A kind of preparation method of pseudo methyl ionone
By using a combination method of deep eutectic solvent and a modified layered hydrotalcite catalyst in the synthesis of pseudomethylionone, the problems of difficulty in recovering the catalyst, poor environmental protection of solvents and uneven reaction conditions are solved, and efficient and environmentally friendly pseudomethylionone preparation is achieved.
Patent Information
- Application Number
- CN202411247608.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-06
- Publication Date
- 2025-05-02
- Estimated Expiration
- 2044-09-06
AI Technical Summary
The prior art has problems such as difficulty in the synthesis of pseudomethylionone, poor environmental protection of solvents, and uneven reaction conditions.
A deep eutectic solvent composed of choline chloride and ethylene glycol is used as the solvent, and a layered hydrotalcite modified with calcium stearate is used as the alkaline solid catalyst to react under a nitrogen environment, and the temperature is controlled at 40-50°C to improve the reaction efficiency and product purity.
The preparation of pseudomethylionone with high yield and high purity is achieved, and the catalyst is recoverable, the solvent is environmentally friendly, and the reaction conditions are mild.
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Figure BDA0005031273950000071
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of organic synthesis, and specifically relates to a method for preparing pseudomethyl ionone. Background Art
[0002] Methyl ionone is a homologue of ionone, but its aroma is better than ionone. Its beautiful and soft fragrance and good stability are deeply favored by people. The synthesis of pseudo-methyl ionone is an important step in the synthesis of methyl ionone. For a long time, people have done a lot of research on the synthesis of pseudo-methyl ionone in terms of the type and dosage of condensing agent, reaction temperature and time, material ratio and mechanism. At present, most pseudo-methyl ionone is generated by base catalysis, and the use of base will cause serious pollution to the environment.
[0003] After searching, the patent with application number 2016112293040 discloses a method for preparing methyl ionone and its intermediates. The invention uses citral and butanone as raw materials, PEG as solvent, and metal hydroxide as condensation agent to carry out Aldol condensation reaction to synthesize pseudo-methyl ionone. However, this method has the problems of excessive butanone and solvent and catalyst recovery.
[0004] Patent No. 2023102664862 discloses a method for preparing pseudomethyl ionone, which uses supercritical CO2 and N-methylpyrrolidone as solvents, and uses alkaline mesoporous molecular sieves as heterogeneous catalysts to catalyze citral and butanone to prepare pseudomethyl ionone. This method greatly improves the selectivity of the product pseudoisomethyl ionone, and the product yield is 94-97%, but the supercritical CO2 used in this method requires the use of high-pressure reaction equipment, which greatly increases energy consumption. Summary of the invention
[0005] In view of this, the object of the present invention is to provide a method for preparing pseudomethylionone, which has the advantages of mild reaction conditions, recyclable catalyst and environmentally friendly solvent.
[0006] Based on the above purpose, the present invention provides a preparation method of pseudomethyl ionone, comprising the following steps: under a nitrogen environment, adding a layered alkaline solid catalyst and a deep eutectic solvent into a reactor, stirring for 10-20 minutes, then heating to 40-50°C, dropping citral and butanone into the reactor, stirring and reacting for 4-5 hours after the dropwise addition, filtering, and distilling under reduced pressure to obtain pseudomethyl ionone.
[0007] Furthermore, the preparation method of the layered alkaline solid catalyst is:
[0008] (1) dissolving magnesium nitrate and aluminum nitrate in deionized water to obtain solution A;
[0009] (2) dissolving sodium hydroxide and sodium carbonate in deionized water to obtain solution B;
[0010] (3) Solution A and Solution B are mixed, the pH is controlled between 9 and 10, stirred at room temperature for 10 to 20 minutes, and then calcium stearate is added, stirred at 40° C. for 10 to 20 minutes, and then aged at 140° C. for 8 to 10 hours, filtered, washed with deionized water until neutral, and dried to obtain a layered alkaline solid catalyst;
[0011] Preferably, the molar ratio of magnesium nitrate to aluminum nitrate in step (1) is 3:1.
[0012] Preferably, the amount of deionized water added in step (1) is 200% of the total weight of magnesium nitrate and aluminum nitrate.
[0013] Preferably, the amount of deionized water added in step (2) is 300% of the total weight of sodium hydroxide and sodium carbonate.
[0014] Preferably, the molar ratio of sodium hydroxide to sodium carbonate in step (2) is 16:1.
[0015] Preferably, in step (3), the weight ratio of solution A to solution B is 1:0.756.
[0016] Preferably, the amount of calcium stearate added in step (3) is 5-10% of the total weight of magnesium nitrate and aluminum nitrate.
[0017] Furthermore, the deep eutectic solvent consists of choline chloride and ethylene glycol in a molar ratio of 1:2.
[0018] Preferably, the molar ratio of citral to butanone is 1:1.1-1.5.
[0019] Preferably, the added amount of the layered alkaline solid catalyst is 30-40% of the weight of citral.
[0020] Preferably, the deep eutectic solvent is added in an amount of 200-300% of the weight of citral.
[0021] Preferably, the preparation method of the deep eutectic solvent is as follows: choline chloride and ethylene glycol are mixed, and stirred at 75-80° C. for 1-2 hours to obtain a deep eutectic solvent.
[0022] Compared with the prior art, the present invention has the following beneficial effects:
[0023] The present invention adopts a deep eutectic solvent composed of choline chloride and ethylene glycol as a solvent for aldol condensation reaction of citral and butanone. The deep eutectic solvent composed of choline chloride and ethylene glycol has good polarity, can effectively dissolve citral and butanone, and create a good environment for the reaction; and in the deep eutectic solvent, due to its high solubility and favorable hydrogen bonding effect, the reactant molecules can be better transported to the active sites of the catalyst, thereby improving the reaction rate, purity and yield. Compared with the use of traditional methanol solvent, the yield is increased from 45.6% to 95.5%, and the purity is increased from 95.2% to 99.5%, and the choline chloride and ethylene glycol required to form the deep eutectic solvent are both low-cost, environmentally friendly organic substances.
[0024] The present invention adopts layered hydrotalcite modified by calcium stearate as the alkaline solid catalyst. The introduction of calcium stearate increases the alkaline site and strength on the one hand, and increases the interlayer distance on the other hand, thereby providing a suitable collision space for reactant molecules. Most importantly, the introduction of stearic acid chains allows hydrophobic cavities to be present between the hydrotalcite layers, and reactant molecules are more likely to be enriched between the hydrotalcite layers, thereby increasing the collision probability and further increasing the yield. In addition, the hydrophobic chains near the active sites help to dehydrogenate the 3-C of butanone to form a carbon anion, which then attacks the aldehyde carbon of citral to form pseudoisomethylionone.
[0025] The deep eutectic solvent composed of choline chloride and ethylene glycol in the present invention has a synergistic catalytic effect with the layered hydrotalcite modified by calcium stearate. The deep eutectic solvent composed of choline chloride and ethylene glycol helps to transport the reactant molecules to the hydrophobic inner cavity of the layered hydrotalcite modified by calcium stearate, thereby improving the reaction rate. DETAILED DESCRIPTION
[0026] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.
[0027] Preparation Example 1
[0028] (1) dissolving 44.5 g of magnesium nitrate and 21.3 g of aluminum nitrate in 131.6 g of deionized water to obtain solution A;
[0029] (2) dissolving 32 g of sodium hydroxide and 5.3 g of sodium carbonate in 111.9 g of deionized water to obtain solution B;
[0030] (3) 197.4 g of solution A and 149.2 g of solution B were mixed, the pH was controlled between 9 and 10, and the mixture was stirred at room temperature for 10 min. Then 3.29 g of calcium stearate was added, and the mixture was stirred at 40° C. for 10 min. The mixture was allowed to stand for aging at 140° C. for 8 h, filtered, washed with deionized water until neutral, and dried to obtain a layered alkaline solid catalyst A.
[0031] Preparation Example 2
[0032] (1) dissolving 44.5 g of magnesium nitrate and 21.3 g of aluminum nitrate in 131.6 g of deionized water to obtain solution A;
[0033] (2) dissolving 32 g of sodium hydroxide and 5.3 g of sodium carbonate in 111.9 g of deionized water to obtain solution B;
[0034] (3) 197.4 g of solution A and 149.2 g of solution B were mixed, the pH was controlled between 9 and 10, and the mixture was stirred at room temperature for 10 min. Then 4.34 g of calcium stearate was added, and the mixture was stirred at 40° C. for 10 min. The mixture was allowed to stand for aging at 140° C. for 9 h, filtered, washed with deionized water until neutral, and dried to obtain a layered alkaline solid catalyst B.
[0035] Preparation Example 3
[0036] (1) dissolving 44.5 g of magnesium nitrate and 21.3 g of aluminum nitrate in 131.6 g of deionized water to obtain solution A;
[0037] (2) dissolving 32 g of sodium hydroxide and 5.3 g of sodium carbonate in 111.9 g of deionized water to obtain solution B;
[0038] (3) 197.4 g of solution A and 149.2 g of solution B were mixed, the pH was controlled between 9 and 10, and the mixture was stirred at room temperature for 20 min. Then, 6.58 g of calcium stearate was added, and the mixture was stirred at 40° C. for 20 min. The mixture was allowed to stand for aging at 140° C. for 10 h, filtered, washed with deionized water until neutral, and dried to obtain a layered alkaline solid catalyst C.
[0039] Preparation Example 4
[0040] (1) dissolving 44.5 g of magnesium nitrate and 21.3 g of aluminum nitrate in 131.6 g of deionized water to obtain solution A;
[0041] (2) dissolving 32 g of sodium hydroxide and 5.3 g of sodium carbonate in 111.9 g of deionized water to obtain solution B;
[0042] (3) 197.4 g of solution A and 149.2 g of solution B were mixed, the pH was controlled between 9 and 10, and the mixture was stirred at room temperature for 10 min. Then 1.78 g of calcium nitrate was added, and the mixture was stirred at 40° C. for 10 min. The mixture was aged at 140° C. for 9 h, filtered, washed with deionized water until neutral, and dried to obtain a layered alkaline solid catalyst D.
[0043] Preparation Example 5
[0044] Choline chloride and ethylene glycol were mixed in a molar ratio of 1:2 and stirred at 80° C. for 2 h to obtain a deep eutectic solvent.
[0045] Embodiment 1
[0046] Under nitrogen environment, 4.57g of layered basic solid catalyst A and 38.55g of deep eutectic solvent were added to the reactor, stirred for 10min, and then heated to 40°C, 15.22g of citral and 9.25g of butanone were added dropwise to the reactor, stirred for 4h after the addition, filtered and rinsed with 100g of deep eutectic solvent, the filtrate was combined, and the fraction at 267Pa / 123-125°C was collected to obtain pseudomethyl ionone with a yield of 92.5% and a purity of 99.2%. Among them, the proportion of pseudoisomethyl ionone was 90.5%.
[0047] Embodiment 2
[0048] Under nitrogen environment, 5.36g of layered basic solid catalyst B and 38.55g of deep eutectic solvent were added to the reactor, stirred for 15min, and then heated to 45°C, 15.22g of citral and 9.25g of butanone were added dropwise to the reactor, stirred for 4.5h after the addition, filtered and rinsed with 100g of deep eutectic solvent, the filtrate was combined, and the fraction at 267Pa / 123-125°C was collected to obtain pseudomethyl ionone with a yield of 95.5% and a purity of 99.5%. Among them, the proportion of pseudoisomethyl ionone was 93.4%.
[0049] Embodiment 3
[0050] Under nitrogen environment, 6.09g of layered basic solid catalyst C and 38.55g of deep eutectic solvent were added to the reactor, stirred for 10min, and then heated to 40°C, 15.22g of citral and 9.25g of butanone were added dropwise to the reactor, stirred for 4h after the addition, filtered and rinsed with 100g of deep eutectic solvent, the filtrate was combined, and the fraction at 267Pa / 123-125°C was collected to obtain pseudomethyl ionone with a yield of 95.8% and a purity of 99.1%. Among them, the proportion of pseudoisomethyl ionone was 91.2%.
[0051] Embodiment 4
[0052] Under nitrogen environment, 5.36g of layered basic solid catalyst B and 30.44g of deep eutectic solvent were added to the reactor, stirred for 15min, and then heated to 45°C, 15.22g of citral and 9.25g of butanone were added dropwise to the reactor, stirred for 4.5h after the addition, filtered and rinsed with 100g of deep eutectic solvent, the filtrate was combined, and the fraction at 267Pa / 123-125°C was collected to obtain pseudomethyl ionone with a yield of 93.5% and a purity of 98.9%. Among them, the proportion of pseudoisomethyl ionone was 90.2%.
[0053] Embodiment 5
[0054] Under nitrogen environment, 5.36g of layered basic solid catalyst B and 45.66g of deep eutectic solvent were added to the reactor, stirred for 20min, and then heated to 50°C, 15.22g of citral and 9.25g of butanone were added dropwise to the reactor, stirred for 5h after the addition, filtered and rinsed with 100g of deep eutectic solvent, the filtrate was combined, and the fraction at 267Pa / 123-125°C was collected to obtain pseudomethyl ionone with a yield of 96.3% and a purity of 99.3%. Among them, the proportion of pseudoisomethyl ionone was 93.3%.
[0055] Embodiment 6
[0056] Under nitrogen environment, 5.36g of layered basic solid catalyst B and 38.55g of deep eutectic solvent were added to the reactor, stirred for 15min, and then heated to 45°C, 15.22g of citral and 7.93g of butanone were added dropwise to the reactor, stirred for 4-5h after the addition, filtered and rinsed with 100g of deep eutectic solvent, the filtrate was combined, and the fraction at 267Pa / 123-125°C was collected to obtain pseudomethyl ionone with a yield of 90.1% and a purity of 99.4%. Among them, the proportion of pseudoisomethyl ionone was 93.8%.
[0057] Embodiment 7
[0058] Under nitrogen environment, 5.36g of layered basic solid catalyst B and 38.55g of deep eutectic solvent were added to the reactor, stirred for 15min, and then heated to 45°C, 15.22g of citral and 10.81g of butanone were added dropwise to the reactor, stirred for 5h after the addition, filtered and rinsed with 100g of deep eutectic solvent, the filtrate was combined, and the fraction at 267Pa / 123-125°C was collected to obtain pseudomethyl ionone with a yield of 95.8% and a purity of 99.6%. Among them, the proportion of pseudoisomethyl ionone was 92.5%.
[0059] Comparative Example 1
[0060] Under nitrogen environment, 5.36g of layered basic solid catalyst D and 38.55g of deep eutectic solvent were added to the reactor, stirred for 15min, and then heated to 45°C, 15.22g of citral and 9.25g of butanone were added dropwise to the reactor, stirred for 4.5h after the addition, filtered and rinsed with 100g of deep eutectic solvent, the filtrate was combined, and the fraction at 267Pa / 123-125°C was collected to obtain pseudomethyl ionone with a yield of 79.3% and a purity of 90.2%. Among them, the proportion of pseudoisomethyl ionone was 81.3%.
[0061] Comparative Example 2
[0062] Under nitrogen environment, 5.36g of layered basic solid catalyst D and 38.55g of methanol were added to the reactor, stirred for 15min, and then heated to 45°C, 15.22g of citral and 9.25g of butanone were added dropwise to the reactor, and stirred for 4.5h after the addition was completed, filtered and rinsed with 100g of deep eutectic solvent, the filtrate was combined, and the fraction at 267Pa / 123-125°C was collected to obtain pseudo-methyl ionone with a yield of 45.6% and a purity of 95.2%, of which the proportion of pseudo-isomethyl ionone was 87.6%. Among them, the proportion of pseudo-isomethyl ionone was 87.6%.
[0063] The yield and purity of pseudo-methyl ionone and the proportion of pseudo-isomethyl ionone in the examples and comparative examples are shown in Table 1.
[0064] Table 1 Product analysis results
[0065]
[0066] It can be seen from Examples 1 to 7 that the present invention can be used to prepare pseudo-methyl ionone with high yield and high purity, and the proportion of pseudo-isomethyl ionone is as high as 93.4%. Methyl ionone has six isomers, among which α-isomethyl ionone has the best aroma and the greatest use value. It is mainly synthesized from pseudo-isomethyl ionone, so the content of pseudo-isomethyl ionone is an important indicator for the preparation of pseudo-methyl ionone.
[0067] It can be seen from Example 2 and Comparative Example 1 that the layered hydrotalcite modified with calcium stearate can effectively improve the yield and purity of pseudo-methyl ionone, and most importantly, increase the proportion of pseudo-isomethyl ionone in the product. This is mainly because the 3-C of butanone is more easily activated and dehydrogenated to form a carbon anion in the hydrophobic layered hydrotalcite cavity, and then attacks the aldehyde carbon of citral to form pseudo-isomethyl ionone.
[0068] It can be seen from Example 2 and Comparative Example 2 that, compared with the traditional solvent methanol, the deep eutectic solvent composed of choline chloride and ethylene glycol can greatly improve the yield and purity of pseudomethyl ionone. This is mainly because the deep eutectic solvent composed of choline chloride and ethylene glycol has good polarity, which can effectively dissolve citral and butanone, creating a good environment for the reaction; and in the deep eutectic solvent, due to its high solubility and favorable hydrogen bonding, the reactant molecules can be better transported to the active sites of the catalyst, thereby increasing the reaction rate, purity and yield.
[0069] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.
Claims
1. A method for preparing pseudomethyl ionone, characterized in that: The following steps are involved: Under a nitrogen environment, a layered alkaline solid catalyst and a deep eutectic solvent are added to a reactor, stirred for 10-20 minutes, and then heated to 40-50°C, and citral and butanone are added dropwise to the reactor. After the addition is completed, the reaction is stirred for 4-5 hours, filtered, and distilled under reduced pressure to obtain pseudomethyl ionone; The preparation method of the layered alkaline solid catalyst is: (1) dissolving magnesium nitrate and aluminum nitrate in deionized water to obtain solution A; (2) dissolving sodium hydroxide and sodium carbonate in deionized water to obtain solution B; (3) Solution A and Solution B are mixed, the pH is controlled between 9 and 10, stirred at room temperature for 10 to 20 minutes, and then calcium stearate is added, stirred at 40° C. for 10 to 20 minutes, and then aged at 140° C. for 8 to 10 hours, filtered, washed with deionized water until neutral, and dried to obtain a layered alkaline solid catalyst; The deep eutectic solvent consists of choline chloride and ethylene glycol in a molar ratio of 1:2; The added amount of the layered alkaline solid catalyst is 30-40% of the weight of citral; The added amount of the deep eutectic solvent is 200-300% of the weight of citral.
2. The method for preparing pseudomethylionone according to claim 1, characterized in that: The molar ratio of citral to butanone is 1:1.1-1.
5.
3. The method for preparing pseudomethylionone according to claim 1, characterized in that: The preparation method of the deep eutectic solvent is as follows: choline chloride and ethylene glycol are mixed, and stirred at 75-80° C. for 1-2 hours to obtain a deep eutectic solvent.
4. The method for preparing pseudomethylionone according to claim 1, characterized in that: The molar ratio of magnesium nitrate to aluminum nitrate in step (1) is 3:
1.
5. The method for preparing pseudomethylionone according to claim 1, characterized in that: The amount of deionized water added in step (1) is 200% of the total weight of magnesium nitrate and aluminum nitrate; the amount of deionized water added in step (2) is 300% of the total weight of sodium hydroxide and sodium carbonate.
6. The method for preparing pseudomethylionone according to claim 1, characterized in that: The molar ratio of sodium hydroxide to sodium carbonate in the step (2) is 16:
1.
7. The method for preparing pseudomethylionone according to claim 1, characterized in that: In the step (3), the weight ratio of solution A to solution B is 1:0.
756.
8. The method for preparing pseudomethylionone according to claim 1, characterized in that: In the step (3), the amount of calcium stearate added is 5-10% of the total weight of magnesium nitrate and aluminum nitrate.