Method for treating ester-containing fusel oil

Abstract

The invention relates to the field of chemical waste treatment, and discloses a treatment method of ester-containing fusel oil. The treatment method comprises the following steps: S1, in the presence of a metal oxide, mixing ester-containing fusel oil and ester for reaction; and S2, separating glycollate and / or ethylene glycol acetate from the reaction product obtained in S1. The method provided by the invention has the advantages of simple process steps, high efficiency and low energy consumption, and the introduction of the metal oxide accelerates the reaction rate and improves the yield of glycollate.

Description

Technical Field

[0001] The present invention relates to the field of chemical waste treatment, in particular to a treatment method for ester-containing fusel oil. Background Art

[0002] Polyglycolide (PGA), also known as polyglycolic acid, is a highly crystalline, biodegradable aliphatic polymer with rapid degradation. It is primarily used in medical consumables, mulch films, and other fields. However, there is no mature, environmentally friendly MG production process in China. The industrial process still primarily relies on hydrolysis with chloroacetic acid and carbonylation and re-esterification of formaldehyde molecules. These processes are complex, lengthy, costly, environmentally polluting, and produce low yields of the target product. However, my country has abundant coal resources. Dimethyl oxalate (DMO) is produced from coal-to-syngas, which is then hydrogenated to methyl glycolate (MG), which is then used to produce polyglycolic acid (PGA). Research has revealed that the PGA production process also contains a significant amount of acetate byproducts. Utilizing these acetate byproducts by reacting them with low-boiling-point esters to recover the valuable monomers would have significant economic value. However, limited research is currently underway in this area. Therefore, developing a technology to extract glycolic acid from the acetate byproduct is of great significance. Summary of the Invention

[0003] The present invention aims to overcome the problem in the prior art of being unable to recover valuable glycolic acid esters and ethylene glycol acetate from ester-containing fusel oil, and to provide a method for treating ester-containing fusel oil. The method increases the yield of glycolic acid esters and produces ethylene glycol acetate as a by-product in the presence of a metal oxide.

[0004] In order to achieve the above object, the present invention provides a method for treating ester-containing fusel oil, the method comprising the following steps:

[0005] S1. In the presence of a metal oxide, mixing an ester-containing fusel oil and an ester to react;

[0006] S2. Separating glycolate and / or glycol acetate from the reaction product obtained in S1.

[0007] Through the above technical solution, the beneficial effects of the present invention include at least:

[0008] The method provided by the present invention has simple process steps, high efficiency and low energy consumption. The introduction of metal oxides accelerates the reaction rate, improves the yield of glycolate, and reduces the solvent purity requirement. While increasing the yield of glycolate, ethylene glycol acetate is produced as a by-product, which is economical and practical. Ester-containing fusel oil can be fully utilized, subsequent processes are simplified, separation difficulty is reduced, and the economic benefits of the enterprise are increased.

[0009] In a preferred embodiment of the present invention, glycolate esters are recovered from fusel oil produced in a dimethyl oxalate hydrogenation unit, with ethylene glycol acetate as a byproduct. Fusel oil from dimethyl oxalate hydrogenation units is rich in various ester oligomers. The method provided by the present invention can convert high-boiling products such as ester oligomers and rapidly recover ester oligomers from fusel oil using low-boiling esters, thereby improving the quality and efficiency of fusel oil waste and bringing significant economic benefits to the PGA production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 The present invention is a flowchart of a method for treating ester-containing fusel oil in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0011] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0012] The present invention provides a method for treating ester-containing fusel oil, which comprises the following steps:

[0013] S1. In the presence of a metal oxide, mixing an ester-containing fusel oil and an ester to react;

[0014] S2. Separating glycolate and / or glycol acetate from the reaction product obtained in S1.

[0015] According to the present invention, preferably, the metal oxides include: zinc oxide, zirconium oxide and aluminum oxide.

[0016] The present invention has no particular limitation on the valence of zinc in zinc oxide, the valence of zirconium in zirconium oxide, and the valence of aluminum in aluminum oxide. Preferably, the zinc oxide is ZnO; and / or the zirconium oxide is ZrO2; and / or the aluminum oxide is Al2O3.

[0017] In order to make the zinc oxide, zirconium oxide and aluminum oxide in the metal oxide play a better synergistic role, preferably, the contents of zinc oxide, zirconium oxide and aluminum oxide in the metal oxide are 20-80wt%, 5-45wt% and 1-30wt% respectively.

[0018] Furthermore, in the metal oxide, the contents of zinc oxide, zirconium oxide and aluminum oxide are 40-70 wt%, 10-40 wt% and 5-20 wt% respectively.

[0019] In the present invention, the method for preparing the metal oxide may include: coprecipitating, impregnating, or mechanically mixing the above-mentioned metal salt solution and / or the above-mentioned metal oxide, preferably the metal salt solution, to prepare a precursor, and then drying, calcining, and forming the precursor to obtain the metal oxide. The metal salt solution may be, for example, a metal nitrate solution, a metal sulfate solution, a metal chloride solution, or a metal acetate solution; preferably, a metal nitrate solution.

[0020] In a preferred embodiment of the present invention, the preparation method of the metal oxide comprises: dissolving zinc nitrate, zirconium nitrate, and aluminum nitrate in deionized water to a solid-liquid ratio of 1:(3-50) to obtain solution A; and dissolving an alkaline precipitant in deionized water to a solid-liquid ratio of 1:(3-50) to obtain solution B. Solutions A and B are mixed in parallel, then aged at 40-80°C for 1-4 hours; then solid-liquid separation and drying are performed; and then calcined at 300-650°C for 1-6 hours to obtain the metal oxide. The alkaline precipitant may be sodium carbonate, sodium hydroxide, or potassium hydroxide, preferably sodium carbonate. Solid-liquid separation may be performed by filtration; and drying may be performed in a drying oven, and drying conditions may include drying at 50-130°C for 1-12 hours.

[0021] In another preferred embodiment of the present invention, the metal oxide preparation method comprises: mechanically mixing zinc oxide, zirconium oxide, and aluminum oxide for 1-3 hours; drying, and then calcining at 300-650°C for 1-6 hours to obtain the metal oxide. The mechanical mixing can be performed in a ball mill; the drying can be performed in a drying oven, and the drying conditions can include drying at 50-130°C for 1-12 hours.

[0022] In the present invention, zinc nitrate, zirconium nitrate and aluminum nitrate may exist in a form containing or not containing bound water. Zinc nitrate may be Zn(NO3)2·6H2O, zirconium nitrate may be Zr(NO3)4·5H2O, and aluminum nitrate may be Al(NO3)3·9H2O. In the present invention, the amounts of zinc nitrate, zirconium nitrate and aluminum nitrate are calculated in the form of Zn(NO3)2·6H2O, Zr(NO3)4·5H2O and Al(NO3)3·9H2O, respectively.

[0023] According to the present invention, the ester-containing fusel oil can be fusel oil from a dimethyl oxalate hydrogenation unit. The fusel oil from a dimethyl oxalate hydrogenation unit contains various ester oligomers and is mainly used for incineration or waste treatment, with low economic value. Preferably, the ester-containing fusel oil comprises: at least one of ethylene glycol, glycolic acid, and methyl glycolate, and a polymer generated by a polymerization reaction of at least one of ethylene glycol, glycolic acid, and methyl glycolate. The polymer (i.e., ester oligomer) refers to a homopolymer or copolymer that can be obtained by polymerization reaction of glycolic acid, methyl glycolate, ethylene glycol, etc.

[0024] Furthermore, the ester-containing fusel oil also includes: monohydric alcohols such as methanol, ethanol, and butanol, dihydric alcohols such as propylene glycol and butanediol, ethers such as dimethyl ether and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, and at least one of ketones such as 1,4-dioxane-2,5-dione.

[0025] According to the present invention, preferably, the content of the polymer in the ester-containing fusel oil is 5 wt% or more; preferably 10-80 wt%.

[0026] According to the present invention, preferably, in the ester-containing fusel oil, the content of ethylene glycol is 10-80 wt %, the content of methyl glycolate is 0-30 wt %, and the content of glycolic acid is 0-10 wt %.

[0027] In order to further promote the conversion of high-boiling products such as oligoesters, the ester is preferably selected from low-boiling esters, more preferably methyl acetate and / or ethyl acetate. Methyl acetate and ethyl acetate are selected, and the corresponding glycolate recovered is methyl glycolate and ethyl glycolate, respectively.

[0028] Furthermore, the ester is methyl acetate.

[0029] According to the present invention, the ester may contain a small amount of saturated alcohol, preferably selected from C1-C4 saturated monohydric alcohols, such as methanol. The content of saturated alcohol in the ester is not higher than 20wt%, preferably not higher than 15wt%. When the ester does not contain saturated alcohol, the polymer in the ester-containing fusel oil has a higher conversion rate, but the inventors have found that when the content of the saturated alcohol in the ester meets this range, the saturated alcohol and the ester oligomer undergo transesterification to generate glycolate, and the transesterification reaction between ethylene glycol and the ester is not excessively suppressed. An appropriate amount of alcohol content can reduce the refining requirements for the solvent raw material, reduce costs, and does not significantly affect the reaction process.

[0030] According to the present invention, preferably, in S1, the ester-containing fusel oil and the ester are mixed in a weight ratio of 1:(0.5-30), preferably 1:(1.1-5).

[0031] In order to make the metal oxide better promote the reaction, preferably, the amount of the metal oxide is 1-50g based on 100g of the ester-containing fusel oil.

[0032] According to the present invention, preferably, the reaction pressure is 0.1-8 MPa; the reaction temperature is not higher than the boiling point of the ester and its azeotrope under the same pressure conditions, preferably, the reaction temperature is 80-250°C, and the reaction time is 1 min-6 h.

[0033] Furthermore, the reaction pressure is 1-4 MPa; the reaction temperature is 130-190° C.; and the reaction time is 10 min-3 h.

[0034] In S2, light components with a lower boiling point than glycolate are first separated; then glycolate is separated and removed; and then ethylene glycol acetate, with a higher boiling point than glycolate, is separated from the heavy components to separate the ethylene glycol acetate. The heavy components serve as the final bottom feed, thereby recovering glycolate and / or ethylene glycol acetate.

[0035] The present invention does not particularly limit the method for separating light components having a boiling point lower than that of glycolate. For example, distillation, distillation concentration, adsorption, and extraction can be used. Preferably, distillation is used to separate the light components. Both atmospheric distillation and reduced pressure distillation can be used. Preferably, the distillation is carried out at a temperature not higher than 160°C.

[0036] The present invention does not particularly limit the method for separating glycolate esters. For example, atmospheric distillation, vacuum distillation, atmospheric distillation, vacuum distillation, pressurized distillation, etc. can be used. Preferably, the glycolate ester is separated by vacuum distillation, preferably at a temperature not higher than 160°C.

[0037] The present invention does not particularly limit the method for separating ethylene glycol acetate. For example, atmospheric distillation, vacuum distillation, atmospheric distillation, vacuum distillation, pressurized distillation, etc. can be used. Preferably, vacuum distillation is used to separate ethylene glycol acetate, and the distillation is preferably carried out at a temperature not higher than 160°C.

[0038] According to a preferred embodiment of the present invention, in S2, the separation method includes:

[0039] a. subjecting the reaction product obtained in S1 to a first distillation at 101-151 kPa and 60-160° C., controlling the number of plates in the first distillation to 5-40 and the reflux ratio to 0.2-9;

[0040] Alternatively, the reaction product obtained in S1 is subjected to a first distillation under the conditions of 50 Pa-101 kPa and 50-150° C., with the number of plates of the first distillation controlled to be 5-40 and the reflux ratio to be 0.2-9, to obtain light components and undistilled materials from the first distillation;

[0041] b. subjecting the undistilled material from the first distillation to a second distillation at 100 Pa-101 kPa and 50-160 ° C., controlling the number of plates in the second distillation to 5-40 and the reflux ratio to 0.2-9, to obtain the undistilled material from the second distillation and glycolate;

[0042] c. The undistilled material from the second distillation is subjected to a third distillation under the conditions of 50 Pa-101 kPa and 50-160 ° C., the number of plates of the third distillation is controlled to be 20-100, and the reflux ratio is 1-20, to obtain heavy components and ethylene glycol acetate.

[0043] According to the present invention, preferably, the treatment method further comprises: returning at least part of the remaining material after separating the glycolate and / or glycol acetate to S1 for mixing with the ester.

[0044] According to a preferred embodiment of the present invention, Figure 1 A method for treating ester-containing fusel oil is described, comprising the following steps: mixing and reacting ester-containing fusel oil, methyl acetate, and a metal oxide in a reaction unit, and then introducing the reaction products into a separation unit to obtain methyl glycolate and ethylene glycol acetate, a light component having a lower boiling point than the glycolate, and a heavy component having a higher boiling point than the ethylene glycol acetate. The methyl glycolate and ethylene glycol acetate are withdrawn from the separation unit as products, and at least a portion of the light component having a lower boiling point than the glycolate and at least a portion of the heavy component having a higher boiling point than the ethylene glycol acetate are returned to the reaction unit to continue the reaction.

[0045] The present invention will be described in detail below through examples and comparative examples. In the following examples, unless otherwise specified, conventional methods are used; and the reagents and materials used, unless otherwise specified, can be obtained from commercial sources.

[0046] The composition of the components was determined using gas chromatography using the normalization method. The type and content of each component were determined based on the chromatographic peaks. The specific molecular structures of heavy impurities and oligomers were difficult to determine. However, their retention times in the spectra were constant, and the content of oligomers changed significantly after the reaction, while the content of heavy impurities remained unchanged before and after the reaction. This allowed the identification of the types and contents of each component.

[0047] The composition of fusel oil is as follows: 5 wt% of methyl glycolate, 22 wt% of ethylene glycol, 63 wt% of oligomers, and 10 wt% of heavy impurities; and the pH value is 3.9.

[0048] Oligomer conversion % = (weight of oligomers in fusel oil - weight of oligomers in reaction product) ÷ weight of oligomers in fusel oil × 100%;

[0049] Glycolate selectivity (%) = (weight of glycolate in the reaction product - weight of glycolate in fusel oil) ÷ (weight of oligomers in fusel oil - weight of oligomers in the reaction product) × 100%;

[0050] Selectivity of ethylene glycol acetate (%) = (weight of ethylene glycol acetate in the reaction product - weight of ethylene glycol acetate in fusel oil) ÷ (weight of oligomers in fusel oil - weight of oligomers in the reaction product) × 100%;

[0051] Glycolate yield (%) = weight of glycolate in glycolate product / weight of glycolate in reaction product × 100%;

[0052] Yield of ethylene glycol acetate (%) = weight of ethylene glycol acetate in the ethylene glycol acetate product / weight of glycolate in the reaction product × 100%.

[0053] Example 1

[0054] Preparation of metal oxides:

[0055] Weigh 23.76 grams of zinc nitrate hexahydrate, 8.71 grams of zirconium nitrate pentahydrate, and 7.36 grams of aluminum nitrate nonahydrate and dissolve them in 500 milliliters of deionized water to obtain solution A. Separately, dissolve 14.63 grams of sodium carbonate in 150 milliliters of deionized water to obtain solution B. Add solution A and solution B to a beaker in parallel and mix, then age at 70°C for 2 hours. After filtering, dry at 110°C for 8 hours, and calcine at 450°C for 4 hours. The resulting metal oxide has a composition of 65% by weight ZnO, 25% by weight ZrO2, and 10% by weight Al2O3. This metal oxide is defined as metal oxide S1.

[0056] Recovery of glycolate and glycol acetate from fusel oil:

[0057] 100 g of fusel oil, 200 g of methyl acetate and 2 g of S1 metal oxide were added to a reactor. The temperature was raised to 170°C under nitrogen protection, the system pressure was maintained at 3 MPa, and the temperature was kept for 30 minutes. After cooling, the reaction liquid was analyzed by chromatography. The conversion rate of the oligomer was 73.8%, and the selectivities of methyl glycolate and ethylene glycol acetate in the obtained product were 47.3% and 154.8%, respectively.

[0058] The reaction product was first separated into light components in a primary separation tower at an operating pressure of 40 kPa, 20 plates, and a reflux ratio of 5. A stream rich in light components was obtained at the top of the tower, and the bottom liquid phase was fed to the product tower. The product tower was operated at a pressure of 10 kPa, 20 plates, and a reflux ratio of 5. Methyl glycolate product was obtained at the top of the tower, and the bottom liquid was fed to the by-product tower. In the by-product tower, operating pressure of 10 kPa, 100 plates, and a reflux ratio of 10, ethylene glycol acetate product was obtained at the top of the tower, and heavy components were obtained in the bottom. The light component stream yielded 155 g, of which methyl acetate had a purity of 87.2%; 25 g of methyl glycolate product had a purity of 98% and a yield of 90.74%; and 70 g of ethylene glycol acetate product had a purity of 97% and a yield of 94.31%.

[0059] Example 2

[0060] Preparation of Metal Oxide: The metal oxide was prepared according to the method described in Example 1, except that the raw material amounts, drying conditions, and calcination conditions were changed: drying at 50°C for 12 hours and calcining at 550°C for 2 hours. The resulting metal oxide had a composition of 50 wt% ZnO, 30 wt% ZrO2, and 20 wt% Al2O3. This catalyst was designated Metal Oxide S2.

[0061] Recovery of glycolate and glycol acetate from fusel oil:

[0062] 100 g of fusel oil, 300 g of methyl acetate and 2 g of S2 metal oxide were added to a reactor. The temperature was raised to 150°C under nitrogen protection, the system pressure was maintained at 1 MPa, and the mixture was kept warm for 1 hour. After cooling, the reaction liquid was taken for chromatographic analysis. The conversion rate of the oligomer was 68.3%, and the selectivities of methyl glycolate and ethylene glycol acetate in the obtained product were 46% and 153.5%, respectively.

[0063] The reaction product was first separated into light components in a primary separation tower operating at 40 kPa, 20 plates, and a reflux ratio of 5. A stream rich in light components was obtained at the top of the tower, and the bottom liquid phase was fed to the product tower. The product tower was operated at 10 kPa, 20 plates, and a reflux ratio of 5. Methyl glycolate product was obtained at the top of the tower, and the bottom liquid was fed to the by-product tower. In the by-product tower, operating at 10 kPa, 100 plates, and a reflux ratio of 10, ethylene glycol acetate product was obtained at the top of the tower, while heavy components were obtained in the bottom. The light component stream yielded 255 g, of which methyl acetate had a purity of 90.7%; 23 g of methyl glycolate product had a purity of 98% and a yield of 90.89%; and 63 g of ethylene glycol acetate product had a purity of 97% and a yield of 92.59%.

[0064] Example 3

[0065] Preparation of Metal Oxide: The metal oxide was prepared according to the method for preparing the metal oxide in Example 1, except that the raw material amounts, drying conditions, and calcination conditions were changed to: drying at 130°C for 1 hour, and calcining at 650°C for 1 hour. The resulting metal oxide had a composition of 40 wt% ZnO, 40 wt% ZrO2, and 20 wt% Al2O3. This metal oxide was defined as Metal Oxide S3.

[0066] Recovery of glycolate and glycol acetate from fusel oil:

[0067] 100 g of fusel oil, 400 g of methyl acetate and 2 g of S3 metal oxide were added to a reactor. The temperature was raised to 130°C under nitrogen protection, the pressure was maintained at 4 MPa, and the temperature was kept for 3 hours. After cooling, the reaction liquid was taken for chromatographic analysis. The conversion rate of the oligomer was 67.5%, and the selectivities of methyl glycolate and ethylene glycol acetate in the obtained product were 44.7% and 150.6%, respectively.

[0068] The reaction product was first separated into light components in a primary separation tower at an operating pressure of 40 kPa, 20 plates, and a reflux ratio of 5. A stream rich in light components was obtained at the top of the tower, and the bottom liquid phase was fed to the product tower. The product tower was operated at a pressure of 10 kPa, 20 plates, and a reflux ratio of 5. Methyl glycolate product was obtained at the top of the tower, and the bottom liquid was fed to the by-product tower. In the by-product tower, operating pressure of 10 kPa, 100 plates, and a reflux ratio of 10, ethylene glycol acetate product was obtained at the top of the tower, while heavy components were obtained in the bottom. The light component stream yielded 353 g, of which methyl acetate had a purity of 93.8%; 22 g of methyl glycolate product had a purity of 98% and a yield of 89.83%; and 62 g of ethylene glycol acetate product had a purity of 97% and a yield of 93.97%.

[0069] Example 4

[0070] Preparation of Metal Oxide: The metal oxide was prepared according to the method for preparing the metal oxide in Example 1, except that the raw material amounts and calcination conditions were changed to 300°C for 6 hours. The resulting metal oxide had a composition of 70 wt% ZnO, 10 wt% ZrO2, and 20 wt% Al2O3. This metal oxide was defined as metal oxide S4.

[0071] Recovery of glycolate and glycol acetate from fusel oil:

[0072] 100 g of fusel oil, 100 g of methyl acetate and 2 g of S4 metal oxide were added to a reactor. The temperature was raised to 190°C under nitrogen protection, the system pressure was maintained at 2 MPa, and the temperature was kept for 20 minutes. After cooling, the reaction liquid was analyzed by chromatography. The conversion rate of the oligomer was 69.8%, and the selectivities of methyl glycolate and ethylene glycol acetate in the obtained product were 47.7% and 154.5%, respectively.

[0073] The reaction product was first separated into light components in a primary separation tower at an operating pressure of 40 kPa, 20 plates, and a reflux ratio of 5. A stream rich in light components was obtained at the top of the tower, and the bottom liquid phase was fed to the product tower. The product tower was operated at a pressure of 10 kPa, 20 plates, and a reflux ratio of 5. Methyl glycolate product was obtained at the top of the tower, and the bottom liquid was fed to the by-product tower. In the by-product tower, operating pressure of 10 kPa, 100 plates, and a reflux ratio of 10, ethylene glycol acetate product was obtained at the top of the tower, and heavy components were obtained in the bottom. The light component stream was 60 g, of which methyl acetate had a purity of 62.9%; the methyl glycolate product was 24 g, with a purity of 98% and a yield of 90.46%; and the ethylene glycol acetate product was 65 g, with a purity of 97% and a yield of 92.72%.

[0074] Example 5

[0075] Preparation of Metal Oxide: The metal oxide was prepared according to the method of Example 1, except that the raw material amounts and aging conditions were changed to 40°C for 4 hours. The resulting metal oxide had a composition of 65 wt% ZnO, 30 wt% ZrO2, and 5 wt% Al2O3. This metal oxide was designated as Metal Oxide S5.

[0076] Recovery of glycolate and glycol acetate from fusel oil:

[0077] 100 g of fusel oil, 500 g of methyl acetate and 2 g of S5 metal oxide were added to a reactor. The temperature was raised to 190°C under nitrogen protection, the system pressure was maintained at 3 MPa, and the temperature was kept for 10 minutes. After cooling, the reaction liquid was analyzed by chromatography. The conversion rate of the oligomer was 71.4%, and the selectivities of methyl glycolate and ethylene glycol acetate in the obtained product were 44.9% and 152%, respectively.

[0078] The reaction product was first separated into light components in a primary separation tower operating at 40 kPa, 20 plates, and a reflux ratio of 5. A stream rich in light components was obtained at the top of the tower, and the bottom liquid phase was fed to the product tower. The product tower was operated at 10 kPa, 20 plates, and a reflux ratio of 5. Methyl glycolate product was obtained at the top of the tower, and the bottom liquid was fed to the by-product tower. In the by-product tower, operating at 10 kPa, 100 plates, and a reflux ratio of 10, ethylene glycol acetate product was obtained at the top of the tower, while heavy components were obtained in the bottom. The light component stream was 445 g, of which methyl acetate had a purity of 94.9%; 23 g of methyl glycolate product had a purity of 98% and a yield of 89.44%; and 67 g of ethylene glycol acetate product had a purity of 97% and a yield of 95.01%.

[0079] Example 6

[0080] Preparation of metal oxides:

[0081] Weigh 11 grams of analytically pure zinc oxide, 6 grams of analytically pure zirconium oxide, and 3 grams of analytically pure aluminum oxide, add them to a ball mill, mix them mechanically for 2 hours, dry them in a drying oven at 100°C for 8 hours, and then calcine them at 450°C for 4 hours. The resulting metal oxide has a composition of 55% by weight of ZnO, 30% by weight of ZrO₂, and 15% by weight of Al₂O₃. This metal oxide is defined as metal oxide S6.

[0082] Recovery of glycolate and glycol acetate from fusel oil:

[0083] 100 g of fusel oil, 300 g of methyl acetate and 2 g of S6 metal oxide were added to a reactor. The temperature was raised to 170°C under nitrogen protection, the system pressure was maintained at 3 MPa, and the temperature was kept for 30 minutes. After cooling, the reaction liquid was analyzed by chromatography. The conversion rate of the oligomer was 65.7%, and the selectivities of methyl glycolate and ethylene glycol acetate in the obtained product were 41.5% and 147.1%, respectively.

[0084] The reaction product was first separated into light components in a primary separation tower operating at 40 kPa, 20 plates, and a reflux ratio of 5. A stream rich in light components was obtained at the top of the tower, and the bottom liquid phase was fed to the product tower. The product tower was operated at 10 kPa, 20 plates, and a reflux ratio of 5. Methyl glycolate product was obtained at the top of the tower, and the bottom liquid was fed to the by-product tower. In the by-product tower, operating at 10 kPa, 100 plates, and a reflux ratio of 10, ethylene glycol acetate product was obtained at the top of the tower, and heavy components were obtained in the bottom. The light component stream yielded 170 g, of which methyl acetate had a purity of 91.3%; 20 g of methyl glycolate product had a purity of 98% and a yield of 88.29%; and 58 g of ethylene glycol acetate product had a purity of 97% and a yield of 92.38%.

[0085] Example 7

[0086] Preparation of Metal Oxide: The metal oxide was prepared according to the method for preparing the metal oxide in Example 6, except that the raw material amounts and calcination conditions were changed to 550°C for 3 hours. The resulting metal oxide had a composition of 45 wt% ZnO, 35 wt% ZrO2, and 20 wt% Al2O3. This metal oxide was defined as Metal Oxide S7.

[0087] Recovery of glycolate and glycol acetate from fusel oil:

[0088] 100 g of fusel oil, 100 g of methyl acetate and 2 g of S7 metal oxide were added to a reactor. The temperature was raised to 160°C under nitrogen protection, the system pressure was maintained at 2 MPa, and the temperature was kept for 1 hour. After cooling, the reaction liquid was analyzed by chromatography. The conversion rate of the oligomer was 64.4%, and the selectivities of methyl glycolate and ethylene glycol acetate in the obtained product were 39.4% and 145.8%, respectively.

[0089] The reaction product was first separated into light components in a primary separation tower at an operating pressure of 40 kPa, 20 plates, and a reflux ratio of 5. A stream rich in light components was obtained at the top of the tower, and the bottom liquid phase was fed to the product tower. The product tower was operated at a pressure of 10 kPa, 20 plates, and a reflux ratio of 5. Methyl glycolate product was obtained at the top of the tower, and the bottom liquid was fed to the by-product tower. In the by-product tower, operating pressure of 10 kPa, 100 plates, and a reflux ratio of 10, ethylene glycol acetate product was obtained at the top of the tower, and heavy components were obtained in the bottom. The light component stream was 70 g, of which methyl acetate had a purity of 68.2%; 19 g of methyl glycolate product had a purity of 98% and a yield of 88.67%; and 57 g of ethylene glycol acetate product had a purity of 97% and a yield of 93.4%.

[0090] Example 8

[0091] Metal oxides were prepared and glycolate and ethylene glycol acetate were recovered from fusel oil using the method of Example 1, except that the raw material amounts were varied. The resulting metal oxide had a composition of 80 wt% ZnO, 5 wt% ZrO₂, and 15 wt% Al₂O₃. Chromatographic analysis of the reaction solution revealed a 62.4% oligomer conversion, with selectivities of 38.4% for methyl glycolate and 142.7% for ethylene glycol acetate, respectively.

[0092] The light component stream is 168g, of which methyl acetate has a purity of 89.4%; methyl glycolate product is 18g, with a purity of 98% and a yield of 87.76%; and ethylene glycol acetate product is 54g, with a purity of 97% and a yield of 93.37%.

[0093] Example 9

[0094] Metal oxides were prepared and glycolate and ethylene glycol acetate were recovered from fusel oil using the method of Example 1, except that the amounts and types of raw materials were varied. The resulting metal oxide had a composition of 65 wt% ZnO, 25 wt% CaO, and 10 wt% Al₂O₃. Chromatographic analysis of the reaction solution revealed an oligomer conversion of 59.52%, with selectivities of 38.67% for methyl glycolate and 130% for ethylene glycol acetate, respectively.

[0095] The light component stream is 173g, of which methyl acetate has a purity of 89.7%; methyl glycolate product is 18g, with a purity of 98% and a yield of 90.46%; and ethylene glycol acetate product is 47g, with a purity of 97% and a yield of 92.1%.

[0096] Example 10

[0097] Metal oxides were prepared and glycolate and ethylene glycol acetate were recovered from fusel oil according to the method of Example 1, except that 0.5 g of S1 metal oxide was used instead of 2 g of S1 metal oxide. Chromatographic analysis of the reaction solution revealed a 67.6% conversion of the oligomers, and the selectivities for methyl glycolate and ethylene glycol acetate in the resulting product were 46.7% and 151.4%, respectively.

[0098] The light component stream is 158g, of which methyl acetate has a purity of 88.8%; methyl glycolate product is 23g, with a purity of 98% and a yield of 90.52%; and ethylene glycol acetate product is 63g, with a purity of 97% and a yield of 94.74%.

[0099] Example 11

[0100] Metal oxides were prepared and glycolate and ethylene glycol acetate were recovered from fusel oil according to the method of Example 1, except that the weight ratio of fusel oil to methyl acetate was different. Specifically, 50 g of methyl acetate was used instead of 200 g of methyl acetate. Chromatographic analysis of the reaction solution revealed a 42.9% conversion of the oligomers, with selectivities of 34.3% and 83.3% for methyl glycolate and ethylene glycol acetate, respectively.

[0101] The light component stream is 50g, of which the purity of methyl acetate is 66.2%; the methyl glycolate product is 12g, with a purity of 98% and a yield of 82.53%; and the ethylene glycol acetate product is 20g, with a purity of 97% and a yield of 86.22%.

[0102] Example 12

[0103] Metal oxides were prepared and glycolate and ethylene glycol acetate were recovered from fusel oil according to the method of Example 1, except that the method of "raising the temperature to 180°C under nitrogen protection" was replaced by "raising the temperature to 100°C under nitrogen protection." Chromatographic analysis of the reaction liquid revealed a 55.7% conversion of the oligomers, and the selectivities of methyl glycolate and ethylene glycol acetate in the resulting product were 41.3% and 136.8%, respectively.

[0104] The light component stream is 174g, of which methyl acetate has a purity of 88.7%; methyl glycolate product is 17g, with a purity of 98% and a yield of 85.44%; and ethylene glycol acetate product is 46g, with a purity of 97% and a yield of 92.96%.

[0105] Example 13

[0106] Metal oxides were prepared and glycolate and ethylene glycol acetate were recovered from fusel oil according to the method of Example 1, except that 200 g of ethyl acetate was substituted for 200 g of methyl acetate. Chromatographic analysis of the reaction solution revealed a 38.1% conversion of the oligomers, and the selectivities of ethyl glycolate and ethylene glycol acetate in the resulting product were 31.7% and 125%, respectively.

[0107] The light component stream is 188g, of which the purity of ethyl acetate is 89.5%; the ethyl glycolate product is 10g, with a purity of 98% and a yield of 77.78%; and the ethylene glycol acetate product is 28g, with a purity of 97% and a yield of 90.53%.

[0108] The results of the above examples and comparative examples show that Examples 1-13, using the method provided by the present invention, can effectively convert oligomers in fusel oil at a lower temperature and in a shorter reaction time, and have high selectivity for glycolate and ethylene glycol acetate, thereby effectively recovering glycolate and ethylene glycol acetate without generating complex by-products.

[0109] In addition, Example 8 varied the composition of the metal oxides, Example 9 replaced the ZrO2 in the metal oxide with CaO, Example 10 reduced the amount of metal oxide used in the reaction, Example 12 lowered the reaction temperature, and Example 13 replaced ethyl acetate with methyl acetate. Compared to Example 1, the oligomer conversion rates of Examples 8-10, 12, and 13 all decreased. Furthermore, Example 11 reduced the amount of methyl acetate used during the reaction. Compared to Example 1, not only did Example 11 reduce the oligomer conversion rate, but the purity of the methyl acetate in the light component stream was also reduced, making it unusable for mixing with fusel oil in the reaction. Examples 4 and 7 also used relatively low amounts of methyl acetate during the reaction. Similarly, the purity of the methyl acetate in the light component stream was also reduced, making it unusable for mixing with fusel oil in the reaction. This shows that when the composition and content of each component of the metal oxide, the amount of the metal oxide used during the reaction, the reaction conditions, and the type of ester meet the optimal conditions, the conversion rate of the oligomer can be further improved; moreover, when the ratio of fusel oil to ester meets the optimal conditions, the purity of the ester in the light component can be further improved, thereby enabling the reuse of the ester in the light component.

[0110] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for treating ester-containing fusel oil, characterized in that: The processing method comprises the following steps: S1. In the presence of a metal oxide, mixing an ester-containing fusel oil and an ester to react; S2. Separating glycolate and / or glycol acetate from the reaction product obtained in S1.

2. The processing method according to claim 1, characterized in that: The metal oxides include zinc oxide, zirconium oxide and aluminum oxide.

3. The processing method according to claim 2, characterized in that: In the metal oxide, the contents of zinc oxide, zirconium oxide and aluminum oxide are 20-80wt%, 5-45wt% and 1-30wt% respectively; Preferably, in the metal oxide, the contents of zinc oxide, zirconium oxide and aluminum oxide are 40-70wt%, 10-40wt% and 5-20wt% respectively.

4. The processing method according to any one of claims 1 to 3, characterized in that: The ester-containing fusel oil comprises: at least one of ethylene glycol, glycolic acid and methyl glycolate, and a polymer generated by polymerization reaction of at least one of ethylene glycol, glycolic acid and methyl glycolate.

5. The processing method according to claim 4, characterized in that: The content of the polymer in the ester-containing fusel oil is 5wt% or more; preferably 10-80wt%; Preferably, in the ester-containing fusel oil, the content of ethylene glycol is 10-80wt%, the content of methyl glycolate is 0-30wt%, and the content of glycolic acid is 0-10wt%.

6. The processing method according to any one of claims 1 to 5, characterized in that: The ester is selected from methyl acetate and / or ethyl acetate, more preferably methyl acetate.

7. The processing method according to any one of claims 1 to 6, characterized in that: In S1, the ester-containing fusel oil and the ester are mixed in a weight ratio of 1:(0.5-30), preferably 1:(1.1-5); Preferably, based on 100 g of the ester-containing fusel oil, the amount of the metal oxide is 1-50 g.

8. The processing method according to any one of claims 1 to 7, characterized in that: The reaction conditions include: reaction pressure of 0.1-8 MPa, preferably 1-4 MPa; temperature of 80-250° C., preferably 130-190° C.; time of 1 min-6 h, preferably 10 min-3 h.

9. The processing method according to any one of claims 1 to 8, characterized in that: In S2, the separation method comprises: a. subjecting the reaction product obtained in S1 to a first distillation at 101-151 kPa and 60-160° C.; Alternatively, the reaction product obtained in S1 is subjected to a first distillation under the conditions of 50Pa-101kPa and 50-150°C to obtain a light component and undistilled material from the first distillation; b. subjecting the undistilled material of the first distillation to a second distillation under the conditions of 100 Pa-101 kPa and 50-160 ° C. to obtain the undistilled material of the second distillation and glycolate; c. The undistilled material from the second distillation is distilled for a third time under the conditions of 50Pa-101kPa and 50-160°C to obtain heavy components and ethylene glycol acetate.

10. The processing method according to any one of claims 1 to 9, characterized in that: The treatment method further comprises: returning at least part of the remaining material after separating the glycolic acid ester and / or ethylene glycol acetate to S1 for mixing with the ester.

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