CN110759808A

CN110759808A - Production process and production system of 1, 3-butanediol

Info

Publication number: CN110759808A
Application number: CN201810835027.0A
Authority: CN
Inventors: 滕文彬; 王春梅; 杜桂强; 宋世晶; 郝小军; 祝秀林
Original assignee: DONGYING HI-TECH SPRING CHEMICAL INDUSTRIAL Co Ltd
Current assignee: DONGYING HI-TECH SPRING CHEMICAL INDUSTRIAL Co Ltd
Priority date: 2018-07-26
Filing date: 2018-07-26
Publication date: 2020-02-07

Abstract

The invention provides a production process of 1, 3-butanediol, which comprises the following steps of firstly, feeding an acetaldehyde solution and a catalyst into a microchannel reactor for condensation reaction, then adding an acidic substance for neutral adjustment, and obtaining an intermediate product; and then carrying out hydrogenation reaction on the intermediate product obtained in the step to obtain the 1, 3-butanediol. The production process of 1, 3-butanediol provided by the invention greatly improves the selectivity of 3-hydroxybutyraldehyde and the once-through conversion rate of acetaldehyde in the acetaldehyde condensation reaction process, and improves the selectivity and yield index of the final product 1, 3-butanediol; meanwhile, the production cost of the 1, 3-butanediol is reduced, and a process route for producing the 1, 3-butanediol, which can be applied industrially, is provided.

Description

Production process and production system of 1, 3-butanediol

Technical Field

The invention belongs to the technical field of 1, 2-propylene glycol synthesis, and particularly relates to a production process and a production system of 1, 3-butanediol.

Background

1, 3-butanediol, 1,3-BDO for short, the molecular formula is C₄H₁₀O₂The liquid is colorless and tasteless at normal temperature, has no corrosiveness, has little irritation to skin, has low toxicity and is widely applied. The 1, 3-butanediol has the characteristics of reactivity of dihydric alcohol, no odor, low toxicity, good water solubility and the like, is mainly used for organic synthesis, is a raw material of polyester resin and alkyd resin, a raw material of plasticizer, a raw material of polyurethane coating, and can be prepared into unsaturated polyester resin with monomers such as phthalic anhydride, maleic anhydride and the like, wetting agent and softening agent, intermediate of medicine and dye, surfactant, plasticizer, coupling agent, solvent, food additive and flavoring agent, and also can be used as a moisturizer and softener of textiles, tobacco and paper, antibacterial agent of cheese or meat and the like. In addition, it is widely used as a moisturizer in cosmetics, such as astringent, cream, lotion, toothpaste, etc. 1, 3-butanediol can be classified into technical grade and LO + grade. The former has relatively low price and is widely used as industrial solvent with low requirement on the quality of DPG, production raw materials of unsaturated resin, nitrocellulose varnish and the like; the latter is expensive and is mainly used in fields requiring high-quality raw materials such as perfume, cosmetics, detergents, food additives and the like. Such as 1, 3-butanediol, is mainly used as a humectant in cosmetics, has good bacteriostatic action, and can be used for producing various lotions, ointments and toothpastes. Moreover, 1, 3-butanediol is used as an antibacterial agent for dairy products and meat products because of its antibacterial effect. 1, 3-butanediol is used as an important organic synthesis intermediate, and the application of the intermediate in various fields is continuously developed and extended. Due to the low toxicity and excellent performance of the 1, 3-D, the future development prospect is good.

In the prior art, the production method of 1, 3-butanediol mainly comprises the following steps: (1) acetaldehyde condensation hydrogenation process; (2) condensing and hydrolyzing propylene and formaldehyde; (3) reacting acrolein with 2, 2-dimethyl-1, 3-propanediol; (4) biological methods, and the like. In the industrial production of 1, 3-butanediol, the above-mentioned conventional industrial production methods all have problems of low selectivity, a large amount of by-products, difficulty in post-treatment, and the like. In contrast, the acetaldehyde condensation hydrogenation process is the predominant process for producing 1, 3-butanediol. Therefore, the current production method of 1, 3-butanediol mainly adopts an acetaldehyde condensation hydrogenation method, but is in the laboratory research and development stage at home, even if laboratory devices such as flasks or reaction kettles are adopted, the problems of low conversion rate, poor selectivity and the like still exist, and no industrial production device is reported. In addition, the industrial production method of 1, 3-butanediol introduced in foreign documents adopts acetaldehyde condensation hydrogenation process to prepare 1, 3-butanediol, and the intermediate product is (2, 6-dimethyl, 1, 3-dioxane, 4-hexanol) which is then hydrogenated to generate 1, 3-butanediol. The process also has the problems of low selectivity, low yield of 1, 3-butanediol and the like.

Therefore, how to find a production process route of 1, 3-butanediol with high development conversion rate, good selectivity and high purity, which can be applied industrially, solves the technical problems existing in the practical application, is very important for realizing large-scale industrial production of 1, 3-butanediol and solving the urgent situation that the domestic high-end market mainly depends on import at present, and also becomes one of the problems to be solved urgently by a plurality of production enterprises in the industry and a front-line research and development staff.

Disclosure of Invention

In view of the above, the technical problem to be solved by the present invention is to provide a production process and a production system of 1, 3-butanediol, the production process and the production system provided by the present invention greatly improve the conversion rate, selectivity and purity of 1, 3-butanediol products, and the process route is simple and suitable for industrial mass production.

The invention provides a production process of 1, 3-butanediol, which comprises the following steps:

1) feeding the acetaldehyde solution and a catalyst into a microchannel reactor for condensation reaction, and then adding an acidic substance for neutral adjustment to obtain an intermediate product;

2) and (3) carrying out hydrogenation reaction on the intermediate product obtained in the step to obtain the 1, 3-butanediol.

Preferably, the feeding amount of the acetaldehyde solution is 5-35 kg/h;

the feeding amount of the catalyst is 0.2-2 kg/h;

the condensation reaction time is 2-30 min;

the temperature of the condensation reaction is 0-50 ℃.

Preferably, the microchannel reactor comprises a single-tube microchannel reactor or a shell and tube microchannel reactor;

the diameter of the channel of the microchannel reactor is 5-25 mm;

the size of the shell of the microchannel reactor is 100-800 mm;

the length of the tube of the microchannel reactor is 50-30000 mm;

the acetaldehyde solution and catalyst are fed into the tube side of a microchannel reactor.

Preferably, the feeding further comprises a mixing step in a line mixer;

the mass concentration of the acetaldehyde solution is 20-80%;

the catalyst comprises a basic solution;

the mass concentration of the alkali solution is 0.01-5%;

the flow ratio of the acetaldehyde solution to the alkali solution is 10: (0.02-2).

Preferably, the alkali solution comprises one or more of a sodium hydroxide solution, a potassium hydroxide solution and a sodium bicarbonate solution;

the neutral pH value is 5-8;

the acidic substance comprises one or more of acetic acid, dilute hydrochloric acid, dilute sulfuric acid, formic acid, benzoic acid, carbonic acid and hydrofluoric acid.

Preferably, a rectification separation step is further included before the hydrogenation reaction;

the pressure of the rectification separation is 10-50 KPa;

the temperature of the top of the rectification separation tower is-20-2 ℃;

the temperature of a tower kettle for rectification separation is 40-85 ℃;

the rectification separation mode is a packing type rectification separation mode;

the temperature of the hydrogenation reaction is 30-100 ℃;

the pressure of the hydrogenation reaction is 1.5-5.5 MPa;

the time of the hydrogenation reaction is 0.5-4 hours.

Preferably, the hydrogenation reaction further comprises one or more of filtering, light component removal separation, evaporation separation and rectification again;

the pressure of the light component removal separation is 5-50 KPa;

the temperature of the top of the light component removal separation tower is 20-70 ℃;

the temperature of the tower kettle for removing light components and separating is 100-150 ℃.

The invention also provides a production system of the 1, 3-butanediol, which comprises a microchannel reactor;

a pipeline neutralization device connected with the outlet of the microchannel reactor;

and the hydrogenation reaction kettle is connected with the outlet of the pipeline neutralization device.

Preferably, the system further comprises a pipeline mixer;

the pipeline mixer is provided with an acetaldehyde solution inlet and a catalyst inlet;

the outlet of the pipeline mixer is connected with the inlet of the microchannel reactor;

the system also includes a packed rectification column;

the outlet of the pipeline neutralization device is connected with the feed inlet of the packed rectifying tower, the outlet of the top of the packed rectifying tower is connected with the inlet of the microchannel reactor, and the outlet of the bottom of the packed rectifying tower is connected with the hydrogenation reaction kettle;

the number of the sections of the filler rectifying tower is 2-5 sections;

the height of the filler layer of each section of the filler rectifying tower is 2-5 m.

Preferably, the system further comprises a light component removal tower, a thin film evaporator and a second rectifying tower;

an outlet of the hydrogenation reaction kettle is connected with a side inlet of the light component removal tower, and a tower kettle outlet of the light component removal tower is connected with an inlet of the thin film evaporator;

the steam outlet of the thin film evaporator is connected with the side inlet of the second rectifying tower;

the second rectifying tower is a filler rectifying tower;

the number of the second rectifying tower sections is 3-6;

the height of the filler layer of each section of the second rectifying tower is 3-6 m;

the second rectification column has a side product outlet.

The invention provides a production process of 1, 3-butanediol, which comprises the following steps of firstly, feeding an acetaldehyde solution and a catalyst into a microchannel reactor for condensation reaction, then adding an acidic substance for neutral adjustment, and obtaining an intermediate product; and then carrying out hydrogenation reaction on the intermediate product obtained in the step to obtain the 1, 3-butanediol. Compared with the prior art, the method aims at solving the problems of low selectivity, more byproducts, difficult post-treatment and the like of the conventional common industrial production method of the 1, 3-butanediol. The acetaldehyde condensation hydrogenation process still has the problems of low conversion rate, poor selectivity and the like no matter in a laboratory research and development stage or an industrial method.

The invention provides an industrial production process and a production system for preparing 1, 3-butanediol by using acetaldehyde as a raw material and performing condensation reaction and hydrogenation. According to the process method, acetaldehyde is taken as a raw material and then reacts with a catalyst in a microchannel reactor in a condensation reaction to generate 3-hydroxy butyraldehyde, and an acidic substance is directly added into a microchannel after the condensation reaction to neutralize the reacted material to be neutral. After crude material containing unreacted acetaldehyde is rectified and separated out acetaldehyde, the product 1, 3-butanediol and by-product n-butanol are obtained by hydrogenation. The production process of 1, 3-butanediol provided by the invention greatly improves the selectivity of 3-hydroxybutyraldehyde and the once-through conversion rate of acetaldehyde in the acetaldehyde condensation reaction process, and improves the selectivity and yield index of the final product 1, 3-butanediol; meanwhile, the production cost of the 1, 3-butanediol is reduced, and a process route for producing the 1, 3-butanediol, which can be applied industrially, is provided.

Experimental results show that the production process provided by the invention can improve the selectivity of 1, 3-butanediol from 60-70% to more than 85%, the yield from 85% to 98%, and the purity of the butanediol to more than 99.5%, and effectively improves the selectivity and yield of target products, the aging cost and the energy consumption.

Drawings

FIG. 1 is a schematic diagram of the main process flow of a 1, 3-butanediol production system provided by the present invention;

FIG. 2 is a schematic view of a process flow of a 1, 3-butanediol production system provided in example 1 of the present invention.

Detailed Description

For a further understanding of the invention, preferred embodiments of the invention are described below in conjunction with the examples, but it should be understood that these descriptions are included merely to further illustrate the features and advantages of the invention and are not intended to limit the invention to the claims.

All of the starting materials of the present invention, without particular limitation as to their source, may be purchased commercially or prepared according to conventional methods well known to those skilled in the art.

All the raw materials of the present invention are not particularly limited in purity, and the present invention preferably employs industrial purity or purity which is conventional in the art of dipropylene glycol production.

All the noun expressions and acronyms of the invention belong to the conventional noun expressions and acronyms in the field, each noun expression and acronym is clearly and definitely clear in the relevant application field, and a person skilled in the art can clearly, exactly and uniquely understand the noun expressions and acronyms.

The invention provides a production process of 1, 3-butanediol, which is characterized by comprising the following steps:

According to the invention, firstly, an acetaldehyde solution and a catalyst are fed into a microchannel reactor for condensation reaction, and then an acidic substance is added for neutral adjustment to obtain an intermediate product.

The specific parameters of the acetaldehyde solution in the present invention are not particularly limited, and the acetaldehyde solution used in such reaction, which is well known to those skilled in the art, may be selected and adjusted by those skilled in the art according to actual production conditions, raw material conditions and product requirements, and the mass concentration of the acetaldehyde solution in the present invention is preferably 20% to 80%, more preferably 30% to 70%, and still more preferably 40% to 60%.

The feeding amount of the acetaldehyde solution is not particularly limited in the invention, and the feeding amount for the reaction is known to those skilled in the art, and can be selected and adjusted by those skilled in the art according to actual production conditions, raw material conditions and product requirements, and the feeding amount of the acetaldehyde solution is preferably 5 to 35kg/h, more preferably 10 to 30kg/h, and more preferably 15 to 25 kg/h.

The acetaldehyde solution is not particularly limited in the present invention, and may be selected and adjusted by those skilled in the art according to actual production conditions, raw material conditions and product requirements, by using a conventional catalyst for such a reaction, which is well known to those skilled in the art, and the catalyst of the present invention preferably includes an alkali solution, more preferably one or more of a sodium hydroxide solution, a potassium hydroxide solution and a sodium bicarbonate solution, and more preferably a sodium hydroxide solution, a potassium hydroxide solution or a sodium bicarbonate solution. The mass concentration of the alkali solution is preferably 0.01% to 5%, more preferably 0.05% to 4.5%, more preferably 0.1% to 4%, more preferably 0.5% to 3.5%, more preferably 1% to 3%, more preferably 1.5% to 2.5%.

The feeding amount of the catalyst is not particularly limited in the present invention, and the feeding amount of the catalyst used in the reaction is well known to those skilled in the art, and can be selected and adjusted by those skilled in the art according to actual production conditions, raw material conditions and product requirements, and the feeding amount of the catalyst in the present invention is preferably 0.2 to 2kg/h, more preferably 0.5 to 1.8kg/h, more preferably 0.8 to 1.5kg/h, and more preferably 1.0 to 1.3 kg/h.

The invention has no special limitation on the parameters of the microchannel reactor, and the parameters are conventional parameters for the microchannel reactor, which are well known to those skilled in the art, and the parameters can be selected and adjusted by the skilled in the art according to the actual production situation, the raw material situation and the product requirement. The diameter (pipe diameter) of the channel of the microchannel reactor is preferably 5-25 mm, more preferably 8-22 mm, more preferably 10-20 mm, and more preferably 12-18 mm. The size of the shell of the microchannel reactor is preferably 100-800 mm, more preferably 200-700 mm, more preferably 300-600 mm, and more preferably 400-500 mm. The length of the microchannel reactor is preferably 50-30000 mm, more preferably 500-25000 mm, more preferably 1000-20000 mm, more preferably 5000-15000 mm, more preferably 8000-12000 mm. The acetaldehyde solution and the catalyst are preferably fed into a tube side of a microchannel reactor, namely a reaction medium passes through the tube side, and a heat exchange medium passes through the shell side.

In order to further improve the reaction effect, the method preferably further comprises a mixing step in a pipeline mixer before the acetaldehyde solution is fed into the microchannel reactor, namely, the acetaldehyde solution and the catalyst are preferably mixed in the pipeline mixer and then fed into the microchannel reactor for condensation reaction. The present invention is not particularly limited with respect to the specific parameters of the line mixer, as the usual parameters for such mixers are well known to the skilled person, which can be selected and adjusted by the skilled person according to the actual production situation, raw material situation and product requirements, more preferably a microchannel mixer.

The invention has no special limitation on the parameters of the condensation reaction, and the conventional parameters of the condensation reaction known by the technicians in the field can be used, and the technicians in the field can select and adjust the parameters according to the actual production condition, the raw material condition and the product requirement, in order to further ensure the reaction effect and improve the performance parameters of the product, the time of the condensation reaction is preferably 2-30 min, more preferably 7-25 min, and more preferably 12-20 min. The condensation reaction temperature is preferably 0-50 ℃, more preferably 0-40 ℃, more preferably 0-30 ℃, more preferably 0-20 ℃, and can also be 5-20 ℃ or 10-15 ℃. The pressure of the condensation reaction according to the invention is preferably atmospheric pressure.

The invention preferably adopts the microchannel mixer as a mixing place, the characteristic dimension of the channel in the microchannel mixer reaches micron order, and the raw materials are mixed at molecular level by convection action and molecular diffusion before reaction, thereby improving the mass transfer effect in the reaction process and providing guarantee for the subsequent reaction. The invention particularly takes the microchannel reactor as a reaction site, utilizes the characteristic of the diameter of the low channel of the microchannel reactor, has high-efficiency mass transfer effect and fully mixes materials, provides guarantee for condensation reaction of acetaldehyde solution, and ensures that the key temperature parameter control is more accurate, thereby ensuring that the reaction is carried out at low temperature, effectively widening the control range of the reaction temperature and being beneficial to the control of actual production; and the raw materials are in a laminar flow state in the channel, so that the back mixing phenomenon does not exist, the chance of redundant contact between the materials in the reaction process is effectively avoided, and the occurrence of side reaction is reduced, thereby effectively improving the selectivity of the 1, 3-butanediol, and overcoming the defects of low product selectivity, high by-product and the like of the synthesized 1, 3-butanediol.

The specific choice of the acidic substance is not particularly limited in the present invention, and the acidic substance for adjusting the pH value is known to those skilled in the art, and can be selected and adjusted by those skilled in the art according to actual production conditions, raw material conditions and product requirements, and the acidic substance in the present invention preferably includes one or more of acetic acid, dilute hydrochloric acid, dilute sulfuric acid, formic acid, carbonic acid and hydrofluoric acid, and more preferably acetic acid, dilute hydrochloric acid, dilute sulfuric acid, formic acid, benzoic acid, carbonic acid or hydrofluoric acid.

The specific range of the neutral pH value is not particularly limited, and the neutral range of the pH value of the reaction known to those skilled in the art can be selected and adjusted by those skilled in the art according to actual production conditions, raw material conditions and product requirements, and the neutral pH value in the invention is preferably 5-8, more preferably 5.5-7.5, and more preferably 6-7.

The intermediate product obtained by the above steps is not particularly limited in the present invention, and in the present invention, the intermediate product preferably includes 3-hydroxybutyraldehyde, crotonaldehyde, acetaldehyde and water, that is, the main product is 3-hydroxybutyraldehyde, and also includes crotonaldehyde as by-product, unreacted acetaldehyde and water in the raw material.

According to the invention, the intermediate product obtained in the above step is subjected to hydrogenation reaction to obtain 1, 3-butanediol.

In order to further improve the reaction effect, the method preferably further comprises a rectification separation step before the intermediate product is subjected to the hydrogenation reaction, namely, the intermediate product is preferably rectified firstly, acetaldehyde is separated, and then the hydrogenation reaction is carried out. The specific parameters of the rectification separation are not particularly limited, and the common rectification separation parameters for the reaction, which are well known to those skilled in the art, can be selected and adjusted by those skilled in the art according to actual production conditions, raw material conditions and product requirements, and the pressure of the rectification separation is preferably 10-50 KPa, more preferably 15-45 KPa, more preferably 20-40 KPa, and more preferably 25-35 KPa. The tower top temperature of the rectification separation is preferably-20-2 ℃, more preferably-18-0 ℃, more preferably-15-3 ℃, more preferably-12-5 ℃ and more preferably-10-7 ℃. The temperature of the tower kettle for rectification separation is preferably 40-85 ℃, more preferably 50-75 ℃ and more preferably 60-65 ℃. The mode of the rectification separation is preferably the packed rectification separation.

The specific parameters of the hydrogenation reaction are not particularly limited, and the parameters of the common hydrogenation reaction for the reaction are known by those skilled in the art, and the parameters can be selected and adjusted by those skilled in the art according to the actual production situation, the raw material situation and the product requirement, and the pressure of the hydrogenation reaction is preferably 1.5-5.5 MPa, more preferably 2-5 MPa, more preferably 2.5-4.5 MPa, and more preferably 3-4 MPa. The temperature of the hydrogenation reaction is preferably 30-100 ℃, more preferably 40-90 ℃, more preferably 50-80 ℃, and more preferably 60-70 ℃. The time of the hydrogenation reaction is preferably 0.5 to 4 hours, more preferably 1 to 3.5 hours, more preferably 1.5 to 3 hours, and more preferably 2 to 2.5 hours. The hydrogenation reaction is preferably a catalytic hydrogenation reaction, and the catalyst for the hydrogenation reaction comprises one or more of a raney nickel catalyst, a palladium carbon catalyst and a rhodium catalyst, and more preferably the raney nickel catalyst, the palladium carbon catalyst or the rhodium catalyst.

In order to further ensure the effect of the final product and complete and refine the whole production process, the method preferably further comprises the steps of filtering, light component removal and separation, evaporation and separation and rectification again after the hydrogenation reaction, and more preferably sequentially comprises the steps of filtering and separation, light component removal and separation, evaporation and separation and rectification again.

The present invention has no particular limitation on the specific parameters of the above steps, and the post-treatment steps for such reactions, which are well known to those skilled in the art, can be selected and adjusted by those skilled in the art according to the actual production situation, raw material situation and product requirement, and the filtration in the present invention is preferably filtration separation, in particular, filtration separation of the catalyst. The light component removal separation is preferably rectification light component removal separation. The pressure of the light component removal separation is preferably 5-50 KPa, more preferably 15-40 KPa, and more preferably 25-30 KPa. The tower top temperature of the light component removal separation is preferably 20-70 ℃, more preferably 30-60 ℃, and more preferably 40-50 ℃. The temperature of the tower kettle for light component removal and separation is preferably 100-150 ℃, more preferably 110-140 ℃, and more preferably 120-130 ℃. The mode of evaporation separation in the present invention is preferably thin film evaporation separation. The pressure of the secondary rectification is preferably 1-50KPa, more preferably 5-45 KPa, more preferably 10-40 KPa, and more preferably 20-30 KPa. The tower top temperature of the re-rectification is preferably 100-140 ℃, more preferably 105-135 ℃, more preferably 120-132 ℃, more preferably 122-130 ℃, and more preferably 123-126 ℃. The temperature of the tower bottom for re-rectification is preferably 100-170 ℃, more preferably 110-155 ℃, and more preferably 125-135 ℃. The mode of rectification again is preferably packed rectification separation.

In order to further ensure the effect of the final product and complete and refine the whole production process, the invention specifically comprises the following steps:

(1) condensation unit: before the start of operation, firstly, pressing and testing the process system to be tight, confirming that the system has no leakage point, mixing an acetaldehyde aqueous solution and an alkali liquor together, then introducing the mixture into a microchannel reactor, keeping the temperature of the microchannel reactor at 0-50 ℃, keeping the concentration of the acetaldehyde aqueous solution within the range of 20-100%, the concentration range of the alkali liquor is 0.01-1%, and the introduction ratio of the acetaldehyde aqueous solution to the alkali liquor is 10: (0.02-2). And (3) after the condensation reaction is finished, introducing an acetic acid solution into the reaction materials, and neutralizing the reaction materials to be neutral.

(2) An acetaldehyde separation unit: the materials after acetaldehyde condensation contain acetaldehyde, 3-hydroxy butyraldehyde, crotonaldehyde, water and other materials, acetaldehyde is separated and removed through an acetaldehyde removing tower, and then hydrogenation reaction is carried out to produce the 1, 3-butanediol. According to the invention, a filler rectifying tower is adopted to separate and remove acetaldehyde, the operating pressure of the tower is 0-50 KPa, the temperature of the top of the tower is-20-2 ℃, the temperature of the bottom of the tower is 40-85 ℃, and the tower adopts three sections of stainless steel wire mesh fillers.

(3) A hydrogenation unit: adding the material subjected to acetaldehyde removal into a hydrogenation reaction kettle, introducing nitrogen to replace air in the reaction kettle, introducing hydrogen to replace nitrogen after replacement is finished, heating to raise the temperature, introducing hydrogen when the temperature is kept at about 50-80 ℃, performing hydrogenation reaction for 0.5-4 hours under the condition that the pressure of the reaction kettle is kept at 2.0-5.5 MPa, sampling and analyzing the reaction material to remove materials containing carbonyl such as butenal, trihydroxybutyraldehyde and acetaldehyde, and stopping the hydrogenation reaction.

(4) The light component tower for removing 1, 3-butanediol: after the hydrogenation catalyst is separated from the hydrogenated material, the tower is operated under negative pressure, the pressure is 0-50 KPa, the temperature at the top of the tower is 20-70 ℃, the temperature at the bottom of the tower is 100-150 ℃, and the tower is filled with stainless steel wire mesh.

(5)1, 3-butanediol product: and (3) after removing light component materials, feeding the materials into a film evaporator to evaporate and remove sodium acetate salts, directly feeding steam into a 1, 3-butanediol product rectifying tower, further removing light component impurities at the tower top, removing heavy component impurities at the tower bottom, and collecting a 1, 3-butanediol product at the side line.

The above steps of the present invention provide a process for producing 1, 3-butanediol based on the instability of the acetaldehyde condensation intermediate 3-hydroxybutyraldehyde, temperatures above 85 ℃ or rapid decomposition to crotonaldehyde under acidic conditions. Or 3-hydroxybutyraldehyde and acetaldehyde are further condensed into (2, 6-dimethyl, 1, 3-dioxane, 4-hexanol), the invention improves the conversion per pass of acetaldehyde, improves the selectivity of 3-hydroxybutyraldehyde, and protects the 3-hydroxybutyraldehyde from being decomposed stably before hydrogenation reaction, thereby being taken as the key point for realizing large-scale industrialization and improving yield and selectivity. Aiming at the defects and the characteristics, the invention improves the selectivity of 3-hydroxybutyraldehyde and the single-pass conversion rate of acetaldehyde in the acetaldehyde condensation reaction process and improves the selectivity and yield index of the final product 1, 3-butanediol by optimizing and controlling the reaction temperature of acetaldehyde condensation, the amount of a catalyst sodium hydroxide solution, the type of an acetaldehyde condensation reactor, the neutralization reaction mode, the hydrogenation reaction condition and other modes. Reduces the production cost of the 1, 3-butanediol and provides a process route for producing the 1, 3-butanediol, which can be applied industrially.

The invention provides a method and a system for producing 1, 3-butanediol, wherein liquid sodium hydroxide solution is preferably used as a catalyst, partial acetaldehyde is subjected to condensation reaction to generate butyraldehyde, the reacted material enters a rectifying tower to be separated and removed of unreacted acetaldehyde, hydrogenation reaction is carried out to generate a 1, 3-butanediol crude product, and the 1, 3-butanediol product is obtained after refining and separation. More mainly, an acetaldehyde aqueous solution is preferably adopted, a catalyst is a sodium hydroxide solution, the acetaldehyde solution and the sodium hydroxide solution are subjected to mixing reaction in a microchannel reactor, the reaction temperature is kept between 0 and 20 ℃ stably and optimally, the reaction pressure is normal pressure, an acetic acid solution (acidic substance) is directly injected into the rear section of the microreactor after the condensation reaction is completed in the microreactor, and the acetaldehyde condensation product is neutralized to be neutral. Then rectifying and separating unreacted acetaldehyde under the condition of negative pressure, returning to prepare acetaldehyde solution, and feeding the acetaldehyde solution into the microreactor for recycling. And (3) separating out the 3-hydroxybutyraldehyde solution of the unreacted acetaldehyde, then conveying the solution into a hydrogenation reaction kettle, hydrogenating to generate a 1, 3-butanediol product, and hydrogenating the condensation byproduct crotonaldehyde to generate n-butanol.

The invention starts from the fluid mechanics angle of the reaction process more creatively, abandons the characteristic of stirring and mixed flow state reaction in the prior reaction kettle, changes the reaction into ordered laminar flow, is more beneficial to the reaction and the improvement of the selectivity, particularly adopts a microchannel reactor as a reaction place, utilizes the characteristic of the diameter of a low channel of the microchannel reactor to lead the raw material to be in a laminar flow state in the channel, reduces the back mixing phenomenon, effectively avoids the chance of generating byproducts by contacting the raw material and the product, reduces the occurrence of series reaction, preferentially combines with the microchannel mixer for mixing, thereby effectively improving the selectivity of 1, 3-butanediol in the product, improving the selectivity of 3-hydroxy butyraldehyde and the once-through conversion rate of acetaldehyde in the acetaldehyde condensation reaction process, further improving the selectivity and the yield index of the final product 1, 3-butanediol, and having simple process, mild condition, easy control and more suitability for industrial mass production.

The purity of the product obtained by the method is more than or equal to 99 percent, the chroma is less than or equal to 5, and the selectivity of 1, 3-butanediol reaches more than 89 percent at most.

The invention also provides a production system of 1, 3-butanediol, which is characterized by comprising a microchannel reactor;

The selection and composition of the required equipment in the production system of 1, 3-butanediol, and the corresponding preferred principle of the invention can correspond to the selection and composition of the corresponding equipment in the production process, and the corresponding preferred principle, and are not described in detail herein.

The connection mode is not particularly limited by the present invention, and may be a conventional connection mode in the art, which is well known to those skilled in the art, and can be selected and adjusted by those skilled in the art according to the actual production situation, the raw material situation and the product requirement, and the connection mode is preferably connected by a pipeline, or connected by a pipeline and a pump.

Referring to fig. 1, fig. 1 is a schematic diagram of a main process flow of a 1, 3-butanediol production system provided by the present invention. Wherein, 1, pipeline reactor; 2. a pipeline neutralization reactor; 3. and (3) a hydrogenation reaction kettle, wherein a is an acetaldehyde solution, b is a catalyst, c is an acidic substance, and d is hydrogen.

In the invention, the production system comprises a microchannel reactor. The invention has no special limitation on the parameters of the microchannel reactor, and the parameters are conventional parameters for the microchannel reactor, which are well known to those skilled in the art, and the parameters can be selected and adjusted by the skilled in the art according to the actual production situation, the raw material situation and the product requirement. The diameter (pipe diameter) of the channel of the microchannel reactor is preferably 5-25 mm, more preferably 8-22 mm, more preferably 10-20 mm, and more preferably 12-18 mm. The size of the shell of the microchannel reactor is preferably 100-800 mm, more preferably 200-700 mm, more preferably 300-600 mm, and more preferably 400-500 mm. The length of the microchannel reactor is preferably 50-5000 mm, more preferably 100-4500 mm, more preferably 500-4000 mm, more preferably 1000-3000 mm, and more preferably 1500-2500 mm. The acetaldehyde solution and the catalyst are preferably fed into a tube side of a microchannel reactor, namely a reaction medium passes through the tube side, and a heat exchange medium passes through the shell side.

In the present invention, the production system preferably further comprises a line mixer, more preferably a microchannel mixer. The pipeline mixer is provided with an acetaldehyde solution inlet and a catalyst inlet; the outlet of the pipeline mixer is connected with the inlet of the microchannel reactor. The method has the effects of facilitating the homogeneous mixing before the condensation reaction and improving the reaction efficiency. The structure and parameters of the line mixer are not particularly limited in the present invention, and may be selected and adjusted by those skilled in the art according to actual production conditions, raw material conditions and product requirements, as long as the structure and parameters of the conventional line mixer are well known to those skilled in the art. In other embodiments, other devices having the same function may be included to facilitate the progress of the condensation reaction and to improve the reaction effect.

In the invention, the production system comprises a pipeline neutralization device connected with the outlet of the microchannel reactor. I.e. the inlet of the pipe neutralization device is connected with the outlet of the microchannel reactor. The method has the effects of helping to reduce the occurrence of side reactions and meeting the conditions of subsequent reactions. The structure and parameters of the pipe neutralization apparatus are not particularly limited in the present invention, and may be selected and adjusted by those skilled in the art according to actual production conditions, raw material conditions and product requirements, in accordance with conventional structures and parameters for pipe neutralization apparatuses well known to those skilled in the art. In other embodiments, other devices with the same function may be included to help reduce the occurrence of side reactions, and the conditions for subsequent reactions are preferably satisfied.

In the invention, the production system comprises a hydrogenation reaction kettle connected with the outlet of the pipeline neutralization device. Namely, the outlet of the pipeline neutralization device is connected with the inlet of the hydrogenation reaction kettle. The purpose of this is to carry out a hydrogenation reaction. The structure and parameters of the hydrogenation reactor are not particularly limited in the present invention, and may be conventional structures and parameters for hydrogenation reactors known to those skilled in the art, and those skilled in the art may select and adjust the conventional structures and parameters according to actual production conditions, raw material conditions and product requirements, and the hydrogenation reactor of the present invention is preferably a kettle type batch hydrogenation reactor. In other embodiments, other devices with the same function may be included to facilitate the hydrogenation reaction, which is preferred.

In the present invention, the production system preferably further comprises a packed distillation column. The outlet of the pipeline neutralization device is preferably connected with the feed inlet of the filler rectifying tower, the outlet of the top of the filler rectifying tower is preferably connected with the inlet of the microchannel reactor, and the outlet of the bottom of the filler rectifying tower is preferably connected with the hydrogenation reaction kettle. The top outlet of the packed rectifying tower is preferably connected with the inlet of the pipeline mixer. The method has the effects of separating unreacted acetaldehyde, returning the recovered acetaldehyde to a raw material inlet, recycling, saving energy, protecting environment and reducing cost. In other embodiments, other devices with the same function can be contained, so that recycling is facilitated, energy conservation and environmental protection are achieved, and cost reduction is the preferred scheme.

The structure and parameters of the packed rectifying tower are not particularly limited, and the structure and parameters of the conventional packed rectifying tower known by the technical personnel in the field can be selected and adjusted by the technical personnel in the field according to the actual production situation, the raw material situation and the product requirement, the number of the sections of the packed rectifying tower is preferably 2-5 sections, more preferably 3-5 sections, and more preferably 3-4 sections, in order to further improve the performance of the final product and complete and optimize the production system. The height of the packing layer of each section of the packing rectifying tower is preferably 2-5 meters, more preferably 2-4 meters, and more preferably 3-4 meters. The packing form of the present invention preferably comprises structured packing or random packing, more preferably structured packing. The packing type of the invention preferably comprises one or more of stainless steel wire mesh, ceramic corrugated packing, metal corrugated packing, wood grid packing, raschig ring, pall ring, ladder ring and steel packing ring, more preferably stainless steel wire mesh, ceramic corrugated packing, metal corrugated packing, wood grid packing, raschig ring, pall ring, ladder ring or steel packing ring, and most preferably BX (stainless steel wire mesh) packing. The feeding hole of the filler rectifying tower is preferably arranged below the second section of filler, and the calculation mode of the section number is preferably from the top to the bottom of the rectifying tower from top to bottom.

In the present invention, the production system preferably further comprises a light ends removal column, a thin film evaporator and a second rectification column. The outlet of the hydrogenation reaction kettle is preferably connected with the side inlet of the light component removal tower, the top outlet (removed alcohol and water) of the light component removal tower is preferably connected with a condenser for other utilization, the kettle outlet of the light component removal tower is preferably connected with the inlet of the thin film evaporator, and the steam (namely product) outlet of the thin film evaporator is preferably connected with the side inlet of the second rectifying tower. The method has the effects of separating and purifying the final product, recycling the by-product, saving energy, protecting environment and reducing cost. In other embodiments, other devices with the same function can be contained, so that the separation and purification of the final product are facilitated, the recycling is realized, the energy is saved, the environment is protected, and the cost is reduced to be the preferred scheme.

The structure and parameters of the above-mentioned device are not particularly limited by the present invention, and the structure and parameters of the conventional light component removal column, thin film evaporator and rectifying column known to those skilled in the art can be selected and adjusted according to the actual production situation, raw material situation and product requirement. The number of the sections of the second rectifying tower is preferably 3-6, more preferably 4-6, and even more preferably 4-5. The height of the packing layer of each section of the packing rectifying tower is preferably 3-6 meters, more preferably 4-6 meters, and more preferably 4-5 meters. The packing form of the present invention preferably comprises structured packing or random packing, more preferably structured packing. The packing type of the invention preferably comprises one or more of stainless steel wire mesh, ceramic corrugated packing, metal corrugated packing, wood grid packing, raschig ring, pall ring, ladder ring and steel packing ring, more preferably stainless steel wire mesh, ceramic corrugated packing, metal corrugated packing, wood grid packing, raschig ring, pall ring, ladder ring or steel packing ring, and most preferably BX (stainless steel wire mesh) packing. The feed inlet of the second rectifying tower is preferably arranged below the third section of packing, and the discharge position of the second rectifying tower is preferably a side draw, namely a side product outlet is formed. The discharge port is preferably below the first section of packing. The calculation mode of the number of the sections is preferably from the top to the bottom of the rectifying tower.

In order to further ensure the effect of the final product and complete and refine the whole production system, the generation system can be specifically as follows:

condensation reaction unit: conveying the acetaldehyde solution from the acetaldehyde solution preparation tank and the sodium hydroxide solution from the sodium hydroxide solution preparation tank into a microchannel reactor through pumps respectively, carrying out condensation reaction in the microchannel reactor to generate 3-hydroxybutyraldehyde, wherein the reaction pressure is normal pressure, the reaction temperature is kept at 0-20 ℃ for continuous reaction, and the retention time of materials in the microchannel reactor is kept at 2-30 minutes.

Neutralizing: according to the amount of the added sodium hydroxide solution and the pH value of the reacted materials, directly injecting an acetic acid solution into the rear section of the microreactor to neutralize the reaction product to be neutral.

And (3) recovering acetaldehyde: and (4) conveying the material neutralized to neutral after reaction to a rectifying tower to rectify and separate unreacted acetaldehyde, and returning the material to an acetaldehyde solution preparation tank after condensation to be recycled in the microreactor.

Hydrogenation: and (3) conveying the material in the rectifying tower to a hydrogenation reactor for hydrogenation reaction, and keeping the hydrogenation reaction temperature within the range of 20-80 ℃ and the pressure within the range of 1.5-6.0 MPa for hydrogenation reaction to generate 1, 3-butanediol and a byproduct n-butyl alcohol.

1, 3-butanediol product refining: and (3) filtering and separating the hydrogenated material, rectifying to obtain a crude product of the 1, 3-butanediol, evaporating and desalting by using a film evaporator, condensing a vapor phase, and refining to obtain a 1, 3-butanediol product.

The above steps of the present invention provide a system for producing 1, 3-butanediol based on the instability of acetaldehyde condensation intermediate 3-hydroxybutyraldehyde, temperatures exceeding 85 ℃ or rapid decomposition to crotonaldehyde under acidic conditions. Or 3-hydroxybutyraldehyde and acetaldehyde are further condensed into (2, 6-dimethyl, 1, 3-dioxane, 4-hexanol), the invention improves the conversion per pass of acetaldehyde, improves the selectivity of 3-hydroxybutyraldehyde, and protects the 3-hydroxybutyraldehyde from being decomposed stably before hydrogenation reaction, thereby being taken as the key point for realizing large-scale industrialization and improving yield and selectivity. Aiming at the defects and the characteristics, the invention improves the selectivity of 3-hydroxybutyraldehyde and the once-through conversion rate of acetaldehyde in the acetaldehyde condensation reaction process and improves the selectivity and the yield index of the final product 1, 3-butanediol by optimally controlling the conditions of the type of an acetaldehyde condensation reactor, the mode of neutralization reaction, the mode of hydrogenation reaction and the like. Reduces the production cost of the 1, 3-butanediol and provides a process route for producing the 1, 3-butanediol, which can be applied industrially.

The invention starts from the fluid mechanics angle of the reaction process more creatively, abandons the characteristic of stirring mixed flow state reaction in the prior reaction kettle, changes the reaction into ordered laminar flow, is more beneficial to the reaction and the improvement of selectivity, particularly adopts a microchannel reactor as a reaction place, utilizes the characteristic of the diameter of a low channel of the microchannel reactor to lead the raw material to be in a laminar flow state in the channel, reduces the back mixing phenomenon, effectively avoids the chance of generating by-products by contacting the raw material and the product, reduces the occurrence of series reaction, and preferably combines with the microchannel mixer for mixing, thereby effectively improving the selectivity of 1, 3-butanediol in the product. The invention adopts the microchannel reactor to carry out condensation reaction, the reaction heat is timely removed out of the system, the reaction temperature is easy to control, the generation of side reaction of the condensation reaction is reduced, the generation of high condensation products of acetaldehyde is reduced, therefore, toxic by-products are reduced, and the improvement of the quality of 1, 3-butanediol products is facilitated; the batch kettle type hydrogenation reaction flow is adopted, the process is simple, and the progress of the hydrogenation reaction is easy to control; the adopted desalination mode is membrane evaporation desalination, and the desalination is thorough, so that no residual salt in the material can be ensured; the reaction raw materials, the catalyst and the circulating materials are mixed by adopting the pipeline mixer and then enter the reactor, so that the materials are uniformly mixed in the reactor, the space is saved by adopting the pipeline mixer, and the labor intensity of the operation is saved.

The production process of 1, 3-butanediol provided by the invention greatly improves the selectivity of 3-hydroxybutyraldehyde and the once-through conversion rate of acetaldehyde in the acetaldehyde condensation reaction process, and improves the selectivity and yield index of the final product 1, 3-butanediol; meanwhile, the production cost of the 1, 3-butanediol is reduced, the process is simple, the condition is mild, the control is easy, the method is more suitable for industrial mass production, and a process route for producing the 1, 3-butanediol, which can be industrially applied, is provided.

Experimental results show that the production process provided by the invention can improve the selectivity of 1, 3-butanediol from 60-70% to more than 85%, the yield from 85% to 90%, and the purity of the butanediol to more than 99.5%, so that the selectivity and the yield of a target product, the aging cost and the energy consumption are effectively improved.

For further illustration of the present invention, the following detailed description of the process and system for producing 1, 3-butanediol according to the present invention is provided in conjunction with the following examples, but it should be understood that these examples are carried out on the premise of the technical solution of the present invention, and the detailed embodiments and specific procedures are given only for further illustration of the features and advantages of the present invention, not for limitation of the claims of the present invention, and the scope of protection of the present invention is not limited to the following examples.

Example 1

Referring to FIG. 2, FIG. 2 is a schematic view of a process flow of a 1, 3-butanediol production system provided in example 1 of the present invention. Wherein a is acetaldehyde solution, b is catalyst, c is acid substance, d is hydrogen; 1. a pipeline reactor; 2. a pipeline neutralization reactor, 3, a hydrogenation reaction kettle, 4, an aldehyde removal tower, 5, a filtering and separating device, 6, a light component removal rectifying tower, 7, a thin film evaporator, 8 and a product filler rectifying tower.

A reaction unit: the specification of the pipeline reactor is a fixed tube plate tubular reactor, the diameter of a shell is 159mm, the diameter of an internal reaction tube is phi 19 multiplied by 2mm, and the length is 10000 mm. Mixing raw materials acetaldehyde and liquid alkali in a pipeline mixer, reacting in a reaction tube, introducing a low-temperature aqueous solution with the temperature of 15 ℃ on the shell side, and keeping the reaction temperature not higher than 20 ℃. Acetaldehyde is an acetaldehyde solution with the concentration of 80%, liquid alkali is a sodium hydroxide solution with the concentration of 0.4%, the flow rate of the acetaldehyde solution is 15kg/h, the flow rate of alkali liquor is 0.8kg/h, the PH value of materials at the outlet of the reactor is detected firstly, then 36% acetic acid solution is dripped in, and the PH value of a reaction product is adjusted to be about 7.

An acetaldehyde separation unit: the materials after the acetaldehyde condensation contain acetaldehyde, 3-hydroxy butyraldehyde, crotonaldehyde, water and other materials, the acetaldehyde is separated and removed through an acetaldehyde removing tower, and then the subsequent hydrogenation reaction is carried out to produce the 1, 3-butanediol. Wherein, a filler rectifying tower is adopted to separate and remove acetaldehyde, the operating pressure of the tower is 20KPa, the temperature at the top of the tower is-3.2 ℃, the temperature at the bottom of the tower is 75 ℃, the tower adopts three sections of stainless steel wire mesh fillers, and the side line of the light component removal tower is used for feeding.

And rectifying and separating unreacted acetaldehyde, and returning the condensed acetaldehyde to the acetaldehyde solution preparation tank to be recycled in the microreactor.

A hydrogenation unit: adding the material after removing acetaldehyde into a kettle type intermittent hydrogenation reactor, wherein the volume of the hydrogenation reactor is 4L, adopting Raney nickel catalyst for hydrogenation, the adding amount of the catalyst is 10 percent, the loading amount of the material is 1.5L, introducing nitrogen to replace air in the reaction kettle, introducing hydrogen to replace nitrogen after replacement is finished, then starting heating and raising the temperature, starting introducing hydrogen when the hydrogenation reaction temperature is kept at about 40 ℃, keeping the pressure of the reaction kettle at 3.5MPa, performing hydrogenation reaction for 2 hours, sampling and analyzing the reaction material to remove materials containing carbonyl such as crotonaldehyde, trihydroxy butyraldehyde and acetaldehyde, and then stopping the hydrogenation reaction.

The light component tower for removing 1, 3-butanediol: and (3) filtering the hydrogenated material to separate out a hydrogenation catalyst, and rectifying, removing light and separating to obtain a crude product of the 1, 3-butanediol. Wherein the pressure of the light component removal separation is 30 KPa. The overhead temperature was 46 ℃. The temperature of the bottom of the column was 137 ℃. The tower adopts stainless steel wire gauze packing and side feeding.

Referring to table 1, table 1 shows data of continuous sampling of the outlet of crude 1, 3-butanediol after light component removal in the light component removal column in the preparation process of example 1 of the present invention.

TABLE 1

1, 3-butanediol product refining:

1, 3-butanediol product: and (3) after removing light component materials, feeding the materials into a film evaporator to evaporate and remove sodium acetate, directly feeding steam into a 1, 3-butanediol product rectifying tower (a second rectifying tower), further removing light component impurities at the tower top, removing heavy component impurities at the tower bottom, and collecting a 1, 3-butanediol product at the side line.

Wherein, the product filler rectifying tower is 4 sections of fillers, each section is 4 meters in height, and the pressure is 2 KPa. The overhead temperature was 118 ℃. The temperature of the bottom of the column was 132 ℃. The tower adopts stainless steel wire gauze packing, side feeding and side discharging.

The 1, 3-butanediol product prepared in the embodiment 1 of the invention is detected, and the purity of the refined 1, 3-butanediol is more than or equal to 99.5 percent, the total yield is 90-95 percent, and the chroma is less than 5.

Example 2

A reaction unit: according to the process shown in FIG. 2, the pipeline reactor has a sleeve pipe structure, the inner pipe is a sleeve pipe with a diameter of phi 19X 2 and a length of 18000mm, and low-temperature water is introduced into the jacket to control the reaction temperature to be below 20 ℃. Mixing raw materials acetaldehyde and liquid alkali in a pipeline mixer, and reacting in a pipeline reactor, wherein the concentration of the reaction raw material acetaldehyde is 40%, the concentration of alkali liquor sodium hydroxide is 0.1%, the flow rate of an acetaldehyde solution is 1kg/h, and the flow rate of the alkali liquor is 0.05 kg/h. The PH value of the material at the outlet of the reactor is detected firstly, then 36 percent acetic acid solution is dripped in, and the PH value of the reaction product is adjusted to be about 7.0.

An acetaldehyde separation unit: the materials after the acetaldehyde condensation contain acetaldehyde, 3-hydroxy butyraldehyde, crotonaldehyde, water and other materials, the acetaldehyde is separated and removed through an acetaldehyde removing tower, and then the subsequent hydrogenation reaction is carried out to produce the 1, 3-butanediol. Wherein, a filler rectifying tower is adopted to separate and remove acetaldehyde, the operating pressure of the tower is 30KPa, the temperature of the top of the tower is 2.2 ℃, the temperature of the bottom of the tower is 83 ℃, the tower adopts three sections of stainless steel wire mesh fillers, and the side line of the light component removal tower is fed.

A hydrogenation unit: adding the material after removing acetaldehyde into a kettle type intermittent hydrogenation reactor, wherein the volume of the hydrogenation reactor is 4L, adopting Raney nickel catalyst for hydrogenation, the adding amount of the catalyst is 10 percent, the loading amount of the material is 1.5L, introducing nitrogen to replace air in the reaction kettle, introducing hydrogen to replace nitrogen after replacement is finished, then starting heating and raising the temperature, starting introducing hydrogen when the hydrogenation reaction temperature is kept at about 40 ℃, keeping the pressure of the reaction kettle at 3.8MPa, performing hydrogenation reaction for 2 hours, sampling and analyzing the reaction material to remove materials containing carbonyl such as crotonaldehyde, trihydroxy butyraldehyde and acetaldehyde, and then stopping the hydrogenation reaction.

The light component tower for removing 1, 3-butanediol: and (3) filtering the hydrogenated material to separate out a hydrogenation catalyst, and rectifying, removing light and separating to obtain a crude product of the 1, 3-butanediol. Wherein the pressure of the light component removal separation is 35 KPa. The overhead temperature was 51 ℃. The temperature of the bottom of the column was 145 ℃. The tower adopts stainless steel wire gauze packing and side feeding.

Referring to table 2, table 2 shows data of continuous sampling of the outlet of crude 1, 3-butanediol after light component removal in the light component removal column in the preparation process of example 2 of the present invention.

Referring to Table 2, Table 2 shows data of successive sampling in the preparation of example 2 of the present invention

TABLE 2

1, 3-butanediol product refining:

Wherein, the product filler rectifying tower is 4 sections of fillers, each section is 4 meters in height, and the pressure at the top of the tower is 1 KPa. The overhead temperature was 105 ℃. The temperature of the bottom of the column was 128 ℃. The tower adopts stainless steel wire gauze packing, side feeding and side discharging.

The 1, 3-butanediol product prepared in the embodiment 2 of the invention is detected, and the purity of the refined 1, 3-butanediol is more than or equal to 99.5 percent, the total yield is 90-95 percent, and the chroma is less than 5.

The above detailed description of a process and system for the highly selective production of 1, 3-butanediol provided by the present invention, and the principles and embodiments of the present invention described herein using specific examples, is provided merely to facilitate an understanding of the process and its core concepts, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated processes. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention. The scope of the invention is defined by the claims and may include other embodiments that occur to those skilled in the art. Such other embodiments are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. The production process of 1, 3-butanediol is characterized by comprising the following steps:

2. The production process according to claim 1, wherein the feeding amount of the acetaldehyde solution is 5 to 35 kg/h;

the feeding amount of the catalyst is 0.2-2 kg/h;

the condensation reaction time is 2-30 min;

the temperature of the condensation reaction is 0-50 ℃.

3. The production process of claim 1 wherein the microchannel reactor comprises a single-tube microchannel reactor or a shell-and-tube microchannel reactor;

the diameter of the channel of the microchannel reactor is 5-25 mm;

the size of the shell of the microchannel reactor is 100-800 mm;

the length of the tube of the microchannel reactor is 50-30000 mm;

4. The process of claim 1 wherein the feeding further comprises a mixing step in a line mixer;

the mass concentration of the acetaldehyde solution is 20-80%;

the catalyst comprises a basic solution;

the mass concentration of the alkali solution is 0.01-5%;

5. The production process according to claim 1, wherein the alkali solution comprises one or more of a sodium hydroxide solution, a potassium hydroxide solution, and a sodium bicarbonate solution;

the neutral pH value is 5-8;

6. The production process according to claim 1, further comprising a rectification separation step before the hydrogenation reaction;

the pressure of the rectification separation is 10-50 KPa;

the temperature of the top of the rectification separation tower is-20-2 ℃;

the temperature of a tower kettle for rectification separation is 40-85 ℃;

the temperature of the hydrogenation reaction is 30-100 ℃;

the pressure of the hydrogenation reaction is 1.5-5.5 MPa;

the time of the hydrogenation reaction is 0.5-4 hours.

7. The production process of claim 1, wherein the hydrogenation reaction is further followed by one or more of filtration, light ends removal separation, evaporative separation, and re-rectification steps;

the pressure of the light component removal separation is 5-50 KPa;

8. A1, 3-butanediol production system is characterized by comprising a microchannel reactor;

9. The production system of claim 8, further comprising a pipeline mixer;

the system also includes a packed rectification column;

the number of the sections of the filler rectifying tower is 2-5 sections;

10. The production system of claim 8, further comprising a light ends removal column, a thin film evaporator, and a second rectification column;

the second rectifying tower is a filler rectifying tower;

the number of the second rectifying tower sections is 3-6;

the second rectification column has a side product outlet.