A method for recovering 2,4,6-trimethylphenol from 2,6-dimethylphenol raffinate

Abstract

The present application relates to the technical field of separation and purification, in particular to a method for recovering 2,4,6-trimethylphenol from 2,6-dimethylphenol residue, comprising: cooling the 2,6-dimethylphenol residue to 15±1 DEG C, and keeping the temperature for 10-40 min, then blowing out the liquid material by compressed gas; heating and melting the crystallized solid material, keeping the temperature for 0-40 min, then cooling to 30±1 DEG C, keeping the temperature for 10-40 min, then blowing out the liquid material by compressed gas; heating and melting the crystallized solid material, keeping the temperature for 0-40 min, then cooling to 40-45 DEG C, keeping the temperature for 10-40 min, then blowing out the liquid material by compressed gas; heating and melting the crystallized solid material, and discharging to obtain 2,4,6-trimethylphenol. The present application significantly improves the recovery rate and purity of 2,4,6-trimethylphenol by multiple melting and crystallization in stages and blowing out the liquid material by compressed gas.

Description

Technical Field

[0001] This invention relates to the field of separation and purification technology, and in particular to a method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue. Background Technology

[0002] The English name for 2,4,6-trimethylphenol is 2,4,6-Trimethylphenol. Its molecular formula is C9H12O, and its molecular weight is 136.19. It has a boiling point of 220℃, a melting point of 70-72℃, and a density of 0.9809. It is a white or beige crystalline powder with a strong phenolic odor, slightly soluble in water, and soluble in methanol, ether, chloroform, etc. Its structural formula is:

[0003]

[0004] 2,4,6-Tricresol is primarily used as an intermediate in the synthesis of vitamin E, and as a raw material for the synthesis of dyes, pigments, pharmaceuticals, and adhesives. It can also be used as an additive in epoxy resins. The main methods for synthesizing 2,4,6-tricresol are: 1) reacting p-cresol and methanol at high temperature with a catalyst; 2) reacting 2,4-xylenol and methanol at high temperature with a catalyst. However, these methods all rely on raw materials, resulting in higher production and material costs.

[0005] In the alkylation of phenol and methanol to produce o-cresol and 2,6-xylenol, 2,4,6-trimethylphenol is a major byproduct. After purifying o-cresol and 2,6-xylenol using a distillation column, the main component of the residue at the bottom of the column is 2,4,6-trimethylphenol, with a content of 60-70%. The remaining components include 2,6-xylenol (melting point 43-45℃), 2,4-xylenol (melting point 26℃), 2,5-xylenol (melting point 75-77℃), 2,3,6-trimethylphenol (melting point 59-62℃), and various impurities such as ether peaks, which increases the difficulty of purifying 2,4,6-trimethylphenol.

[0006] Existing purification methods mainly include: 1) distillation using a distillation column; and 2) recrystallization. Distillation requires the complete removal of low-boiling-point substances such as 2,6-xylenol, 2,4-xylenol, 2,3-xylenol, and 2,5-xylenol, followed by distillation of 2,4,6-trimethylphenol from the residual liquid. Since 2,4,6-trimethylphenol and 2,3,6-trimethylphenol have similar boiling points, it is difficult to achieve a product purity of over 99%. Recrystallization requires the addition of a solvent, necessitating solvent recovery, resulting in significant energy consumption and a low yield.

[0007] Therefore, it is necessary to provide an improved method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residues to increase yield and purity while reducing energy consumption. Summary of the Invention

[0008] The purpose of this invention is to provide a method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue. This method involves multiple stages of melting and crystallization, followed by blowing out the liquid material using compressed gas, thereby significantly improving the recovery rate and purity of 2,4,6-trimethylphenol.

[0009] To achieve the above objective, the present invention provides a method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue, comprising the following steps:

[0010] S1. Cool the residual 2,6-xylenol liquid to 15±5℃, keep it at that temperature for 10 to 40 minutes, and then blow out the liquid material using compressed gas.

[0011] S2. Heat and melt the solid material crystallized in step S1, keep it at that temperature for 0 to 40 minutes, then cool it down to 30±5℃ and keep it at that temperature for 10 to 40 minutes. Then use compressed gas to blow out the liquid material.

[0012] S3. Heat and melt the solid material crystallized in step S2, keep it at that temperature for 0 to 40 minutes, then cool it down to 40±5℃ and keep it at that temperature for 10 to 40 minutes. Then use compressed gas to blow out the liquid material.

[0013] S4. The solid material crystallized in step S3 is heated and melted, and discharged to obtain 2,4,6-trimethylphenol.

[0014] By utilizing the different melting points of materials with varying impurity contents, segmented multiple melting and crystallization is performed. After each crystallization, compressed gas is used to thoroughly blow out the liquid material, effectively removing as many liquid impurities as possible from the crystals, thus improving the purity of the final 2,4,6-trimethylphenol. Furthermore, this invention eliminates the need for additional solvents, reducing both raw material usage and 2,4,6-trimethylphenol loss, thereby increasing the yield.

[0015] Furthermore, the 2,6-xylenol residue mainly comprises 2,6-xylenol, 2,4-xylenol, 2,3-xylenol, 2,4,6-trimethylphenol, and 2,3,6-trimethylphenol; in some embodiments, the 2,6-xylenol residue also includes other impurities such as ethers. The mass content of 2,4,6-trimethylphenol is 60-75%, preferably 60-70%. This invention is particularly suitable for recovering 2,4,6-trimethylphenol from 2,6-xylenol residues within this content range.

[0016] Furthermore, the mass content of 2,6-xylenol is 0-1.5%, preferably 0.5-1%; the mass content of 2,4-xylenol is 0-30%, preferably 10-25%; the mass content of 2,3-xylenol is 0-5%, preferably 1-4%; and the mass content of 2,3,6-trimethylphenol is 0-15%.

[0017] Furthermore, in step S1, the temperature of the 2,6-xylenol residue before cooling is ≥70℃, preferably 70±1℃; and / or, in steps S2 to S4, the final temperature of the heating and melting is ≥70±1℃.

[0018] Furthermore, in step S1, the temperature is lowered by introducing cooling water at 15±5℃; preferably 15±1℃.

[0019] In step S2, the temperature is lowered by introducing cooling water at 30±5℃, preferably 30±1℃;

[0020] In step S3, the temperature is lowered by introducing cooling water at 40±5℃, preferably 40±1℃. The present invention has a fast cooling rate, thus resulting in high purification efficiency.

[0021] Furthermore, steps S1 to S4 are all carried out in a melt crystallizer, which includes a tube side, a shell side, and a jacket. Circulating cooling water is introduced into the tube side and the jacket, and the 2,6-xylenol residue is introduced into the shell side.

[0022] Furthermore, the gauge pressure of the compressed gas is 0.002-0.05 MPa, preferably 0.01-0.05 MPa; by using high pressure to carry out the liquid material, it helps to reduce the impurity content.

[0023] Furthermore, the compressed gas is one or more of compressed air, nitrogen, and inert gas.

[0024] Furthermore, this includes the following steps:

[0025] S1. Add the 2,6-xylenol residue at a temperature above 70°C to the crystallizer, and pass in cooling water at 15±1°C to keep the 2,6-xylenol residue at 15±1°C for 20 to 35 minutes. Then, use compressed gas to blow out the liquid material until no material flows out of the outlet.

[0026] S2. Introduce hot water at 70°C or above to heat and melt the solid material crystallized in step S1. After holding the temperature for 0 to 40 minutes, introduce cooling water at 30±1°C to keep the molten material at 30±1°C for 20 to 35 minutes. Then, use compressed gas to blow out the liquid material until no material flows out of the outlet.

[0027] S3. Introduce hot water at 70°C or above to heat and melt the solid material crystallized in step S2. After holding the temperature for 0 to 40 minutes, introduce cooling water at 40±5°C, preferably 40±1°C, and hold the temperature for 10 to 40 minutes. Then, use compressed gas to blow out the liquid material until no material flows out of the outlet.

[0028] S4. Introduce hot water at a temperature above 70°C to completely melt the solid material crystallized in step S3, and then discharge the material to obtain 2,4,6-trimethylphenol.

[0029] Furthermore, the liquid material collected in step S1 is 20-30% of the mass of the 2,6-xylenol residue, wherein the mass content of 2,4,6-trimethylphenol is less than 42% of the liquid material.

[0030] And / or, the liquid material collected in step S2 is 0 to 10% of the mass of the 2,6-xylenol residue, wherein the mass content of 2,4,6-trimethylphenol is less than 35% of the liquid material.

[0031] And / or, the liquid material collected in step S3 is 0 to 10% of the mass of the 2,6-xylenol residue, wherein the mass content of 2,4,6-trimethylphenol is less than 45% of the liquid material.

[0032] Furthermore, the 2,4,6-trimethylphenol obtained in step S4 has a purity of ≥98% and a yield of ≥50%, preferably ≥55%.

[0033] The beneficial effects of this invention are as follows:

[0034] The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue provided by this invention significantly improves the recovery rate and purity of 2,4,6-trimethylphenol by multi-stage melting and crystallization and forcefully blowing out the liquid material with compressed gas, while also saving energy, reducing carbon emissions, and improving recovery efficiency. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 This is a diagram illustrating the cooling and heating process of the method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue provided in the embodiments.

[0037] Figure 2 This is a schematic diagram of the crystallizer used in this invention;

[0038] Figure 3 This is a chromatogram of the final melt obtained in Example 1. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention are described clearly and completely below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0040] This invention aims to provide a simple, feasible method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue, which can reduce production energy consumption. Specifically, it includes:

[0041] (1) Add the 2,6-xylenol residue with a temperature greater than 70℃ to the crystallization kettle, cool it down to 15℃, keep it at that temperature for 30 minutes, and close the vent valve. Open the bottom valve and press in 0.05MPa compressed air from above the material until no material flows out of the outlet.

[0042] (2) Close the bottom valve, reheat the material to 70°C, add it to the crystallization vessel, cool it down to 30°C, keep it at that temperature for 30 minutes, and close the vent valve. Open the bottom valve and press in 0.05MPa compressed air from above the material until no material flows out of the outlet.

[0043] (3) Close the bottom vessel, reheat the material to 70°C, add it to the crystallization vessel, cool it to 45°C, keep it at that temperature for 30 minutes, and close the vent valve. Open the bottom vessel and press in 0.05MPa compressed air from above the material until no material flows out of the outlet.

[0044] (4) Raise the material temperature to 70°C until it is completely melted, open the bottom valve to release it, and obtain the finished product.

[0045] like Figure 2 As shown, the crystallizer used in this method is a heat exchanger with good heat exchange effect. The tube side and jacket are filled with circulating cooling water, the shell is the material phase, and the tube side is filled with cooling water phase.

[0046] Figure 2 In the diagram, A is the feed inlet, B is the discharge outlet, C is the water inlet, D is the water outlet, E is the tube-side water inlet, and F is the thermometer port.

[0047] This invention combines a column temperature of 145℃, a detector and injection temperature of 260℃, a nitrogen pressure of 0.29MPa, an air pressure of 0.4 MPa, a hydrogen pressure of 0.2MPa, and an Agilent DB-5 column model to perform qualitative and quantitative analysis of various components. Specific embodiments are as follows.

[0048] Example 1

[0049] A method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residues includes the following steps:

[0050] Table 1. Composition and content of 2,6-xylenol residue

[0051]

[0052] Step 1

[0053] 690.00 g of 2,6-xylenol residue at 80℃ was added to the crystallization vessel. Cooling water at 15℃ was circulated into the tubes, and the temperature was maintained for 30 minutes. The vent valve was then closed. The bottom vessel was opened, and compressed air at 0.05 MPa was introduced from above the material until no material flowed out of the outlet. 181.30 g of material was extracted.

[0054] Table 2 Composition content of extruded materials

[0055]

[0056] Step Two

[0057] Close the bottom valve, open the vent valve, and introduce 70°C hot water into the tubes, maintain the temperature for 30 minutes, then close the vent valve. Introduce 30°C cooling water into the tubes, maintain the temperature for 30 minutes, then close the vent valve. Open the bottom vessel and pressurize the material with 0.05MPa nitrogen gas from above until no material flows out of the outlet. 154.00 grams of material were extracted.

[0058] Table 3 Composition content of extruded materials

[0059]

[0060] Step 3

[0061] Close the bottom valve, open the vent valve, and introduce 70°C hot water into the tubes, maintain the temperature for 30 minutes, then close the vent valve. Introduce 40°C cooling water into the tubes, maintain the temperature for 30 minutes, then close the vent valve. Open the bottom vessel and pressurize the material from above with 0.05MPa compressed air until no material flows out of the outlet. 54.00 grams of material were extracted.

[0062] Table 4 Composition content of extruded materials

[0063]

[0064] Open the bottom valve, close the vent valve, and introduce 70°C hot water into the tubes. Maintain this temperature for 30 minutes to melt the material in the crystallization vessel. 245.10 grams of material were obtained.

[0065] Table 5 Composition Content of Materials

[0066]

[0067] It can be seen that the final material contains more than 98% 2,4,6-trimethylphenol.

[0068] Example 2

[0069] A method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residues includes the following steps:

[0070] Table 6. Component content of 2,6-xylenol residue

[0071]

[0072] Step 1

[0073] 690.00 g of 2,6-xylenol residue at 85°C was added to the crystallization vessel. Cooling water at 15°C was circulated into the tubes, and the temperature was maintained for 40 minutes. The vent valve was then closed. The bottom vessel was opened, and compressed air at 0.05 MPa was introduced from above the material until no material flowed out of the outlet. 180.90 g of material was extracted.

[0074] Table 7 Composition content of extruded materials

[0075]

[0076] Step Two

[0077] Close the bottom valve, open the vent valve, and introduce 70°C hot water into the tubes, maintain the temperature for 30 minutes, then close the vent valve. Introduce 30°C cooling water into the tubes, maintain the temperature for 30 minutes, then close the vent valve. Open the bottom vessel and pressurize the material from above with 0.06 MPa air until no material flows out of the outlet. 156.00 grams of material were extracted.

[0078] Table 8 Composition content of extruded materials

[0079]

[0080] Step 3

[0081] Close the bottom valve, open the vent valve, and introduce 70°C hot water into the tubes, maintain the temperature for 30 minutes, then close the vent valve. Introduce 40°C cooling water into the tubes, maintain the temperature for 30 minutes, then close the vent valve. Open the bottom vessel and pressurize the material from above with 0.05MPa compressed air until no material flows out of the outlet. 53.00 grams of material were extracted.

[0082] Table 9 Composition content of extruded materials

[0083]

[0084] Open the bottom valve, close the vent valve, and introduce 75°C hot water into the tubes. Maintain this temperature for 30 minutes to melt the material in the crystallization vessel. 243.80 grams of material were obtained.

[0085] Table 10 Composition Content of Materials

[0086]

[0087] Example 3

[0088] A method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residues includes the following steps:

[0089] Table 11 Components and Contents of 2,6-Xylenol Residual Liquid

[0090]

[0091] Step 1

[0092] 690.00 g of 2,6-xylenol residue at 75°C was added to the crystallization vessel. Cooling water at 19°C was circulated into the tubes, and the temperature was maintained for 35 minutes. The vent valve was then closed. The bottom vessel was opened, and compressed air at 0.04 MPa was introduced from above the material until no material flowed out of the outlet. 181.00 g of material was extracted.

[0093] Table 12 Composition content of extruded materials

[0094]

[0095] Step Two

[0096] Close the bottom valve, open the vent valve, and introduce 72°C hot water into the tubes, maintain the temperature for 30 minutes, then close the vent valve. Introduce 28°C cooling water into the tubes, maintain the temperature for 30 minutes, then close the vent valve. Open the bottom vessel and pressurize the material with 0.05MPa nitrogen gas from above until no material flows out of the outlet. 155.00 grams of material were extracted.

[0097] Table 13 Composition content of extruded materials

[0098]

[0099] Step 3

[0100] Close the bottom valve, open the vent valve, and introduce 73°C hot water into the tubes, maintain the temperature for 30 minutes, then close the vent valve. Introduce 41°C cooling water into the tubes, maintain the temperature for 30 minutes, then close the vent valve. Open the bottom vessel and pressurize the material with 0.06MPa nitrogen gas from above until no material flows out of the outlet. 54.30 grams of material were extracted.

[0101] Table 14 Composition content of extruded materials

[0102]

[0103] Open the bottom valve, close the vent valve, and introduce 75°C hot water into the tubes. Maintain this temperature for 30 minutes to melt the material in the crystallization vessel. 244.30 grams of material were obtained.

[0104] Table 15 Composition Content of Materials

[0105]

[0106] As can be seen from Examples 1-3, the final yield and purity of 2,4,6-trimethylphenol were not significantly different after three recovery experiments of the raw materials, which demonstrates the feasibility and stability of the recovery method of the present invention and facilitates practical application.

[0107] Comparative Example 1

[0108] A method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residues includes the following steps:

[0109] Table 16 Components and Contents of 2,6-Xylenol Residual Liquid

[0110]

[0111] Step 1

[0112] Except for the absence of compressed air, all other conditions remain unchanged. 690.00 g of 2,6-xylenol residue at 85°C is added to the crystallization vessel. Cooling water at 15°C is circulated into the tubes, and the temperature is maintained for 40 minutes. The vent valve is then closed. The bottom vessel is opened, and 62.30 g of liquid material is released.

[0113] Table 17 Composition Content of Materials

[0114]

[0115] Step Two

[0116] Except for not using compressed air, all other conditions remain unchanged. Close the bottom valve, open the vent valve, and introduce 70°C hot water into the tubes, maintain the temperature for 30 minutes, and then close the vent valve. Introduce 30°C cooling water into the tubes, maintain the temperature for 30 minutes, and then close the vent valve. Open the bottom vessel and release 160.30 grams of liquid material.

[0117] Table 18 Composition Content of Materials

[0118]

[0119] Step 3

[0120] Except for not using compressed air, all other conditions remain unchanged. Close the bottom valve, open the vent valve, and introduce 70°C hot water into the tubes, maintain the temperature for 30 minutes, and then close the vent valve. Introduce 40°C cooling water into the tubes, maintain the temperature for 30 minutes, and then close the vent valve. Open the bottom vessel and release 58.21 grams of liquid material.

[0121] Table 19 Composition Content of Materials

[0122]

[0123] Open the bottom valve, close the vent valve, and introduce 75°C hot water into the tubes. Maintain this temperature for 30 minutes to melt the material in the crystallization vessel. 297.3 grams of material were obtained.

[0124] Table 20 Composition Content of Materials

[0125]

[0126] As can be seen from Comparative Example 1, when the material is discharged naturally after each melting and crystallization without the use of compressed gas, the total output of the melt crystallization is significantly reduced, and the content of 2,4,6-trimethylphenol entrained increases. This is because due to the surface tension between the crystals, the material with a lower melting point that is entrained cannot be discharged smoothly, resulting in a higher content of impurities in the final material and a lower purity of 2,4,6-trimethylphenol.

[0127] In summary, this invention involves sequentially performing melt crystallization at three temperatures: 15±5℃, 30±5℃, and 40±5℃. During this process, due to the relatively high content of 2,4,6-trimethylphenol, it crystallizes out first during cooling. The 2,4,6-trimethylphenol that does not form crystals then forms eutectic materials with materials of lower and higher melting points, existing in liquid form. By using compressed gas to pressurize the material from above, all liquid material in the gaps of the crystals can be effectively expelled, minimizing impurities. Finally, through three gradient melt crystallization operations, 2,4,6-trimethylphenol with a purity of over 98% can be obtained.

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue, characterized in that, Includes the following steps: S1. Cool the residual 2,6-xylenol liquid to 15±5℃, keep it at that temperature for 10~40min, and then blow out the liquid material using compressed gas; S2. Heat and melt the solid material crystallized in step S1, keep it at that temperature for 0~40 min, then cool it down to 30±5℃, keep it at that temperature for 10~40 min, and then blow out the liquid material using compressed gas. S3. Heat and melt the solid material crystallized in step S2, keep it at that temperature for 0~40 minutes, then cool it down to 40±5℃, keep it at that temperature for 10~40 minutes, and then blow out the liquid material using compressed gas. S4. The solid material crystallized in step S3 is heated and melted, and discharged to obtain 2,4,6-trimethylphenol; The components of the 2,6-xylenol residue include 2,6-xylenol, 2,4-xylenol, 2,3-xylenol, 2,4,6-trimethylphenol and 2,3,6-trimethylphenol; wherein the mass content of 2,4,6-trimethylphenol is 60-75%.

2. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 1, characterized in that, The mass content of the 2,4,6-trimethylphenol is 60-70%.

3. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 1 or 2, characterized in that, The mass content of 2,6-xylenol in the 2,6-xylenol residue is 0.5% to 1%. Alternatively, the mass content of 2,4-xylenol is 10%~25%; Alternatively, the mass content of 2,3-xylenol is 1% to 4%; Alternatively, the mass content of 2,3,6-trimethylphenol is 15%.

4. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 1 or 2, characterized in that, In step S1, the temperature of the 2,6-xylenol residue before cooling is ≥70℃.

5. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 3, characterized in that, In step S1, the temperature of the 2,6-xylenol residue before cooling is ≥70℃.

6. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 1 or 2, characterized in that, In step S1, the temperature of the 2,6-xylenol residue before cooling is ≥75℃.

7. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 3, characterized in that, In step S1, the temperature of the 2,6-xylenol residue before cooling is ≥75℃.

8. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 1 or 2, characterized in that, In step S1, cooling water at 15±5℃ is introduced to lower the temperature; In step S2, cooling water at 30±5℃ is introduced to lower the temperature; In step S3, cooling water at 40±5℃ is introduced to lower the temperature.

9. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 3, characterized in that, In step S1, cooling water at 15±5℃ is introduced to lower the temperature; In step S2, cooling water at 30±5℃ is introduced to lower the temperature; In step S3, cooling water at 40±5℃ is introduced to lower the temperature.

10. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 1 or 2, characterized in that, In step S1, cooling water at 15±1℃ is introduced to lower the temperature; In step S2, the temperature is lowered by introducing cooling water at 30±1℃; In step S3, cooling water at 40±1℃ is introduced to lower the temperature.

11. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 3, characterized in that, In step S1, cooling water at 15±1℃ is introduced to lower the temperature; In step S2, cooling water at 30±1℃ is introduced to lower the temperature; In step S3, cooling water at 40±1℃ is introduced to lower the temperature.

12. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 1, 2, 5, 7, 9 or 11, characterized in that, Steps S1 to S4 are all carried out in a melt crystallizer, which includes a tube side, a shell side, and a jacket. Circulating cooling water is introduced into the tube side and the jacket, and the 2,6-xylenol residue is introduced into the shell side.

13. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 3, characterized in that, Steps S1 to S4 are all carried out in a melt crystallizer, which includes a tube side, a shell side, and a jacket. Circulating cooling water is introduced into the tube side and the jacket, and the 2,6-xylenol residue is introduced into the shell side.

14. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 4, characterized in that, Steps S1 to S4 are all carried out in a melt crystallizer, which includes a tube side, a shell side, and a jacket. Circulating cooling water is introduced into the tube side and the jacket, and the 2,6-xylenol residue is introduced into the shell side.

15. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 6, characterized in that, Steps S1 to S4 are all carried out in a melt crystallizer, which includes a tube side, a shell side, and a jacket. Circulating cooling water is introduced into the tube side and the jacket, and the 2,6-xylenol residue is introduced into the shell side.

16. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 8, characterized in that, Steps S1 to S4 are all carried out in a melt crystallizer, which includes a tube side, a shell side, and a jacket. Circulating cooling water is introduced into the tube side and the jacket, and the 2,6-xylenol residue is introduced into the shell side.

17. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 10, characterized in that, Steps S1 to S4 are all carried out in a melt crystallizer, which includes a tube side, a shell side, and a jacket. Circulating cooling water is introduced into the tube side and the jacket, and the 2,6-xylenol residue is introduced into the shell side.

18. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to any one of claims 1, 2, 5, 7, 9, 11, 13-17, characterized in that, The gauge pressure of the compressed gas is 0.002-0.05 MPa; And / or, the compressed gas is one or more of compressed air, nitrogen, and inert gas.

19. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 3, characterized in that, The gauge pressure of the compressed gas is 0.002-0.05 MPa; And / or, the compressed gas is one or more of compressed air, nitrogen, and inert gas.

20. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 4, characterized in that, The gauge pressure of the compressed gas is 0.002-0.05 MPa; And / or, the compressed gas is one or more of compressed air, nitrogen, and inert gas.

21. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 6, characterized in that, The gauge pressure of the compressed gas is 0.002-0.05 MPa; And / or, the compressed gas is one or more of compressed air, nitrogen, and inert gas.

22. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 8, characterized in that, The gauge pressure of the compressed gas is 0.002-0.05 MPa; And / or, the compressed gas is one or more of compressed air, nitrogen, and inert gas.

23. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 10, characterized in that, The gauge pressure of the compressed gas is 0.002-0.05 MPa; And / or, the compressed gas is one or more of compressed air, nitrogen, and inert gas.

24. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 12, characterized in that, The gauge pressure of the compressed gas is 0.002-0.05 MPa; And / or, the compressed gas is one or more of compressed air, nitrogen, and inert gas.

25. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 1, characterized in that, Includes the following steps: S1. Add the 2,6-xylenol residue at a temperature above 70°C to the crystallizer, and pass in cooling water at 15±1°C to keep the 2,6-xylenol residue at 15±1°C for 20~35 minutes. Then use compressed gas to blow out the liquid material until no material flows out of the outlet. S2. Introduce hot water at 70°C or above to heat and melt the solid material crystallized in step S1. After holding the temperature for 0-40 minutes, introduce cooling water at 30±1°C to keep the molten material at 30±1°C for 20-35 minutes. Then, use compressed gas to blow out the liquid material until no material flows out of the outlet. S3. Introduce hot water at 70°C or above to heat and melt the solid material crystallized in step S2. After holding the temperature for 0-40 minutes, introduce cooling water at 40±1°C to keep the molten material at 40±1°C for 10-40 minutes. Then, use compressed gas to blow out the liquid material until no material flows out of the outlet. S4. Introduce hot water at a temperature above 70°C to heat the solid material crystallized in step S3 until it is completely melted, and then discharge it to obtain 2,4,6-trimethylphenol.

26. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to any one of claims 1, 2, 5, 7, 9, 11, 13-17, 19-25, characterized in that, The liquid material in step S1 is 20-30% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S1 is less than 42%. And / or, the liquid material in step S2 is 10% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S2 is less than 35%. And / or, the liquid material in step S3 is 10% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S3 is less than 45%.

27. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 3, characterized in that, The liquid material in step S1 is 20-30% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S1 is less than 42%. And / or, the liquid material in step S2 is 10% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S2 is less than 35%. And / or, the liquid material in step S3 is 10% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S3 is less than 45%.

28. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 4, characterized in that, The liquid material in step S1 is 20-30% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S1 is less than 42%. And / or, the liquid material in step S2 is 10% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S2 is less than 35%. And / or, the liquid material in step S3 is 10% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S3 is less than 45%.

29. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 6, characterized in that, The liquid material in step S1 is 20-30% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S1 is less than 42%. And / or, the liquid material in step S2 is 10% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S2 is less than 35%. And / or, the liquid material in step S3 is 10% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S3 is less than 45%.

30. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 8, characterized in that, The liquid material in step S1 is 20-30% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S1 is less than 42%. And / or, the liquid material in step S2 is 10% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S2 is less than 35%. And / or, the liquid material in step S3 is 10% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S3 is less than 45%.

31. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 10, characterized in that, The liquid material in step S1 is 20-30% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S1 is less than 42%. And / or, the liquid material in step S2 is 10% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S2 is less than 35%. And / or, the liquid material in step S3 is 10% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S3 is less than 45%.

32. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 12, characterized in that, The liquid material in step S1 is 20-30% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S1 is less than 42%. And / or, the liquid material in step S2 is 10% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S2 is less than 35%. And / or, the liquid material in step S3 is 10% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S3 is less than 45%.

33. The method for recovering 2,4,6-trimethylphenol from 2,6-xylenol residue according to claim 18, characterized in that, The liquid material in step S1 is 20-30% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S1 is less than 42%. And / or, the liquid material in step S2 is 10% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S2 is less than 35%. And / or, the liquid material in step S3 is 10% of the mass of the 2,6-xylenol residue, and the mass content of 2,4,6-trimethylphenol in the liquid material in step S3 is less than 45%.

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