A method for catalytic hydrolysis of 3,3'-oxybis(cyclohex-2-en-1-one) using carbon materials

Abstract

This invention discloses a method for the catalytic hydrolysis of 3,3'-oxybis(cyclohexane-2-en-1-one) using carbon materials. Under the action of a bio-carbon-supported potassium-magnesium oxide catalyst rich in strongly basic sites, 3,3'-oxybis(cyclohexane-2-en-1-one) undergoes a hydrolysis reaction to produce 1,3-cyclohexanedione. The raw material 3,3'-oxybis(cyclohexane-2-en-1-one) is a byproduct of the resorcinol process for preparing 1,3-cyclohexanedione, and is inexpensive and readily available. The catalytic hydrolysis of 3,3'-oxybis(cyclohexane-2-en-1-one) to produce 1,3-cyclohexanedione achieves value-added processing of byproducts from the CHD industry, reduces solid waste generation, lowers the production cost of 1,3-cyclohexanedione, and has significant socio-economic benefits.

Description

Technical Field

[0001] This invention belongs to the field of herbicides, specifically relating to a method for the catalytic hydrolysis of 3,3'-oxybis(cyclohex-2-en-1-one) using carbon materials. Background Technology

[0002] 1,3-Cyclohexanedione is a key chemical intermediate, mainly used in the synthesis of pesticides, pharmaceuticals, and new materials. Currently, the annual demand exceeds 10,000 tons, with pesticides accounting for approximately 75% of the usage. It is primarily used in the production of triketone herbicides such as sulfadiazine, mesotrione, quinclorac, dichloroquinoline, dioxopyritrione, fenquiline, cyclosulfonyl, and furazolidone (Formula 1).

[0003]

[0004] Formula 1: Structural formula of some triketone herbicides

[0005] There are two main industrial production processes for 1,3-cyclohexanedione both domestically and internationally (Formula 2): (1) Condensation method, using sodium alkoxide as the condensing agent and amides as the reaction medium. γ methyl acetobutyrate is cyclized and rearranged via acid precipitation to synthesize 1,3-cyclohexanedione, or α,β - Unsaturated carboxylic acid esters and ketones are synthesized into 1,3-cyclohexanedione through condensation, cyclization and acid rearrangement; (2) Resorcinol catalytic hydrogenation method, resorcinol is used as the starting material, and 1,3-cyclohexanedione is synthesized through alkalization, catalytic hydrogenation and acid rearrangement.

[0006]

[0007] Equation 2: Reaction routes for condensation and hydrogenation

[0008] As shown in Equation 2, both the condensation method and the resorcinol catalytic hydrogenation method involve the acidification and rearrangement of the enol salt intermediate. This process generates 3,3'-oxybis(cyclohexyl-2-en-1-one) impurities, affecting the crystallization quality of the product. The cumbersome purification process significantly increases the product refining cost, and solid waste and wastewater treatment further increase production costs. Controlling the content of 3,3'-oxybis(cyclohexyl-2-en-1-one) impurities in the wastewater and achieving in-situ decomposition of these impurities into 1,3-cyclohexanedione during production will greatly reduce product production costs and waste treatment costs. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides a method for the catalytic hydrolysis of 3,3'-oxybis(cyclohex-2-en-1-one) using carbon materials. This method is simple, achieves the hydrolysis of 3,3'-oxybis(cyclohex-2-en-1-one) impurities with extremely high conversion rates, yields a high amount of the target product 1,3-cyclohexanedione, and allows for easy separation and reuse of the catalyst, with no waste generated during the process.

[0010] The objective of this invention is achieved through the following technical solutions: Phenolic salts are constructed in lignin molecules by reacting the abundant phenolic hydroxyl groups in natural lignin with alkali metal hydroxides and alkaline earth metal salts, followed by high-temperature pyrolysis to prepare carbon materials. Alkali metal and alkaline earth metal sites anchored to carbon are constructed on the surface of the carbon material by utilizing the redox reaction of carbon with alkali metal oxides and alkaline earth metal oxides at high temperatures. Graphitized carbon is constructed in the carbon material by utilizing the abundant aromatic structures in natural lignin. The π-π interaction between the graphitized carbon and 3,3'-oxybis(cyclohexane-2-en-1-one) promotes adsorption activation, thereby promoting the hydrolysis reaction of 3,3'-oxybis(cyclohexane-2-en-1-one). A suitable ratio of alkali metals to alkaline earth metals in the catalyst promotes the hydrolysis reaction of 3,3'-oxybis(cyclohexane-2-en-1-one).

[0011] The chemical formula for the reaction in this invention is:

[0012]

[0013] In the above technical solution, the method of catalyzing the hydrolysis of 3,3'-oxybis(cyclohex-2-en-1-one) with carbon materials, under the action of a bio-carbon supported potassium magnesium oxide catalyst rich in strong basic sites, 3,3'-oxybis(cyclohex-2-en-1-one) undergoes a hydrolysis reaction to generate 1,3-cyclohexanedione.

[0014] In the above technical solution, the method for catalyzing the hydrolysis of 3,3'-oxybis(cyclohexyl-2-en-1-one) using carbon materials involves catalyst preparation. The catalyst preparation method utilizes the reaction of phenolic hydroxyl groups abundant in natural lignin with alkali metal hydroxides and alkaline earth metal salts to construct phenolic salts within the lignin molecules, followed by high-temperature pyrolysis to prepare the carbon material. The redox reaction between carbon and alkali metal oxides and alkaline earth metal oxides at high temperatures constructs carbon-anchored alkali metal and alkaline earth metal sites on the surface of the carbon material. Utilizing the abundant aromatic structures in natural lignin, graphitized carbon is constructed within the carbon material. The π-π interaction between the graphitized carbon and 3,3'-oxybis(cyclohexyl-2-en-1-one) promotes adsorption activation, thereby accelerating the hydrolysis reaction of 3,3'-oxybis(cyclohexyl-2-en-1-one). A suitable ratio of alkali metals to alkaline earth metals in the catalyst promotes the hydrolysis reaction of 3,3'-oxybis(cyclohexyl-2-en-1-one).

[0015] In the above technical solution, the bio-carbon supported potassium magnesium oxide catalyst rich in strong alkaline sites comprises an alkali metal hydroxide, which is either sodium hydroxide or potassium hydroxide, with the alkali metal having a mass percentage content of 1-6%, preferably 2-5%; an alkaline earth metal salt, which is either magnesium nitrate or magnesium chloride, with the magnesium metal having a mass percentage content of 2-12%, preferably 4-10%; and a ratio of alkali metal to alkaline earth metal in the catalyst of 1:12-3:1, preferably 1:2-2:1.

[0016] In the above technical solution, the method for catalyzing the hydrolysis of 3,3'-oxybis(cyclohexyl-2-en-1-one) with carbon materials has a mass ratio of catalyst to 3,3'-oxybis(cyclohexyl-2-en-1-one) of 0.01:1-0.1:1, preferably 0.03:1-0.06:1;

[0017] In the above technical solution, the method for catalyzing the hydrolysis of 3,3'-oxybis(cyclohex-2-en-1-one) with carbon materials has a mass ratio of 3,3'-oxybis(cyclohex-2-en-1-one) to water of 1:5-1:20, preferably 1:10-1:15.

[0018] In the above technical solution, the method for catalyzing the hydrolysis of 3,3'-oxybis(cyclohexyl-2-en-1-one) using carbon materials, the reaction temperature is 50-100 °C. o C, preferably 60-80 o C; The reaction time is 2-24 h, preferably 6-18 h.

[0019] The preparation process of the catalyst is as follows:

[0020] Take 10-15 g of lignin, 0.100-0.280 g of sodium hydroxide and / or potassium hydroxide, 0.366-0.838 g of magnesium salt, and 100-150 mL of water, mix, heat to 70-95 ℃ and stir for 10-24 h, filter to obtain a solid, and dry to obtain a catalyst precursor; place the catalyst precursor under nitrogen protection at 800-900 °C o The catalyst was obtained after pyrolysis of C for 1-3 h.

[0021] Compared with existing technologies, this invention has the following advantages: Existing technologies employ source control of impurity generation, requiring strict control of acidification conditions, placing high demands on worker operation, equipment control, and investment, thus affecting production efficiency, and cannot completely avoid impurity generation. This invention adopts a previously unreported "generation followed by decomposition" strategy. Based on the generation mechanism of 3,3'-oxybis(cyclohexyl-2-en-1-one), a highly efficient bio-carbon-supported alkali metal and alkaline earth metal oxide catalyst rich in strongly basic sites is developed to achieve the hydrolysis and decomposition of 3,3'-oxybis(cyclohexyl-2-en-1-one) impurities into 1,3-cyclohexanedione. Attached Figure Description

[0022] Figure 1 Scanning electron microscope image of catalyst 1;

[0023] Figure 2 Raman spectrum of catalyst 1;

[0024] Figure 3 The CO2-TPD spectrum of catalyst 1 shows that the stronger and more numerous the basic sites, the stronger the adsorption of carbon dioxide and the higher the desorption temperature. The horizontal axis represents the desorption temperature.

[0025] Figure 4 Scanning electron microscope image of catalyst 2;

[0026] Figure 5 Raman spectrum of catalyst 2;

[0027] Figure 6 The CO2-TPD spectrum of catalyst 2 shows that the stronger and more numerous the basic sites, the stronger the adsorption of carbon dioxide and the higher the desorption temperature. The horizontal axis represents the desorption temperature.

[0028] Figure 7 Scanning electron microscope image of catalyst 3;

[0029] Figure 8 Raman spectrum of catalyst 3;

[0030] Figure 9 The CO2-TPD spectrum of catalyst 3 shows that the stronger and more numerous the basic sites, the stronger the adsorption of carbon dioxide and the higher the desorption temperature. The horizontal axis represents the desorption temperature. Detailed Implementation

[0031] The technical solution of the present invention is described in detail below with reference to the embodiments, but the scope of the present invention is not limited to the following embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The 3,3'-oxybis(cyclohexyl-2-en-1-one) used in the present invention is a by-product separated during factory production and is not a commercially available product. The specific method of obtaining it is as follows: A mixture of 55 g (0.5 mol) of resorcinol, 49 g (0.49 mol) of 40% NaOH aqueous solution, 1 g of Pd / C with a mass content of 5% and 70.6 g of water is reacted in a high-pressure reactor (the gas inside the reactor is hydrogen) at 70 °C for 4 h, while maintaining the hydrogen pressure inside the reactor at 0.5 MPa. After the reaction is completed, the product is subjected to acid precipitation crystallization using 15% dilute sulfuric acid to obtain a solid. The components are analyzed by liquid chromatography and liquid chromatography-mass spectrometry and are found to be a mixture of 3,3'-oxybis(cyclohexyl-2-en-1-one) and 1,3-cyclohexanedione. 20 g of a mixture (a mixture of 3,3'-oxybis(cyclohexane-2-en-1-one) and 1,3-cyclohexanedione) was dissolved in 10 mL of dichloromethane and separated by column chromatography to obtain 3,3'-oxybis(cyclohexane-2-en-1-one). The developing solvent was petroleum ether:ethyl acetate = 20:1 (v / v). The mass of 3,3'-oxybis(cyclohexane-2-en-1-one) was 5.3 g. The product was confirmed to be 3,3'-oxybis(cyclohexane-2-en-1-one) by NMR and LC-MS analysis. After 20 batches of preparation and chromatography, a total mass of 100 g of 3,3'-oxybis(cyclohexane-2-en-1-one) was collected.

[0032] Example 1

[0033] 10.2 g of lignin, 0.118 g of sodium hydroxide, 0.838 g of magnesium nitrate, and 100 mL of deionized water were placed in a 250 mL flask, heated to 80 °C, and stirred for 12 h. The mixture was filtered to obtain a solid, which was then freeze-dried to obtain a catalyst precursor. The catalyst precursor was placed in a quartz boat, which was then placed in a tube furnace. Nitrogen gas was passed through the furnace at room temperature for 30 min (at a flow rate of 10 mL / min). Then, while maintaining a constant nitrogen flow rate, the temperature was increased to 800 °C. o C (heating rate is 5) o (C / min). The nitrogen gas flow rate remains constant at 800. o After pyrolysis at C for 1 hour, the temperature was slowly lowered to 30°C. o C (cooling rate is 5) o C / min). The black solid inside the quartz boat was ground into powder in an agate mortar to obtain catalyst 1, weighing 3.4 g. Scanning electron microscopy revealed that the catalyst surface was relatively smooth. Figure 1ICP analysis revealed that the sodium and magnesium content in catalyst 1 was 2% and 4% by mass, respectively. Raman spectroscopy confirmed the presence of graphitic carbon in catalyst 1. Figure 2 Clearly distinct strongly basic sites can be observed in the CO2-TPD spectrum, see [link / reference]. Figure 3 .

[0034] 13.1 g of lignin, 0.266 g of potassium hydroxide, 0.366 g of magnesium chloride, and 150 mL of deionized water were placed in a 250 mL flask and heated to 80 °C with stirring for 12 h. The mixture was filtered to obtain a solid, which was then freeze-dried to obtain a catalyst precursor. The catalyst precursor was placed in a quartz boat, which was then placed in a tube furnace. Nitrogen gas was passed through the furnace at room temperature for 30 min (at a flow rate of 10 mL / min). Then, while maintaining a constant nitrogen flow rate, the temperature was increased to 800 °C. o C (heating rate is 5) o (C / min). The nitrogen gas flow rate remains constant at 800. o After pyrolysis at C for 1 hour, the temperature was slowly lowered to 30°C. o C (cooling rate is 5) o C / min). The black solid inside the quartz boat was ground into powder in an agate mortar to obtain catalyst 2, weighing 3.7 g. Scanning electron microscopy revealed that the catalyst surface was relatively smooth. Figure 4 ICP analysis revealed that catalyst 1 contained 5% potassium and 2.5% magnesium by mass. Raman spectroscopy showed that catalyst 2 contained graphitic carbon. Figure 5 Clearly distinct strongly basic sites can be observed in the CO2-TPD spectrum, see [link / reference]. Figure 6 .

[0035] 10.1 g of lignin, 0.177 g of sodium hydroxide, 0.404 g of magnesium chloride, and 130 mL of deionized water were placed in a 250 mL flask and heated to 80 °C with stirring for 12 h. The mixture was filtered to obtain a solid, which was then freeze-dried to obtain a catalyst precursor. The catalyst precursor was placed in a quartz boat, which was then placed in a tube furnace. Nitrogen gas was passed through the furnace at room temperature for 30 min (at a flow rate of 10 mL / min). Then, while maintaining a constant nitrogen flow rate, the temperature was increased to 800 °C. o C (heating rate is 5) o (C / min). The nitrogen gas flow rate remains constant at 800. o After pyrolysis at C for 1 hour, the temperature was slowly lowered to 30°C. o C (cooling rate is 5) o C / min). The black solid inside the quartz boat was ground into powder in an agate mortar to obtain catalyst 3, weighing 3.4 g. Scanning electron microscopy revealed that the catalyst surface was relatively smooth. Figure 7 ICP analysis revealed that catalyst 1 contained 3% sodium and 3% magnesium by mass. Raman spectroscopy showed that catalyst 3 contained graphitic carbon. Figure 8 Clearly distinct strongly basic sites can be observed in the CO2-TPD spectrum, see [link / reference]. Figure 9 .

[0036] Example 2

[0037] Take 100 g of an aqueous solution containing 3,3'-oxybis(cyclohexyl-2-en-1-one) (mass concentration 10%), add 0.3 g of catalyst 1, and heat to 80°C. o C, the reaction was stirred for 6 h. After the reaction, the solid catalyst was recovered by filtration, and the filtrate was sampled and analyzed by liquid chromatography. The content of 3,3'-oxybis(cyclohexane-2-en-1-one) in the aqueous solution decreased to 0.08% by mass. The filtrate was then sent to the subsequent process, where 1,3-cyclohexanedione was adsorbed using macroporous adsorption resin. The resin was then regenerated using a 45% sodium hydroxide aqueous solution. The eluent was crystallized by acid precipitation with 15% dilute sulfuric acid (pH=3) to obtain 1,3-cyclohexanedione with a yield of 96%. Liquid chromatography analysis and comparison with standards confirmed that the product was 1,3-cyclohexanedione.

[0038] Example 3

[0039] Take 100 g of an aqueous solution containing 3,3'-oxybis(cyclohexyl-2-en-1-one) (15% by mass), add 0.6 g of catalyst 2, and heat to 60°C. o C. The reaction was stirred for 18 h. After the reaction, the catalyst was recovered by filtration, and the filtrate was sampled and analyzed by liquid chromatography. The content of 3,3'-oxybis(cyclohexane-2-en-1-one) in the aqueous solution decreased to 0.09%. The filtrate was then sent to the subsequent process, where 1,3-cyclohexanedione was adsorbed using macroporous adsorption resin. The resin was then regenerated using a 45% sodium hydroxide aqueous solution. The eluent was crystallized by acid precipitation with 15% dilute sulfuric acid (pH=3) to obtain 1,3-cyclohexanedione with a yield of 98%. Liquid chromatography analysis and comparison with standards confirmed that the product was 1,3-cyclohexanedione.

[0040] Example 4

[0041] Take 100 g of an aqueous solution containing 3,3'-oxybis(cyclohexyl-2-en-1-one) (mass concentration 12%), add 0.4 g of catalyst 3, and heat to 70°C. oC. The reaction was stirred for 14 h. After the reaction, the catalyst was recovered by filtration, and the filtrate was sampled and analyzed by liquid chromatography. The content of 3,3'-oxybis(cyclohexane-2-en-1-one) in the aqueous solution decreased to 0.08%. The filtrate was then sent to the subsequent process, where 1,3-cyclohexanedione was adsorbed using macroporous adsorption resin. The resin was then regenerated using a 45% sodium hydroxide aqueous solution. The eluent was crystallized by acid precipitation with 15% dilute sulfuric acid (pH=3) to obtain 1,3-cyclohexanedione with a yield of 97%. Liquid chromatography analysis and comparison with standards confirmed that the product was 1,3-cyclohexanedione.

[0042] Comparative Example

[0043] The preparation processes for catalysts such as NaMg / Al2O3 (active metal Na is sodium hydroxide, Mg salt is magnesium chloride), KMg / ZrO2 (active metal K is potassium hydroxide, Mg salt is magnesium chloride), NaMg / CeO2 (active metal Na is sodium hydroxide, Mg salt is magnesium chloride), CuMg / activated carbon (active metal Cu salt is copper chloride, Mg salt is magnesium chloride), FeMg / activated carbon (active metal Fe salt is ferric chloride, Mg salt is magnesium chloride), and CuFe / activated carbon (active metal Cu salt is copper chloride, Fe salt is ferric chloride) are as follows:

[0044] 1) Active metal salts, or active metal salts and active metal hydroxides, are loaded onto a support using an equal-volume impregnation method to obtain catalyst precursors;

[0045] 2) Place the catalyst precursor in a quartz boat, then place the quartz boat in a tube furnace and purge with nitrogen at room temperature for 30 min (at a flow rate of 10 mL / min). Then, maintaining a constant nitrogen flow rate, raise the temperature to 800 °C. o C (heating rate is 5) o (C / min). The nitrogen gas flow rate remains constant at 800. o After pyrolysis at C for 1 hour, the temperature was slowly lowered to 30°C. o C (cooling rate is 5) o The solid inside the quartz boat was ground into powder in an agate mortar to obtain the catalyst. ICP analysis showed that the mass percentages of active metal elements in the catalyst were 2% and 4%, respectively.

[0046] Catalysts NaMg / Al2O3 (2% Na, 4% Mg by mass of active metal elements), KMg / ZrO2 (2% K, 4% Mg by mass of active metal elements), NaMg / CeO2 (2% Na, 4% Mg by mass of active metal elements), CuMg / activated carbon (2% Cu, 4% Mg by mass of active metal elements), FeMg / activated carbon (2% Fe, 4% Mg by mass of active metal elements), and CuFe / activated carbon (2% Cu, 4% Fe by mass of active metal elements) were prepared by equal-volume impregnation method. Compared with catalyst 3, the catalytic reaction process and conditions were the same as in Example 4, except that different catalysts were used.

[0047] Table 1 Catalytic effect of catalysts

[0048] Serial Number catalyst yield 1 Catalyst 3 of the present invention 97% 2 <![CDATA[NaMg / Al2O3]]> No response 3 <![CDATA[KMg / ZrO2]]> No response 4 <![CDATA[NaMg / CeO2]]> 1% 5 CuMg / Activated Carbon No response 6 FeMg / activated carbon No response 7 CuFe / activated carbon No response 8 No catalyst added No response

Claims

1. A method for the catalytic hydrolysis of 3,3'-oxybis(cyclohexyl-2-en-1-one) using carbon materials, characterized in that: Under the catalysis of bio-carbon supported potassium oxide and / or sodium oxide rich in strong basic sites and magnesium oxide catalyst, 3,3'-oxybis(cyclohexyl-2-en-1-one) undergoes a hydrolysis reaction to generate 1,3-cyclohexanedione. The catalyst is prepared as follows: 10-15 g of lignin, 0.100-0.280 g of sodium hydroxide and / or potassium hydroxide, 0.366-0.838 g of magnesium salt, and 100-150 mL of water are mixed, heated to 70-95 °C, stirred for 10-24 h, filtered to obtain a solid, and dried to obtain a catalyst precursor; the catalyst precursor is then heated under nitrogen protection at 800-900 °C. o The catalyst was obtained after pyrolysis of C for 1-3 h.

2. The method for catalytic hydrolysis of 3,3'-oxybis(cyclohexyl-2-en-1-one) using carbon materials according to claim 1, characterized in that: The alkali metal potassium and / or sodium have a mass percentage content of 1-6% in the catalyst; the magnesium salt is one or two of magnesium nitrate and magnesium chloride, and the magnesium metal has a mass percentage content of 2-12% in the catalyst.

3. The method for catalytic hydrolysis of 3,3'-oxybis(cyclohexyl-2-en-1-one) using carbon materials according to claim 2, characterized in that: The mass ratio of alkali metal to magnesium metal in the catalyst is 1:12-3:

1.

4. The method for catalytic hydrolysis of 3,3'-oxybis(cyclohexyl-2-en-1-one) using carbon materials according to claim 1, characterized in that: The mass ratio of the catalyst to 3,3'-oxybis(cyclohex-2-en-1-one) is 0.01:1 to 0.1:

1.

5. The method for catalytic hydrolysis of 3,3'-oxybis(cyclohexyl-2-en-1-one) using carbon materials according to claim 1, characterized in that: The mass ratio of 3,3'-oxybis(cyclohex-2-en-1-one) to water is 1:5 to 1:

20.

6. The method for catalytic hydrolysis of 3,3'-oxybis(cyclohexyl-2-en-1-one) using carbon materials according to claim 1, 4, or 5, characterized in that: The reaction temperature is 50-100°C. o C; The reaction time is 2-24 h.

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