] Further, in step (2), the Rh-Xantphos / SBA-15 catalyst is obtained by loading metallic rhodium and Xantphos ligand onto an SBA-15 molecular sieve support, with a rhodium loading of 0.8-1.2 wt%, a molar ratio of Xantphos ligand to rhodium of 2-5:1, and a pore size of 6-8 nm for the SBA-15 molecular sieve; the packing volume of the Rh-Xantphos / SBA-15 catalyst is 60-70% of the effective volume of the hydroformylation reactor.

[0016] Furthermore, the oxidation reaction temperature in step (3) is 70–90°C.

[0017] Furthermore, in step (3), the TS-1 molecular sieve has a pore size of 0.55±0.05nm and a titanium-silicon molar ratio of 1:30~50.

[0018] Furthermore, in step (3), the TS-1 molecular sieve is filled along the axial direction of the fixed bed, and the bed height-to-diameter ratio is 3:1.

[0019] Furthermore, the polymerization reactor, hydroformylation reactor, and oxidation reactor are fixed-bed reactors.

[0020] The beneficial effects of this invention are as follows:

[0021] This invention proposes a continuous process for preparing neodecanoic acid via propylene trimerization-branched nonene hydroformylation-oxidation. The process utilizes a solid phosphoric acid catalyst to catalyze the trimerization of propylene into branched nonene, a Rh-Xantphos / SBA-15 catalyst to catalyze the hydroformylation of branched nonene to obtain neodecanoic acid, and a TS-1 molecular sieve catalyst to catalyze the oxidation of neodecanoic acid to obtain neodecanoic acid. The catalysts at each stage have high catalytic efficiency, resulting in high conversion rates of the corresponding raw materials and high product selectivity, ensuring a high yield of neodecanoic acid. Furthermore, the catalyst activity remains high even after long-term operation, with minimal impact on the neodecanoic acid yield, thus facilitating the continuous production of neodecanoic acid. Detailed Implementation

[0022] This invention provides a process for the continuous preparation of neodecanoic acid via propylene trimerization-branched nonene hydroformylation-oxidation. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0023] In this invention, there are no special restrictions on the source of any raw materials; they can be commercially available.

[0024] This invention provides a process for the continuous preparation of neodecanoic acid via propylene trimerization-branched nonene hydroformylation-oxidation, the steps of which are as follows:

[0025] (1) Propylene trimerization into branched nonene

[0026] In the propylene trimerization stage, propylene is continuously fed into a propylene polymerization reactor packed with a solid phosphoric acid catalyst. The reaction temperature is 160–200℃, the reaction pressure is 4.0–6.0 MPa, and the propylene feed volume hourly space velocity is 30–80 h⁻¹. -1 The polymerization reaction yielded a mixed product containing branched nonene;

[0027] (2) Hydroformylation of branched nonene yields neodecanoal

[0028] In the hydroformylation stage of branched nonene, a mixture containing branched nonene and syngas containing CO and H2 are continuously fed into a hydroformylation reactor packed with Rh-Xantphos / SBA-15 catalyst. The reaction temperature is 80–100 °C, the reaction pressure is 1.5–2.5 MPa, and the volume hourly space velocity (VHSV) of the branched nonene mixture is 10–20 h⁻¹. -1 The volume hourly space velocity of the syngas is 100–150 h⁻¹. -1 The mixture containing neodecanoic acid was obtained by hydroformylation.

[0029] (3) Neodecanoic acid is obtained by oxidation of neodecanoic acid.

[0030] In the neodecanoic acid oxidation stage, a mixture containing neodecanoic acid and air are continuously introduced into an oxidation reactor packed with TS-1 molecular sieves. The reaction temperature is 70–90℃, the reaction pressure is 0.1–0.5 MPa, and the volume hourly space velocity (VHSV) of neodecanoic acid is 10–20 h⁻¹. -1 The air velocity is 100–150 h⁻¹. -1 The oxidation reaction yielded a mixed product containing neodecanoic acid;

[0031] (4) Purification of neodecanoic acid

[0032] In the purification stage of neodecanoic acid, the mixed product containing neodecanoic acid is purified by three-stage distillation, that is, it is purified sequentially by a dehydration distillation column, a product distillation column, and a heavy component distillation column to obtain a high-purity neodecanoic acid product with a purity of over 99%.

[0033] In a preferred embodiment of the present invention, in step (1), the stage of propylene trimerization into branched nonene is controlled by three-section temperature control, namely, the temperature of the upper preheating section of the reactor is controlled at 160-170°C, the temperature of the middle main reaction section is controlled at 170-190°C, and the temperature of the lower product stabilization section is controlled at 190-200°C.

[0034] In a preferred embodiment of the present invention, the purity of the raw material propylene in step (1) is 99.5% or higher.

[0035] In a preferred embodiment of the present invention, the solid phosphoric acid catalyst in step (1) is obtained by supporting H3PO4 on a γ-Al2O3 support, wherein the loading of H3PO4 is 80-90 wt%, the particle size of the solid phosphoric acid catalyst is 0.5-1.0 mm, and the specific surface area is 200-250 m². 2 / g, packing density 0.8~1.0g / cm³ 3 .

[0036] In a preferred embodiment of the present invention, the CO:H2 molar ratio of the synthesis gas in step (2) is 1:1 to 2, and nitrogen is used for protection during the polymerization reaction, with an oxygen content of ≤10ppm in the nitrogen.

[0037] In a preferred embodiment of the present invention, the Rh-Xantphos / SBA-15 catalyst in step (2) is obtained by loading metallic rhodium and Xantphos bidentate ligand onto an SBA-15 molecular sieve support, wherein the rhodium loading in the catalyst accounts for 0.8-1.2 wt% of the total mass of the catalyst, the molar ratio of Xantphos bidentate ligand to rhodium is 2-5:1, the pore size of the SBA-15 molecular sieve is 6-8 nm, and the packing height of the Rh-Xantphos / SBA-15 catalyst is 60-70% of the effective volume of the hydroformylation reactor.

[0038] In addition, the aforementioned Rh-Xantphos / SBA-15 catalyst employs a zeolite-confined heterogeneous rhodium catalyst, which effectively suppresses the loss of Rh-Xantphos catalytic components.

[0039] In a preferred embodiment of the present invention, the pore size of the TS-1 molecular sieve in step (3) is 0.55±0.05nm, and the titanium-silicon molar ratio is 1:30~50.

[0040] In addition, the titanium active center in the TS-1 molecular sieve can promote the generation of reactive oxygen species from O2, attack the aldehyde group to form a peroxy acid intermediate, and simultaneously realize the activation of CH bond and the insertion of O atom to complete the conversion of aldehyde to acid.

[0041] In a preferred embodiment of the present invention, the TS-1 molecular sieve in step (3) is filled along the axial direction of the fixed bed reactor, and the bed height-to-diameter ratio is 3:1.

[0042] In a preferred embodiment of the present invention, in step (4), during the three-stage distillation purification stage, the dehydration distillation column operates at a temperature of 60–65°C and a pressure of -0.08 MPa to remove water from the mixture; the product distillation column operates at a temperature of 150–155°C and a pressure of -0.05 MPa to separate neodecanoic acid; and the heavy component distillation column operates at a temperature of 180–185°C and a pressure of -0.03 MPa to recover residues.

[0043] In a preferred embodiment of the present invention, each reactor is a fixed-bed reactor, that is, a solid catalyst is packed inside the reactor to form a stacked bed of a certain height. At the same time, gaseous or liquid materials flow through the gaps between particles through the stationary fixed bed to realize a heterogeneous reaction process.

[0044] The process path for the above continuous production is as follows:

[0045]

[0046] Based on the above-described process of the present invention, continuous production of neodecanoic acid is achieved.

[0047] Example 1

[0048] This embodiment utilizes a hydroformylation-oxidation method to continuously prepare neodecanoic acid from propylene trimer-branched nonene, with the following steps:

[0049] (1) Propylene trimerization into branched nonene

[0050] A vertical fixed-bed reactor (Φ500×6000mm, 316L stainless steel) was used as the propylene polymerization reactor, and it was packed with 85wt% H3PO4 / γ-Al2O3 solid phosphoric acid catalyst. The particle size of the solid phosphoric acid catalyst ranged from 0.5 to 1.0 mm, and the specific surface area was 200 to 250 m². 2 / g, packing density 0.9g / cm³ 3 ; Propylene with a purity of 99.8% was subjected to a 50-hour process. -1 The volume hourly space velocity (VHSV) is introduced into the propylene polymerization reactor. The reaction pressure is set to 5.0 MPa. The overall reaction process is controlled by a three-section temperature control system. The temperature of the upper preheating section of the reactor is controlled at 160°C, the temperature of the middle main reaction section is controlled at 180°C, and the temperature of the lower product stabilization section is controlled at 200°C. The polymerization reaction yields a mixed product containing branched nonene.

[0051] (2) Hydroformylation of branched nonene yields neodecanoal

[0052] A tubular fixed-bed reactor (Φ800×8000mm, Hastelloy C276) was used as the hydroformylation reactor, and it was packed with Rh-Xantphos / SBA-15 catalyst. The catalyst had a rhodium loading of 1.0wt%, a Xantphos ligand to rhodium molar ratio of 3:1, and an SBA-15 molecular sieve pore size of 6-8nm. The packing volume of the Rh-Xantphos / SBA-15 catalyst was 65% of the effective volume of the hydroformylation reactor. The mixed product containing branched nonene obtained in step (1) was pumped into the hydroformylation reactor, and synthesis gas of CO and H2 (CO:H2 molar ratio 1:1.2) was simultaneously introduced. The reaction temperature was controlled at 90℃, the reaction pressure at 2.0MPa, and the volume hourly space velocity of the branched nonene mixed product was 1.5h. -1 The volume hourly space velocity of the syngas is 120 h⁻¹. -1 The mixture containing neodecanoic acid was obtained by hydroformylation.

[0053] (3) Neodecanoic acid is obtained by oxidation of neodecanoic acid.

[0054] A vertical fixed-bed reactor (Φ600×1800mm, 304 stainless steel) was used as the oxidation reactor, and TS-1 molecular sieves with a pore size of 0.55±0.05nm and a titanium-silicon molar ratio of 1:40 were packed at a TS-1 molecular sieve catalyst density of 0.55Kg / m³. 3 The mixed product containing neodecanoic acid obtained in step (2) is pumped into the oxidation reactor, and air is simultaneously introduced. The reaction temperature is controlled at 80°C, the operation is carried out at atmospheric pressure, and the air space velocity is 110 h⁻¹. -1 The oxidation reaction yielded a mixed product containing neodecanoic acid;

[0055] (4) Purification of neodecanoic acid

[0056] The mixed product containing neodecanoic acid was purified by distillation, specifically using a three-stage distillation process to obtain high-purity neodecanoic acid. The first-stage dehydration tower operated at 60–65°C and -0.08 MPa to remove moisture from the mixture, achieving a moisture removal rate of 0.15 tons per ton of product. The second-stage product tower operated at 155°C and -0.05 MPa to separate neodecanoic acid and collect the product. The third-stage heavy component tower operated at 182°C and -0.03 MPa to recover residual heavy components.

[0057] In the above continuous production process of neodecanoic acid, after the operation stabilizes, samples of the mixed products obtained in steps (1), (2), and (3) are taken and analyzed respectively:

[0058] For the mixed product containing branched nonene obtained in step (1), gas chromatography analysis showed that the propylene conversion rate was 95.6%, the content of 3,6-dimethyl-1-heptene in the mixed product was 86.2% (i.e., the selectivity of 3,6-dimethyl-1-heptene was 86.2%), the content of trimethylhexene was 10.3%, and the heavy component was 3.5%.

[0059] For the mixed product containing neodecaldehyde obtained in step (2), gas chromatography analysis showed that the nonene conversion rate was 96.5%, the neodecaldehyde content in the mixed product was 89.3% (i.e., the neodecaldehyde selectivity was 89.3%), and the n-decane byproduct content was 4.2%.

[0060] The mixed product containing neodecanoic acid obtained in step (3) was analyzed by high performance liquid chromatography. The conversion rate of neodecanoic acid was 99.1%, the content of neodecanoic acid in the mixed product was 97.8% (i.e., the selectivity of neodecanoic acid was 97.8%), and the content of isodecanoic acid byproduct was 2.2%.

[0061] In the above continuous production process of neodecanoic acid, after 1000 hours of continuous operation, samples of the mixed products obtained in steps (1), (2), and (3) were taken and analyzed respectively:

[0062] For the mixed product containing branched nonene obtained in step (1), the propylene conversion rate was 80.4% and the selectivity of 3,6-dimethyl-1-heptene content in the mixed product was 83.9%.

[0063] For the mixed product containing neodecaldehyde obtained in step (2), gas chromatography analysis showed that the rhodium loss was 0.05 ppm, the nonene conversion rate was 85.9%, the neodecaldehyde content in the mixed product was 79.8% (i.e., the neodecaldehyde selectivity was 79.8%), and the n-decane byproduct content was 8.3%.

[0064] The mixed product containing neodecanoic acid obtained in step (3) was analyzed by high performance liquid chromatography. The conversion rate of neodecanoic acid was 95.0%, the content of neodecanoic acid in the mixed product was 90.3% (i.e., the selectivity of neodecanoic acid was 90.3%), and the content of isodecanoic acid byproduct was 5.1%.

[0065] The test results after 1000 hours of operation show that the catalytic activity of each catalyst is relatively stable during the continuous production of neodecanoic acid.

[0066] In addition, after the molecular sieve has been running continuously for 2000 hours in step (3) above, it is thermally regenerated (treated at 450°C for 6 hours under nitrogen protection). After regeneration, the oxidation efficiency is restored to 98.5% of the initial value.

[0067] The test results of Example 1 show that after 1000 hours of continuous operation, the conversion rate of each raw material and the selectivity of the product are still high, demonstrating the continuous production of neodecanoic acid.

[0068] Example 2

[0069] The difference between this embodiment and embodiment 1 is that, in the process of preparing neodecanoic acid, the three sections of the propylene polymerization reactor are set to have different temperatures in step (1) when propylene is triploidized into branched nonene.

[0070] Specifically, when the temperature of the upper preheating section of the reactor is 140℃, the temperature of the middle main reaction section is 160℃, and the temperature of the lower product stabilization section is 180℃, the propylene conversion rate is 89.2%, and the selectivity of 3,6-dimethyl-1-heptene is 80.3%.

[0071] When the temperature of the upper preheating section of the reactor is 180℃, the temperature of the middle main reaction section is 200℃, and the temperature of the lower product stabilization section is 210℃, the propylene conversion rate is 98.1%, the selectivity of 3,6-dimethyl-1-heptene is 83.5%, and the heavy component is 6.2%.

[0072] Example 3

[0073] The difference between this embodiment and embodiment 1 is that in the process of preparing neodecanoic acid, step (2) is set to obtain neodecanoic acid by hydroformylation of branched nonene, and the reaction pressure in the hydroformylation reactor is 1.5 MPa and 2.5 MPa respectively.

[0074] When the reaction pressure is 1.5 MPa, the conversion rate of nonene is 92.3% and the selectivity of neodecanoal is 84.1%.

[0075] When the reaction pressure is 2.5 MPa, the conversion rate of nonene is 97.8%, the selectivity of neodecanoal is 87.6%, and the content of n-decane byproduct increases to 5.5%.

[0076] Example 4

[0077] The difference between this embodiment and embodiment 1 is that in the process of preparing neodecanoic acid, step (3) is set to oxidize neodecanoic acid to obtain neodecanoic acid, and the reaction temperature in the oxidation reactor is 60℃ and 100℃ respectively.

[0078] When the reaction temperature is 60℃, the conversion rate of neodecanoic acid is 95.2%, and the selectivity of neodecanoic acid is 92.1%.

[0079] When the reaction temperature is 100℃, the conversion rate of neodecanoic acid is 99.5%, the selectivity of neodecanoic acid is 94.3%, and the over-oxidation leads to an increase in by-products of 2.3%.

[0080] Application Example 1

[0081] The neodecanoic acid (purity >99.2%) prepared in Example 1 was converted into neodecanoic acid glycidyl ester, which was then mixed with bisphenol A type epoxy resin at a 1:1 molar ratio to prepare an anti-corrosion coating. Salt spray testing was conducted according to GB / T 1771-2007: after 1500 hours, the coating showed no blistering or peeling, and the adhesion remained at grade 1 (grade 0 is optimal).

[0082] Application Example 2

[0083] The neodecanoic acid (purity >99.2%) prepared in Example 1 was converted into cerium neodecanoate and applied to rare earth separation. The cerium neodecanoate extractant was used to treat mixed rare earth ore in Baotou, and the lanthanum-cerium separation coefficient reached 156, which is 30% higher than that of the traditional P507 extractant (separation coefficient ≤120).

[0084] It should be noted that any parts not mentioned in this invention can be achieved by using or referencing existing technologies.

[0085] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A process for the continuous preparation of neodecanoic acid via propylene trimerization-branched nonene hydroformylation-oxidation, characterized in that, Including the following steps: (1) Propylene is continuously fed into a propylene polymerization reactor filled with a solid phosphoric acid catalyst to undergo a polymerization reaction, which causes propylene to trimelinate into a mixed product containing branched nonene. (2) The mixed product containing branched nonene and the synthesis gas of CO and H2 are continuously fed into a hydroformylation reactor packed with Rh-Xantphos / SBA-15 catalyst to undergo hydroformylation reaction and obtain a mixed product containing neodecanoic acid. (3) The mixed product containing neodecanoic acid and air are continuously passed into an oxidation reactor filled with TS-1 molecular sieve to undergo an oxidation reaction and obtain a mixed product containing neodecanoic acid. (4) The mixed product containing neodecanoic acid is purified by distillation to obtain high-purity neodecanoic acid product.

2. The process for the continuous preparation of neodecanoic acid by propylene trimerization-branched nonene hydroformylation-oxidation according to claim 1, characterized in that, In step (1), the polymerization reaction temperature is 160-200℃ and the reaction pressure is 4.0-6.0MPa.

3. The process for the continuous preparation of neodecanoic acid by propylene trimerization-branched nonene hydroformylation-oxidation according to claim 1, characterized in that, In step (1), the solid phosphoric acid catalyst is obtained by supporting H3PO4 on a γ-Al2O3 support, with an H3PO4 loading of 80–90 wt%, a particle size range of 0.5–1.0 mm, and a specific surface area of ​​200–250 m². 2 / g, packing density 0.8~1.0g / cm³ 3 .

4. The process for the continuous preparation of neodecanoic acid by propylene trimerization-branched nonene hydroformylation-oxidation according to claim 1, characterized in that, In step (2), the CO:H2 molar ratio of the synthesis gas is 1:1 to 2, and nitrogen is used for protection during the polymerization reaction, with an oxygen content of ≤10ppm in the nitrogen.

5. The process for the continuous preparation of neodecanoic acid by propylene trimerization-branched nonene hydroformylation-oxidation according to claim 1, characterized in that, In step (2), the hydroformylation reaction temperature is 80-100℃ and the reaction pressure is 1.5-2.5MPa.

6. The process for the continuous preparation of neodecanoic acid by propylene trimerization-branched nonene hydroformylation-oxidation according to claim 1, characterized in that, In step (2), the Rh-Xantphos / SBA-15 catalyst is obtained by loading metallic rhodium and Xantphos ligand onto an SBA-15 molecular sieve support, with a rhodium loading of 0.8-1.2 wt%, a molar ratio of Xantphos ligand to rhodium of 2-5:1, a pore size of 6-8 nm for the SBA-15 molecular sieve, and a packing volume of 60-70% of the effective volume of the hydroformylation reactor.

7. The process for the continuous preparation of neodecanoic acid by propylene trimerization-branched nonene hydroformylation-oxidation according to claim 1, characterized in that, The oxidation reaction temperature in step (3) is 70–90 °C.

8. The process for the continuous preparation of neodecanoic acid by propylene trimerization-branched nonene hydroformylation-oxidation according to claim 1, characterized in that, In step (3), the TS-1 molecular sieve has a pore size of 0.55±0.05nm and a titanium-silicon molar ratio of 1:30~50.

9. The process for the continuous preparation of neodecanoic acid by propylene trimerization-branched nonene hydroformylation-oxidation according to claim 1, characterized in that, In step (3), the TS-1 molecular sieve is filled along the axial direction of the fixed bed reactor, and the bed height-to-diameter ratio is 3:

1.

10. A process for the continuous preparation of neodecanoic acid by propylene trimerization-branched nonene hydroformylation-oxidation according to any one of claims 1-9, characterized in that, The polymerization reactor, hydroformylation reactor, and oxidation reactor are fixed-bed reactors.

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