A process for the preparation of hexadienedioic acid using alkylbenzene

Abstract

The application discloses a method for preparing hexadienedioic acid by using alkylbenzene, which comprises the following steps: adding a photocatalyst into an alkylbenzene-containing aqueous solution, wherein the photocatalyst is a transition metal-containing compound, controlling the pH value of the aqueous solution to be greater than 7, and then performing an oxidation reaction under anoxic conditions under light irradiation, so that the alkylbenzene is converted into hexadienedioic acid, wherein the anoxic condition refers to that the dissolved oxygen content of the alkylbenzene-containing aqueous solution is 4-10 mg / L. The method directly uses alkylbenzene as a raw material instead of phenol compounds, the raw material is easy to obtain and low in cost. Moreover, the method directly uses natural light as an energy source, does not add any harmful elements into the system during the preparation process, the photocatalyst can be recycled, and the process is green and environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of organic chemical technology, specifically relating to a method for preparing edodecidic acid using alkylbenzenes. Background Technology

[0002] Adipatecanic acid (commonly known as mucoagulant) is an unsaturated dicarboxylic acid. In the organic synthesis industry, adipatecanic acid serves as a basic raw material for resins, pharmaceuticals, food, and pesticides. Because of its stereooriented configuration, active dicarboxylic acid groups, and conjugated double bonds, adipatecanic acid can undergo numerous reactions and is considered a valuable and important platform chemical with wide applications, including as a surfactant, flame retardant, UV light stabilizer, thermosetting plastic, and thermoplastic plastic.

[0003] For example, mucoconic acid has a strong absorption effect on 260nm ultraviolet light and is mainly used in UV-protective agents and special military products. For instance, some countries have widely adopted mucoconic acid as a UV absorber in sunscreens, and it is especially used as a major additive in beach and sea bath cosmetics. In the military field, mucoconic acid can be used in aerospace stealth aircraft coatings, special photosensitive resins, and electronic materials. Furthermore, adipadienoic acid, as a precursor to adipic acid, can be used to synthesize nylon-6,6, and is an important monomer for synthetic plastics and other polymers.

[0004] Currently, adipodecanic acid is mainly prepared by microbial methods, but the resulting product has a low purity. Although adipodecanic acid prepared by chemical methods has advantages such as simple synthesis process, high product purity, and low price, the chemical method mainly uses phenol as a raw material, resulting in higher raw material costs.

[0005] To address the aforementioned problems, this invention is proposed. Summary of the Invention

[0006] The first aspect of the present invention provides a method for preparing sorbitic acid using alkylbenzene, comprising the following steps: adding a photocatalyst to an aqueous solution containing alkylbenzene, wherein the photocatalyst is a compound containing a transition metal, controlling the pH value of the aqueous solution to be greater than 7, and then carrying out an oxidation reaction under anaerobic conditions under light irradiation to convert alkylbenzene into sorbitic acid, wherein the anaerobic condition refers to the dissolved oxygen content of the aqueous solution containing alkylbenzene being 4-10 mg / L.

[0007] Preferably, the pH value of the aqueous solution is controlled to be 8-10.

[0008] Preferably, air is intermittently introduced into the aqueous solution containing alkylbenzene under sealed conditions so that the dissolved oxygen content of the aqueous solution containing alkylbenzene is 4-10 mg / L.

[0009] Preferably, the lighting conditions are as follows: the light source is natural light or simulated sunlight, and the light intensity is 10–60 mW / cm². 2 The illumination time is controlled until the content of the product edetate no longer increases, at which point the irradiation is stopped.

[0010] Preferably, the alkylbenzene is selected from one or more of toluene, o-xylene, m-xylene, p-xylene, and ethylbenzene.

[0011] Preferably, the transition metal-containing compound is selected from one or more of the following: compounds containing divalent and / or trivalent iron, compounds containing divalent and / or trivalent manganese, compounds containing divalent and / or monovalent copper, and compounds containing divalent and / or trivalent cobalt.

[0012] The compound containing divalent and / or trivalent iron is selected from one or more of ferric chloride, ferrous chloride, ferric sulfate, ferrous sulfate, ferric carbonate, ferric phosphate, ferric hydroxide, ferric hydroxyoxide, ferric oxide, and ferric oxide.

[0013] The compound containing divalent and / or trivalent manganese is selected from one or more of manganese dichloride (II), manganese trichloride (III), manganese sulfate (II), manganese sulfate (III), manganese carbonate (II), manganese carbonate (III), manganese phosphate (II), manganese phosphate (III), manganese tetroxide, manganese trioxide, and manganese hydroxide, or a mixture thereof.

[0014] The divalent and / or monovalent copper compound is selected from one or more of the following: copper chloride, cuprous chloride, copper sulfate, cuprous sulfate, copper acetate, copper oxalate, copper carbonate, cuprous carbonate, copper phosphate, cuprous phosphate, copper hydroxide, copper oxide, and cuprous oxide.

[0015] The divalent and / or trivalent cobalt compound is selected from one or more of cobalt(II) chloride, cobalt(III) chloride, cobalt(II) sulfate, cobalt(III) sulfate, cobalt(II) carbonate, cobalt(III) carbonate, cobalt(II) phosphate, cobalt(III) phosphate, cobalt tetroxide, cobalt(II) oxide, and cobalt hydroxide, or a mixture thereof.

[0016] It should be noted that the method of this invention is a biomimetic method, and the "oxygen deficiency" in this method is relative to the "aerobic" state in biological treatment. "Aerobic" generally refers to the continuous aeration of water, with sufficient oxygen to saturate the water with dissolved oxygen. Because the method of this invention needs to control the oxidation depth, an "aerobic" environment is not suitable. For ordinary thermal (dark) reactions without light, the oxidation depth can be controlled by the reaction time at a constant reaction temperature. However, the method of this invention directly utilizes sunlight for the reaction. Due to the inconsistent intensity of sunlight (even including unpredictable factors such as cloudy skies and alternating sunshine and overcast conditions), and the varying water temperatures throughout the year, it is impossible to control the oxidation depth by accurately controlling the time. Therefore, this invention uses the method of controlling dissolved oxygen content to limit the oxidation depth. Air is intermittently introduced into the aqueous solution containing alkylbenzene under sealed conditions to control the dissolved oxygen content of the aqueous solution at 4-10 mg / L. This results in a low dissolved oxygen concentration in the solution, similar to an "oxygen-deficient" state, because no reaction can occur without oxygen, while the presence of excessive oxygen leads to deep oxidation to carbon dioxide.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The method for preparing edodecanedic acid using alkylbenzene provided by this invention directly uses alkylbenzene as a raw material, rather than phenolic compounds. The raw material is economical and readily available, resulting in low cost. Furthermore, it directly utilizes natural light as an energy source and oxygen from the air as an oxidant. No harmful elements are added to the system during the preparation process, and the photocatalyst can be recycled, making the process green and environmentally friendly.

[0019] 2. This invention involves adding a photocatalyst (a transition metal compound) to an aqueous solution containing alkylbenzene, controlling the pH of the solution to be greater than 7, and then conducting an oxidation reaction under anaerobic conditions under light irradiation to convert alkylbenzene into sorbitic acid. The anaerobic condition refers to a dissolved oxygen content of 4-10 mg / L in the aqueous solution containing alkylbenzene. The inventiveness of this invention lies in conducting the reaction under anaerobic conditions. Furthermore, it was unexpectedly discovered during the process that an alkaline environment with a pH greater than 7, more preferably pH 8-10, is also important for the conversion of alkylbenzene to sorbitic acid. This is because when the water is acidic, sorbitic acid is easily further oxidized to CO2, resulting in a decrease in the yield of sorbitic acid.

[0020] 3. The method for preparing edetate of the present invention is simple and very suitable for industrial production. Attached Figure Description

[0021] Figure 1 This is a liquid chromatography (LC) chromatogram of the product edadienediaic acid prepared from toluene.

[0022] Figure 2 The image shows the mass spectrum (MS) of the product edadienedioic acid prepared from toluene. Figure 1 The mass spectrum of the peak with an elution time of 1.71 minutes.

[0023] Figure 3 This is a liquid chromatography (LC) chromatogram of the product edadienediaic acid prepared from o-xylene.

[0024] Figure 4 This is the mass spectrum (MS) of the product edadienediic acid prepared from o-xylene. Figure 3 The mass spectrum of the peak with an elution time of 1.72 minutes.

[0025] Figure 5 This is a liquid chromatography (LC) chromatogram of the product edadienediaic acid prepared from m-xylene.

[0026] Figure 6 The image shows the mass spectrum (MS) of the product edadienediic acid prepared from m-xylene. Figure 5 The mass spectrum of the peak with an elution time of 1.72 minutes.

[0027] Figure 7 This is a liquid chromatography (LC) chromatogram of the product edadienediaic acid prepared from p-xylene.

[0028] Figure 8 The image shows the mass spectrum (MS) of the product edadienediic acid prepared from p-xylene. Figure 7 The mass spectrum of the peak with an elution time of 1.72 minutes. Detailed Implementation

[0029] The present invention will be specifically described below with reference to embodiments, but the implementation of the present invention is not limited thereto. Experimental methods not specifically described in the embodiments are generally performed under conventional conditions and conditions described in the technical manual, or according to the manufacturer's recommendations. Unless otherwise specified, the general equipment, materials, reagents, etc., used are commercially available. The raw materials required in the following embodiments and comparative examples are all commercially available.

[0030] Example 1:

[0031] In 100 mL of an aqueous solution containing approximately 100 mg / L toluene, with an initial dissolved oxygen content of 9.0 mg / L, 20 mg of ferric chloride was added. The initial pH was adjusted to 8-8.5 using sodium hydroxide (pH measurement may have some error; in actual experiments, pH may change as the photochemical reaction proceeds, so the initial value is used here). The solution was then sealed and placed in a photoreactor under a light intensity of approximately 10-30 mW / cm².2 Under sunlight, air was intermittently introduced into the toluene aqueous solution under sealed conditions to control the dissolved oxygen content of the toluene aqueous solution at 4-10 mg / L. In the actual experiment, the light intensity changed continuously with the reaction. Unlike conventional laboratory experiments using artificial light sources, this invention uses natural light. The intensity of natural light varies from morning to afternoon, and the invention's advantage lies in its closer approximation of natural aquatic environments and lighting conditions. Therefore, this invention can directly utilize sunlight in later applications. High-performance liquid chromatography-mass spectrometry (LC-MS) was used to track the reaction progress. No stirring was performed during the reaction until the content of adipate no longer increased. After the reaction was complete, adipate was concentrated and separated using an anion exchange column. The remaining unreacted toluene was then returned to the photoreactor for further reaction. LC-MS analysis of the solution obtained by anion exchange column elution showed the production of adipate (mass-to-charge ratio m / z = 141.0), as shown in the attached figure. Figure 1 and 2 As shown.

[0032] Example 2:

[0033] In a 100 mL aqueous solution containing approximately 100 mg / L o-xylene, with an initial dissolved oxygen content of 8.0 mg / L, 25 mg of manganese hydroxide and 25 mg of ferric hydroxide were added. The initial pH was adjusted to 8.5-9 using sodium hydroxide (pH measurement may have some error). In actual experiments, this pH value will change as the photochemical reaction proceeds; therefore, the initial value is written here. The solution was then sealed and placed in a photoreactor under a light intensity of approximately 18-35 mW / cm². 2 Under sunlight, air was intermittently introduced into the toluene aqueous solution under sealed conditions to control the dissolved oxygen content of the toluene aqueous solution at 4-10 mg / L. In the actual experiment, the light intensity changed constantly with the reaction. Unlike conventional laboratory experiments using artificial light sources, this invention uses natural light. The intensity of natural light varies from morning to afternoon, and the invention's advantage lies in its closer approximation of natural aquatic environments and lighting conditions. Therefore, this invention can directly utilize sunlight in later applications. High-performance liquid chromatography-mass spectrometry (LC-MS) was used to track the reaction progress. No stirring was performed during the reaction until the content of adipate no longer increased. After the reaction was complete, manganese hydroxide and ferric hydroxide (which could be reused) were filtered out, and adipate was concentrated and separated using an anion exchange column. The remaining unreacted o-xylene was returned to the photoreactor for further reaction. LC-MS analysis of the solution obtained by anion exchange column elution showed the production of adipate (mass-to-charge ratio m / z = 140.9), and the presence of attached... Figure 3 and 4As shown.

[0034] Example 3:

[0035] In 100 mL of an aqueous solution containing approximately 100 mg / L of m-xylene, with an initial dissolved oxygen content of 8.5 mg / L, 50 mg of copper hydroxide was added, and the initial pH was adjusted to 9-9.5 using sodium hydroxide (pH measurement may have some error). In actual experiments, this pH will change as the photochemical reaction proceeds; therefore, the initial pH value is used here. The solution was then sealed and placed in a photoreactor under a light intensity of approximately 20-45 mW / cm². 2 Under sunlight, air was intermittently introduced into the toluene aqueous solution under sealed conditions to control the dissolved oxygen content of the toluene aqueous solution at 4-10 mg / L. In the actual experiment, the light intensity changed constantly with the reaction. Unlike conventional laboratory experiments using artificial light sources, this invention uses natural light. The intensity of natural light itself varies from morning to afternoon, and the invention's advantage lies in its closer approximation of natural aquatic environments and lighting conditions. Therefore, this invention can directly utilize sunlight in later applications. High-performance liquid chromatography-mass spectrometry (LC-MS) was used to track the reaction progress. No stirring was performed during the reaction until the content of adipate no longer increased. After the reaction was complete, copper hydroxide (which could be reused) was filtered out, and adipate was concentrated and separated using an anion exchange column. The remaining unreacted m-xylene was returned to the photoreactor for further reaction. LC-MS analysis of the solution obtained by anion exchange column elution showed the production of adipate (mass-to-charge ratio m / z = 140.9), and the presence of... Figure 5 and 6 As shown.

[0036] Example 4:

[0037] In a 100 mL aqueous solution containing approximately 100 mg / L of p-xylene, with an initial dissolved oxygen content of 6.5 mg / L, 50 mg of cobalt trioxide was added, and the initial pH was adjusted to 8.5-9 with sodium hydroxide (pH measurement may have some error). In actual experiments, this pH value will change as the photochemical reaction proceeds; therefore, the initial value is written here. The solution was then sealed and placed in a photoreactor under a light intensity of approximately 20-60 mW / cm². 2Under sunlight, air was intermittently introduced into the toluene aqueous solution under sealed conditions to control the dissolved oxygen content of the toluene aqueous solution at 4-10 mg / L. In the actual experiment, the light intensity changed constantly with the reaction. Unlike conventional laboratory experiments using artificial light sources, this invention uses natural light. The intensity of natural light varies from morning to afternoon, and the invention's advantage lies in its closer approximation of natural aquatic environments and lighting conditions. Therefore, this invention can directly utilize sunlight in later applications. High-performance liquid chromatography-mass spectrometry (LC-MS) was used to track the reaction progress. No stirring was performed during the reaction until the content of adipate no longer increased. After the reaction was complete, cobalt trioxide (which can be reused) was filtered out, and adipate was concentrated and separated using an anion exchange column. The remaining unreacted p-xylene was returned to the photoreactor for further reaction. LC-MS analysis of the solution obtained by anion exchange column elution showed the production of adipate (mass-to-charge ratio m / z = 140.9), and the presence of... Figure 7 and 8 As shown.

[0038] Example 5:

[0039] In a 100 mL aqueous solution containing approximately 50 mg / L ethylbenzene, with an initial dissolved oxygen content of 8.5 mg / L, 50 mg of manganese phosphate was added, and the initial pH was adjusted to 9.5-10 with sodium hydroxide (pH measurement may have some error). In actual experiments, this pH value will change as the photochemical reaction proceeds; therefore, the initial pH value is written here. The solution was then sealed and placed in a photoreactor under a light intensity of approximately 10-30 mW / cm². 2 The dissolved oxygen content of the toluene aqueous solution was controlled at 4-10 mg / L by intermittently introducing air into the solution under sealed conditions under sunlight. In the actual experiment, the light intensity varied continuously, unlike conventional laboratory experiments using artificial light sources. This invention uses natural light, whose intensity varies from morning to afternoon. Furthermore, the invention closely approximates the natural aquatic environment and lighting conditions, allowing for direct use of sunlight in later applications. The reaction progress was monitored using high-performance liquid chromatography-mass spectrometry (LC-MS). No stirring was performed during the reaction until the content of adipatecic acid ceased to increase. After the reaction was complete, manganese phosphate (which could be reused) was filtered out, and adipatecic acid was concentrated and separated using an anion exchange column. The remaining unreacted ethylbenzene was returned to the photoreactor for further reaction. LC-MS analysis of the solution obtained by anion exchange column elution showed the production of adipatecic acid.

[0040] Example 6:

[0041] A gas containing toluene was bubbled through 100 mL of water until the toluene concentration stopped increasing. The initial dissolved oxygen content in the toluene-containing aqueous solution was 9.0 mg / L. 0.01 g of ferric hydroxide and 0.01 g of manganese tetroxide were added to the resulting toluene-containing aqueous solution, and the pH was adjusted to 8-8.5 (pH measurement may have some error). In actual experiments, this pH value will change as the photochemical reaction proceeds; therefore, the initial pH value is used here. The solution was then sealed and placed in a photoreactor under a light intensity of approximately 25-50 mW / cm². 2 The toluene aqueous solution was exposed to sunlight, and dissolved oxygen was controlled at 4-10 mg / L by intermittently introducing air into the solution under sealed conditions. In the actual experiment, the light intensity varied continuously with the reaction, unlike conventional laboratory experiments using artificial light sources. This invention uses natural light, whose intensity varies from morning to afternoon. Furthermore, the invention's advantage lies in its closer approximation of natural aquatic environments and lighting conditions; therefore, sunlight can be directly utilized in later applications. High-performance liquid chromatography-mass spectrometry (LC-MS) was used to track the reaction progress, and no stirring was performed during the reaction. After the reaction was complete, ferric hydroxide and manganese tetroxide (which can be reused) were filtered out, and adipodecanic acid was concentrated and separated using an anion exchange column. The remaining unreacted toluene was returned to the photoreactor for further reaction. LC-MS analysis of the solution obtained by anion exchange column elution showed the production of adipodecanic acid.

[0042] Example 7:

[0043] This embodiment investigated the effect of pH on the photodegradation of adipate. The initial TOC of the water body was approximately 100 mg / L, and the water was exposed to natural light with an intensity of 15–32 mW / cm². 2 The illumination time was 5 hours. After 5 hours of irradiation, the TOC of water with an initial pH of 4.0-4.5 was 71.1 mg / L, while the TOC of water with an initial pH of 7.5-8.0 was 98.6 mg / L. The TOC did not decrease significantly. As can be seen from the table below, an alkaline environment with a pH greater than 7 is also important for the conversion of alkylbenzenes to adipate, because when the water becomes acidic, adipate is easily further oxidized to CO2 (manifested as a decrease in the TOC of the adipate-containing aqueous solution), resulting in a decrease in the adipate yield.

[0044] Table 1 Effect of pH on photodegradation of adipadienoic acid a

[0045]

[0046] The initial TOC was approximately 100 mg / L, under open natural light with a light intensity of 15–32 mW / cm². 2 The illumination time is 5 hours.

[0047] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing adipadienoic acid using alkylbenzene, characterized in that, Includes the following steps: A photocatalyst, which is a compound containing a transition metal, is added to an aqueous solution containing alkylbenzene. The pH of the aqueous solution is controlled to be greater than 7. Then, an oxidation reaction is carried out under light conditions and under anaerobic conditions to convert alkylbenzene into adipedioic acid. The anaerobic condition refers to the dissolved oxygen content of the aqueous solution containing alkylbenzene being 4-10 mg / L. Control the pH of the aqueous solution to 8-10; Air is intermittently introduced into an aqueous solution containing alkylbenzene under sealed conditions to achieve a dissolved oxygen content of 4-10 mg / L; the alkylbenzene is selected from one or more of toluene, o-xylene, m-xylene, p-xylene, and ethylbenzene. The compound containing a transition metal is one of ferric chloride, manganese hydroxyoxide, ferric hydroxide, copper hydroxide, cobalt trioxide, manganese phosphate, and manganese tetroxide.

2. The method according to claim 1, characterized in that, The specific lighting conditions are as follows: the light source is natural light or simulated sunlight, and the light intensity is 10~60mW / cm². 2 The illumination time is controlled until the content of adipadienoic acid in the product no longer increases, at which point the irradiation is stopped.

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