Process for the preparation of hydrocarbyl carboxylic acids and their use

Abstract

The application relates to the technical field of organic synthesis, and discloses a preparation method of a hydrocarbyl carboxylic acid, which comprises the following steps: mixing a hydrocarbyl aldehyde, an oxidizing agent and a first metal salt to perform pre-reaction, and then mixing the reaction system obtained through the pre-reaction with a second metal salt to perform reaction; wherein the first metal salt is selected from at least one of a sodium salt, a potassium salt, a calcium salt, a lithium salt, an iron salt and a copper salt; and the second metal salt is selected from at least one of a zinc salt, a manganese salt, a cobalt salt, a palladium salt and a silver salt. The preparation method of the hydrocarbyl carboxylic acid can greatly shorten the reaction time, and improve the raw material conversion rate, the target product selectivity and the target product purity of the aldehyde oxidation acid reaction.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, and specifically to a method for preparing and applying a hydrocarbon-based carboxylic acid. Background Technology

[0002] Isooctanoic acid is an important organic chemical product with wide applications in coatings, pharmaceuticals, synthetic fibers, pesticides, and other fields. Isooctanoic acid glycerides, as excellent plasticizers, are widely used in the plastics industry. With the rise of downstream markets, the demand for isooctanoic acid is increasing year by year, indicating significant development potential.

[0003] Currently, there are two main technical routes for the production of isooctanoic acid: One route uses isooctyl alcohol as a raw material, oxidizing it in a strongly alkaline environment to obtain isooctanoate, which is then neutralized and distilled under reduced pressure to obtain isooctanoic acid. This method has a long process flow, high energy consumption, and requires intermittent operation, making it difficult to scale up production. The second route uses n-butyraldehyde as a raw material, undergoing a condensation reaction to obtain the intermediate 2-ethyl-2-hexenal, which is then selectively hydrogenated to obtain 2-ethyl-2-hexanal, and finally oxidized to obtain isooctanoic acid. Because the aldehyde oxidation method has reliable raw material sources and is a continuous process, it is easy to scale up production, and many large companies in Europe and America use this route.

[0004] CN1410407A discloses a method for manufacturing 2-ethylhexanoic acid. This patent uses a falling film reactor with an optimal reaction temperature of 30-50℃, but the equipment investment is large and the selectivity is low. CN1422840A discloses a method for manufacturing 2-ethylhexanoic acid. This patent uses a reaction tower as the reaction equipment, which accelerates the reaction rate and can improve the selectivity to over 96%, but the subsequent treatment of the catalyst is very difficult.

[0005] The liquid-gas oxidation of isooctaldehyde is a classic chain radical reaction. The oxidation efficiency is closely related to the structure of the aldehyde itself. Generally, straight-chain aliphatic aldehydes exhibit high selectivity, while α-branched aldehydes are more prone to side reactions, leading to decreased selectivity. Therefore, a catalyst is needed to improve the reactivity and selectivity during the reaction.

[0006] Therefore, improving the conversion rate and selectivity of isooctaldehyde to isooctanoic acid is a key technical challenge that urgently needs to be overcome in this field, and a preparation method needs to be developed to address this challenge. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems of low raw material conversion rate, low target product selectivity and low purity in the production of isooctaldehyde from isooctaldehyde in the prior art, and to provide a method for preparing and applying a hydrocarbon carboxylic acid.

[0008] To achieve the above objectives, the present invention provides a method for preparing a hydrocarbon carboxylic acid, characterized in that the method includes: mixing a hydrocarbon aldehyde, an oxidant and a first metal salt for a pre-reaction, and then mixing the reaction system obtained from the pre-reaction with a second metal salt for a reaction;

[0009] The first metal salt is selected from at least one of sodium salt, potassium salt, calcium salt, lithium salt, iron salt, and copper salt;

[0010] The second metal salt is selected from at least one of zinc salt, manganese salt, cobalt salt, palladium salt, and silver salt.

[0011] The second aspect of the present invention provides the application of the method described in one aspect of the present invention in improving the feed conversion rate and / or the selectivity of the target product in the oxidation of hydrocarbon aldehydes to prepare hydrocarbon carboxylic acids.

[0012] Through the above technical solutions, the method for preparing hydrocarbon carboxylic acids described in this invention can greatly shorten the reaction time and improve the raw material conversion rate, product selectivity, and product purity of the aldehyde oxidation to acid reaction. Detailed Implementation

[0013] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0014] As mentioned above, the present invention provides a method for preparing a hydrocarbon carboxylic acid, characterized in that the method includes: mixing a hydrocarbon aldehyde, an oxidant and a first metal salt for a pre-reaction, and then mixing the reaction system obtained from the pre-reaction with a second metal salt for a reaction;

[0015] The first metal salt is selected from at least one of sodium salt, potassium salt, calcium salt, lithium salt, iron salt, and copper salt;

[0016] The second metal salt is selected from at least one of zinc salt, manganese salt, cobalt salt, palladium salt, and silver salt.

[0017] In some embodiments of the present invention, preferably, the hydrocarbon group is selected from C6-C18 alkyl groups, and more preferably from C7-C12 branched alkyl groups.

[0018] In some embodiments of the present invention, preferably, the first metal salt is selected from at least one of sodium salts, potassium salts, calcium salts, lithium salts, iron salts, and copper salts of organic acids.

[0019] In some embodiments of the present invention, preferably, the second metal salt is selected from at least one of organic acid zinc salt, organic acid manganese salt, organic acid cobalt salt, organic acid palladium salt, and organic acid silver salt.

[0020] In some embodiments of the present invention, preferably, the hydrocarbon group is selected from heptyl, isoheptyl, octyl, isooctyl, nonyl, or isononyl.

[0021] In some embodiments of the present invention, preferably, the first metal salt is selected from at least one of sodium salts, potassium salts, and calcium salts of organic acids.

[0022] In some embodiments of the present invention, preferably, the second metal salt is selected from at least one of organic manganese salt, organic cobalt salt, and organic palladium salt.

[0023] In some embodiments of the present invention, preferably, the organic acids providing the organic acid ions in the first metal salt and the second metal salt are each independently selected from substituted or unsubstituted C2-C12 hydrocarbon carboxylic acids and / or polyC2-C12 hydrocarbon carboxylic acids.

[0024] In some embodiments of the present invention, preferably, the hydrocarbon group is selected from octyl or isooctyl.

[0025] In some embodiments of the present invention, preferably, the first metal salt is selected from sodium salts and / or potassium salts of organic acids.

[0026] In some embodiments of the present invention, preferably, the second metal salt is selected from organic manganese salts and / or organic cobalt salts.

[0027] In some embodiments of the present invention, preferably, the organic acids providing the organic acid ions in the first metal salt and the second metal salt are each independently selected from at least one of substituted or unsubstituted trifluoroacetic acid, tervastatinic acid, octanoic acid, isooctanoic acid, succinic acid, polymaleic acid, and lauric acid.

[0028] In some embodiments of the present invention, preferably, the pre-reaction and / or reaction are carried out in the presence of a solvent.

[0029] In some embodiments of the present invention, preferably, the solvent content is 14-50 wt%, more preferably 25-40 wt%, based on the total weight of the hydrocarbon aldehyde, the first metal salt, the second metal salt, and the solvent.

[0030] In some embodiments of the present invention, preferably, the solvent is selected from C6-C12 alkyl carboxylic acids, and more preferably at least one of hexanoic acid, isohexanoic acid, heptanoic acid, isoheptanoic acid, octanoic acid, isooctanoic acid, nonanoic acid, and isononanoic acid.

[0031] In some embodiments of the present invention, preferably, the oxidant is selected from oxygen-containing gases, and more preferably air and / or oxygen.

[0032] In some embodiments of the present invention, preferably, the pre-reaction and / or reaction is carried out in a microbubble generator.

[0033] In some embodiments of the present invention, preferably, the mass ratio of the hydrocarbon aldehyde to the first metal salt is 25-80:1, more preferably 27-40:1.

[0034] In some embodiments of the present invention, preferably, the mass ratio of the hydrocarbon aldehyde to the second metal salt is 7-11:1, more preferably 8-10:1.

[0035] In some embodiments of the present invention, preferably, the volume ratio of the hydrocarbon aldehyde to the oxidant is 1:50-100000, more preferably 1:100-10000.

[0036] In some embodiments of the present invention, preferably, the pre-reaction pressure is 0.1-10 MPa, more preferably 1-7 MPa.

[0037] In some embodiments of the present invention, preferably, the temperature of the pre-reaction is 25-80°C, more preferably 30-70°C.

[0038] In some embodiments of the present invention, preferably, the pre-reaction time is 0.5-4h, more preferably 0.5-2h.

[0039] In some embodiments of the present invention, preferably, the reaction pressure is 0.1-10 MPa, more preferably 2-7 MPa.

[0040] In some embodiments of the present invention, preferably, the reaction temperature is 30-150°C, more preferably 40-120°C.

[0041] In some embodiments of the present invention, preferably, the reaction time is 0.1-2 hours, more preferably 0.2-1 hours.

[0042] The second aspect of the present invention provides the application of the method described in one aspect of the present invention in improving the feed conversion rate and / or the selectivity of the target product in the oxidation of hydrocarbon aldehydes to prepare hydrocarbon carboxylic acids.

[0043] In this invention, isooctaldehyde may include various isomers of octanaldehyde, preferably 2-ethylhexanal. The same applies to isooctanoic acid, preferably 2-ethylhexanoic acid.

[0044] The present invention will be described in detail below through examples. In the following examples and comparative examples, isooctaldehyde refers to 2-ethylhexanal, and isooctanoic acid refers to 2-ethylhexanoic acid; the formula for the conversion rate of reactants is: reactants The formula for product yield is: Product purity was determined using gas chromatography. Unless otherwise specified, all raw materials are commercially available products.

[0045] Example 1

[0046] 10.00g of isooctaldehyde, 0.37g of sodium isooctanoate, and 55.00g of isooctanoic acid were mixed and added to the first microbubble generator. Air was bubbled into the bottom, stirring was started, and the pressure inside the reactor was adjusted to 4.5MPa. The reaction temperature was controlled at 60℃, and the reaction time was 1 hour. After the reaction was completed, the liquid was pumped into the second microbubble generator, and 1.43g of manganese isooctanoate was added. The pressure inside the reactor was adjusted to 4.5MPa, the reaction temperature was controlled at 40℃, and the reaction time was 0.5 hours. After the reaction was completed, the liquid was transferred to a glass flask, and after vacuum distillation, the middle distillate was collected.

[0047] The concentrations of each substance before and after the reaction were determined by gas chromatography, and the results were converted into conversion rate and selectivity. The results are shown in Table 1.

[0048] Example 2

[0049] 10.00g of isooctaldehyde, 0.25g of sodium isooctanoate, and 55.00g of isooctanoic acid were mixed and added to the first microbubble generator. Air was bubbled into the bottom, stirring was started, and the pressure inside the reactor was adjusted to 3.5MPa. The reaction temperature inside the reactor was controlled at 30℃, and the reaction time was 1 hour. After the reaction was completed, the liquid was transferred to the second microbubble generator using a pump. 0.93g of manganese isooctanoate was added, the pressure inside the reactor was adjusted to 7MPa, the reaction temperature was controlled at 120℃, and the reaction time was 0.2 hours. After the reaction was completed, the liquid was transferred to a glass flask, and after vacuum distillation, the middle distillate was collected.

[0050] The concentrations of each substance before and after the reaction were determined by gas chromatography, and the results were converted into conversion rate and selectivity. The results are shown in Table 1.

[0051] Example 3

[0052] 10.00g of isooctaldehyde, 0.36g of sodium isooctanoate, and 55.00g of isooctanoic acid were mixed and added to the first microbubble generator. Air was bubbled into the bottom, stirring was started, and the pressure inside the reactor was adjusted to 0.5MPa. The reaction temperature was controlled at 50℃, and the reaction time was 1.5 hours. After the reaction was completed, the liquid was pumped into the second microbubble generator, and 1.12g of manganese isooctanoate was added. The pressure inside the reactor was 5.5MPa, the reaction temperature was controlled at 60℃, and the reaction time was 0.4 hours. After the reaction was completed, the liquid was transferred to a glass flask, and after vacuum distillation, the middle distillate was collected.

[0053] The concentrations of each substance before and after the reaction were determined by gas chromatography, and the results were converted into conversion rate and selectivity. The results are shown in Table 1.

[0054] Example 4

[0055] 10.00g of isooctaldehyde, 0.31g of sodium isooctanoate, and 55.00g of isooctanoic acid were mixed and added to the first microbubble generator. Air was bubbled into the bottom, stirring was started, and the pressure inside the reactor was adjusted to 1MPa. The reaction temperature was controlled at 70℃, and the reaction time was 0.5 hours. After the reaction was completed, the liquid was transferred to the second microbubble generator using a pump. 1.26g of manganese isooctanoate was added, the pressure inside the reactor was adjusted to 2MPa, the reaction temperature was controlled at 90℃, and the reaction time was 0.8 hours. After the reaction was completed, the liquid was transferred to a glass flask, and after vacuum distillation, the middle distillate was collected.

[0056] The concentrations of each substance before and after the reaction were determined by gas chromatography, and the results were converted into conversion rate and selectivity. The results are shown in Table 1.

[0057] Example 5

[0058] 10.00g of isooctaldehyde, 0.37g of sodium isooctanoate, and 55.00g of isooctanoic acid were mixed and added to the first reaction vessel. Stirring was started, and the pressure inside the reactor was adjusted to 4.5MPa. The reaction temperature was controlled at 60℃, and the reaction time was 1 hour. After the reaction was complete, the liquid was transferred to the second reaction vessel using a pump. 1.43g of manganese isooctanoate was added, the pressure inside the reactor was adjusted to 4.5MPa, the reaction temperature was controlled at 40℃, and the reaction time was 0.5 hours. After the reaction was complete, the liquid was transferred to a glass flask, and after vacuum distillation, the middle distillate was collected.

[0059] The concentrations of each substance before and after the reaction were determined by gas chromatography, and the results were converted into conversion rate and selectivity. The results are shown in Table 1.

[0060] Comparative Example 1

[0061] 10.00g of isooctaldehyde, 0.37g of sodium isooctanoate, 1.43g of manganese isooctanoate, and 55.00g of isooctanoic acid were mixed and added to the first microbubble generator. Air was bubbled into the bottom, stirring was started, and the pressure inside the reactor was adjusted to 4.5MPa. The reaction temperature was controlled at 60℃, and the reaction time was 1 hour. After the reaction was completed, the liquid was transferred to the second microbubble generator using a pump. The pressure inside the reactor was 4.5MPa, the reaction temperature was controlled at 40℃, and the reaction time was 0.5 hours. After the reaction was completed, the liquid was transferred to a glass flask, and after vacuum distillation, the middle distillate was collected.

[0062] The concentrations of each substance before and after the reaction were determined by gas chromatography, and the results were converted into conversion rate and selectivity. The results are shown in Table 1.

[0063] Comparative Example 2

[0064] 10.00g of isooctaldehyde, 0.37g of sodium isooctanoate, and 55.00g of isooctanoic acid were mixed and added to the first microbubble generator. Air was bubbled into the bottom, stirring was started, and the pressure inside the reactor was adjusted to 4.5MPa. The reaction temperature was controlled at 60℃, and the reaction time was 1 hour. After the reaction was completed, the liquid was transferred to the second microbubble generator using a pump. 0.69g of sodium isooctanoate was added, the pressure inside the reactor was adjusted to 4.5MPa, the reaction temperature was controlled at 40℃, and the reaction time was 0.5 hours. After the reaction was completed, the liquid was transferred to a glass flask, and after vacuum distillation, the middle distillate was collected.

[0065] The concentrations of each substance before and after the reaction were determined by gas chromatography, and the results were converted into conversion rate and selectivity. The results are shown in Table 1.

[0066] Comparative Example 3

[0067] 10.00 g of isooctaldehyde, 0.77 g of manganese isooctanoate, and 55.00 g of isooctanoic acid were mixed and added to the first microbubble generator. Air was bubbled into the bottom, stirring was started, and the pressure inside the reactor was adjusted to 4.5 MPa. The reaction temperature was controlled at 60°C, and the reaction time was 1 hour. After the reaction was completed, the liquid was pumped into the second microbubble generator, and 1.43 g of manganese isooctanoate was added. The pressure inside the reactor was adjusted to 4.5 MPa, the reaction temperature was controlled at 40°C, and the reaction time was 0.5 hours. After the reaction was completed, the liquid was transferred to a glass flask, and after vacuum distillation, the middle distillate was collected.

[0068] The concentrations of each substance before and after the reaction were determined by gas chromatography, and the results were converted into conversion rate and selectivity. The results are shown in Table 1.

[0069] Comparative Example 4

[0070] 10.00g of isooctaldehyde, 1.43g of manganese isooctanoate, and 55.00g of isooctanoic acid were mixed and added to the first microbubble generator. Air was bubbled into the bottom, stirring was started, and the pressure inside the reactor was adjusted to 4.5MPa. The reaction temperature was controlled at 60℃, and the reaction time was 1 hour. After the reaction was completed, the liquid was transferred to the second microbubble generator using a pump. 0.37g of sodium isooctanoate was added, the pressure inside the reactor was adjusted to 4.5MPa, the reaction temperature was controlled at 40℃, and the reaction time was 0.5 hours. After the reaction was completed, the liquid was transferred to a glass flask, and after vacuum distillation, the middle distillate was collected.

[0071] The concentrations of each substance before and after the reaction were determined by gas chromatography, and the results were converted into conversion rate and selectivity. The results are shown in Table 1.

[0072] Table 1

[0073] Conversion rate / % Selectivity / % Product purity / % Example 1 99.35 98.21 99.94 Example 2 99.23 98.45 99.93 Example 3 99.29 98.19 99.73 Example 4 99.33 98.58 99.97 Example 5 98.89 97.47 99.95 Comparative Example 1 90.08 96.71 84.66 Comparative Example 2 91.04 96.13 88.72 Comparative Example 3 91.12 91.56 88.58 Comparative Example 4 90.06 95.58 82.35

[0074] As can be seen from Table 1, under the process conditions used in this invention, the reaction exhibits excellent raw material conversion rate, product selectivity, and product purity.

[0075] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing a hydrocarbon-based carboxylic acid, characterized in that, The method includes: mixing a hydrocarbon aldehyde, an oxidant and a first metal salt for a pre-reaction, and then mixing the reaction system obtained from the pre-reaction with a second metal salt for a reaction; The first metal salt is selected from at least one of sodium salt, potassium salt, calcium salt, lithium salt, iron salt, and copper salt; The second metal salt is selected from at least one of zinc salt, manganese salt, cobalt salt, palladium salt, and silver salt.

2. The method according to claim 1, wherein, The hydrocarbon group is selected from C6-C18 alkyl groups, preferably C7-C12 branched alkyl groups; And / or, the first metal salt is selected from at least one of the following: sodium salt of organic acid, potassium salt of organic acid, calcium salt of organic acid, lithium salt of organic acid, iron salt of organic acid, and copper salt of organic acid; And / or, the second metal salt is selected from at least one of organic acid zinc salt, organic acid manganese salt, organic acid cobalt salt, organic acid palladium salt and organic acid silver salt.

3. The method according to claim 2, wherein, The hydrocarbon group is selected from heptyl, isoheptyl, octyl, isooctyl, nonyl, or isononyl; And / or, the first metal salt is selected from at least one of sodium salts, potassium salts, and calcium salts of organic acids; And / or, the second metal salt is selected from at least one of organic acid manganese salt, organic acid cobalt salt, and organic acid palladium salt; And / or, the organic acids providing the organic acid ions in the first metal salt and the second metal salt are each independently selected from substituted or unsubstituted C2-C12 alkyl carboxylic acids and / or polyC2-C12 alkyl carboxylic acids.

4. The method according to claim 3, wherein, The hydrocarbon group is selected from octyl or isooctyl; And / or, the first metal salt is selected from sodium salts and / or potassium salts of organic acids; And / or, the second metal salt is selected from organic acid manganese salts and / or organic acid cobalt salts; And / or, the organic acids providing the organic acid ions in the first metal salt and the second metal salt are each independently selected from at least one of substituted or unsubstituted trifluoroacetic acid, tervastatinic acid, octanoic acid, isooctanoic acid, succinic acid, polymaleic acid, and lauric acid.

5. The method according to any one of claims 1-4, wherein, The pre-reaction and / or reaction are carried out in the presence of a solvent; Preferably, based on the total weight of the hydrocarbon aldehyde, the first metal salt, the second metal salt, and the solvent, the content of the solvent is 14-50 wt%, more preferably 25-40 wt%. Preferably, the solvent is selected from C6-C12 alkyl carboxylic acids, and more preferably at least one of hexanoic acid, isohexanoic acid, heptanoic acid, isohexanoic acid, octanoic acid, isooctanoic acid, nonanoic acid, and isononanoic acid.

6. The method according to any one of claims 1-5, wherein, The oxidant is selected from oxygen-containing gases, preferably air and / or oxygen; Preferably, the pre-reaction and / or reaction are carried out in a microbubble generator.

7. The method according to any one of claims 1-6, wherein, The mass ratio of the hydrocarbon aldehyde to the first metal salt is 25-80:1, preferably 27-40:1; Preferably, the mass ratio of the hydrocarbon aldehyde to the second metal salt is 7-11:1, more preferably 8-10:1; Preferably, the volume ratio of the hydrocarbon aldehyde to the oxidant is 1:50-100000, more preferably 1:100-10000.

8. The method according to any one of claims 1-7, wherein, The pressure of the pre-reaction is 0.1-10 MPa, preferably 1-7 MPa; Preferably, the temperature of the pre-reaction is 25-80℃, more preferably 30-70℃; Preferably, the pre-reaction time is 0.5-4 hours, and more preferably 0.5-2 hours.

9. The method according to any one of claims 1-8, wherein, The reaction pressure is 0.1-10 MPa, preferably 2-7 MPa; Preferably, the reaction temperature is 30-150℃, more preferably 40-120℃; Preferably, the reaction time is 0.1-2 hours, more preferably 0.2-1 hours.

10. The application of the method according to any one of claims 1-9 in improving the feed conversion rate and / or target product selectivity in the oxidation of hydrocarbon aldehydes to prepare hydrocarbon carboxylic acids.