A method for producing low-phenol residual ethylene glycol phenyl ether

Abstract

This invention provides a method for producing low-phenol-residue ethylene glycol phenyl ether. The method comprises the following steps: S1: Phenol reacts with ethylene oxide under the action of an alkaline catalyst to obtain a crude product; S2: The crude product is neutralized to neutral or acidic using acid and mixed with an alkaline solution; S3: The above mixed solution is passed through a hydrophobic medium to collect, settle, and separate to obtain a crude ethylene glycol phenyl ether product with low phenol residue; S4: The crude product with low phenol residue is subjected to vacuum distillation to obtain high-purity, low-phenol-residue ethylene glycol phenyl ether. The ethylene glycol phenyl ether product produced by this invention has excellent quality, with a purity greater than 99.9% and phenol residue less than 1 ppm, thus reducing the impact of phenol residue on downstream applications from the product source.

Description

Technical Field

[0001] This invention belongs to the field of ethylene glycol ethers, and specifically relates to a method for producing ethylene glycol phenyl ether with low phenol residue. Background Technology

[0002] Ethylene glycol phenyl ether, also known as phenoxyethanol, is a low-volatility, high-boiling-point colorless oily solvent with excellent solubility and broad-spectrum antibacterial properties. Industrial production of ethylene glycol phenyl ether involves reacting phenol with ethylene oxide to obtain industrial-grade products. Further purification and separation are performed to obtain daily-chemical-grade products, depending on purity and phenol residue requirements. Industrial-grade products are mainly used as solvents, additives, or intermediates in paints, inks, coatings, and UV curing processes. Daily-chemical-grade products are mainly used as preservatives in detergents, cosmetics, and pharmaceuticals. For products above the daily-chemical grade, with increasingly stringent requirements regarding phenol residue, obtaining high-purity ethylene glycol phenyl ether with low phenol residue has become a focus. Light industry standards require that cosmetic raw materials contain ≥99.0% ethylene glycol phenyl ether and ≤10ppm phenol.

[0003] Currently, the industrial production method for ethylene glycol phenyl ether involves catalytic synthesis using phenol and ethylene oxide as raw materials. The resulting industrial-grade product has a purity of approximately 90%-95%, with phenol residue exceeding 500 ppm, far below the industry standards for cosmetics. Purification of ethylene glycol phenyl ether primarily involves vacuum distillation, vacuum rectification, or cooling crystallization; however, while these methods can effectively improve product purity, they cannot reduce phenol residue to below 1 ppm. Summary of the Invention

[0004] The purpose of this invention is to provide a method for producing ethylene glycol phenyl ether with low phenol residue. This method can increase the purity of the product to over 99.9 wt% and the phenol residue to <1 ppm, which fully meets the application requirements of daily chemical products.

[0005] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0006] A method for producing ethylene glycol phenyl ether with low phenol residue, the method comprising the following steps:

[0007] S1: Phenol reacts with ethylene oxide under the action of an alkaline catalyst to obtain the crude product;

[0008] S2: Neutralize the crude product to neutral or acidic using acid, and mix it with the alkaline solution for 10-60 minutes;

[0009] S3: The above mixed solution is passed through a hydrophobic medium to aggregate, settle, and separate to obtain a crude ethylene glycol phenyl ether product with low phenol residue;

[0010] S4: The crude ethylene glycol phenyl ether with low phenol residue is subjected to vacuum distillation to obtain high-purity ethylene glycol phenyl ether with low phenol residue.

[0011] In this invention, the alkaline catalyst in S1 is one or more of sodium hydroxide, potassium hydroxide, cesium hydroxide, barium hydroxide, calcium hydroxide, lithium hydroxide, sodium methoxide, potassium methoxide, metallic sodium, and metallic potassium.

[0012] In this invention, the amount of catalyst used in S1 is 0.05%-0.5% of the mass of phenol;

[0013] In this invention, the molar ratio of phenol to ethylene oxide in S1 is 1:(1.05-1.1);

[0014] In this invention, the gauge pressure in S1 is controlled at 0.1-0.5 MPa and the temperature is controlled at 110-180℃.

[0015] In this invention, the acid mentioned in S2 is one or more of phosphoric acid solution, sulfuric acid solution, hydrochloric acid solution and nitric acid solution, such as common 85% phosphoric acid solution, 98% sulfuric acid solution, 37% hydrochloric acid solution, 68% nitric acid solution, etc.

[0016] In this invention, in S2, the crude product is neutralized to neutral or acidic conditions using acid, preferably with the pH controlled at 4-7.

[0017] In this invention, the alkaline solution in S2 is one or more of sodium hydroxide solution, potassium hydroxide solution, and calcium hydroxide solution, and the concentration of the alkaline solution is 0.1 mol / L-1 mol / L;

[0018] In this invention, the amount of alkaline solution used in S2 is 50%-300% of the crude product mass.

[0019] In this invention, the hydrophobic medium in S3 is an inorganic hydrophobic medium or an organic hydrophobic medium;

[0020] In this invention, the inorganic hydrophobic medium is one or more of hydrophobic ceramic membranes, metal membranes, and geopolymers;

[0021] In this invention, the organic hydrophobic medium is one or more of polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, and silicone;

[0022] In this invention, the pore size of the hydrophobic medium is 0.01 μm-10 μm, preferably 0.1-5 μm;

[0023] In this invention, the temperature of step S3 is 50-180℃ and the pressure is gauge pressure 0.1-0.5MPa.

[0024] In this invention, the pressure control gauge pressure of the vacuum distillation in step S4 is -0.095 to -0.1 MPa, the temperature is 115-135℃, and the reflux ratio is 0.1-1.

[0025] This invention utilizes the weak acidity of residual phenol in the crude product, which reacts with an alkaline solution to form phenol salts that dissolve in the alkaline solution, thereby transferring phenol from the crude product to the alkaline solution. Then, based on the difference in hydrophilicity and hydrophobicity and density between the two, hydrophobic materials are used to separate them to obtain a crude ethylene glycol phenyl ether product with low phenol residue. The crude product is then further purified by distillation to obtain a high-purity ethylene glycol phenyl ether product with low phenol residue.

[0026] In this invention, the low-phenol-residue ethylene glycol phenyl ether obtained by the above production method has a phenol content of <1 ppm and an ethylene glycol phenyl ether content of >99.9 wt%.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The production method described in this invention can obtain a high-purity ethylene glycol phenyl ether product with an effective content >99.9 wt%.

[0029] (2) This invention utilizes the principle of alkaline extraction combined with efficient coalescence technology to efficiently reduce the phenol residue in ethylene glycol phenyl ether products to below 1 ppm. Detailed Implementation

[0030] The following embodiments further illustrate the technical solutions provided by the present invention, but the present invention is not limited to the listed embodiments, and also includes any other known modifications within the scope of the present invention.

[0031] The raw materials used are 99% phenol, 95% potassium hydroxide, 95% sodium hydroxide, 85% phosphoric acid solution, 98% sulfuric acid, 37% hydrochloric acid solution, and 68% nitric acid solution. Ethylene oxide is a Wanhua Chemical product, industrial grade.

[0032] The reactor used is a 3L stainless steel reactor, and all pressures are gauge pressures; the coalescing separator is a coalescing separation device filled with hydrophobic material.

[0033] The purity of ethylene glycol phenyl ether and the content of high-grade phenol (>10 ppm) were tested according to the national standard QBT5290-2018. Low-grade phenol residue (≤10 ppm) was tested using an Agilent 1260 Infinity liquid chromatograph.

[0034] Example 1

[0035] 500g of phenol and 0.5g of potassium hydroxide were added to a 3L stainless steel reactor. After nitrogen purging, the temperature was raised to 120℃, and 246g of ethylene oxide was continuously added for ring-opening polymerization. The reaction pressure was controlled at 0.3MPaG. After the feeding was completed, the reaction continued until the pressure in the reactor no longer decreased, and crude ethylene glycol phenyl ether was obtained.

[0036] Add phosphoric acid solution to the crude product until the pH reaches 5, then add 746g of 0.5mol / L sodium hydroxide solution to the reaction vessel and mix thoroughly with the crude product for 30min.

[0037] The above mixture was input into a solution containing 0.2m 2 Polypropylene hydrophobic medium (pore size 1μm) is treated by a coalescing separator at a reaction temperature of 100℃ and a reaction pressure of 0.2MPaG. After coalescing treatment, the organic phase is a crude product of ethylene glycol phenyl ether with low phenol residue, and the aqueous phase is an alkaline solution that can be recycled.

[0038] The crude ethylene glycol phenyl ether with low phenol residue was purified by distillation. The pressure inside the column was controlled at -0.095 MPaG, the bottom temperature at 130℃, and the reflux ratio at 0.2. The top of the column yielded a high-purity ethylene glycol phenyl ether product with low phenol residue.

[0039] The test results for ethylene glycol phenyl ether were: purity 99.95%, phenol 0.2 ppm.

[0040] Example 2

[0041] 500g of phenol and 1g of sodium hydroxide were added to a 3L stainless steel reactor. After nitrogen purging, the temperature was raised to 150℃, and 257g of ethylene oxide was continuously added for ring-opening polymerization. The reaction pressure was controlled at 0.1MPaG. After the feeding was completed, the reaction continued until the pressure in the reactor no longer decreased, and crude ethylene glycol phenyl ether was obtained.

[0042] Add sulfuric acid solution to the crude product until the pH reaches 6, then add 379g of 0.1mol / L potassium hydroxide solution to the reaction vessel and mix thoroughly with the crude product for 20min.

[0043] The above mixture was input into a solution containing 0.2m 2 The hydrophobic ceramic membrane (1 μm pore size) was treated by a coalescing separator at a reaction temperature of 150 °C and a reaction pressure of 0.1 MPaG. After coalescing, the organic phase was a crude product of ethylene glycol phenyl ether with low phenol residue, and the aqueous phase was an alkaline solution that could be recycled.

[0044] The crude ethylene glycol phenyl ether with low phenol residue was purified by distillation. The pressure inside the column was controlled at -0.098 MPaG, the bottom temperature at 115℃, and the reflux ratio at 0.5. The top of the column yielded a high-purity ethylene glycol phenyl ether product with low phenol residue.

[0045] The test results for ethylene glycol phenyl ether were: purity 99.93%, phenol 0.1 ppm.

[0046] Example 3

[0047] 500g of phenol and 2.5g of sodium methoxide were added to a 3L stainless steel reactor. After nitrogen purging, the temperature was raised to 130℃, and 253g of ethylene oxide was continuously added for ring-opening polymerization. The reaction pressure was controlled at 0.4MPaG. After the feeding was completed, the reaction continued until the pressure in the reactor no longer decreased, and crude ethylene glycol phenyl ether was obtained.

[0048] Add hydrochloric acid solution to the crude product until the pH reaches 7, then add 1505g of 0.8mol / L sodium hydroxide solution to the reaction vessel and mix thoroughly with the crude product for 60min.

[0049] The above mixture was input into a solution containing 0.2m 2 The hydrophobic polytetrafluoroethylene (0.5 μm pore size) is treated by a coalescing separator at a reaction temperature of 180℃ and a reaction pressure of 0.5 MPaG. After coalescing treatment, the organic phase is a crude product of ethylene glycol phenyl ether with low phenol residue, and the aqueous phase is an alkaline solution that can be recycled.

[0050] The crude ethylene glycol phenyl ether with low phenol residue was purified by distillation. The pressure inside the column was controlled at -0.096 MPaG, the bottom temperature at 135℃, and the reflux ratio at 1. The top of the column yielded a high-purity ethylene glycol phenyl ether product with low phenol residue.

[0051] The test results for ethylene glycol phenyl ether were: purity 99.99% and phenol 0.2 ppm.

[0052] Example 4

[0053] 500g of phenol and 0.25g of metallic sodium were added to a 3L stainless steel reactor. After nitrogen purging, the temperature was raised to 110℃, and 246g of ethylene oxide was continuously added for ring-opening polymerization. The reaction pressure was controlled at 0.5MPaG. After the feeding was completed, the reaction continued until the pressure in the reactor no longer decreased, and crude ethylene glycol phenyl ether was obtained.

[0054] Add nitric acid solution to the crude product until the pH reaches 4, then add 2237g of 0.3mol / L potassium hydroxide solution to the reaction vessel and mix thoroughly with the crude product for 10min.

[0055] The above mixture was input into a solution containing 0.2m 2 The hydrophobic polypropylene (pore size 0.3μm) is treated by a coalescing separator at a reaction temperature of 50℃ and a reaction pressure of 0.3MPaG. After coalescing, the organic phase is a crude product of ethylene glycol phenyl ether with low phenol residue, and the aqueous phase is an alkaline solution that can be recycled.

[0056] The crude ethylene glycol phenyl ether product with low phenol residue was purified by distillation. The pressure inside the column was controlled at -0.097 MPaG, the bottom temperature at 120℃, and the reflux ratio at 0.1. The top of the column yielded a high-purity ethylene glycol phenyl ether product with low phenol residue.

[0057] The test results for ethylene glycol phenyl ether were: purity 99.92% and phenol 0.3 ppm.

[0058] Example 5

[0059] 500g of phenol and 1.5g of potassium methoxide were added to a 3L stainless steel reactor. After nitrogen purging, the temperature was raised to 180℃, and 250g of ethylene oxide was continuously added for ring-opening polymerization. The reaction pressure was controlled at 0.2MPaG. After the feeding was completed, the reaction continued until the pressure in the reactor no longer decreased, and crude ethylene glycol phenyl ether was obtained.

[0060] Add phosphoric acid solution to the crude product until the pH reaches 6, then add 600g of 1mol / L potassium hydroxide solution to the reaction vessel and mix thoroughly with the crude product for 50min.

[0061] The above mixture was input into a solution containing 0.2m 2 The hydrophobic silicone (5μm pore size) was treated by a coalescing separator at a reaction temperature of 80℃ and a reaction pressure of 0.4MPaG. After coalescing, the organic phase was a crude ethylene glycol phenyl ether product with low phenol residue, and the aqueous phase was an alkaline solution that could be recycled.

[0062] The crude ethylene glycol phenyl ether with low phenol residue was purified by distillation. The pressure inside the column was controlled at -0.099 MPaG, the bottom temperature at 125℃, and the reflux ratio at 0.8. The top of the column yielded a high-purity ethylene glycol phenyl ether product with low phenol residue.

[0063] The test results for ethylene glycol phenyl ether were: purity 99.97% and phenol 0.1 ppm.

[0064] Comparative Example 1

[0065] Compared with Example 1, the difference is that this comparative example does not use alkaline solution agglomeration treatment.

[0066] 500g of phenol and 0.5g of potassium hydroxide were added to a 3L stainless steel reactor. After nitrogen purging, the temperature was raised to 120℃, and 246g of ethylene oxide was continuously added for ring-opening polymerization. The reaction pressure was controlled at 0.3MPaG. After the feeding was completed, the reaction continued until the pressure in the reactor no longer decreased, and crude ethylene glycol phenyl ether was obtained.

[0067] Phosphoric acid solution was added to the crude product until the pH reached 5. The crude ethylene glycol phenyl ether product was then purified by distillation. The pressure inside the column was controlled at -0.095 MPaG, the bottom temperature at 130℃, and the reflux ratio at 0.2. Ethylene glycol phenyl ether product was obtained at the top of the column.

[0068] The test results for ethylene glycol phenyl ether were: purity 99.82% and phenol 620 ppm.

[0069] Comparative Example 2

[0070] Compared with Example 1, the difference is that this comparative example does not undergo distillation purification.

[0071] 500g of phenol and 0.5g of potassium hydroxide were added to a 3L stainless steel reactor. After nitrogen purging, the temperature was raised to 120℃, and 246g of ethylene oxide was continuously added for ring-opening polymerization. The reaction pressure was controlled at 0.3MPaG. After the feeding was completed, the reaction continued until the pressure in the reactor no longer decreased, and crude ethylene glycol phenyl ether was obtained.

[0072] Add phosphoric acid to the crude product until the pH reaches 5, then add 746g of 0.5mol / L sodium hydroxide solution to the reaction vessel and mix thoroughly with the crude product for 30min.

[0073] The above mixture was input into a solution containing 0.2m 2 Polypropylene hydrophobic medium (pore size 1μm) is treated by a coalescing separator at a reaction temperature of 100℃ and a reaction pressure of 0.2MPaG. After coalescing treatment, the organic phase is a crude product of ethylene glycol phenyl ether with low phenol residue, and the aqueous phase is an alkaline solution that can be recycled.

[0074] The test results for ethylene glycol phenyl ether were: purity 95.25%, phenol 0.8 ppm.

[0075] Comparative Example 3

[0076] Compared with Example 1, the difference is that this comparative example does not perform coalescence separation, but uses a static liquid separation method to separate the crude ethylene glycol phenyl ether product and the aqueous alkaline solution.

[0077] 500g of phenol and 0.5g of potassium hydroxide were added to a 3L stainless steel reactor. After nitrogen purging, the temperature was raised to 120℃, and 246g of ethylene oxide was continuously added for ring-opening polymerization. The reaction pressure was controlled at 0.3MPaG. After the feeding was completed, the reaction continued until the pressure in the reactor no longer decreased, and crude ethylene glycol phenyl ether was obtained.

[0078] Add phosphoric acid solution to the crude product until the pH reaches 5, then add 746g of 0.5mol / L sodium hydroxide solution to the reaction vessel and mix thoroughly with the crude product for 30min.

[0079] The above mixture was allowed to stand for 60 minutes to separate into two phases. The organic phase was crude ethylene glycol phenyl ether, and the aqueous phase was an alkaline solution.

[0080] The crude ethylene glycol phenyl ether product was purified by distillation. The pressure inside the column was controlled at -0.095 MPaG, the bottom temperature at 130℃, and the reflux ratio at 0.2. Ethylene glycol phenyl ether product was obtained at the top of the column.

[0081] The test results for ethylene glycol phenyl ether were: purity 99.55% and phenol 8.6 ppm.

[0082] Those skilled in the art will understand that modifications or adjustments can be made to the present invention based on the teachings of this specification. These modifications or adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A method for producing ethylene glycol phenyl ether with low phenol residue, characterized in that, The method includes the following steps: S1: Phenol reacts with ethylene oxide under the action of an alkaline catalyst to obtain the crude product; S2: Neutralize the crude product to neutral or acidic using acid, and then mix it with an alkaline solution; S3: The mixed solution obtained in S2 is passed through a hydrophobic medium to aggregate, settle, and separate to obtain a crude ethylene glycol phenyl ether product with low phenol residue; S4: The crude product is subjected to vacuum distillation to obtain ethylene glycol phenyl ether with low phenol residue; The hydrophobic medium in S3 is an inorganic hydrophobic medium or an organic hydrophobic medium. The inorganic hydrophobic medium is one or more of hydrophobic ceramic membranes, metal membranes, and geopolymers. The organic hydrophobic medium is one or more of polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, and silicone.

2. The method according to claim 1, characterized in that, The alkaline catalyst described in S1 is one or more of sodium hydroxide, potassium hydroxide, cesium hydroxide, barium hydroxide, calcium hydroxide, lithium hydroxide, sodium methoxide, potassium methoxide, metallic sodium, and metallic potassium. And / or, the amount of alkaline catalyst used in S1 is 0.05%-0.5% of the mass of phenol.

3. The method according to claim 1, characterized in that, The molar ratio of phenol to ethylene oxide in S1 is 1:(1.05-1.1).

4. The method according to claim 1, characterized in that, In S1, phenol reacts with ethylene oxide, with the gauge pressure controlled at 0.1-0.5 MPa and the temperature at 110-180℃.

5. The method according to claim 1, characterized in that, The acid mentioned in S2 is one or more of phosphoric acid solution, sulfuric acid solution, hydrochloric acid solution and nitric acid solution.

6. The method according to claim 5, characterized in that, In S2, acid is used to control the pH of the crude product to 4-7.

7. The method according to claim 1, characterized in that, The alkaline solution in S2 is one or more of sodium hydroxide solution, potassium hydroxide solution, and calcium hydroxide solution.

8. The method according to claim 7, characterized in that, The concentration of the alkaline solution in S2 is 0.1 mol / L-1 mol / L, and the amount of alkaline solution used is 50%-300% of the crude product mass.

9. The method according to claim 8, characterized in that, Mix S2 with alkaline solution for 10-60 minutes.

10. The method according to claim 1, characterized in that, The hydrophobic medium described in S3 has a pore size of 0.01 μm-10 μm.

11. The method according to claim 10, characterized in that, The hydrophobic medium described in S3 has a pore size of 0.1-5 μm.

12. The method according to claim 10 or 11, characterized in that, The temperature of S3 is 50-180℃, and the pressure is gauge pressure 0.1-0.5MPa.

13. The method according to claim 1, characterized in that, The pressure control gauge for vacuum distillation described in S4 is -0.095 to -0.1 MPa, the temperature is 115-135℃, and the reflux ratio is 0.1-1.