Recovery method and application of thymol
By extracting and distilling the cyclohexane crystallization mother liquor with aqueous solutions such as methanol and ethanol, the problems of waste and environmental hazards in thymeol production are solved, and efficient recycling and low-cost thymeol production are achieved.
Patent Information
- Application Number
- CN202411440277.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-15
- Publication Date
- 2025-01-17
AI Technical Summary
It is difficult to recover the thymeol in the cyclohexane crystallization mother liquor during the production process of existing thymeol, resulting in waste of raw materials and products, increasing investment costs, and causing harm to the environment, which is not in line with the concept of green chemistry development.
Use aqueous solutions such as methanol, ethanol, propanol, butanol, pentanol, acetone or butanone as extraction agent to extract the cyclohexane crystallization mother liquor multiple times, and then distillate, separate and recover thymethol to reduce hazardous waste. produce.
It improves the recycling rate of thymeol, reduces the cost of hazardous waste treatment, reduces the harm to the environment, and is in line with the concept of green chemistry development.
Smart Images
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Figure BDA0005086160640000091
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of waste treatment in the production of flavors and fragrances, and in particular to a method for recovering thymol and an application thereof. Background Art
[0002] Thymol is also known as thymol. As one of the most produced and widely used spices in the world, the production method of thymol has always attracted people's attention. Thymol is widely used in all flavors for its elegant and lasting aroma, and is used in food, medicine, daily chemical industry and other fields.
[0003] In traditional thymol production, crude thymol is obtained through a single crystallization process. The specific process is generally to dissolve thymol in a crystallization solvent and obtain thymol through crystallization. The mother liquor is distilled to recover the solvent. The remaining hazardous waste treated as distillation waste contains uncrystallized thymol and high-boiling byproduct diisopropyl-meta-cresol. In the past, high-boiling byproducts were generally treated as hazardous waste and entrusted to qualified units for treatment. However, this not only caused a waste of raw materials and products and increased investment costs, but also this high-boiling byproduct is harmful and will cause certain harm to the environment during the treatment process, which is not in line with the concept of green chemistry development. Summary of the invention
[0004] The main purpose of the present invention is to provide a method for recovering thymol and application thereof, so as to solve the problem that it is difficult to recover thymol in cyclohexane crystallization mother liquor in the prior art.
[0005] In order to achieve the above-mentioned purpose, according to the first aspect of the present invention, a method for recovering thymol is provided, which comprises: S1) mixing cyclohexane crystallization mother liquor with an extraction solution, performing extraction, and obtaining an extraction phase and an oil phase; the extraction solution comprises an aqueous solution of one or more of the following compounds: methanol, ethanol, propanol, butanol, pentanol, acetone or butanone; S2) repeatedly performing extraction, and performing a first recovery of all extraction phases to obtain a total extraction phase; performing a second recovery of all oil phases to obtain a total oil phase; S3) mixing the total extraction phase and the total oil phase, performing a first distillation treatment, and obtaining a first distillation product; S4) performing a second distillation treatment on the first distillation product to obtain thymol.
[0006] Further, in S1), the extraction comprises: heating and stirring the liquid obtained by mixing the cyclohexane crystallization mother liquor with the extraction solution; preferably, the number of extractions is 1-3 times.
[0007] Furthermore, the mass ratio of cyclohexane crystallization mother liquor to extraction solution is 1:1.5-2.0.
[0008] Furthermore, the heating temperature is 45-65° C.; preferably, the stirring time is 1-2 hours.
[0009] Furthermore, the mass proportion of the compound in the extraction solution is 15-25%.
[0010] Furthermore, in S2), the second recovery includes: mixing all the oil phases, and then performing distillation and concentration treatment to obtain a total oil phase; preferably, the first recovery includes: mixing all the extraction phases to obtain a total extraction phase.
[0011] Further, S3) includes: mixing the total extract phase and the total oil phase for a first distillation treatment, and sequentially separating the extract solution and the cyclohexane aqueous solution to obtain a first distillation product; preferably, the mixing mass ratio of the total extract phase to the total oil phase is 1:3.4-4.25.
[0012] Furthermore, the temperature of the first distillation treatment is 65-80°C.
[0013] Furthermore, in S4), the temperature of the second distillation treatment is 100°C, and the pressure of the second distillation treatment is 200Pa.
[0014] According to a second aspect of the present invention, there is provided an application of any one of the above-mentioned methods for recovering thymol in cyclohexane crystallization mother liquor.
[0015] By applying the technical scheme of the present invention, the aqueous solution of one or more of the following compounds: methanol, ethanol, propanol, butanol, pentanol, acetone or butanone is used as an extractant to repeatedly extract the cyclohexane crystallization mother liquor, so that most of the thymol in the cyclohexane crystallization mother liquor can be separated; after the extraction is completed, all the extraction phases and the oil phase are recovered and mixed, and the first distillation treatment and the second distillation treatment are sequentially performed, so that thymol with improved recovery rate can be obtained. DETAILED DESCRIPTION
[0016] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.
[0017] As mentioned in the background technology, in the process of producing thymol in the prior art, it is difficult to recycle all thymol, and the distillation residue still contains thymol and harmful by-products. This kind of distillation rubber is a hazardous waste and needs to be entrusted to a qualified unit for treatment. This not only causes waste of raw materials and products, increases investment costs, but also causes certain harm to the environment during the by-product treatment process, which does not conform to the concept of green chemical development. Therefore, in this application, the inventor attempts to provide a new method for recovering thymol, which can improve the recovery rate of thymol while reducing the generation of harmful by-products, reducing the cost of hazardous waste treatment, and more in line with the concept of green development, thus proposing a series of protection schemes for this application.
[0018] In a first typical embodiment of the present application, a method for recovering thymol is provided, and the method comprises: S1) mixing cyclohexane crystallization mother liquor with an extraction solution, performing extraction, and obtaining an extraction phase and an oil phase; the extraction solution comprises an aqueous solution of one or more of the following compounds: methanol, ethanol, propanol, butanol, pentanol, acetone or butanone; S2) after repeated extraction, all extraction phases are first recovered to obtain a total extraction phase; all oil phases are second recovered to obtain a total oil phase; S3) the total extraction phase and the total oil phase are mixed, and a first distillation treatment is performed to obtain a first distillation product; S4) the first distillation product is subjected to a second distillation treatment to obtain thymol.
[0019] In the prior art, in the process of producing thymol, crude thymol is dissolved in a crystallization solvent and crystallized to obtain thymol, the mother liquor is distilled to recover the solvent, and the remainder is treated as distillation residue. The distillation residue contains high-boiling byproduct diisopropyl metacresol, which is a hazardous waste and needs to be entrusted to a qualified unit for treatment. However, the distillation residue also contains some uncrystallized thymol, and direct treatment causes waste of raw materials and products. Moreover, this byproduct is harmful and will cause harm to the environment during the treatment process, which is not in line with the concept of green development.
[0020] The inventor of the present application has found through a large number of experiments that when the above-mentioned extraction solution in the present application is used to extract the cyclohexane crystallization mother liquor, it has a good separation effect, and most of the thymol in the cyclohexane crystallization mother liquor can be extracted and separated. The present application uses the above-mentioned extraction solution to extract the cyclohexane crystallization mother liquor multiple times, and all the extraction phases and all the oil phases are mixed and then subjected to subsequent rectification treatment, and finally most of the thymol in the cyclohexane crystallization mother liquor can be recovered, and the rectification tailings produced are small, and only incineration treatment is required; and the present application is mixed with the total extraction phase and the total oil phase for the first rectification treatment, and the solvent is recovered, which can reduce the energy consumption of solvent recovery, further reduce the cost of production, and is conducive to improving the effect of the second rectification treatment, so that most of the thymol in the cyclohexane mother liquor can be fully recovered, and the content of phenolic substances in the wastewater is reduced, so that it meets environmental protection requirements and reduces environmental protection pressure. The thymol recovery method of the present application not only improves the yield of thymol, but also reduces the generation of hazardous waste, reduces production costs and hazardous waste treatment costs, reduces environmental damage compared to the prior art, and is more in line with the concept of green development. Preferably, the above-mentioned extraction solution includes an aqueous solution of one or more of the following compounds: acetone, methanol or propanol.
[0021] In a preferred embodiment, in S1), the extraction comprises: heating and stirring the liquid obtained by mixing the cyclohexane crystallization mother liquor with the extraction solution; preferably, the number of extractions is 1-3 times, including but not limited to 1, 2 or 3 times; more preferably, the number of extractions is 2 times.
[0022] In a preferred embodiment, the mass ratio of cyclohexane crystallization mother liquor to the extraction solution is 1:1.5-2.0, including but not limited to 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2; preferably, the heating temperature is 45-65°C, including but not limited to 45°C, 46°C, 47°C, 48°C, 49°C, 50°C, 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C or 65°C; preferably, the stirring time is 1-2 hours, including but not limited to 1, 1.5 or 2 hours.
[0023] The present application repeatedly extracts the cyclohexane crystallization mother liquor, and controls the number of repetitions, the mass ratio of the cyclohexane crystallization mother liquor to the extraction solution, the heating temperature, and the stirring time within the above ranges, so as to fully extract the thymol in the cyclohexane crystallization mother liquor, obtain a better extraction effect, facilitate the subsequent first distillation and second distillation treatments, fully recover the thymol remaining in the cyclohexane crystallization mother liquor, reduce the generation of distillation waste, improve the yield of thymol, reduce the generation of harmful by-products, and reduce the production cost.
[0024] In a preferred embodiment, the mass percentage of the compound in the extraction solution is 15-25%, including but not limited to 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24% or 25%.
[0025] By controlling the mass proportion of the above-mentioned extract in the compound to 15-25%, the efficiency and effect of thymol extraction can be improved, which is beneficial to the subsequent distillation treatment, improves the final recovery rate and purity of thymol, reduces the formation of hazardous waste of distillation tailings, conforms to the concept of green development, and is more conducive to promotion.
[0026] In a preferred embodiment, in S2), the second recovery includes: mixing all oil phases, and then performing distillation and concentration treatment to obtain a total oil phase; preferably, the first recovery includes: mixing all extraction phases to obtain a total extraction phase.
[0027] The distillation and concentration treatment methods known to those skilled in the art are all applicable to the second recovery mentioned above in this application, and can be adjusted according to actual production needs to obtain the above-mentioned total extraction phase, that is, to recover the extraction solution in the extraction system of this application.
[0028] In a preferred embodiment, S3) includes mixing the total extract phase and the total oil phase for a first distillation treatment, separating the extract solution and the cyclohexane aqueous solution in sequence, and obtaining a first distillation mixed liquid product; preferably, the mixing mass ratio of the total extract phase to the total oil phase is 1:3.4-4.25, including but not limited to 1:3.4, 1:3.5, 1:3.6, 1:3.7, 1:3.8, 1:3.9, 1:4, 1:4.1, 1:4.11, 1:4.12, 1:4.13, 1:4.14, 1:4.15, 1:4.16, 1:4.17, 1:4.18, 1:4.19, 1:4.20, 1:4.21, 1:4.22, 1:4.23, 1:4.24 or 1:4.25.
[0029] In a preferred embodiment, in S4), the temperature of the first distillation treatment is 65-80°C, including but not limited to 65°C, 70°C, 75°C or 80°C; preferably, the method of the first distillation treatment includes azeotropic distillation.
[0030] The present application recovers the solvent in the total oil phase and the total extract phase by mixing the total oil phase and the total extract phase, performing azeotropic distillation at normal pressure (standard atmospheric pressure, 101.325 kPa), and controlling the temperature of the azeotropic distillation within the above-mentioned range, thereby improving the separation effect of thymol and the solvent. Compared with the solvent recovery method in the prior art, the energy consumption of solvent recovery is reduced, and the production cost is further reduced.
[0031] In a preferred embodiment, in S4), the temperature of the second distillation treatment is 100°C, including but not limited to 100°C, 135°C, 140°C, 145°C or 150°C, and the pressure of the second distillation treatment is 200Pa, including but not limited to 200, 210, 220, 230, 240, 250, 260, 270, 280, 290 or 300Pa; preferably, the second distillation treatment method includes vacuum distillation.
[0032] The present application performs vacuum distillation on the first distillation product and controls the parameters of the vacuum distillation within the above range, thereby effectively separating thymol in the first distillation product and ultimately obtaining thymol with high yield and high purity.
[0033] In a second typical embodiment of the present application, there is provided an application of any one of the above-mentioned methods for recovering thymol in cyclohexane crystallization mother liquor.
[0034] The beneficial effects of the present application will be further explained in detail below in conjunction with specific embodiments.
[0035] Example 1
[0036] (1) 800 kg of 20% acetone aqueous solution (extraction solution) was added to 500 kg of cyclohexane crystallization mother liquor for producing thymol (the crystallization mother liquor contained 35 to 35.5 kg of thymol, about 35 kg of diisopropyl-meta-cresol, and the remainder was solvent cyclohexane), heated to 50° C., and stirred for 2 hours to perform the first extraction.
[0037] (2) After extraction, the mixture is allowed to stand until it is completely separated into a first acetone extraction phase and a first cyclohexane oil phase.
[0038] (3) Add 800 kg of 20% acetone aqueous solution to the first cyclohexane oil phase, repeat steps (1) and (2) to perform a second extraction, and obtain a second acetone extraction phase and a second cyclohexane oil phase.
[0039] (4) The first cyclohexane oil phase and the second cyclohexane oil phase obtained in step (2) and step (3) are mixed, and the cyclohexane is recovered by distillation and concentration to obtain a cyclohexane total oil phase, and the remaining distillation residue is incinerated.
[0040] (5) The first acetone extraction phase and the second acetone extraction phase were mixed to obtain a total extraction phase of about 1700 kg, 450 kg of cyclohexane total oil phase was added, and the mixture entered a continuous distillation tower (Ningbo Mingxin Chemical Machinery Co., Ltd., 2218-T03-031) for a first distillation treatment (azeotropic distillation at a temperature of 75°C), and the acetone aqueous solution and the cyclohexane aqueous solution were separated in turn (after the cyclohexane and water were separated, they were both recycled and applied to the next round of extraction system) to obtain a first distillation product.
[0041] (6) The first distillation product is subjected to a second distillation treatment at a pressure of 200 Pa and a temperature of 100° C. to obtain thymol.
[0042] Example 2
[0043] The only difference between this embodiment and embodiment 1 is that in step (1), 800 kg of 30% acetone aqueous solution is added as the extraction solution, and the other steps remain unchanged.
[0044] Example 3
[0045] The only difference between this embodiment and embodiment 1 is that in step (1), 800 kg of 10% acetone aqueous solution is added as the extraction solution, and the other steps remain unchanged.
[0046] Example 4
[0047] The only difference between this embodiment and embodiment 1 is that the extraction solution in step (1) is 1000 kg of 20% acetone aqueous solution, and the other steps remain unchanged.
[0048] Example 5
[0049] The only difference between this embodiment and embodiment 1 is that in step (1), 600 kg of 20% acetone aqueous solution is added as the extraction solution, and the other steps remain unchanged.
[0050] Example 6
[0051] (1) Add 800 kg of 20% methanol aqueous solution to 500 kg of cyclohexane crystallization mother liquor for producing thymol (the crystallization mother liquor contains 35-35.5 kg of thymol, about 35 kg of diisopropyl-meta-cresol, and the remainder is solvent cyclohexane), heat to 50° C., stir for 2 hours, and perform the first extraction.
[0052] (2) After extraction, the mixture is allowed to stand until it is completely separated into a first methanol extraction phase and a first cyclohexane oil phase.
[0053] (3) Add 800 kg of 20% methanol aqueous solution to the first cyclohexane oil phase, repeat steps (1) and (2) to perform a second extraction, and obtain a second methanol extraction phase and a second cyclohexane oil phase.
[0054] (4) The first cyclohexane oil phase and the second cyclohexane oil phase obtained in step (2) and step (3) are mixed, and the cyclohexane is concentrated and recovered for reuse to obtain a cyclohexane total oil phase, and the remaining distillation residue is incinerated.
[0055] (5) The first methanol extraction phase and the second methanol extraction phase are mixed to obtain a total extraction phase of about 1700 kg, 450 kg of cyclohexane total oil phase is added, and the mixture enters a continuous distillation tower for a first distillation treatment (azeotropic distillation at a temperature of 75° C.), the solvent is recovered, and the methanol solution and the cyclohexane aqueous solution are separated in turn (after the cyclohexane and water are separated by stratification, they are both recovered and applied to the next round of extraction system) to obtain a first distillation product.
[0056] (6) The first distillation product is subjected to a second distillation treatment at a pressure of 200 Pa and a temperature of 100° C. to obtain thymol.
[0057] Example 7
[0058] (1) Add 800 kg of 20% ethanol aqueous solution to 500 kg of cyclohexane crystallization mother liquor for producing thymol (the crystallization mother liquor contains 35-35.5 kg of thymol, about 35 kg of diisopropyl-meta-cresol, and the remainder is solvent cyclohexane), heat to 50° C., stir for 2 hours, and perform the first extraction.
[0059] (2) After extraction, the mixture is allowed to stand until it is completely separated into a first ethanol extraction phase and a first cyclohexane oil phase.
[0060] (3) Add 800 kg of 20% ethanol aqueous solution to the cyclohexane oil phase obtained in step (2), repeat the operations of steps (1) and (2) to perform a second extraction, and obtain an ethanol extraction phase and a cyclohexane oil phase.
[0061] (4) The first cyclohexane oil phase and the second cyclohexane oil phase obtained in step (2) and step (3) are mixed, and the cyclohexane is concentrated and recovered for reuse to obtain a cyclohexane total oil phase, and the remaining distillation residue is incinerated.
[0062] (5) The first ethanol extraction phase and the second ethanol extraction phase obtained in step (2) and step (3) are mixed to obtain a total extraction phase of about 1700 kg, and the mixture is fed into a continuous distillation tower for a first distillation treatment (azeotropic distillation at a temperature of 65° C.), wherein azeotropic distillation is used to separate ethanol, cyclohexane and an aqueous solution (after cyclohexane and water are separated by stratification, they are both recovered and applied to the next round of extraction system), thereby obtaining a first distillation product.
[0063] (6) The first distillation product is subjected to a second distillation treatment at a pressure of 200 Pa and a temperature of 100° C. to obtain thymol.
[0064] Example 8
[0065] The only difference between this embodiment and embodiment 3 is that in step (1), the extraction solution of this embodiment is 800 kg of 20% propanol aqueous solution, and the other steps remain unchanged.
[0066] Example 9
[0067] The only difference between this embodiment and embodiment 3 is that in step (1), the extraction solution of this embodiment is 800 kg of 20% butanol aqueous solution, and the other steps remain unchanged.
[0068] Example 10
[0069] The only difference between this embodiment and embodiment 3 is that in step (1), the extraction solution of this embodiment is 800 kg of 20% amyl alcohol aqueous solution, and the other steps remain unchanged.
[0070] Embodiment 11
[0071] (1) Add 800 kg of 20% butanone aqueous solution to 500 kg of cyclohexane crystallization mother liquor for producing thymol (the crystallization mother liquor contains 35-35.5 kg of thymol, about 35 kg of diisopropyl-meta-cresol, and the remainder is solvent cyclohexane), heat to 50° C., stir for 2 hours, and perform the first extraction.
[0072] (2) After extraction, the mixture is allowed to stand until it is completely separated into a first butanone extraction phase and a first cyclohexane oil phase.
[0073] (3) Add 800 kg of 20% butanone aqueous solution to the first cyclohexane oil phase, repeat steps (1) and (2) to perform a second extraction, and obtain a second butanone extract phase and a second cyclohexane oil phase.
[0074] (4) The first cyclohexane oil phase and the second cyclohexane oil phase obtained in step (2) and step (3) are mixed, and the cyclohexane is concentrated and recovered for reuse to obtain a cyclohexane total oil phase, and the remaining distillation residue is incinerated.
[0075] (5) The first butanone extraction phase and the second butanone extraction phase are mixed to obtain a total extraction phase of about 1700 kg, 450 kg of cyclohexane total oil phase is added, and the mixture enters a continuous distillation tower for a first distillation treatment (azeotropic distillation at a temperature of 75° C.), and the cyclohexane aqueous solution (after cyclohexane and water are separated and recycled into the next round of extraction system) and the butanone solution are separated in turn to obtain a first distillation product.
[0076] (6) The first distillation product is subjected to a second distillation treatment at a pressure of 200 Pa and a temperature of 100° C. to obtain thymol.
[0077] Example 12
[0078] The only difference between this embodiment and embodiment 1 is that in step (1), heating to 80° C. is performed, and the other steps remain unchanged.
[0079] Embodiment 13
[0080] The only difference between this embodiment and embodiment 1 is that in step (1), heating to 30° C. is performed, and the other steps remain unchanged.
[0081] Embodiment 14
[0082] The only difference between this embodiment and embodiment 1 is that in step (1), heating to 65° C. is performed, and the other steps remain unchanged.
[0083] Embodiment 15
[0084] The only difference between this embodiment and embodiment 1 is that in step (1), heating to 45° C. is performed, and the other steps remain unchanged.
[0085] Example 16
[0086] The only difference between this embodiment and embodiment 1 is that in step (1), the stirring time is 3 hours, and the other steps remain unchanged.
[0087] Embodiment 17
[0088] The only difference between this embodiment and embodiment 1 is that in step (1), the stirring time is 0.5 hours, and the other steps remain unchanged.
[0089] Embodiment 18
[0090] The difference between this embodiment and embodiment 1 is that the extraction is repeated 3 times, and the other steps remain unchanged.
[0091] Embodiment 19
[0092] The difference between this embodiment and embodiment 1 is that only one acetone aqueous solution extraction operation is performed, and the other steps remain unchanged.
[0093] Comparative Example 1
[0094] (1) 500 kg of cyclohexane crystallization mother liquor for producing thymol enters a continuous distillation tower for distillation to recover the solvent, separates the cyclohexane solution, and obtains a first distillation product.
[0095] (2) The first distillation product is subjected to vacuum distillation (second distillation treatment) at a pressure of 200 Pa and a temperature of 100° C. to obtain thymol, and the remaining distillation residue is incinerated.
[0096] Comparative Example 2
[0097] The difference between this embodiment and embodiment 1 is that in step (1), the extraction solution is 800 kg of 20% aqueous ether solution, and the other steps remain unchanged.
[0098] Comparative Example 3
[0099] The only difference between this embodiment and embodiment 1 is that in step (1), the extraction solution is 800 kg of 20% isobutyl acetate aqueous solution, and the other steps remain unchanged.
[0100] Comparative Example 4
[0101] The only difference between this embodiment and embodiment 1 is that in step (1), the extraction solution is 800 kg of 20% heptane aqueous solution, and the other steps remain unchanged.
[0102] Comparative Example 5
[0103] The only difference between this embodiment and embodiment 1 is that in step (1), the extraction solution is 800 kg of 20% dichloromethane aqueous solution, and the other steps remain unchanged.
[0104] Comparative Example 6
[0105] The only difference between this embodiment and embodiment 1 is that in step (1), the extraction solution is 800 kg of 20% chloroform aqueous solution, and the other steps remain unchanged.
[0106] Comparative Example 7
[0107] The only difference between this embodiment and embodiment 1 is that in step (1), the extraction solution is 800 kg of aqueous solution, and the other steps remain unchanged.
[0108] The secondary extraction cyclohexane oil phases in Examples 1 to 17 and Comparative Examples 2 to 7, the cyclohexane oil phase obtained by the tertiary extraction in Example 18, and the primary cyclohexane oil phase in Example 19 were subjected to gas chromatography detection. The results are shown in Table 1.
[0109] Table 1
[0110]
[0111]
[0112] The recovery amounts and contents of thymol in Examples 1 to 13 and Comparative Examples 1 to 7 are shown in Table 2.
[0113] Table 2
[0114] Thymol recovery kg Thymol Content Example 1 34.5 99.70％ Example 2 34.6 98.80％ Example 3 33.5 99.70％ Example 4 34.4 99.50％ Example 5 33.6 99.70％ Example 6 33.5 99.50％ Example 7 29.1 99.20％ Example 8 30.5 99.30％ Example 9 28.5 99.30％ Example 10 27.9 98.90％ Embodiment 11 28.9 99.10％ Example 12 34.3 98.30％ Embodiment 13 32.5 99.50％ Embodiment 14 34.2 99.50％ Embodiment 15 33.9 99.70％ Example 16 34.1 99.60％ Embodiment 17 33.4 99.40％ Embodiment 18 34.4 99.60％ Embodiment 19 27.8 98.70％ Comparative Example 1 24.5 97.50％ Comparative Example 2 0 0.00％ Comparative Example 3 0 0.00％ Comparative Example 4 0 0.00％ Comparative Example 5 0 0.00％ Comparative Example 6 0 0.00％ Comparative Example 7 0 0.00％
[0115] It can be seen from Table 1 and Table 2 that the method of recovering thymol from the cyclohexane crystallization mother liquor of thymol in the present application can reduce the hazardous waste that needs to be outsourced while improving the yield of thymol, which is in line with the concept of green chemistry development. From Examples 1 to 17, it can be seen that using acetone solution as an extracting liquid has a better separation effect on the crystallization mother liquor of thymol, which is better than aqueous solutions of other compounds; from Examples 1, 18 and 19, it can be seen that the more extraction times, the better, and 2 times can achieve a better extraction effect.
[0116] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those described herein, for example.
[0117] From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: the thymol recovery method of the present application, by utilizing the extraction solution of the present application to efficiently separate uncrystallized thymol from the cyclohexane crystallization mother liquor, significantly improves the yield of thymol, and can obtain high-purity thymol through distillation, thereby reducing the hazardous waste that needs to be outsourced for treatment, reducing the cost of hazardous waste treatment, and complying with the concept of green chemistry development.
[0118] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A method for recovering thymol, characterized in that, The recovery method comprises: S1) mixing the cyclohexane crystallization mother liquor with the extraction solution, performing extraction, and obtaining an extract phase and an oil phase; The extraction solution comprises an aqueous solution of one or more of the following compounds: methanol, ethanol, propanol, butanol, pentanol, acetone or butanone; S2) repeating the extraction, and performing a first recovery on all the extract phases to obtain a total extract phase; All the oil phases are subjected to a second recovery to obtain a total oil phase; S3) mixing the total extract phase and the total oil phase, and performing a first rectification process to obtain a first distillation product; S4) subjecting the first distillation product to a second distillation treatment to obtain the thymol.
2. The recycling method according to claim 1, characterized in that: In S1), the extraction comprises: heating and stirring the liquid obtained by mixing the cyclohexane crystallization mother liquor and the extraction solution; Preferably, the extraction is performed 1-3 times.
3. The recycling method according to claim 2, characterized in that: The mass ratio of the cyclohexane crystallization mother liquor to the extraction solution is 1:1.5-2.
0.
4. The recycling method according to claim 2, characterized in that: The heating temperature is 45-65°C; Preferably, the stirring time is 1-2 hours.
5. The recycling method according to claim 1, characterized in that: The mass proportion of the compound in the extraction solution is 15-25%.
6. The recycling method according to claim 1, characterized in that: In said S2), said second recovery comprises: after mixing all said oil phases, performing distillation and concentration treatment to obtain said total oil phase; Preferably, the first recovery comprises: mixing all the extraction phases to obtain the total extraction phase.
7. The recycling method according to claim 1, characterized in that: The S3) comprises: mixing the total extract phase and the total oil phase to perform a first distillation treatment, and sequentially separating the extract solution and the cyclohexane aqueous solution to obtain a first distillation product; Preferably, the mixing mass ratio of the total extraction phase to the total oil phase is 1:3.4-4.
25.
8. The recycling method according to claim 7, characterized in that: The temperature of the first distillation treatment is 65-80°C.
9. The recycling method according to claim 1, characterized in that: In the S4), the temperature of the second distillation treatment is 100°C, and the pressure of the second distillation treatment is 200Pa.
10. Use of the method for recovering thymol according to any one of claims 1 to 9 for recovering thymol from cyclohexane crystallization mother liquor.