Process for the preparation of 1,1,4,4-tetramethoxy-2-butene and its use

Abstract

The application discloses a preparation method of 1,1,4,4-tetramethoxy-2-butene and application thereof, and belongs to the field of organic chemical synthesis. The method comprises the following steps: chloroacetaldehyde dimethyl acetal and triphenylphosphine are reacted to generate acetaldehyde dimethyl acetal phosphonium salt; and the acetaldehyde dimethyl acetal phosphonium salt is reacted with glyoxal monoacetal to generate 1,1,4,4-tetramethoxy-2-butene. The method is high in efficiency, environmental protection, simple in operation and friendly to the environment.

Description

TECHNICAL FIELD

[0001] The application discloses a preparation method and application of 1,1,4,4-tetramethoxy-2-butene and belongs to the field of organic chemical synthesis. BACKGROUND

[0002] Carotenoids have a wide range of applications in food coloring and antioxidant fields. 2,7-dimethyl-2,4,6-octatriene-1,8-dial (abbreviated as decadienal) is a key intermediate for synthesizing carotenoids, and 1,1,4,4-tetramethoxy-2-butene is a key raw material for synthesizing decadienal. Patent CN114214648B uses furan as a raw material to synthesize 1,1,4,4-tetramethoxy-2-butene by an electrochemical method. This method needs to brominate furan, which is environmentally polluting, complex and has a low yield. SUMMARY

[0003] According to the deficiencies of the prior art, the application discloses a preparation method and application of 1,1,4,4-tetramethoxy-2-butene, which is simple to operate, friendly to the environment and has a high yield of 1,1,4,4-tetramethoxy-2-butene. Specifically, the application can be realized by the following technical scheme:

[0004] A preparation method of 1,1,4,4-tetramethoxy-2-butene, comprising the following steps:

[0005] Chloral dimethyl acetal, triphenylphosphine and a base are added to an organic solvent, and an acetal dimethyl phosphine salt is obtained by drying;

[0006] The acetal dimethyl phosphine salt and glyoxal monoacetal are mixed to obtain a mixed solution containing triphenylphosphine oxide and 1,1,4,4-tetramethoxy-2-butene;

[0007] A polar solvent is added to the mixed solution, and 1,1,4,4-tetramethoxy-2-butene is obtained by distillation.

[0008] Further, the organic solvent includes a mixture of any one or more of toluene, dichloromethane, tetrahydrofuran, n-hexane, n-heptane and dioxane.

[0009] Preferably, the organic solvent is dichloromethane.

[0010] Further, the molar ratio of the chloral dimethyl acetal and triphenylphosphine is 1:1-1.5.

[0011] Preferably, the molar ratio of the chloral dimethyl acetal and triphenylphosphine is 1:1-1.2.

[0012] Furthermore, the reaction temperature of the mixture of chloroacetaldehyde dimethyl acetal, triphenylphosphine, and alkali is 0–100°C.

[0013] Preferably, the reaction temperature of the chloroacetaldehyde dimethyl acetal, triphenylphosphine and alkali mixture is 20-60°C.

[0014] Furthermore, the alkali includes sodium methoxide or potassium hydroxide.

[0015] Preferably, the alkali is potassium hydroxide.

[0016] Furthermore, the molar ratio of acetaldehyde dimethyl phosphonate to glyoxal monoacetal is 1:1 to 1.5.

[0017] Preferably, the molar ratio of acetaldehyde dimethyl phosphine salt to glyoxal monoacetal is 1:1 to 1.2.

[0018] Furthermore, the organic solvent for the mixed reaction of acetaldehyde dimethyl phosphonate and glyoxal monoacetal includes any one or more mixtures of toluene, dichloromethane, tetrahydrofuran, n-hexane, n-heptane, methyl tert-butyl ether, and dioxane.

[0019] Preferably, the organic solvent for the mixed reaction of acetaldehyde dimethylphosphonic salt and glyoxal monoacetal is toluene.

[0020] Furthermore, the polar solvent includes any one or a mixture of n-hexane, n-heptane, and petroleum ether.

[0021] Preferably, the polar solvent is n-heptane.

[0022] Furthermore, the distillation conditions include a heating temperature of 130–150°C, a vacuum pump pressure of 500–600 Pa, and a separation temperature of 110–112°C.

[0023] The beneficial effects of this invention are:

[0024] (1) The preparation method of the present invention is simple to operate and environmentally friendly.

[0025] (2) The method of the present invention produces 1,1,4,4-tetramethoxy-2-butene with high purity and recovery rate. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the preparation route of the present invention.

[0027] Figure 2 The high-performance liquid chromatograms of 2,7-dimethyl-2,4,6-octtriene-1,8-dialdehyde prepared in Examples 6 and 7 are shown. Detailed Implementation

[0028] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0029] Embodiment 1

[0030] A preparation method of 1,1,4,4-tetramethoxy-2-butene, specifically comprising the following steps:

[0031] (1) Preparation of acetaldehyde dimethyl phosphonate

[0032] Put 400 ml of dichloromethane and 60.3 g of chloroacetaldehyde dimethyl into a reaction bottle, start stirring, weigh 150 g of triphenylphosphine, warm up in a water bath, control a slight positive pressure, and keep the temperature in the reactor at 40-45℃, and keep refluxing at constant temperature for 5 h. Continue to warm up to 60-64℃, keep refluxing at constant temperature for 1 h. Cool down to room temperature, drop 108 g of 30% potassium hydroxide aqueous solution, continue stirring for 30 min after dropping is completed, stand to separate layers, recover the organic phase, separate the product, and vacuum dry to obtain 164.8 g of acetaldehyde dimethyl phosphonate.

[0033] (2) Preparation of 1,1,4,4-tetramethoxy-2-butene

[0034] Put 400 ml of dichloromethane and 60.3 g of chloroacetaldehyde dimethyl into a reaction bottle, start stirring, weigh 150 g of triphenylphosphine, warm up in a water bath, control a slight positive pressure, and keep the temperature in the reactor at 40-45℃, and keep refluxing at constant temperature for 5 h. Continue to warm up to 60-64℃, keep refluxing at constant temperature for 1 h. Cool down to room temperature, drop 108 g of 30% potassium hydroxide aqueous solution, continue stirring for 30 min after dropping is completed, stand to separate layers, recover the organic phase, separate the product, and vacuum dry to obtain 164.8 g of acetaldehyde dimethyl phosphonate.

[0035] Embodiment 2

[0036] A preparation method of 1,1,4,4-tetramethoxy-2-butene, specifically comprising the following steps:

[0037] (1) Preparation of acetaldehyde dimethyl phosphonate

[0038] Into the reaction bottle, 550 ml of n-hexane and 80.4 g of chloral hydrate dimethyl acetal were put, stirring was started, 200 g of triphenylphosphine was weighed, water bath was warmed, the temperature in the reactor was controlled at 35-40°C, and constant temperature reflux reaction was carried out for 5 h. The temperature was continuously increased to 60-64°C, constant temperature reflux reaction was carried out for 1 h. The temperature was decreased to room temperature, 30% sodium hydroxide aqueous solution 103.2 g was added dropwise, after the dropwise addition was completed, stirring was continued for 30 min, and then it was left to stand to separate the layers. The organic phase was recovered, the product was separated, and vacuum drying was carried out to obtain acetal phosphonium salt 219.73 g.

[0039] (2) Preparation of 1,1,4,4-tetramethoxy-2-butene

[0040] Into the reaction bottle, 550 ml of n-hexane and 80.4 g of chloral hydrate dimethyl acetal were put, stirring was started, 200 g of triphenylphosphine was weighed, water bath was warmed, the temperature in the reactor was controlled at 35-40°C, and constant temperature reflux reaction was carried out for 5 h. The temperature was continuously increased to 60-64°C, constant temperature reflux reaction was carried out for 1 h. The temperature was decreased to room temperature, 30% sodium hydroxide aqueous solution 103.2 g was added dropwise, after the dropwise addition was completed, stirring was continued for 30 min, and then it was left to stand to separate the layers. The organic phase was recovered, the product was separated, and vacuum drying was carried out to obtain acetal phosphonium salt 219.73 g.

[0041] Example 3:

[0042] A method for preparing 1,1,4,4-tetramethoxy-2-butene, specifically comprising the following steps:

[0043] (1) Preparation of acetal phosphonium salt

[0044] Into the reaction bottle, 550 ml of n-hexane and 80.4 g of chloral hydrate dimethyl acetal were put, stirring was started, 200 g of triphenylphosphine was weighed, water bath was warmed, the temperature in the reactor was controlled at 35-40°C, and constant temperature reflux reaction was carried out for 5 h. The temperature was continuously increased to 60-64°C, constant temperature reflux reaction was carried out for 1 h. The temperature was decreased to room temperature, 30% sodium hydroxide aqueous solution 103.2 g was added dropwise, after the dropwise addition was completed, stirring was continued for 30 min, and then it was left to stand to separate the layers. The organic phase was recovered, the product was separated, and vacuum drying was carried out to obtain acetal phosphonium salt 219.73 g.

[0045] (2) Preparation of 1,1,4,4-tetramethoxy-2-butene

[0046] Into the reaction bottle, 550 ml of toluene was added, and acetaldehyde dimethyl phosphonate 217.89 g was added, and the temperature was lowered to 0-5°C, and 221.6 g of 30% glyoxal monoacetal aqueous solution was slowly added into the reaction bottle, after the addition was completed, the temperature was raised to 35-40°C, and constant temperature reaction was carried out for 2 h. After the reaction was completed, it was statically stratified at room temperature for 1 h. The organic phase was distilled under reduced pressure to recover toluene, and when the toluene recovery was completed, 800 ml of n-heptane was added, stirred and dissolved for 30 min, and the by-product triphenyl phosphine oxide was removed by filtration. The filtrate was recovered with n-heptane, and when the n-heptane recovery was completed, the outer temperature was controlled at 130-150°C, the vacuum pump pressure was controlled at 500-600 Pa, and the fraction of 110-112°C was collected by distillation under reduced pressure to obtain 1,1,4,4-tetramethoxy-2-butene 105.3 g. Gas chromatography analysis showed that the content of 1,1,4,4-tetramethoxy-2-butene was 99.27%, and the yield was 92.59%.

[0047] Example 4:

[0048] A method for preparing 1,1,4,4-tetramethoxy-2-butene, specifically comprising the following steps:

[0049] (1) Preparation of acetaldehyde dimethyl phosphonate

[0050] Into the reaction bottle, 550 ml of toluene was added, and acetaldehyde dimethyl phosphonate 217.89 g was added, and the temperature was lowered to 0-5°C, and 221.6 g of 30% glyoxal monoacetal aqueous solution was slowly added into the reaction bottle, after the addition was completed, the temperature was raised to 35-40°C, and constant temperature reaction was carried out for 2 h. After the reaction was completed, it was statically stratified at room temperature for 1 h. The organic phase was distilled under reduced pressure to recover toluene, and when the toluene recovery was completed, 800 ml of n-heptane was added, stirred and dissolved for 30 min, and the by-product triphenyl phosphine oxide was removed by filtration. The filtrate was recovered with n-heptane, and when the n-heptane recovery was completed, the outer temperature was controlled at 130-150°C, the vacuum pump pressure was controlled at 500-600 Pa, and the fraction of 110-112°C was collected by distillation under reduced pressure to obtain 1,1,4,4-tetramethoxy-2-butene 105.3 g. Gas chromatography analysis showed that the content of 1,1,4,4-tetramethoxy-2-butene was 99.27%, and the yield was 92.59%.

[0051] (2) Preparation of 1,1,4,4-tetramethoxy-2-butene

[0052] Into the reaction bottle, 550 ml of toluene was added, and acetaldehyde dimethyl phosphonate 217.89 g was added, and the temperature was lowered to 0-5°C, and 221.6 g of 30% glyoxal monoacetal aqueous solution was slowly added into the reaction bottle, after the addition was completed, the temperature was raised to 35-40°C, and constant temperature reaction was carried out for 2 h. After the reaction was completed, it was statically stratified at room temperature for 1 h. The organic phase was distilled under reduced pressure to recover toluene, and when the toluene recovery was completed, 800 ml of n-heptane was added, stirred and dissolved for 30 min, and the by-product triphenyl phosphine oxide was removed by filtration. The filtrate was recovered with n-heptane, and when the n-heptane recovery was completed, the outer temperature was controlled at 130-150°C, the vacuum pump pressure was controlled at 500-600 Pa, and the fraction of 110-112°C was collected by distillation under reduced pressure to obtain 1,1,4,4-tetramethoxy-2-butene 105.3 g. Gas chromatography analysis showed that the content of 1,1,4,4-tetramethoxy-2-butene was 99.27%, and the yield was 92.59%.

[0053] Example 5:

[0054] A method for preparing 1,1,4,4-tetramethoxy-2-butene, specifically comprising the following steps:

[0055] (1) Preparation of acetaldehyde dimethyl phosphonate

[0056] Into a reaction bottle, 550 ml of dioxane and 80.4 g of chloroacetaldehyde dimethyl were added, stirring was started, 200 g of triphenyl phosphine was weighed, water bath was warmed, the temperature in the reactor was controlled at 35-40℃, and constant temperature reflux reaction was carried out for 5 h. The temperature was continuously increased to 60-64℃, constant temperature reflux reaction was carried out for 1 h. The temperature was decreased to room temperature, 144 g of 30% potassium hydroxide aqueous solution was added dropwise, stirring was continued for 30 min after the dropwise addition was completed, and it was left to stand to separate the layers. The organic phase was recovered, the product was separated, and acetaldehyde dimethyl phosphonate 217.89 g was obtained by vacuum drying.

[0057] (2) Preparation of 1,1,4,4-tetramethoxy-2-butene

[0058] Into a reaction bottle, 550 ml of dioxane and 80.4 g of chloroacetaldehyde dimethyl were added, stirring was started, 200 g of triphenyl phosphine was weighed, water bath was warmed, the temperature in the reactor was controlled at 35-40℃, and constant temperature reflux reaction was carried out for 5 h. The temperature was continuously increased to 60-64℃, constant temperature reflux reaction was carried out for 1 h. The temperature was decreased to room temperature, 144 g of 30% potassium hydroxide aqueous solution was added dropwise, stirring was continued for 30 min after the dropwise addition was completed, and it was left to stand to separate the layers. The organic phase was recovered, the product was separated, and acetaldehyde dimethyl phosphonate 217.89 g was obtained by vacuum drying.

[0059] Example 6:

[0060] An application of 1,1,4,4-tetramethoxy-2-butene, specifically comprising the following steps:

[0061] (1) 1,1,4,4-tetramethoxy-2-butene obtained in Example 1 was added to 30 g, 200 ml of toluene and 3 g of ferric trichloride were added and stirred, propenyl methyl ether was added dropwise at 0-5℃, and the dropwise addition was completed in 10 h, and it was incubated for 2 h. Water was added to quench the reaction, it was left to stand to separate the layers, and the organic phase was used as it was.

[0062] (2) The organic phase obtained in step (1) is added with 200 ml of 1% sulfuric acid, stirred and heated to 80°C, and kept for 7 hours, then hot layered, the water layer is removed, and 100 ml of 0.5% sodium carbonate solution is added to the organic phase, the reaction temperature is controlled at 70-80°C for 5 hours, cooled to 5°C, filtered, and dried at 55°C under vacuum to obtain 2,7-dimethyl-2,4,6-octatriene-1,8-dial 24 g, the content is 99.57% by liquid chromatography analysis, and the yield is 85.85%.

[0063] Example 7:

[0064] An application of 1,1,4,4-tetramethoxy-2-butene, specifically comprising the following steps:

[0065] (1) The 1,1,4,4-tetramethoxy-2-butene obtained in Example 2 is put into 30 g, 200 ml of toluene and 2 g of ferric trichloride is added and stirred, and propenyl methyl ether is added dropwise at 0-5°C, the dropwise addition is completed in 10 hours, and the reaction is kept for 2 hours, then water is added to quench the reaction, and the organic phase is obtained by standing and layering.

[0066] (2) The organic phase obtained in step (1) is added with 200 ml of 1% oxalic acid, stirred and heated to 90°C, and kept for 6 hours, then hot layered, the water layer is removed, and 100 ml of 0.5% sodium carbonate solution is added to the organic phase, the reaction temperature is controlled at 70-80°C for 5 hours, cooled to 5°C, filtered, and dried at 55°C under vacuum to obtain 2,7-dimethyl-2,4,6-octatriene-1,8-dial 23.67 g, the content is 99.41% by liquid chromatography analysis, and the yield is 84.67%.

[0067] From the above experimental results, it can be seen that:

[0068] (1) The 1,1,4,4-tetramethoxy-2-butene prepared by the method disclosed in the present application has a content of >98%, and the yield of 1,1,4,4-tetramethoxy-2-butene recovered is >90%, indicating that the 1,1,4,4-tetramethoxy-2-butene prepared by the present application has high purity and high recovery rate;

[0069] (2) The by-product triphenyl phosphine oxide produced in the experiment can be effectively filtered, and has no pollution to the environment.

[0070] The above examples have described the technical solutions and beneficial effects of the present application in detail, and it should be understood that the above description is only a specific embodiment of the present application, and is not used to limit the present application. Any modification, supplement and equivalent replacement made within the principle range of the present application shall be included in the protection scope of the present application.

Claims

1. A process for the preparation of 1,1,4,4-tetramethoxy-2-butene, characterized in that, The method comprises the following steps: chloral hydrate dimethyl acetal, triphenyl phosphine and a base are added into an organic solvent, and a chloral hydrate dimethyl acetal phosphonium salt is obtained by drying; the chloral hydrate dimethyl acetal phosphonium salt and glyoxal monoacetal are mixed to obtain a mixed solution containing triphenyl phosphine oxide and 1,1,4,4-tetramethoxy-2-butene; a polar solvent is added into the mixed solution, and 1,1,4,4-tetramethoxy-2-butene is obtained by distillation; the molar ratio of the chloral hydrate dimethyl acetal and the triphenyl phosphine is 1:1-1.5; the molar ratio of the chloral hydrate dimethyl acetal phosphonium salt and the glyoxal monoacetal is 1:1-1.5; the distillation conditions include a heating temperature of 130-150℃, a vacuum pump pressure of 500-600 Pa and a separation temperature of 110-112℃.

2. The method of claim 1, wherein, the organic solvent includes a mixture of any one or more of toluene, dichloromethane, tetrahydrofuran, n-hexane, n-heptane and dioxane.

3. The method of claim 1, wherein, the temperature of the mixed reaction of the chloral hydrate dimethyl acetal, the triphenyl phosphine and the base is 0-100℃.

4. The method of claim 1, wherein, the base includes sodium methoxide or potassium hydroxide.

5. The method of claim 1, wherein, the organic solvent for the mixed reaction of the chloral hydrate dimethyl acetal phosphonium salt and the glyoxal monoacetal includes a mixture of any one or more of toluene, dichloromethane, tetrahydrofuran, n-hexane, n-heptane, methyl tert-butyl ether and dioxane.

6. The method of claim 1, wherein, the polar solvent includes a mixture of any one or more of n-hexane, n-heptane and petroleum ether.

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