Preparation method of 2-ethyl acrolein, 2-methyl butanol and 2-methyl butyraldehyde

Abstract

The invention relates to a preparation method of 2-ethyl acrolein, 2-methyl butanol and 2-methyl butyraldehyde. The preparation method of the 2-ethyl acrolein comprises the following steps: mixing formaldehyde, organic amine, organic acid and a solvent to obtain a first mixture; the first mixture is prepared from the following components in parts by mass: 10 to 55 parts of formaldehyde, 1 part of organic amine, 0.2 to 1 part of organic acid and 20 to 90 parts of solvent; mixing the first mixture with n-butyraldehyde, carrying out a condensation reaction, and then carrying out oil-phase and water-phase separation to obtain an oil phase; and carrying out rectification purification on the oil phase to obtain the 2-ethyl acrolein. In the preparation of the 2-ethyl acrolein, the formaldehyde, the organic amine, the organic acid and the solvent are mixed to form a mixture, and then the mixture is mixed with the n-butyraldehyde solution; the selectivity and the purity of the 2-ethyl acrolein can be improved.

Description

Technical Field

[0001] The present invention relates to the field of fine chemicals, and particularly to a preparation method of 2-ethylacrolein, 2-methylbutanol and 2-methylbutyraldehyde. Background Art

[0002] 2-ethylacrolein is a key intermediate for synthesizing various complex organic molecules. For example, in the process of synthesizing certain drug molecules with special biological activities, it can participate in various chemical reactions through its carbon-carbon double bond and aldehyde group. Such as condensation reaction with compounds containing amino group to generate nitrogen-containing heterocyclic compounds. These nitrogen-containing heterocyclic compounds may have potential pharmacological activities in the field of medicinal chemistry, such as antibacterial, antiviral or antitumor activities.

[0003] In the perfume industry, 2-ethylacrolein can be used as a precursor for synthesizing perfumes. Through a series of chemical reactions, such as hydrogenation reduction, oxidation, esterification and other reactions, compounds with special fragrances can be synthesized. For example, the aldehyde group is converted into a hydroxyl group through a hydrogenation reduction reaction, and then an esterification reaction occurs with an organic acid to generate ester perfumes with a fruity fragrance.

[0004] Traditionally, the preparation method of 2-ethylacrolein is mainly to react formaldehyde and n-butyraldehyde under the action of catalyst systems such as sodium carbonate, sodium carbonate / tetrabutylphosphonium bromide, pyrrolidine / propionic acid, sodium carbonate / sodium dodecyl sulfate, etc. to generate 2-ethylacrolein. In the traditional preparation method, when aldehyde compounds and formaldehyde undergo a condensation reaction to generate the product enal, there are many aldol condensation side reactions, and by-products such as 2,2-hydroxymethylbutyraldehyde and 2,2-hydroxymethylbutanol will be produced. These by-products form an azeotrope with the target product 2-ethylacrolein, resulting in difficulties in distillation purification. Summary of the Invention

[0005] Based on this, it is necessary to provide a preparation method of 2-ethylacrolein, which has a higher purity and selectivity for the obtained 2-ethylacrolein. Further, a preparation method of 2-methylbutanol and a preparation method of 2-methylbutyraldehyde are provided.

[0006] The first aspect of the present application provides a preparation method of 2-ethylacrolein, including the following steps:

[0007] Mix formaldehyde, organic amine, organic acid and solvent to obtain a first mixture; by mass, in the first mixture, it includes: 10 parts to 55 parts of formaldehyde, 1 part of organic amine, 0.2 part to 1 part of organic acid and 20 parts to 90 parts of solvent;

[0008] Mix the first mixture with n-butyraldehyde, carry out a condensation reaction, and then carry out oil phase and water phase separation to obtain an oil phase;

[0009] The oil phase is rectified and purified to obtain the 2-ethylacrolein.

[0010] In the preparation of the above 2-ethylacrolein, formaldehyde, an organic amine, an organic acid, and a solvent are first mixed to form a mixed material, and then mixed with a n-butanal solution; in the first mixed material, the concentrations of the catalyst components, the organic amine and the organic acid, are diluted. When the formaldehyde in the first mixed material contacts the n-butanal, due to the low catalyst concentration, the condensation reaction rate of 2-ethylacrolein and n-butanal can be reduced, by-products can be reduced, and the selectivity of 2-ethylacrolein can be improved. Further controlling the mass ratio of formaldehyde, organic amine, organic acid, and solvent in the first mixed material, further controlling the concentration of the catalyst components, controlling the condensation reaction rate of 2-ethylacrolein and n-butanal, reducing the generation of by-products with boiling points close to that of 2-ethylacrolein, and improving the selectivity of 2-ethylacrolein. Combining with the rectification and purification steps in the subsequent steps, 2-ethylacrolein with higher purity can be obtained.

[0011] In some embodiments, the preparation method satisfies at least one of the following conditions:

[0012] (1) The organic amine is a secondary amine;

[0013] (2) The organic acid is selected from at least one of acetic acid, propionic acid, butyric acid, and valeric acid;

[0014] (3) The solvent is water.

[0015] In some embodiments, the mass ratio of the first mixed material to the n-butanal is (1.0 - 1.5):1.

[0016] In some embodiments, the preparation method satisfies at least one of the following conditions:

[0017] (1) The temperature of the condensation reaction is 70°C - 100°C;

[0018] (2) The time of the condensation reaction is 1 h - 3 h.

[0019] In some embodiments, the condensation reaction is carried out in a tubular reactor.

[0020] In the second aspect of the present application, a preparation method of 2-methylbutanol is provided, including the following steps:

[0021] Using the preparation method described in the first aspect, 2-ethylacrolein is prepared;

[0022] The 2-ethylacrolein is mixed with hydrogen and subjected to a hydrogenation reaction under the condition of a nickel-based catalyst to obtain a reaction solution; the reaction solution is subjected to rectification separation to obtain 2-methylbutanol;

[0023] The molar ratio of the hydrogen to the 2-ethylacrolein is (5 to 6):1.

[0024] In some embodiments, the nickel-based catalyst is an alumina-supported nickel catalyst with a nickel mass percentage of 5 wt% to 50 wt%.

[0025] In some embodiments, the preparation method satisfies at least one of the following conditions:

[0026] (1) The temperature of the hydrogenation reaction is 130°C to 150°C;

[0027] (2) The pressure of the hydrogenation reaction is 0.2 MPa to 1 MPa;

[0028] (3) The mass space velocity in the hydrogenation reaction is 0.5 h -1 ~1.0 h -1 .

[0029] In some embodiments, the hydrogenation reaction is carried out in a fixed bed.

[0030] The third aspect of the present application provides a method for preparing 2-methylbutyraldehyde, which includes the following steps:

[0031] Using the preparation method described in the first aspect, prepare 2-ethylacrolein;

[0032] Mix the 2-ethylacrolein with hydrogen, carry out a hydrogenation reaction under the condition of a nickel-based catalyst to obtain a reaction solution; carry out rectification separation on the reaction solution to obtain 2-methylbutyraldehyde;

[0033] The molar ratio of the hydrogen to the 2-ethylacrolein is (0.5 to 1):1. Detailed implementation manners

[0034] The technical solutions of the present application will be further described in detail below in conjunction with specific embodiments. The present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosed content of the present application more thorough and comprehensive.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the specification of this application herein are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0036] In this application, selectivity refers to the proportion of a specific reactant being converted into the target product when there are multiple possible reaction pathways. It reflects the preference of a chemical reaction for generating a specific product and is measured by the percentage of the amount of the target product in the total amount of all reaction products.

[0037] 2-Methylbutanol is mainly used in the fields of essence and fragrance, food flavor additives, pharmaceutical products, organic synthesis intermediates, etc. With the rapid development of the domestic economy, the food and cosmetics industries have developed by leaps and bounds, and the market prospect of isopentanol is relatively good.

[0038] Traditionally, the preparation methods of 2-methylbutanol mainly include the fusel oil separation method and the olefin carbonylation synthesis method. In the fusel oil separation method, it is difficult to separate 2-methylbutanol and 3-methylbutanol, and it is difficult to obtain high-purity 2-methylbutanol.

[0039] Through research, it is found that 2-ethylacrolein and hydrogen can obtain 2-methylbutanol with relatively high selectivity under specific conditions. At the same time, 2-ethylacrolein and hydrogen can also obtain 2-methylbutanal with relatively high selectivity under specific conditions.

[0040] In one embodiment of this application, a preparation method of 2-ethylacrolein is provided, including the following steps S11 to S13:

[0041] S11: Mix formaldehyde, organic amine, organic acid and solvent to obtain a first mixture. By mass, the first mixture includes: 10 parts to 55 parts of formaldehyde, 1 part of organic amine, 0.2 parts to 1 part of organic acid, and 20 parts to 90 parts of solvent.

[0042] S12: Mix the first mixture with n-butyraldehyde, carry out a condensation reaction, and then carry out oil-phase and water-phase separation to obtain an oil phase.

[0043] S13: Rectify and purify the oil phase to obtain 2-ethylacrolein.

[0044] The process of the condensation reaction occurring in the above steps is as follows:

[0045]

[0046] In the preparation of the above-mentioned 2-ethylacrolein, formaldehyde, organic amine, organic acid and solvent are first mixed to form a mixed material, and then mixed with n-butyraldehyde solution; in the first mixed material, the concentrations of the catalyst components organic amine and organic acid are diluted. When the formaldehyde in the first mixed material contacts n-butyraldehyde, due to the low catalyst concentration, the condensation reaction rate of 2-ethylacrolein and n-butyraldehyde can be reduced, by-products can be reduced, and the selectivity of 2-ethylacrolein can be improved. Further, the mass ratio of formaldehyde, organic amine, organic acid and solvent in the first mixed material is controlled, the concentration of the catalyst components is further controlled, the condensation reaction rate of 2-ethylacrolein and n-butyraldehyde is controlled, the generation of by-products with boiling points close to that of 2-ethylacrolein is reduced, and the selectivity of 2-ethylacrolein is improved. Combining with the rectification and purification steps in the subsequent steps, 2-ethylacrolein with higher purity can be obtained.

[0047] As an example, in the first mixed material, the mass parts of formaldehyde can be 10 parts, 12 parts, 14 parts, 15 parts, 18 parts, 20 parts, 21 parts, 22 parts, 24 parts, 25 parts, 26 parts, 27 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 51 parts, 52 parts, 53 parts or 55 parts. It can also be any value within the range formed by any two of the above point values as the end values. Further, in the first mixed material, the mass parts of formaldehyde are 20 parts to 27 parts.

[0048] As an example, in the first mixed material, the mass parts of organic acid can be 0.2 parts, 0.24 parts, 0.26 parts, 0.27 parts, 0.28 parts, 0.3 parts, 0.34 parts, 0.35 parts, 0.36 parts, 0.4 parts, 0.42 parts, 0.45 parts, 0.48 parts, 0.49 parts, 0.5 parts, 0.55 parts, 0.6 parts, 0.61 parts, 0.62 parts, 0.65 parts, 0.7 parts, 0.8 parts, 0.9 parts or 1 part. It can also be any value within the range formed by any two of the above point values as the end values. Further, in the first mixed material, the mass parts of organic acid can be 0.2 parts to 0.7 parts. Further preferably, in the first mixed material, the mass parts of organic acid can be 0.25 parts to 0.65 parts.

[0049] As an example, in the first mixed material, the mass parts of solvent can be 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 70 parts, 80 parts or 90 parts. It can also be any value within the range formed by any two of the above point values as the end values. Further, in the first mixed material, the mass parts of organic acid can be 20 parts to 50 parts. Further preferably, in the first mixed material, the mass parts of organic acid can be 25 parts to 45 parts.

[0050] In some embodiments, the mass ratio of the first mixture to n-butyraldehyde is (1.0 to 1.5):1. As an example, the mass ratio of the first mixture to n-butyraldehyde is 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1 or 1.5:1. It can also be any other ratio within the above range.

[0051] In some embodiments, the organic amine is a secondary amine. Further, the organic amine is selected from at least one of diethylamine, dipropylamine, di-n-butylamine and dipentylamine.

[0052] In some embodiments, the organic acid is selected from at least one of acetic acid, propionic acid, butyric acid and valeric acid.

[0053] In some embodiments, the solvent is water.

[0054] In some embodiments, the temperature of the condensation reaction is 70°C to 100°C. As an example, the temperature of the condensation reaction can be 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C. Further, the temperature of the condensation reaction can be a range value formed by any two of the above point values as the end values.

[0055] In some embodiments, the time of the condensation reaction is 1 h to 3 h. As an example, the time of the condensation reaction can be 1 h, 1.5 h, 2 h, 2.5 h or 3 h. Further, the temperature of the condensation reaction can be a range value formed by any two of the above point values as the end values.

[0056] In some embodiments, in step S12, it further includes the step of adding a polymerization inhibitor to n-butyraldehyde. Adding a polymerization inhibitor to n-butyraldehyde can reduce the self-polymerization reaction of 2-ethylacrolein and n-butyraldehyde during the reaction.

[0057] In some embodiments, the polymerization inhibitor is hydroquinone.

[0058] In some embodiments, the addition amount of the polymerization inhibitor is 0.2 wt% to 0.3 wt% of the mass of n-butyraldehyde.

[0059] In some embodiments, the reaction liquid after the condensation reaction is subjected to oil-phase and water-phase separation in an oil-water separation tower to obtain a first oil phase and a water phase.

[0060] In some embodiments, the above steps further include the step of subjecting the water phase obtained after the oil-phase and water-phase separation to stripping in a stripping tower.

[0061] In some embodiments, the above preparation method further includes mixing the second oil phase separated by stripping with the first oil phase to obtain a mixed oil phase; and then rectifying and purifying the mixed oil phase.

[0062] In some embodiments, in step S13, the rectification and purification of the oil phase is carried out in a rectification column.

[0063] In some embodiments, when rectifying and purifying the oil phase, the bottom temperature of the rectification column is controlled at 80°C to 100°C.

[0064] In some embodiments, when rectifying and purifying the oil phase, the vacuum degree of the rectification column is -0.05 MPa to -0.06 MPa.

[0065] In some embodiments, step S13 further includes adding an inhibitor to the oil phase and then rectifying and purifying the oil phase. Adding an inhibitor to the oil phase before rectification and purification can reduce the self-polymerization of 2-ethylacrolein.

[0066] In some embodiments, the amount of the inhibitor added to the oil phase is 0.1 wt% to 0.2 wt% of the mass of the oil phase.

[0067] In some embodiments, the condensation reaction in the above step S12 is carried out in a tubular reactor. By carrying out the above condensation reaction in a tubular reactor, the continuous production of 2-ethylacrolein can be achieved.

[0068] In some embodiments, when carrying out the condensation reaction in the tubular reactor, the feeding speed ratio of the first mixture to n-butyraldehyde is (1.0 to 1.5):1.

[0069] In some embodiments, the feeding speed of the first mixture is 1300 kg / h to 1360 kg / h. Further, the feeding speed of the first mixture is 1318 kg / h to 1360 kg / h.

[0070] In some embodiments, the feeding speed of n-butyraldehyde is 1020 kg / h to 1030 kg / h.

[0071] In another embodiment of the present application, a method for preparing 2-methylbutanol is provided, including the following steps S10 to S30:

[0072] S10. Using the above preparation method to prepare 2-ethylacrolein;

[0073] S20. Mixing 2-ethylacrolein with hydrogen and carrying out a hydrogenation reaction under catalyst conditions to obtain a reaction solution. Among them, the molar ratio of hydrogen to 2-ethylacrolein is (5 to 6):1.

[0074] S30. Carrying out rectification separation on the reaction solution to obtain 2-methylbutanol.

[0075] In the above preparation method, 2-ethylacrolein and hydrogen are used as raw materials, and by controlling the molar ratio of hydrogen to 2-ethylacrolein, a hydrogenation reaction is carried out under the condition of a nickel-based catalyst to obtain 2-methylbutanol. In this method, specific raw materials are used and the raw material ratio is controlled, which can improve the selectivity of the product 2-methylbutanol and reduce the formation of other alcohols with boiling points and other properties similar to those of 2-methylbutanol. Combining with the rectification separation step to remove the unreacted raw material components in the reaction solution, 2-methylbutanol with a higher purity can be obtained.

[0076] As an example, the molar ratio of hydrogen to 2-ethylacrolein can be 5:1, 5.4:1, 5.5:1, 5.8:1 or 6:1. Further, the molar ratio of hydrogen to 2-ethylacrolein can be any other ratio within the above range.

[0077] In some embodiments, the selectivity of 2-methylbutanol prepared by the above hydrogenation reaction is ≥95%.

[0078] In some embodiments, the purity of 2-methylbutanol obtained by the above preparation method is ≥99.5%.

[0079] In some embodiments, the above hydrogenation reaction is carried out in a fixed bed.

[0080] In some embodiments, the nickel-based catalyst is an alumina-supported nickel catalyst with a nickel mass percentage of 5wt% - 50wt%. That is, in the catalyst, alumina is the carrier and nickel is the active substance, and the mass percentage of nickel in the total mass of alumina and nickel is 5wt% - 50wt%.

[0081] In some embodiments, the nickel-based catalyst is an alumina-supported nickel catalyst with a nickel mass percentage of 10wt% - 15wt%; or the nickel-based catalyst is an alumina-supported nickel catalyst with a nickel mass percentage of 40wt% - 45wt%.

[0082] In some embodiments, the temperature of the above hydrogenation reaction is 130°C - 150°C. As an example, the temperature of the above hydrogenation reaction can be 130°C, 132°C, 134°C, 135°C, 136°C, 138°C, 140°C, 142°C, 145°C, 146°C, 148°C or 150°C. Further, the temperature of the above hydrogenation reaction can be a range value formed by any two of the above point values as the end values.

[0083] In some embodiments, the pressure of the above hydrogenation reaction is 0.2 MPa to 1 MPa. As an example, the pressure of the above hydrogenation reaction can be 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, or 1 MPa. Further, the pressure of the above hydrogenation reaction can be a range value formed by any two of the above point values as the end values. It can be understood that the pressure of the above hydrogenation reaction is also the pressure of the reaction equipment system; for example, when the above hydrogenation reaction is carried out in a fixed-bed reactor, the pressure of the above hydrogenation reaction is also the pressure in the fixed-bed reactor.

[0084] In some embodiments, in the hydrogenation reaction, the mass space velocity is 0.5 h -1 ~1.0 h -1 . The mass space velocity is also the mass of the reaction raw material processed by the catalyst per unit time and per unit mass during the hydrogenation reaction. As an example, the mass space velocity in the hydrogenation reaction can be 0.5 h -1 , 0.6 h -1 , 0.7 h -1 , 0.8 h -1 , 0.9 h -1 or 1.0 h -1 . Controlling the mass space velocity in the hydrogenation reaction is beneficial to improving the reaction conversion rate.

[0085] In some embodiments, the above step S30, the step of rectifying and separating the reaction liquid, includes:

[0086] S31. Removing the light components at the top of the tower from the reaction liquid in the light component removal tower.

[0087] In some embodiments, the top temperature of the light component removal tower is 74°C to 97°C.

[0088] In some embodiments, the vacuum degree of the light component removal tower is -0.09 Mpa to 0.095 Mpa.

[0089] In some embodiments, the reflux ratio of the light component removal tower is (3 to 5):1.

[0090] S32. Then, putting the bottom liquid of the light component removal tower into the first rectification tower for rectification and purification, and taking the top component of the first rectification tower to obtain 2-methylbutanol.

[0091] In some embodiments, the top temperature of the first rectification tower is 97°C to 120°C.

[0092] In some embodiments, the vacuum degree of the first rectification tower is -0.09 Mpa to -0.095 Mpa.

[0093] In some embodiments, the reflux ratio of the first rectification tower is (3 to 5):1.

[0094] In another embodiment of the present application, a method for preparing 2-methylbutyraldehyde is provided, including the following steps S10, S40 to S50.

[0095] S10: Using the above-mentioned preparation method, prepare 2-ethylacrolein;

[0096] S40: Mix the above-mentioned 2-ethylacrolein with hydrogen, and carry out a hydrogenation reaction under catalyst conditions to obtain a reaction solution; wherein, the molar ratio of hydrogen to 2-ethylacrolein is (0.5 to 1):1.

[0097] S50: Carry out rectification separation on the reaction solution to obtain 2-methylbutanol.

[0098] As an example, the molar ratio of hydrogen to 2-ethylacrolein can be 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1 or 1:1. Further, the molar ratio of hydrogen to 2-ethylacrolein can be any other ratio within the above range. Preferably, the molar ratio of hydrogen to 2-ethylacrolein is (0.6 to 0.8):1.

[0099] In some embodiments, the selectivity of 2-methylbutyraldehyde prepared by the above hydrogenation reaction is ≥90%.

[0100] In some embodiments, the purity of 2-methylbutyraldehyde obtained by the above preparation method is ≥99.5%.

[0101] In some embodiments, the components of the nickel-based catalyst in the 2-methylbutyraldehyde preparation method are the same as those of the nickel-based catalyst used in the 2-methylbutanol preparation method.

[0102] In some embodiments, the hydrogenation reaction in the 2-methylbutyraldehyde preparation method is carried out in a fixed bed.

[0103] In some embodiments, 10% to 15% of the catalyst is filled in the above fixed bed.

[0104] In some embodiments, the temperature, time, and mass space velocity conditions of the hydrogenation reaction in the 2-methylbutyraldehyde preparation method are the same as those of the hydrogenation reaction in the 2-methylbutanol preparation method. Details are not described herein again.

[0105] In some embodiments, the step S50 of carrying out rectification separation on the reaction solution includes:

[0106] S51: Remove the light components at the top of the tower in the debutanizer for the reaction solution.

[0107] In some embodiments, the parameters of the top temperature, vacuum degree, and reflux ratio of the light component removal column are the same as those of the light component removal column in the preparation method of 2-methylbutanol. Details are not repeated here.

[0108] S52. Place the bottom liquid of the light component removal column into a second rectification column for rectification and purification, and take the top component of the second rectification column to obtain 2-methylbutyraldehyde.

[0109] In some embodiments, the top temperature of the second rectification column is 40°C to 44°C.

[0110] In some embodiments, the vacuum degree of the second rectification column is -0.075 MPa to -0.085 MPa.

[0111] In some embodiments, the reflux ratio of the second rectification column is (3 - 5):1.

[0112] For the purpose of making the objectives, technical solutions, and advantages of the present invention more concise and clear, the present invention is described by the following specific embodiments, but the present invention is by no means limited to these embodiments. The following described embodiments are only preferred embodiments of the present invention and can be used to describe the present invention, and should not be construed as limiting the scope of the present invention. It should be noted that any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

[0113] To better illustrate the present invention, the content of the present invention is further described below in conjunction with embodiments. The following are specific embodiments.

[0114] Example 1

[0115] 1. Condensation reaction: Prepare mixture 1 according to the mass ratio: 21.9 parts of formaldehyde, 1 part of diethylamine, 0.27 part of acetic acid, and 37.3 parts of water; add the polymerization inhibitor hydroquinone to n-butyraldehyde to obtain mixture 2, wherein the addition amount of the polymerization inhibitor is 0.23 wt% of the mass of n-butyraldehyde.

[0116] Pump mixture 1 into a tubular reactor at a speed of 1339.1 kg / h and mixture 2 into the tubular reactor at a speed of 1020.5 kg / h, control the temperature of the tubular reactor at 80°C, and let the liquid react in the tubular reactor for 2 h to obtain a reaction solution. After detection and calculation, the conversion rate of n-butyraldehyde in the reaction solution is 99.5%, and the selectivity of 2-ethylacrolein is 98.5%.

[0117] Introduce the reaction solution into an oil-water separation column for oil-water stratification to obtain an oil phase and a water phase.

[0118] 2. Water phase stripping: Transfer the above water phase to a stripping column, control the bottom temperature within 105°C, collect the overhead material, mix it with the oil phase in step 1, and then enter the next rectification and purification step.

[0119] 3. Distillation of 2-ethylacrolein: Add hydroquinone at 0.1 wt% of the weight of the mixed oil phase as a polymerization inhibitor to the mixed oil phase, then pump it into the distillation column. Control the bottom temperature below 100 °C and the vacuum degree at -0.05 Mpa. The 2-ethylacrolein product is taken out from the top of the column; among them, the purity of 2-ethylacrolein is more than 99%.

[0120] 4. Hydrogenation of 2-ethylacrolein: 2-ethylacrolein and hydrogen enter the fixed-bed continuous hydrogenation after mixing and preheating, which is filled with an alumina-supported nickel catalyst with a nickel content of 40 wt% - 45 wt%. Control the space velocity at 0.5 h -1 , the hydrogen-oil ratio is 5 - 6, the reaction temperature is 130 - 150 °C, and the system pressure is 0.60 Mpa to obtain the crude product of 2-methylbutanol. Through detection and calculation, the conversion rate of 2-ethylacrolein is 99.9%, and the selectivity of 2-methylbutanol is 99.5%.

[0121] 5. Separation and purification of 2-methylbutanol: Pump the crude product of 2-methylbutanol obtained in step 4 into the light component removal column. The light components are taken out from the top of the column, and the bottom liquid of the column is pumped into the 2-methylbutanol refining column. After distillation, the 2-methylbutanol product with a purity > 99.5% is obtained, and the bottom liquid of the column is discharged regularly.

[0122] Example 2

[0123] 1. Condensation reaction: Prepare mixture 1 according to the mass ratio: 14.9 parts of formaldehyde, 1 part of di-n-butylamine, 0.28 part of acetic acid, and 25.3 parts of water; add the polymerization inhibitor hydroquinone to n-butyraldehyde to obtain mixture 2, where the polymerization inhibitor is 0.23 wt% of the mass of n-butyraldehyde.

[0124] Pump mixture 1 at a speed of 1357.9 kg / h and mixture 2 at a speed of 1020.5 kg / h into the tubular reactor. Control the temperature of the tubular reactor at 80 °C, and the liquid reacts in the tubular reactor for 2 h to obtain the reaction liquid. Through detection and calculation, the conversion rate of n-butyraldehyde in the reaction liquid is 95%, and the selectivity of 2-ethylacrolein is 88.5%.

[0125] The reaction liquid enters the oil-water separation tower for oil-water stratification to obtain an oil phase and a water phase.

[0126] 2. Stripping of the water phase: Transfer the above water phase to the stripping column. Control the bottom temperature within 105 °C, take out the materials from the top of the column, mix them with the oil phase in step 1, and then enter the next distillation and purification step.

[0127] 3. Rectification of 2-ethylacrolein: Add hydroquinone accounting for 0.1 wt% of the weight of the mixed oil phase as a polymerization inhibitor to the mixed oil phase, then pump it into a rectification column. Control the bottom temperature below 100°C and the vacuum degree at -0.05 Mpa, and collect the 2-ethylacrolein product from the top of the column. Among them, the purity of 2-ethylacrolein is more than 99%.

[0128] 4. Hydrogenation of 2-ethylacrolein: After 2-ethylacrolein and hydrogen are mixed and preheated, they enter a fixed-bed continuous hydrogenation reactor filled with an alumina-supported nickel catalyst with a nickel content of 40 wt% - 45 wt%. Control the space velocity at 1.0 h -1 , the hydrogen-oil ratio at 5 - 6, the reaction temperature at 130 - 150°C, and the system pressure at 0.60 Mpa to obtain crude 2-methylbutanol. Through detection and calculation, the conversion rate of 2-ethylacrolein is 99.9%, and the selectivity of 2-methylbutanol is 99.5%.

[0129] 5. Separation and purification of 2-methylbutanol: Pump the crude 2-methylbutanol obtained in step 4 into a de-light tower, collect the light components from the top of the tower, pump the bottom liquid of the tower into a 2-methylbutanol refining tower, and rectify to obtain a 2-methylbutanol product with a purity > 99.5%, and regularly discharge the bottom liquid of the tower.

[0130] Example 3

[0131] 1. Condensation reaction: Prepare mixture 1 according to the mass ratio: 26.3 parts of formaldehyde, 1 part of diethylamine, 0.61 part of propionic acid, and 44.8 parts of water; add the polymerization inhibitor hydroquinone to n-butyraldehyde to obtain mixture 2, where the polymerization inhibitor is 0.23 wt% of the mass of n-butyraldehyde.

[0132] Pump mixture 1 at a speed of 1341.0 kg / h and mixture 2 at a speed of 1020.5 kg / h into a tubular reactor, control the temperature of the tubular reactor at 80°C, and let the liquid react in the tubular reactor for 2 h to obtain a reaction liquid. Through detection and calculation, the conversion rate of n-butyraldehyde in the reaction liquid is 95%, and the selectivity of 2-ethylacrolein is 90.5%.

[0133] Introduce the reaction liquid into an oil-water separation tower for oil-water stratification to obtain an oil phase and a water phase. The oil phase is the crude 2-ethylacrolein.

[0134] 2. Stripping of the water phase: Transfer the above water phase to a stripping tower, control the bottom temperature within 105°C, collect the material from the top of the tower, mix it with the oil phase in step 1, and then enter the next rectification and purification step.

[0135] 3. Distillation of 2-ethylacrolein: Add hydroquinone at 0.1 wt% of the weight of the mixed oil phase as a polymerization inhibitor to the mixed oil phase, then pump it into the distillation column. Control the bottom temperature below 100 °C and the vacuum degree at -0.05 Mpa. The 2-ethylacrolein product is taken from the top of the column; among them, the purity of 2-ethylacrolein is more than 99%.

[0136] 4. Hydrogenation of 2-ethylacrolein: After 2-ethylacrolein and hydrogen are mixed and preheated, they enter a fixed-bed continuous hydrogenation reactor filled with an alumina-supported nickel catalyst with a nickel content of 40 wt% - 45 wt%. Control the space velocity at 0.6 h -1 , the hydrogen-oil ratio is 5 - 6, the reaction temperature is 130 - 150 °C, and the system pressure is 0.60 Mpa to obtain the crude product of 2-methylbutanol; among them, the conversion rate of 2-ethylacrolein is 99.9%, and the selectivity of 2-methylbutanol is 99.5%.

[0137] 5. Separation and purification of 2-methylbutanol: Pump the crude product of 2-methylbutanol obtained in step 4 into the light component removal column, take out the light components from the top of the column, and pump the bottom liquid of the column into the 2-methylbutanol refining column. After distillation, a 2-methylbutanol product with a purity > 99.5% is obtained, and the bottom liquid of the column is discharged regularly.

[0138] Example 4

[0139] 1. Condensation reaction: Prepare mixture 1 according to the mass ratio: 14.9 parts of formaldehyde, 1 part of di-n-butylamine, 0.34 part of propionic acid, and 25.3 parts of water; add the polymerization inhibitor hydroquinone to n-butyraldehyde to obtain mixture 2, where the polymerization inhibitor is 0.23 wt% of the mass of n-butyraldehyde.

[0140] Pump mixture 1 at a speed of 1360.8 kg / h and mixture 2 at a speed of 1020.5 kg / h into the tubular reactor, control the temperature of the tubular reactor at 80 °C, and let the liquid react in the tubular reactor for 2 h to obtain the reaction liquid. After detection and calculation, the conversion rate of n-butyraldehyde in the reaction liquid is 85%, and the selectivity of 2-ethylacrolein is 86%.

[0141] Transfer the reaction liquid into an oil-water separation tower for oil-water stratification to obtain an oil phase and a water phase. The oil phase is the crude product of 2-ethylacrolein.

[0142] 2. Stripping of the water phase: Transfer the above water phase into the stripping column, control the bottom temperature within 105 °C, take out the materials from the top of the column, mix them with the oil phase in step 1, and then enter the next distillation and purification step.

[0143] 3. Rectification of 2-ethylacrolein: Add hydroquinone at 0.1 wt% of the weight of the mixed oil phase as a polymerization inhibitor to the mixed oil phase, then pump it into the rectification column. Control the bottom temperature below 100 °C and the vacuum degree at -0.05 Mpa, and collect the 2-ethylacrolein product from the top of the column; among them, the purity of 2-ethylacrolein is more than 99%.

[0144] 4. Hydrogenation of 2-ethylacrolein: After 2-ethylacrolein and hydrogen are mixed and preheated, they enter a fixed-bed continuous hydrogenation reactor filled with an alumina-supported nickel catalyst with a nickel content of 40 wt% - 45 wt%. Control the space velocity at 0.7 h -1 , the hydrogen-oil ratio at 5 - 6, the reaction temperature at 130 - 150 °C, and the system pressure at 0.60 Mpa to obtain the crude product of 2-methylbutanol; after calculation, the conversion rate of 2-ethylacrolein is 99.9%, and the selectivity of 2-methylbutanol is 99.5%.

[0145] 5. Separation and purification of 2-methylbutanol: Pump the above-mentioned crude product of 2-methylbutanol into the light-component removal column, collect the light components from the top of the column, and pump the bottom liquid of the column into the 2-methylbutanol refining column. After rectification, obtain the 2-methylbutanol product with a purity > 99.5%, and regularly discharge the bottom liquid of the column.

[0146] Example 5

[0147] 1. Condensation reaction: Prepare mixture 1 according to the mass ratio: 52.6 parts of formaldehyde, 1 part of diethylamine, 0.49 part of acetic acid, and 89.5 parts of water; add the polymerization inhibitor hydroquinone to n-butanal to obtain mixture 2, where the polymerization inhibitor is 0.23 wt% of the mass of n-butanal.

[0148] Pump mixture 1 at a speed of 1318.8 kg / h and mixture 2 at a speed of 1020.5 kg / h into the tubular reactor, control the temperature of the tubular reactor at 80 °C, and let the liquid react in the tubular reactor for 2 h to obtain the reaction liquid. After detection and calculation, the conversion rate of n-butanal in the reaction liquid is 89.5%, and the selectivity of 2-ethylacrolein is 92%.

[0149] The reaction liquid enters the oil-water separation column for oil-water stratification to obtain an oil phase and a water phase.

[0150] 2. Stripping of the water phase: Transfer the above-mentioned water phase to the stripping column, control the bottom temperature within 105 °C, collect the material from the top of the column, mix it with the oil phase in step 1, and then enter the next rectification and purification step.

[0151] 3. Rectification of 2-ethylacrolein: Add hydroquinone at 0.1 wt% of the weight of the mixed oil phase as a polymerization inhibitor to the mixed oil phase, then pump it into the rectification column. Control the bottom temperature below 100 °C and the vacuum degree at -0.05 Mpa, and collect the 2-ethylacrolein product from the top of the column; among them, the purity of 2-ethylacrolein is more than 99%.

[0152] 4. Hydrogenation of 2-ethylacrolein: After being mixed and preheated, 2-ethylacrolein and hydrogen enter a fixed-bed continuous hydrogenation reactor filled with an alumina-supported nickel catalyst with a nickel content of 40 wt% - 45 wt%. The space velocity is controlled at 0.5 h -1 , the hydrogen-oil ratio is 5 - 6, the reaction temperature is 130 - 150 °C, and the system pressure is 0.60 Mpa to obtain crude 2-methylbutanol. After calculation, the conversion rate of 2-ethylacrolein is 99.9%, and the selectivity of 2-methylbutanol is 99.5%.

[0153] 5. Separation and purification of 2-methylbutanol: The above-mentioned crude 2-methylbutanol is pumped into a de-light tower. The light components are taken out from the top of the tower, and the bottom liquid of the tower is pumped into a 2-methylbutanol refining tower. After distillation, 2-methylbutanol products with a purity > 99.5% are obtained, and the bottom liquid of the tower is discharged regularly.

[0154] Example 6

[0155] 1. Condensation reaction: A mixture 1 is prepared according to the mass ratio: 26.3 parts of formaldehyde, 1 part of diethylamine, 0.49 part of acetic acid, and 44.8 parts of water; Hydroquinone as a polymerization inhibitor is added to n-butyraldehyde to obtain a mixture 2, where the polymerization inhibitor is 0.23 wt% of the mass of n-butyraldehyde.

[0156] The mixture 1 is pumped into a tubular reactor at a speed of 1388.1 kg / h, and the mixture 2 is pumped into the tubular reactor at a speed of 1018.2 kg / h. The temperature of the tubular reactor is controlled at 80 °C, and the liquid reacts in the tubular reactor for 2 h to obtain a reaction solution. After detection and calculation, the conversion rate of n-butyraldehyde in the reaction solution is 99.5%, and the selectivity of 2-ethylacrolein is 88.5%.

[0157] The reaction solution enters an oil-water separation tower for oil-water stratification to obtain an oil phase and a water phase.

[0158] 2. Stripping of the water phase: The above-mentioned water phase is transferred to a stripping tower. The bottom temperature of the tower is controlled within 105 °C. The materials are taken out from the top of the tower and mixed with the oil phase in step 1, and then enter the next distillation and purification step.

[0159] 3. Distillation of 2-ethylacrolein: Hydroquinone is added to the mixed oil phase as a polymerization inhibitor at 0.1 wt% of the weight of the mixed oil phase, and then it is pumped into a distillation tower. The bottom temperature is controlled below 100 °C, and the vacuum degree is controlled at -0.05 Mpa. 2-ethylacrolein products are taken out from the top of the tower; among them, the purity of 2-ethylacrolein is above 99%.

[0160] 4. Hydrogenation of 2-ethylacrolein: After being mixed and preheated, 2-ethylacrolein and hydrogen enter a fixed-bed continuous hydrogenation reactor filled with an alumina-supported nickel catalyst with a nickel content of 40 wt% - 45 wt%. The space velocity is 0.9 h -1, with a hydrogen-oil ratio of 5 - 6, a reaction temperature of 130 - 150 °C, and a system pressure of 0.60 Mpa, crude 2-methylbutanol is obtained; after calculation, the conversion rate of 2-ethylacrolein is 99.9%, and the selectivity of 2-methylbutanol is 99.5%.

[0161] 5. Separation and purification of 2-methylbutanol: Pump the above-mentioned crude 2-methylbutanol into the light component removal column, and the light components are taken out from the top of the column. The bottom liquid of the column is pumped into the 2-methylbutanol refining column, and 2-methylbutanol products with a purity > 99.5% are obtained by rectification, and the bottom liquid of the column is discharged regularly. Among them, the conversion rate of 2-ethylacrolein is 99.9%, and the selectivity of 2-methylbutanol is 99.5%.

[0162] Example 7

[0163] 1. Condensation reaction: Prepare mixture 1 according to the mass ratio: 21.9 parts of formaldehyde, 1 part of diethylamine, 0.27 part of acetic acid, and 37.3 parts of water; add the polymerization inhibitor hydroquinone to n-butyraldehyde to obtain mixture 2, where the polymerization inhibitor is 0.23 wt% of the mass of n-butyraldehyde.

[0164] Pump mixture 1 at a speed of 1339.1 kg / h and mixture 2 at a speed of 1018.2 kg / h into a tubular reactor, control the temperature of the tubular reactor at 80 °C, and the liquid reacts in the tubular reactor for 2 h to obtain a reaction solution. After detection and calculation, the conversion rate of n-butyraldehyde in the reaction solution is 99.5%, and the selectivity of 2-ethylacrolein is 98.5%.

[0165] The reaction solution enters an oil-water separation tower for oil-water stratification to obtain an oil phase and a water phase.

[0166] 2. Water phase stripping: Transfer the above-mentioned water phase to a stripping tower, control the bottom temperature within 105 °C, take out the materials from the top of the tower, mix them with the oil phase in step 1, and then enter the next rectification and purification step.

[0167] 3. Rectification of 2-ethylacrolein: Add hydroquinone at 0.1 wt% of the weight of the mixed oil phase as a polymerization inhibitor to the mixed oil phase, then pump it into a rectification tower, control the bottom temperature below 100 °C, and control the vacuum degree at -0.05 Mpa. 2-ethylacrolein products are taken out from the top of the tower; among them, the purity of 2-ethylacrolein is more than 99%.

[0168] 4. Hydrogenation of 2-ethylacrolein: 2-ethylacrolein and hydrogen enter a fixed-bed selective hydrogenation filled with an alumina-supported nickel catalyst with a nickel content of 10% - 15% after mixing and preheating, and the space velocity is 0.5 h -1, with a hydrogen-oil ratio of 1.0, a reaction temperature of 145 °C, and a system pressure of 0.60 Mpa, crude 2-methylbutanol and 2-methylbutanal were obtained; among them, the conversion rate of 2-ethylacrolein was 99.9%, the selectivity of 2-methylbutanal was 63.5%, and the selectivity of 2-methylbutanol was 34.6%.

[0169] 5. Separation and purification of 2-methylbutanal and 2-methylbutanol: The crude 2-methylbutanal and 2-methylbutanol obtained in step 4 were pumped into the light component removal column at a certain rate. The light components were taken out from the top of the column, and the bottom liquid of the column was pumped into the 2-methylbutanal refining column. After rectification, 2-methylbutanal product with a content > 99.0% was obtained. The bottom liquid of the column was pumped into the 2-methylbutanol refining column. After rectification, 2-methylbutanol product with a content > 99.5% was obtained, and the bottom liquid of the column was discharged regularly.

[0170] Example 8

[0171] Example 8 was basically the same as Example 7, except that the hydrogen-oil ratio in step 4 was different. Specifically, step 4 of this example was as follows:

[0172] 4. Hydrogenation of 2-ethylacrolein: 2-ethylacrolein and hydrogen were preheated after mixing and then entered a fixed-bed continuous selective hydrogenation reactor filled with an alumina-supported nickel catalyst with a nickel content of 10% - 15%. The space velocity was controlled at 0.5 h -1 , with a hydrogen-oil ratio of 0.8, a reaction temperature of 145 °C, and a system pressure of 0.60 Mpa. In the reaction liquid, the conversion rate of 2-ethylacrolein was 99.9%, the selectivity of 2-methylbutanal was 94.1%, and the selectivity of 2-methylbutanol was 4.5%. The obtained crude 2-methylbutanal and 2-methylbutanol were sent to a distillation column for separation and purification.

[0173] Comparative Example 1

[0174] The preparation method of this comparative example was basically the same as that of Example 1, except that the components of mixture 1 were different; specifically, the component ratio in the mixture 1 prepared in this Comparative Example 1 was: 21.9 parts of formaldehyde, 1 part of diethylamine, 0.40 part of butyric acid, and 37.3 parts of water. Other preparation steps and process conditions were the same as those in Example 1.

[0175] The raw material components and ratios used in each example and comparative example are shown in Tables 1, 2, and 3.

[0176] Table 1

[0177]

[0178] Table 2

[0179]

[0180] Table 3

[0181]

[0182] In the table, the conversion rate of n-butanal refers to the percentage of the amount of reacted butanal in the total amount of butanal before the reaction.

[0183] The selectivity of 2-ethylacrolein refers to the percentage of the number of moles of the target product 2-ethylacrolein and the number of moles of reacted butanal.

[0184] The hydrogen-to-oil ratio refers to the molar ratio of hydrogen to the unsaturated bonds in the reactants.

[0185] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0186] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A method for preparing 2-ethylacrolein, characterized in that: The steps include: Mixing formaldehyde, an organic amine, an organic acid and a solvent to obtain a first mixture; the first mixture comprises, by weight, 10 to 55 parts of formaldehyde, 1 part of the organic amine, 0.2 to 1 part of the organic acid and 20 to 90 parts of the solvent; The first mixed material is mixed with n-butyraldehyde to carry out a condensation reaction, and then the oil phase and the water phase are separated to obtain an oil phase; The oil phase is subjected to rectification and purification to obtain the 2-ethylacrolein.

2. The preparation method according to claim 1, characterized in that The preparation method satisfies at least one of the following conditions: (1) The organic amine is a secondary amine; (2) The organic acid is at least one selected from acetic acid, propionic acid, butyric acid and valeric acid; (3) The solvent is water.

3. The preparation method according to claim 1, characterized in that: The mass ratio of the first mixed material to the n-butyraldehyde is (1.0-1.5):

1.

4. The preparation method according to claim 1, characterized in that: The preparation method satisfies at least one of the following conditions: (1) The temperature of the condensation reaction is 70°C to 100°C; (2) The condensation reaction time is 1h~3h.

5. The preparation method according to any one of claims 1 to 4, characterized in that The condensation reaction is carried out in a tubular reactor.

6. A method for preparing 2-methylbutanol, characterized in that: The steps include: Using the preparation method according to any one of claims 1 to 4 to prepare 2-ethylacrolein; The 2-ethylacrolein is mixed with hydrogen, and subjected to a hydrogenation reaction under a nickel catalyst to obtain a reaction liquid; the reaction liquid is subjected to rectification and separation to obtain 2-methylbutanol; The molar ratio of the hydrogen to the 2-ethylacrolein is (5-6):

1.

7. The preparation method according to claim 6, characterized in that: The nickel-based catalyst is an alumina-supported nickel catalyst with a nickel mass percentage of 5wt% to 50wt%.

8. The preparation method according to claim 6, characterized in that: The preparation method satisfies at least one of the following conditions: (1) The temperature of the hydrogenation reaction is 130°C to 150°C; (2) The pressure of the hydrogenation reaction is 0.2MPa~1MPa; (3) The mass space velocity in the hydrogenation reaction is 0.5h -1 ~1.0h -1 .

9. The preparation method according to claim 6, characterized in that: The hydrogenation reaction is carried out in a fixed bed.

10. A method for preparing 2-methylbutanal, characterized in that: The steps include: Using the preparation method according to any one of claims 1 to 4 to prepare 2-ethylacrolein; The 2-ethylacrolein is mixed with hydrogen, and subjected to a hydrogenation reaction under a nickel catalyst to obtain a reaction liquid; the reaction liquid is subjected to rectification and separation to obtain 2-methylbutyraldehyde; The molar ratio of the hydrogen to the 2-ethylacrolein is (0.5-1):1.

Images