Method for deep deacidification of isomethyl ionone cyclization reaction liquid
By combining multi-stage coalescers and alkaline washing, the emulsification problem caused by residual phosphoric acid in the isomethyl ionone cyclization reaction solution was solved, achieving efficient oil-water separation, reducing product loss and wastewater treatment difficulty, and improving safety and environmental protection.
Patent Information
- Application Number
- CN202410631177.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-21
- Publication Date
- 2025-11-21
Smart Images
Figure HDA0004850279640000011
Abstract
Description
Technical Field
[0001] This invention relates to a method for deep deacidification of a reaction solution, specifically a method for deep deacidification of an isomethylionone cyclization reaction solution, belonging to the field of chemical technology. Technical Background
[0002] Isomethylionone is a traditional synthetic fragrance that plays an irreplaceable role in fragrance formulation. Because it blends well with a wide range of floral and woody fragrances, it can be used as a blending agent, modifier, and base fragrance ingredient. Current synthetic methods use citral as a raw material, undergoing condensation and cyclization sequentially to obtain the isomethylionone product.
[0003] The cyclization reaction uses phosphoric acid as a catalyst, added in stoichiometric amounts, and benzene compounds as a solvent. After the reaction, due to the large density difference between the catalyst and the reaction liquid, most of the catalyst can be removed by sedimentation. However, 1000-3000 ppm of phosphoric acid usually remains in the oil phase. Adding water or alkali to neutralize the system can form a stable emulsion system. Even after standing for more than 24 hours, it is difficult to separate the clear oil and water phases. Therefore, the industry often uses alkali neutralization and then washes the phases with saturated brine. The whole process generates a large amount of high-salt, high-COD wastewater, which is not environmentally friendly.
[0004] To address the issue of acid removal from cyclization reaction solutions containing residual phosphoric acid, there is an urgent need to develop a method to overcome the emulsification problem during floor washing. Summary of the Invention
[0005] The purpose of this invention is to provide a method for deep deacidification of isomethylionone cyclization reaction solution. This method can effectively improve oil-water separation efficiency, reduce product loss during separation, and avoid the safety risks posed by residual phosphoric acid to subsequent processes. This method has the advantages of simple operation and is suitable for industrial application.
[0006] During the small-scale study, it was found that phosphoric acid, hydrogen phosphate, dihydrogen phosphate, and phosphate are all good emulsifiers. Oil phases containing residual phosphoric acid can be washed with water or alkali to obtain stable emulsions, resulting in extremely poor phase separation. Among them, the emulsion after water washing can achieve rapid phase separation through a coalescer. However, after multi-stage water washing and phase separation, there is still 30-150 ppm of residual phosphoric acid in the oil phase. This residual phosphoric acid will be concentrated in the bottom of the column during the later product separation process, and there is a risk of corrosion and scaling at high temperatures, posing a safety hazard. After directly using alkali washing, due to the high phosphate content, the emulsifying effect of phosphate stabilizes the emulsion, making it difficult to achieve phase separation through coalescence, and the phase separation effect cannot meet the requirements. The researchers surprisingly found that by first obtaining an oil phase with less than 0.02% residual phosphoric acid through water washing, and then controlling the pH to 6-7 through alkali washing, so that the generated salt exists in the form of a mixture of monohydrogen phosphate and dihydrogen phosphate, the coalescence phase separation effect can be stably reproduced.
[0007] Based on the above research findings, in order to achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:
[0008] A method for deep deacidification of isomethyl ionone cyclization reaction solution includes: mixing the oil phase after sedimentation of the isomethyl ionone cyclization reaction solution with the secondary aqueous phase from the outlet of the second-stage coalescer; separating the primary aqueous phase and primary oil phase in the first-stage coalescer; mixing the primary oil phase with the tertiary aqueous phase separated from the third-stage coalescer and alkaline solution; separating the secondary aqueous phase and secondary oil phase in the second-stage coalescer; mixing the secondary oil phase with water; and separating the tertiary oil phase and tertiary aqueous phase in the third-stage coalescer. The primary aqueous phase has a COD < 2000 ppm, and the acid value in the tertiary oil phase is < 1 mg KOH / kg.
[0009] In this invention, the isomethyl ionone cyclization reaction solution refers to the reaction solution produced by reacting pseudo-isomethyl ionone as a raw material at 60-70°C and atmospheric pressure for 3-6 hours under the catalysis of equimolar phosphoric acid and the solvent of xylene and / or toluene. The solution mainly contains 32-50% xylene / toluene, 38-51% isomethyl ionone and trace amounts of pseudo-isomethyl ionone, and 12-17% aqueous phosphoric acid solution. The settled oil phase mainly contains 39-59% xylene / toluene, 40-60% isomethyl ionone, 0.2-0.4% phosphoric acid, with the remainder being trace amounts of pseudo-isomethyl ionone and water.
[0010] In this invention, the alkali is selected from hydroxides, carbonates or bicarbonates of alkali metals such as potassium hydroxide, sodium hydroxide, sodium bicarbonate, sodium carbonate, potassium bicarbonate, potassium carbonate, and calcium hydroxide, preferably carbonates or bicarbonates.
[0011] In this invention, the concentration of the alkali solution is 5-10%, and the pH is controlled to be 6-7 after the alkali solution is added.
[0012] In this invention, the mass ratio of the secondary oil phase to water is 1:0.3-1.0.
[0013] In this invention, the filter element of the coalescer is selected from the following models: P.1-842, P.3-279, P.3-467, P.3-727, P.3-1039, P.4-362, P.4-559, P.4-842, P.7-965, and P.7-1093.
[0014] In this invention, the operating temperature of the coalescer is 10-70℃, preferably 30-50℃.
[0015] In this invention, the tertiary oil phase is the reaction solution after deep deacidification, in which the acid value is <1mgKOH / kg.
[0016] Compared with the prior art, the beneficial effects of this invention are as follows:
[0017] (1) The method of the present invention has a good coalescence and phase separation effect on oil-water emulsions containing phosphoric acid and phosphates. Compared with the traditional process, there is no high-salt and high-concentration wastewater after washing, product loss is reduced, and the difficulty of wastewater treatment is reduced.
[0018] (2) The study found that the content and type of salt after alkali washing have significant differences in the stability of oil-water emulsion, which in turn affects the oil-water phase separation effect. For oil phase containing more than 1000 ppm of phosphoric acid, if liquid alkali is used to directly neutralize alkali washing, given the high salt concentration in the system, the emulsifying effect of salt will lead to the formation of a stable emulsion, and effective oil-water phase separation cannot be achieved through coalescence. While phosphoric acid has a synergistic emulsifying effect, under water washing conditions, oil-water separation can be achieved through the selection of coalescing filter elements. However, after multiple water washings and coalescing phase separations, the phosphoric acid concentration in the oil phase can only be reduced to 30-150 ppm. This concentration of phosphoric acid will accumulate in the bottom of the tower during subsequent product separation, posing a risk of equipment corrosion and internal surface scaling, thus creating a safety hazard. For the oil phase with phosphoric acid residue <0.02% after water washing, alkaline washing can be used to control the pH to 6-7, so that the generated salt exists in the form of a mixture of monohydrogen phosphate and dihydrogen phosphate. Compared with direct alkaline washing, due to the reduction in salt concentration and the weaker synergistic effect of acidic salts on oil-water emulsification, it is easier to select a suitable filter element to achieve oil-water separation, ensuring the complete removal of phosphoric acid residue in the oil phase. At the same time, due to the coalescence effect, organic matter is prevented from entering the aqueous phase, thus effectively solving the problem of high-salt and high-concentration wastewater in existing processes, significantly improving economic efficiency, and being more environmentally friendly. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of a process flow according to the present invention. Detailed Implementation
[0020] The present invention will be further described in detail below with reference to the embodiments, but the scope of the present invention is not limited to these embodiments.
[0021] Gas chromatographic analysis conditions for the product: Agilent gas chromatograph, RTX-WAX column, 50℃ for 5 min; 10℃ / min to 80℃, hold for 5 min; 10℃ / min to 100℃, hold for 5 min; 10℃ / min to 160℃, hold for 15 min.
[0022] Unless otherwise specified, all other reagents used in the following examples are commercially available.
[0023] Example 1
[0024] 45 kg of xylene and 12 kg of 85% phosphoric acid were added to the reactor. The mixture was purged with nitrogen and pressurized to 0.01 MPa. The mixture was stirred and the temperature was maintained at 65 °C. 45 kg of pseudoisomethyl ionone was added dropwise and stirred for 120 min. The reaction was continued for another 120 min. The conversion rate of pseudoisomethyl ionone in the reactants was 99.7% as monitored by the gas phase. The reaction was then stopped, stirring was stopped, and the mixture was allowed to settle for 30 min. The composition of the oil phase after settling included: 49.83% xylene, 49.68% isomethyl ionone, 0.16% pseudoisomethyl ionone, 0.24% phosphoric acid, and 0.09% water.
[0025] The settled oil phase was mixed with the aqueous phase from the secondary coalescing phase at a flow rate of 1 kg / min to form an emulsion. After the first stage of coalescence, the phases were separated by coalescence at 30 °C. The phosphoric acid content in the primary oil phase was 0.008%, and the COD of the primary aqueous phase was 1420 ppm. The primary oil phase was mixed with the tertiary coalescing aqueous phase, and the pH was adjusted to 6.3 with 5% sodium bicarbonate. After the second stage of coalescence and phase separation, the acid value of the secondary oil phase was 5 mg KOH / kg. The secondary oil phase was mixed with water at a flow rate of 0.4 kg / min to form an emulsion. After the third stage of coalescence, the acid value of the oil phase was 0.52 mg KOH / kg, and the water content of the oil phase was 0.08%.
[0026] The filter elements used in this embodiment are all P.3-279.
[0027] Example 2
[0028] 30 kg of xylene and 14 kg of 75% phosphoric acid were added to the reactor. The mixture was purged with nitrogen and pressurized to 0.01 MPa. The mixture was stirred and the temperature was maintained at 70 °C. 45 kg of pseudoisomethyl ionone was added dropwise and stirred for 150 min. The reaction was continued for 120 min. The conversion rate of pseudoisomethyl ionone in the reactants was 99.6% as monitored by the gas phase. The reaction was then stopped, stirring was stopped, and the mixture was allowed to settle for 10 min. The oil phase composition included: 39.80% xylene, 59.36% isomethyl ionone, 0.24% pseudoisomethyl ionone, 0.36% phosphoric acid, and 0.24% water.
[0029] The settled oil phase was mixed with the aqueous phase from the secondary coalescing phase at a flow rate of 1 kg / min to form an emulsion. After the first stage of coalescence, the phases were separated by coalescence at 25 °C. The phosphoric acid content in the primary oil phase was 0.01%, and the COD of the primary aqueous phase was 1460 ppm. The primary oil phase was mixed with the tertiary coalescing aqueous phase, and the pH was adjusted to 6.5 with 5% sodium carbonate. After the second stage of coalescence and phase separation, the acid value of the secondary oil phase was 3 mg KOH / kg. The emulsion formed by mixing the secondary oil phase with water at a flow rate of 0.4 kg / min was then subjected to tertiary coalescence, resulting in an oil phase with an acid value of 0.43 mg KOH / kg and a water content of 0.11%.
[0030] In this embodiment, the filter element used for primary coalescence is P.3-1039, the filter element used for secondary coalescence is P.4-362, and the filter element used for tertiary coalescence is P.7-965.
[0031] Example 3
[0032] 45 kg of xylene and 10 kg of 85% phosphoric acid were added to the reactor. The mixture was purged with nitrogen and pressurized to 0.01 MPa. The mixture was stirred and the temperature was maintained at 60 °C. 35 kg of pseudoisomethyl ionone was added dropwise and stirred for 100 min. The reaction was continued for 80 min. The conversion rate of pseudoisomethyl ionone in the reactants was 99.7% as monitored by the gas phase. The reaction was then stopped, stirring was stopped, and the mixture was allowed to settle for 34 min. The oil phase composition included: 56.03% xylene, 43.44% isomethyl ionone, 0.13% pseudoisomethyl ionone, 0.26% phosphoric acid, and 0.14% water.
[0033] The settled oil phase was mixed with the aqueous phase from the secondary coalescing phase at a flow rate of 1 kg / min to form an emulsion. After the first stage of coalescence, the phases were separated by coalescence at 40 °C. The phosphoric acid content in the primary oil phase was 0.012%, and the COD of the primary aqueous phase was 1475 ppm. The primary oil phase was mixed with the tertiary coalescing aqueous phase, and the pH was adjusted to 6.8 with 10% sodium hydroxide. After the second stage of coalescence and phase separation, the acid value of the secondary oil phase was 6 mg KOH / kg. The emulsion formed by mixing the secondary oil phase with water at a flow rate of 0.4 kg / min was then subjected to tertiary coalescence, resulting in an oil phase with an acid value of 0.47 mg KOH / kg and a water content of 0.09%.
[0034] In this embodiment, the filter element used for primary coalescence is P.4-559, the filter element used for secondary coalescence is P.3-727, and the filter element used for tertiary coalescence is P.7-965.
[0035] Comparative Example 1
[0036] Take 10 kg of the settled oil phase from Example 1, add sodium bicarbonate to neutralize to pH 7.4, wash and separate the phase with 4 kg of saturated brine. The salt content in the oil phase is 0.34%, the water content is 0.42%, and the organic matter in the aqueous phase is represented by a COD of 87400 ppm.
[0037] Comparative Example 2
[0038] Take 10 kg of the settled oil phase from Example 1, add sodium bicarbonate to neutralize to pH 7.5, let stand for 24 h for phase separation. The oil phase is a yellow emulsion with a salt content of 0.16% and a water content of 2.7%. The organic matter in the aqueous phase is represented by a COD of 76480 ppm.
[0039] Comparative Example 3
[0040] Using the coalescing filter element and settled oil phase from Example 2 as raw materials, the settled oil phase was mixed with the aqueous phase from the secondary coalescing phase at a flow rate of 1 kg / min to form an emulsion. After the first stage of coalescence, the phases were separated at 25°C. The phosphate content in the primary oil phase was 0.012%, and the primary aqueous phase was a milky white liquid with a COD of 32870 ppm. The primary oil phase was mixed with the tertiary coalescing aqueous phase, and the pH was adjusted to 8.3 with 5% sodium hydroxide. After the second stage of coalescence and phase separation, the phosphate content in the secondary oil phase was 0.01%. The emulsion formed by mixing the secondary oil phase with water at a flow rate of 0.4 kg / min was further separated into a yellow milky liquid oil phase after the third stage of coalescence, with a phosphate content of 0.007% and a water content of 0.72%.
Claims
1. A method for deep deacidification of isomethylionone cyclization reaction solution, comprising: The oil phase after sedimentation of the cyclization reaction solution of isomethylionone is mixed with the secondary aqueous phase from the outlet of the second-stage coalescer. After phase separation in the first-stage coalescer, a primary aqueous phase and a primary oil phase are separated. The primary oil phase is mixed with the tertiary aqueous phase separated from the third-stage coalescer and alkaline solution. After phase separation in the second-stage coalescer, a secondary aqueous phase and a secondary oil phase are separated. The secondary oil phase is mixed with water. After phase separation in the third-stage coalescer, a tertiary oil phase and a tertiary aqueous phase are separated. The acid value of the tertiary oil phase is <1 mg KOH / kg.
2. The method according to claim 1, wherein, The settled oil phase contains 39-59% solvent, 40-60% isomethyl ionone, and 0.2-0.4% phosphoric acid.
3. The method according to claim 1, wherein, The alkali is selected from hydroxides, carbonates or bicarbonates of alkali metals, preferably potassium hydroxide, sodium hydroxide, sodium bicarbonate, sodium carbonate, potassium bicarbonate, potassium carbonate, or calcium hydroxide.
4. The method according to claim 1 or 3, wherein, After adding the alkali solution, control the pH to 6-7.
5. The method according to claim 1, wherein, The mass ratio of the secondary oil phase to water is 1:0.3-1.
0.
6. The method according to any one of claims 1-5, wherein, The coalescing filter element is selected from the following models: P.1-842, P.3-279, P.3-467, P.3-727, P.3-1039, P.4-362, P.4-559, P.4-842, P.7-965, and P.7-1093.
7. The method according to any one of claims 1-6, wherein, The operating temperature of the coalescer is 10-70℃, preferably 30-50℃.