Method for the synthesis of 2-methoxypropene

Abstract

The application provides a synthesis method of 2-methoxypropene, which comprises the following steps: step A: performing reverse contact reaction of ethylene glycol and acetone in the presence of a first catalyst and an extractant to generate acetone acetal, separating acetone acetal-containing extract liquid and performing rectification to obtain acetone acetal; step B: contacting the acetone acetal with methanol in the presence of a second catalyst, heating to 100-150 DEG C, increasing the gauge pressure to 0.40-1.50 MPa, performing pressurized reaction rectification to generate 2-methoxypropene, and separating 2-methoxypropene as a target product; the method can reduce the reaction energy barrier, promote the synthesis of 2-methoxypropene under mild reaction conditions, is environment-friendly, low in energy consumption, low in by-product impurities, low in raw material and auxiliary material cost, simple in post-treatment and suitable for continuous industrial production; the pressurized reaction rectification is adopted to directly synthesize 2-methoxypropene from acetone acetal, and the process of synthesizing 2,2-dimethoxypropane and cracking to prepare 2-methoxypropene is reduced.

Description

Technical Field

[0001] This invention relates to the field of organic chemical synthesis technology, specifically to a method for synthesizing 2-methoxypropylene. Background Technology

[0002] 2-Methoxypropylene is an important intermediate compound with wide applications in materials, pharmaceuticals, dyes, and animal feed industries. Currently, the main synthetic routes for 2-methoxypropylene include:

[0003] Route 1: Methanol undergoes an addition reaction with an unsaturated hydrocarbon to produce 2-methoxypropylene;

[0004] Route 2: Synthesize 2,2-dimethoxypropane via indirect or direct methods, and then catalytically cleave 2,2-dimethoxypropane via gas-phase or liquid-phase methods to prepare 2-methoxypropylene.

[0005] Route 1 is simple in its steps, has a high reaction yield, and good selectivity, but it has the following drawbacks:

[0006] (1) Addition reaction catalysts are highly corrosive to equipment at high temperatures;

[0007] (2) The addition reaction is intense, difficult to control, and has poor operational safety;

[0008] (3) The source of the unsaturated hydrocarbon propyne or propadiene used is relatively difficult.

[0009] The advantages of Route 2 direct method for synthesizing 2,2-dimethoxypropane are: the raw materials methanol and acetone are inexpensive and readily available, making it easy to achieve industrial production.

[0010] Disadvantages: Low conversion rate, and methanol, acetone, and 2,2-dimethoxypropane all produce azeotropes.

[0011] Route 2: Indirect synthesis of 2,2-dimethoxypropane

[0012] (1) In an article published in the Journal of Shenyang University of Technology in 2004 by Zhang Xiaojuan of Shenyang University of Technology, ethylene glycol and acetone were used as raw materials, and dichloromethane was selected as the dehydrating agent to synthesize the intermediate 2,2-dimethyl-1,3-dioxocyclopentane, which was then exchanged with methanol to synthesize 2,2-dimethoxypropane. Cyclohexane was then added for distillation to separate 2,2-dimethoxypropane and methanol. In this route, dichloromethane had poor and incomplete dehydration ability, and the separation of 2,2-dimethoxypropane and methanol by distillation with cyclohexane was not effective.

[0013] (2) In an article published in Shaanxi Chemical Industry in 2000 by Yang Shumin et al. from the Xi'an Institute of Modern Chemistry, propylene glycol and acetone were used as raw materials, and petroleum ether at 30-60℃ was selected as a dehydrating agent to synthesize the intermediate 2,2,4-trimethyl-1,3-dioxocyclopentane. This intermediate was then exchanged with methanol to synthesize 2,2-dimethoxypropane, and the methanol was washed away with alkaline water to purify the 2,2-dimethoxypropane. In this route, the dehydrating ability of petroleum ether at 30-60℃ was still very poor and incomplete, and the methanol was washed away with alkaline water, making the subsequent methanol recovery process cumbersome.

[0014] In Route 2, the gas-phase cracking method involves vaporizing 2,2-dimethoxypropane and then passing it through a heated catalyst bed for high-temperature catalytic cracking to obtain 2-methoxypropylene.

[0015] (1) In CN109776284A, a gas-phase cracking reaction is carried out in the presence of SAPO-34 molecular sieve catalyst, and the reaction products are separated by a partitioned distillation column.

[0016] (2) In CN110240540B, catalytic cracking is carried out under the synergistic effect of acidic ceramic packing and co-catalyst, and separation and purification are carried out by a combination of membrane separation technology and distillation.

[0017] Gas-phase pyrolysis consumes a lot of energy, and the catalyst is expensive and has a limited lifespan.

[0018] Liquid-phase pyrolysis can catalytically crack 2,2-dimethoxypropane under mild conditions.

[0019] (1) In 2002, Yang Shumin et al. from the Xi'an Institute of Modern Chemistry published a study on fine chemical intermediates, using benzoic acid and pyridine as catalysts, diethylene glycol dimethyl ether as solvent, and adding a certain amount of succinic anhydride to absorb methanol produced by cracking and promote the reaction toward 2-methoxypropylene. The distillation yield was 80.06%, and the product purity was greater than 98%. This system significantly increased costs due to the use of solvents and the introduction of succinic anhydride.

[0020] (2) In an article published in Anhui Chemical Industry in 2009 by Li Xiaoxi et al. of Wuhan University of Technology, benzoic acid and pyridine were used as catalysts, toluene as solvent, and succinic anhydride was used to absorb methanol. The product yield reached 81.1%, and the purity was greater than 97%. In this system, although using toluene instead of diethylene glycol dimethyl ether as solvent reduced costs, the use of solvent and the introduction of succinic anhydride made the reaction system too complex, causing inconvenience for post-reaction processing.

[0021] (3) In US Patent 5,576,465, Manfred Kaufhold used nonanoic acid to catalytically crack 2,2-dimethoxypropane at 130°C to prepare 2-methoxypropylene, achieving a conversion rate of 78%. The cracked liquid was first washed with water and then distilled to obtain 2-methoxypropylene with a purity of 99.3%. Although no solvent was used in this system, the amount of nonanoic acid used was particularly large, making it difficult to produce industrially. Summary of the Invention

[0022] The purpose of this invention is to overcome the problems of unstable process, high reaction temperature, high energy consumption, high cost of raw materials and auxiliary materials, low purity and complicated post-processing in the synthesis of 2-methoxypropylene, which are not conducive to industrial production. This invention provides a method for synthesizing 2-methoxypropylene with mild reaction conditions, environmental friendliness, low energy consumption, low cost of raw materials and auxiliary materials and simple post-processing, which is suitable for continuous industrial production.

[0023] In summary, existing processes for synthesizing and purifying 2-methoxypropene are unstable, involve high reaction temperatures, high energy consumption, high raw material costs, and complex post-processing, which are unfavorable for industrial production. Therefore, there is a need to find a method for synthesizing and purifying 2-methoxypropene that has mild reaction conditions, is environmentally friendly, has low energy consumption, low raw material costs, and simple post-processing, making it suitable for industrial production.

[0024] To achieve the above objectives, the present invention provides a method for synthesizing 2-methoxypropylene, the method comprising: Step A: in the presence of a first catalyst and an extractant, ethylene glycol and acetone undergo a reverse contact reaction to generate ethylene glycol acetone, the extract containing ethylene glycol acetone is separated and distilled to obtain ethylene glycol acetone; Step B: in the presence of a second catalyst, the ethylene glycol acetone is contacted with methanol, the temperature is raised to 100-150°C, the gauge pressure is raised to 0.40-1.50 MPa and pressure reactive distillation is performed to generate 2-methoxypropylene, and 2-methoxypropylene is separated as the target product.

[0025] Through the above technical solution, the present invention has the following beneficial effects:

[0026] The method of this invention can reduce the reaction energy barrier, promote the synthesis of 2-methoxypropylene under mild reaction conditions, is environmentally friendly, has low energy consumption, few by-product impurities, low raw material and auxiliary material costs, and simple post-processing, making it suitable for continuous industrial production.

[0027] This invention synthesizes ethylene glycol acetone under mild reaction conditions, suitable for continuous industrial production. Acetone, ethylene glycol, and the extractant undergo countercurrent contact and gradient reaction, resulting in high conversion rates and simple post-processing of raw materials. Pressure reactive distillation is used to directly synthesize 2-methoxypropene from ethylene glycol acetone, reducing the processes of synthesizing 2,2-dimethoxypropane and its cracking preparation. This avoids the problem of azeotropes formed by methanol, acetone, and 2,2-dimethoxypropane, simplifying the operation. Attached Figure Description

[0028] Figure 1 This is a reaction extraction column structure and flow chart according to one embodiment of the present invention;

[0029] Figure 2 This is a washing and extraction column structure and flow chart according to one embodiment of the present invention.

[0030] Explanation of reference numerals in the attached figures

[0031] Figure 1 : 1# is the ethylene glycol outlet containing water and the first catalyst, 2# is the extractant inlet, 3# is the acetone inlet, 4# is the ethylene glycol inlet containing the first catalyst, and 5# is the extract outlet containing acetone-ethylene glycol condensate (DMD).

[0032] Figure 2 : 6# is for methanol-containing detergent exports, 7# is for 92-95% 2-methoxypropylene (MPP) imports (2-methoxypropylene stream to be separated), 8# is for detergent imports, and 9# is for 2-methoxypropylene with a content of over 99% (stream after washing) exports. Detailed Implementation

[0033] The endpoints and any values ​​of the ranges 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 endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0034] This invention provides a method for synthesizing 2-methoxypropylene, comprising: Step A: In the presence of a first catalyst and an extractant, ethylene glycol and acetone undergo a reverse contact reaction to generate ethylene glycol acetone, the extract containing ethylene glycol acetone is separated and distilled to obtain ethylene glycol acetone; Step B: In the presence of a second catalyst, the ethylene glycol acetone is contacted with methanol, the temperature is raised to 100-150°C, and the gauge pressure is raised to 0.40-1.50 MPa for pressurized reactive distillation to generate 2-methoxypropylene, and 2-methoxypropylene is separated as the target product.

[0035] Synthesis of ethylene glycol acetone (DMD):

[0036]

[0037] Synthesis of 2-methoxypropylene (MPP):

[0038]

[0039] The synthesis method for 2-methoxypropylene provided by this invention operates under mild reaction conditions, is environmentally friendly, has low energy consumption, produces few by-products and impurities, has low raw material and auxiliary material costs, and is simple to process, making it suitable for continuous industrial production. The synthesis of acetone ethylene glycol condensate also operates under mild reaction conditions, suitable for continuous industrial production. Acetone, ethylene glycol, and the extractant undergo countercurrent contact and gradient reaction, resulting in high conversion rates. Raw material and auxiliary material recovery and processing are simple. Pressure reactive distillation is used to directly synthesize 2-methoxypropylene from acetone ethylene glycol condensate, reducing the processes of synthesizing 2,2-dimethoxypropane and cracking to prepare 2-methoxypropylene. This avoids the problem of azeotropes formed by methanol, acetone, and 2,2-dimethoxypropane, and simplifies the operation.

[0040] According to a preferred embodiment of the present invention, step A is carried out in a reactive extraction column, wherein ethylene glycol containing a first catalyst enters from the upper inlet of the reactive extraction column, acetone enters from the middle inlet of the reactive extraction column, and the extractant enters from the lower inlet of the reactive extraction column; this is illustrative but does not limit the scope of the invention. Figure 1As shown, the synthesis method of 2-methoxypropylene in this invention includes: (1) bringing ethylene glycol, acetone and extractant dissolved in the first catalyst into contact in a reaction extraction column, the extraction column being filled with packing material and including a heat exchange jacket, the temperature in the jacket being controlled by a heat-insulating agent such as heat-insulating hot water, the heat-insulating agent outlet being located at the top of the extraction column, the heat-insulating agent inlet being located at the bottom of the extraction column, preferably the materials entering the column are all preheated to 40-55°C, wherein the ethylene glycol material containing the first catalyst enters from the upper feed port 4# of the reaction extraction column, the acetone enters from the middle feed port 3# of the reaction extraction column, and the extractant enters from the lower feed port 2# of the reaction extraction column, thereby ensuring that the liquid levels of ethylene glycol and extractant are within a range of, for example, 5 cm above and below port 3#, and the extract containing ethylene glycol acetone (abbreviated as DMD) overflows from the extract outlet 5# containing ethylene glycol acetone (DMD). Collect DMD extract, and distill the DMD extract to obtain DMD with a content of more than 98%; (2) Contact DMD, the second catalyst and methanol, heat to 100-150℃, and raise the gauge pressure to 0.40-1.50MPa for pressurized reaction distillation to obtain 2-methoxypropylene (abbreviated as MPP) with a content of 92-95%. The other components are mainly methanol, which can be returned as methanol raw material in step B. 2-methoxypropylene (abbreviated as MPP) with a content of 92-95% is then fed into the washing extraction column and contacted countercurrently with the detergent. The washing extraction column is filled with packing material. The specific steps are as follows: 2-methoxypropylene (2-methoxypropylene stream to be separated) with a content of 92-95% enters from port 7, detergent enters from port 8, and 2-methoxypropylene (stream after washing) flows out from port 9 to obtain MPP with a content of more than 99%. Detergent containing methanol flows out from port 6.

[0041] In the washing and extraction column of the present invention, the packing material is not subject to any special requirements, and will not be described in detail here.

[0042] In this invention, in order to achieve the target temperature, the reaction extraction column includes a heat exchange unit, such as a jacketed insulation layer, for introducing a heat exchange agent, such as insulated hot water.

[0043] In the reaction extraction column of the present invention, the packing material is not subject to any special requirements, and those skilled in the art can select it as needed. The present invention will not describe it in detail here.

[0044] This invention uses an extractive distillation reaction, which, compared to the existing technology that uses a distillation dehydrating agent to remove water generated during the synthesis of acetone ethylene glycol, has the advantages of low energy consumption, high conversion rate, and continuous production capability.

[0045] In step B of this invention, when the temperature is raised to 100-150°C and the gauge pressure is raised to 0.40-1.50 MPa, the reflux ratio can also be controlled. The specific selection is well known to those skilled in the art and can be selected according to actual operation. For example, it is generally 2-10. In the embodiments, reflux ratios of 3 and 6 are used as examples, but this does not limit the scope of the invention.

[0046] According to a preferred embodiment of the present invention, in step B, in the presence of a second catalyst, the acetone ethylene glycol is contacted with methanol, heated to 100-130°C, and the gauge pressure is increased to 0.50-0.8 MPa, and pressure reactive distillation is carried out to generate 2-methoxypropylene, and 2-methoxypropylene is separated as the target product.

[0047] In this invention, the concentration of the first catalyst in ethylene glycol in step A can be selected within a wide range. According to a preferred embodiment of this invention, the concentration of the first catalyst in ethylene glycol is 0.5-5 wt%, preferably 0.5-2.5 wt%.

[0048] In this invention, the volumetric flow rate ratio of acetone, ethylene glycol, and extractant can be selected from a wide range. This is an illustrative example, but does not limit the scope of the invention. According to a preferred embodiment of the invention, the volumetric flow rate ratio of acetone, ethylene glycol, and extractant is 1:1.2-8:1-10, preferably 1:3-4.5:4-6.

[0049] In this invention, there are no special requirements for the contact reaction conditions in step A. According to a preferred embodiment of this invention, the contact reaction conditions include a temperature of 40-55°C.

[0050] According to a preferred embodiment of the present invention, the purity of acetone glycol obtained by distillation is 98% or more, by weight percentage.

[0051] In this invention, the range of extractants that can be selected in step A is relatively wide. According to a preferred embodiment of the present invention, which is illustrated by way of example but does not limit the scope of the present invention, the extractant is selected from at least one of C5-C14 alkanes, preferably selected from at least one of n-hexane, 2-methylpentane, 3-methylpentane, 2,3-dimethylbutane and methylcyclopentane.

[0052] According to a preferred embodiment of the present invention, step B, the step of separating 2-methoxypropylene, includes: feeding the 2-methoxypropylene-containing material obtained in step B into a washing and extraction column and contacting it with a detergent for countercurrent extraction to obtain 2-methoxypropylene with a purity of 99% or higher.

[0053] In this invention, in step B, the detergent has no special requirements. According to a preferred embodiment of the present invention, which is illustrated by way of example but does not limit the scope of the invention, the detergent is selected from at least one of deionized water, dimethyl sulfoxide, ethylene glycol, propylene glycol and glycerol.

[0054] In this invention, the molar ratio of acetone ethylene glycol to methanol in step B can be selected within a wide range. This is an illustrative example, but does not limit the scope of the invention. According to a preferred embodiment of the invention, the molar ratio of acetone ethylene glycol to methanol in step B is 1:2.5-6.

[0055] In this invention, the amount of the second catalyst can be selected from a wide range. This is an illustrative example, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, in step B, the amount of the second catalyst is 0.01-3 wt% of the total weight of the liquid raw material, preferably 0.2-1.6 wt%.

[0056] In this invention, the selection of the first catalyst in step A is not particularly required. According to a preferred embodiment of the present invention, which is illustrated by way of example but does not limit the scope of the present invention, in step A, the first catalyst is selected from at least one of ferric sulfate, ferric chloride, ferric bromide, aluminum sulfate, aluminum trichloride, zinc chloride, stannous dichloride, titanium tetrachloride, zinc trifluoromethanesulfonate, and copper trifluoromethanesulfonate, preferably at least one of ferric sulfate, ferric chloride, aluminum sulfate, aluminum trichloride, zinc chloride, and titanium tetrachloride.

[0057] In this invention, the selection of the second catalyst in step B is not particularly required. According to a preferred embodiment of the present invention, which is illustrated by way of example but does not limit the scope of the present invention, in step A, the second catalyst is selected from at least one of ferric sulfate, ferric chloride, ferric bromide, aluminum sulfate, aluminum trichloride, zinc chloride, stannous dichloride, titanium tetrachloride, zinc trifluoromethanesulfonate, and copper trifluoromethanesulfonate, preferably at least one of ferric sulfate, ferric chloride, aluminum sulfate, aluminum trichloride, zinc chloride, and titanium tetrachloride.

[0058] In this invention, according to a preferred embodiment of the invention, which is illustrated by way of example but does not limit the scope of the invention, step A further includes a step of preheating the material entering the column, preferably at a preheating temperature of 40-55°C.

[0059] According to a preferred embodiment of the present invention, in step A, after separating the extract to obtain acetone ethylene glycol, extractant and acetone are also obtained simultaneously and returned as raw materials for step A; the effluent from the lower outlet is separated to obtain deionized water and ethylene glycol containing the first catalyst, which are also returned as raw materials for step A.

[0060] According to a preferred embodiment of the present invention, the methanol separated by reactive distillation in step B is returned to step B as a methanol feedstock, and the ethylene glycol containing the second catalyst remaining after distillation is returned to step A as a feedstock.

[0061] In the following examples, the percentage content of DMD and MMP was determined by gas chromatography. The gas chromatograph used was a Shimadzu GC-2014C, with a DB-1 column (30m*0.32mm*1.0μm), N2 as the carrier gas, a column temperature of 60℃, a vaporizer temperature of 200℃, a detector temperature of 260℃, and an FID detector type.

[0062] The following embodiments are in accordance with Figure 1 The process shown proceeds to step A (the specific process is as described above and will not be repeated here), according to... Figure 2 The process includes step B, washing, extraction, and separation (the specific process is as described above and will not be repeated here).

[0063] DMD molar yield = (mass of DMD obtained by distillation * DMD content * molecular weight of acetone) / (molecular weight of DMD * mass of acetone consumed);

[0064] MPP molar yield = (MPP mass obtained from washing and extraction * MPP content * DMD molecular weight) / (MPP molecular weight * DMD mass consumed);

[0065] When using the extraction column described in this invention, the volume (referred to as column length) of the reaction extraction column filled with solvent must first be 290 ml. The specific operation is well known to those skilled in the art, and will not be described in detail here. In the examples, deionized water is used as an example, but this does not limit the scope of the invention.

[0066] Example 1

[0067] (1) Prepare a 2.5 wt% ferric sulfate ethylene glycol solution, heat it to 80 ℃ to dissolve it completely, and cool it to 54 ℃ to remove any precipitation. Set aside for later use.

[0068] like Figure 1The volume of solvent-filled column (column length) shown is 290 ml, and the column height is 3 meters. Hot water at 55°C is introduced into the jacket for insulation. The feed material is preheated to 55°C. Hexane is pumped in at 17.5 ml / min from port #2, acetone at 3.5 ml / min from port #3, and a 2.5 wt% ferric sulfate ethylene glycol solution at 14.0 ml / min from port #4. Ethylene glycol containing water and ferric sulfate is controlled to flow out from port #1, ensuring that the ethylene glycol and extractant are separated within 5 cm above and below port #3. The DMD-containing extract overflowing from port #5 is collected. After distillation, DMD purity of over 98% is obtained. After the reaction column and distillation are balanced, the DMD molar yield based on the acetone fed into the column is 75.4%. The acetone and extractant obtained from distillation, as well as the catalyst ethylene glycol solution after dehydration by vacuum distillation, can all be reintroduced into the reaction column to synthesize DMD.

[0069] (2) Add 306g (3.0mol) of DMD, 384g (12.0mol) of methanol, and 10g of anhydrous ferric sulfate to a pressurized reactive distillation vessel. The molar ratio of DMD to methanol is 1:4. Raise the vessel temperature to 130℃ and the gauge pressure to 1.00MPa for reactive distillation. Use a reflux ratio of 3 to collect MPP. Maintain the vessel temperature at 130℃ and gradually reduce the gauge pressure to 0.73MPa. Stop collecting MPP. The methanol obtained from further distillation can be used as the feed methanol for the next batch of pressurized reactive distillation. The remaining ethylene glycol catalyst solution in the vessel is used to prepare DMD. 94.2% MPP is obtained. The other components are mainly methanol. The solution is fed into a washing extraction column and countercurrently contacted with deionized water (e.g., Figure 2 The process yielded 162.5 g of MPP with a purity of over 99%, representing a molar yield of 74.8% based on DMD. The MPP obtained from the distilled washing water was reused in the next batch of washing extraction.

[0070] Example 2

[0071] (1) Prepare a 1.0 wt% aluminum trichloride ethylene glycol solution, heat it to 80 ℃ to dissolve it completely, and cool it to 40 ℃ to remove any precipitation. Set aside for later use.

[0072] like Figure 1The volume of solvent-filled column (column length) shown is 290 ml, and the column height is 3 meters. Hot water at 40°C is introduced into the jacket for insulation. The feed material is preheated to 40°C. 2-Methylpentane (21.0 ml / min) is pumped in through port 2, acetone (3.5 ml / min) through port 3, and a 1.0 wt% aluminum trichloride ethylene glycol solution (15.75 ml / min) through port 4. Water and aluminum trichloride ethylene glycol are controlled to flow out through port 1, ensuring that the ethylene glycol and extractant are separated within 5 cm above and below port 3. The DMD-containing extract overflowing from port 5 is collected. Distillation yields DMD with a purity of over 98%. After the reaction column and distillation are balanced, the DMD molar yield based on the acetone fed into the column is 78.7%. The acetone and extractant obtained from distillation, along with the catalyst ethylene glycol solution after dehydration by vacuum distillation and the distilled acetone, can all be reintroduced into the reaction column to synthesize DMD.

[0073] (2) Add 306g (3.0mol) of DMD, 384g (12.0mol) of methanol, and 4g of anhydrous aluminum trichloride to a pressurized reactive distillation vessel with a molar ratio of DMD:methanol = 1:4. Raise the vessel temperature to 110℃ and perform reactive distillation at a gauge pressure of 0.75MPa with a reflux ratio of 6. Collect MPP, maintain the vessel temperature at 110℃, and gradually reduce the gauge pressure to 0.48MPa. Stop collecting MPP. The methanol obtained from further distillation can be used as the feed methanol for the next batch of pressurized reactive distillation. The remaining ethylene glycol catalyst solution in the vessel is used to prepare DMD. 94.2% MPP is obtained, with the other components mainly being methanol. This is fed into a washing and extraction column and contacted countercurrently with ethylene glycol to obtain 151.0g of MPP with a purity of over 99%, representing a molar yield of 69.3% based on DMD. The MPP obtained from the distillation washing liquid is reused in the next batch of washing and extraction.

[0074] Example 3

[0075] (1) Prepare a 0.5 wt% titanium tetrachloride ethylene glycol solution, heat it to 50 ℃ to dissolve it, and set it aside.

[0076] like Figure 1The volume of solvent-filled column (column length) shown is 290 ml, and the column height is 3 meters. Hot water at 55°C is introduced into the jacket for insulation. The feed material is preheated to 55°C. 3-Methylpentane is pumped in at 14.0 ml / min from port #2, acetone at 3.5 ml / min from port #3, and a 0.5 wt% titanium tetrachloride ethylene glycol solution at 12.25 ml / min from port #4. Ethylene glycol containing water and titanium tetrachloride is controlled to flow out from port #1, ensuring that the ethylene glycol and extractant are separated within 5 cm above and below port #3. The DMD-containing extract overflowing from port #5 is collected. After distillation, DMD purity of over 98% is obtained. After the reaction column and distillation are balanced, the molar yield of DMD based on the acetone fed into the column is 71.5%. The acetone, extractant, and titanium tetrachloride catalyst ethylene glycol solution obtained from distillation (after vacuum distillation) can all be reused to synthesize DMD.

[0077] (2) Add 306g (3.0mol) of DMD, 384g (12.0mol) of methanol, and 2g of titanium tetrachloride to a pressurized reactive distillation vessel. The molar ratio of DMD to methanol is 1:4. Raise the vessel temperature to 100℃ and perform reactive distillation at a gauge pressure of 0.50MPa. Use a reflux ratio of 6 to collect MPP. Maintain the vessel temperature at 100℃ and gradually reduce the gauge pressure to 0.30MPa. Stop collecting MPP. The methanol obtained from further distillation can be used as the feed methanol for the next batch of pressurized reactive distillation. The remaining ethylene glycol catalyst solution in the vessel is used to prepare DMD. 94.2% MPP is obtained, with the other components mainly being methanol. The obtained MPP is fed into a washing extraction column and countercurrently contacted with dimethyl sulfoxide (DMSO). Figure 2 The process yielded 159.3 g of MPP with a purity of over 99%, representing a molar yield of 73.1% based on DMD. The MPP obtained from the distillation washing solution was reused in the next batch of washing extraction.

[0078] Example 4

[0079] All conditions are the same as in Example 1, except that: in step (1) a 5.0 wt% zinc chloride ethylene glycol solution is used, and in step (2) stannous dichloride is used;

[0080] The reaction results are as follows: In step (1), the DMD extract was collected and distilled to obtain more than 98% DMD. After the reaction extraction column and distillation were balanced, the molar yield of DMD was 75.3% based on the acetone fed into the column. The acetone, extractant, and ethylene glycol solution of the catalyst after dehydration by vacuum distillation can all be reused to synthesize DMD.

[0081] The MPP obtained in step (2) was fed into a washing and extraction column and countercurrently contacted with propylene glycol to obtain 141.1 g of MPP with a purity of over 99%, representing a molar yield of 65.1% based on DMD. The MPP obtained from the distillation of the washing solution was reused in the next batch of washing and extraction.

[0082] Example 5

[0083] All conditions are the same as in Example 1, except that in step (2), 306g (3.0mol) of DMD, 480g (15.0mol) of methanol, and 10g of anhydrous ferric sulfate are added to the pressurized reaction distillation vessel, with a molar ratio of DMD:methanol = 1:5.

[0084] The results are as follows: In step (1), the DMD extract was collected and distilled to obtain more than 98% DMD. After the reaction extraction column and distillation were balanced, the molar yield of DMD was 76.1% based on the acetone fed into the column. The recovered acetone, extractant and dehydrated catalyst ethylene glycol solution can all be reused to synthesize DMD.

[0085] The MPP obtained in step (2) was fed into a washing and extraction column and countercurrently contacted with glycerol to obtain 166.6 g of MPP with a purity of over 99%, representing a molar yield of 76.5% based on DMD. The MPP obtained from the distillation of the washing solution was reused in the next batch of washing and extraction.

[0086] Example 6

[0087] All conditions are the same as in Example 1, except that: in step (1) a 2.0 wt% aluminum sulfate ethylene glycol solution is used; and in step (2) anhydrous aluminum sulfate is used.

[0088] The results are as follows: In step (1), the DMD extract was collected and distilled to obtain more than 98% DMD. After the reaction extraction column and distillation were balanced, the molar yield of DMD was 79.5% based on the acetone fed into the column. The acetone, extractant and dehydrated ethylene glycol catalyst solution obtained by distillation can all be reused to synthesize DMD.

[0089] The MPP obtained in step (2) was fed into a washing and extraction column and contacted countercurrently with glycerol to obtain 160.2 g of MPP with a purity of over 99%, representing a molar yield of 73.7% based on DMD. The MPP obtained from the distillation of the washing solution was reused in the next batch of washing and extraction.

[0090] Example 7

[0091] All conditions were the same as in Example 1, except that in step (2), 192g (6.0mol) of methanol was used, and the molar ratio of DMD to methanol was 1:2, resulting in 90.5g of MPP with a purity of over 99%, and the molar yield of MPP based on DMD was 41.7%.

[0092] Comparative Example 1

[0093] All conditions were the same as in Example 1, except that the preparation of DMD in step (1) was not carried out in a reaction extraction column, but was directly fed into a three-necked reaction flask to be stirred according to the raw material volume ratio in step (1) (acetone: 2.5% ferric sulfate ethylene glycol: n-hexane = 1:4:5). After reacting at 54°C for 2 hours, the mixture was separated into layers, and the DMD-containing extract was distilled. Based on the amount of acetone fed, the molar yield of DMD obtained by distillation was 22.5%.

[0094] Comparative Example 2

[0095] All conditions were the same as in Example 1, except that the preparation of DMD in step (1) was not carried out in the reaction extraction column, but was directly fed into the three-necked reaction flask to be stirred according to the raw material volume ratio of step (1) (acetone: 2.5% ferric sulfate ethylene glycol: n-hexane = 1:4:5). After reacting at 54°C for 2 hours, the entire reaction system was directly distilled. Based on the acetone fed, the molar yield of DMD obtained by distillation was 5.6%.

[0096] Comparative Example 3

[0097] All conditions were the same as in Example 1, except that in step (2), MMP was prepared by atmospheric pressure reactive distillation (at room temperature) to obtain 480g of fraction with an MPP content of 5.5% and an MPP molar yield of 12.2% based on DMD. Washing did not yield MPP with a content of more than 99%.

[0098] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for synthesizing 2-methoxypropylene, characterized in that, The method includes: Step A: In the presence of the first catalyst and the extractant, ethylene glycol and acetone undergo a reverse contact reaction to produce acetone ethylene glycol condensate. The extract containing acetone ethylene glycol condensate is separated and then distilled to obtain acetone ethylene glycol condensate. Step B: In the presence of a second catalyst, the acetone ethylene glycol is contacted with methanol, the temperature is raised to 100-150°C, the gauge pressure is raised to 0.40-1.50 MPa, and pressure reactive distillation is carried out to generate 2-methoxypropylene, and 2-methoxypropylene is separated as the target product. In step A, the reaction is carried out in a reaction extraction column, wherein ethylene glycol containing the first catalyst enters from the upper feed port of the reaction extraction column, acetone enters from the middle feed port of the reaction extraction column, and the extractant enters from the lower feed port of the reaction extraction column. In step A, the extractant is selected from at least one of n-hexane, 2-methylpentane, 3-methylpentane, 2,3-dimethylbutane, and methylcyclopentane, and the first catalyst is selected from at least one of ferric sulfate, ferric chloride, aluminum sulfate, aluminum trichloride, zinc chloride, and titanium tetrachloride; in step B, the second catalyst is selected from at least one of ferric sulfate, ferric chloride, aluminum sulfate, aluminum trichloride, zinc chloride, and titanium tetrachloride.

2. The method according to claim 1, wherein, In step B, in the presence of a second catalyst, the acetone ethylene glycol is contacted with methanol, heated to 100-130°C, and the gauge pressure is increased to 0.50-0.8 MPa to perform pressurized reactive distillation to produce 2-methoxypropylene, and 2-methoxypropylene is separated as the target product.

3. The method according to claim 1, wherein, In step A, All materials fed into the column are preheated to 40-55℃; and / or The concentration of the first catalyst in ethylene glycol is 0.5-5 wt%.

4. The method according to claim 3, wherein, In step A, the concentration of the first catalyst in ethylene glycol is 0.5-2.5 wt%.

5. The method according to claim 1, wherein, In step A, The volumetric flow rate ratio of acetone, ethylene glycol, and extractant is 1:1.2-8:1-10.

6. The method according to claim 5, wherein, In step A, the volumetric flow rate ratio of acetone, ethylene glycol, and extractant is 1:3-4.5:4-6.

7. The method according to claim 1, wherein, In step A, Contact reaction conditions include: temperature 40-55℃; and / or The purity of acetone ethylene glycol obtained by distillation is over 98% by weight percentage.

8. The method according to claim 1, wherein, In step B, The steps for separating 2-methoxypropylene include: feeding the 2-methoxypropylene-containing material obtained in step B into a washing and extraction column and contacting it with a detergent for countercurrent extraction to obtain 2-methoxypropylene with a purity of over 99%.

9. The method according to claim 8, wherein, In step B, the detergent is selected from at least one of deionized water, dimethyl sulfoxide, ethylene glycol, propylene glycol, and glycerol.

10. The method according to claim 1, wherein, In step B, The molar ratio of acetone ethylene glycol to methanol is 1:2.5-6; and / or The amount of the second catalyst is 0.01-3 wt% of the total weight of the liquid feedstock.

11. The method according to claim 10, wherein, In step B, the amount of the second catalyst is 0.2-1.6 wt% of the total weight of the liquid feedstock.

Images