A device and method for preparing 4-hydroxybutyraldehyde by continuous hydroformylation of allyl alcohol

Abstract

The present invention discloses a device and method for preparing 4-hydroxybutyraldehyde by continuous hydroformylation of allyl alcohol, including a first reactor, a second reactor and a third reactor, wherein liquid phase material enters the first reactor, the second reactor and the third reactor in sequence through a liquid phase pipeline, and gas phase material enters the first reactor from the third reactor in reverse, and then enters the second reactor. The method utilizes the characteristics of hydroformylation reaction of allyl alcohol and synthesis gas, and the material maintains a high selectivity at the outlets of the first reactor and the second reactor, thereby improving the overall selectivity. Utilizing the characteristics of less gas consumption in the reaction in the third reactor but more gas required to ensure the mixing effect in the reactor, the synthesis gas reversely flows into the third reactor first, and then enters the first and second reactors in sequence, reducing the operating cost of the system compressor and utilizing the pressure difference between the first and second reactors to realize the flow of liquid phase material between the two reactors, in addition, the reaction liquid phase volume can also be reduced.

Description

Technical Field

[0001] The invention relates to a device and a method for continuous hydroformylation of organic matter, in particular to a device and a method for continuous hydroformylation of allyl alcohol to prepare 4-hydroxybutyraldehyde. Background Art

[0002] In recent years, as people's environmental awareness has been increasing, the demand for biodegradable plastics has been increasing. The biodegradable plastics currently on the market include PBAT, PBS and PLA, among which PBAT, as the most mature and widely used material, has seen the fastest growth in demand in recent years. PBAT is a copolymer of PTA, AA and BDO, of which PTA and AA have a large market stock, but BDO has a large production capacity shortage.

[0003] Previously, the more mature methods for synthesizing BDO in the industry were mainly the acetylene aldehyde method and the maleic anhydride hydrogenation method. Among them, the acetylene aldehyde method uses acetylene as a raw material, reacts with formaldehyde under the action of acetylene copper catalyst to produce 1,4-butynediol, and 1,4-butynediol is further hydrogenated to produce 1,4-butanediol. The main problem of this route is that the raw material acetylene and the catalyst acetylene copper are easy to explode, and there is a great risk in industrial production; the maleic anhydride hydrogenation method uses n-butene as a raw material, and produces maleic anhydride through oxidation reaction, and maleic anhydride is hydrogenated to produce 1,4-butanediol. The raw material n-butene resources of this route are scarce, resulting in high costs and fierce market competition. At present, all the devices for producing BDO by maleic anhydride hydrogenation have been shut down. Propylene is oxidized to produce allyl acetate, and then hydrolyzed to obtain allyl alcohol. Allyl alcohol is subjected to hydroformylation reaction to produce 4-hydroxybutyraldehyde, and 4-hydroxybutyraldehyde is further hydrogenated to produce 1,4-butanediol. The route has been widely used in recent years because the raw material propylene has a wide source and mild process conditions. See US Patent US5504261A.

[0004] In the propylene method, allyl alcohol is prepared through the process of hydroformylation reaction of 4-hydroxybutyraldehyde. Since the reaction is accompanied by the generation of a large amount of 4-hydroxybutyraldehyde isomers 2-methyl-3-hydroxypropionaldehyde and the price of the catalyst rhodium used for the reaction is always at a high level, the selectivity of the reaction and the device investment (including equipment investment and catalyst investment) are two key points related to the device benefit. Prior to this, Chinese patent CN101652179A, from the perspective of catalyst, changed the trisubstituted phosphine in the commonly used rhodium complex and phosphine ligand catalyst system into a disubstituted phosphine, thereby improving the ratio of 4-hydroxybutyraldehyde to 2-methyl-3-hydroxypropionaldehyde in the hydroformylation reaction product. During continuous operation, homogeneous catalysts usually need to be separated from the reaction product through processes such as distillation or extraction, and this separation process inevitably causes the loss of catalyst. In addition, the high temperature conditions of the distillation process also cause the deactivation of the catalyst, ultimately leading to the increase of the device operation cost.

[0005] It can be seen that there is an urgent need to develop a device and method for preparing 4-hydroxybutyraldehyde through hydroformylation of allyl alcohol with high conversion rate, high selectivity and higher economy, which is of great significance for the development and application of biodegradable plastic PBAT. Summary of the invention

[0006] In view of the above problems existing in the prior art, the present invention provides a device for preparing 4-hydroxybutyraldehyde by continuous hydroformylation of allyl alcohol. The present invention unexpectedly found in the research on preparing 4-hydroxybutyraldehyde by hydroformylation of allyl alcohol that after the reaction is started, as the reaction proceeds, its selectivity has two high points, such as Figure 1 In addition, from Figure 1 It can also be seen that the tailing of the reaction is more serious, that is, most of the reaction time is used in the reaction end stage. The present invention is by taking into full account the reaction characteristics of the continuous hydroformylation of allyl alcohol, and from the perspective of engineering amplification, under the premise of reducing device investment and running cost, a reactor scheme is designed by further experiment, and the present invention uses three reactors in series, wherein the first and second reactors are kettle reactors, and the third reactor is a multi-stage bubbling column reactor. The conversion rate (defined as theoretical conversion rate in the present invention) of the first and second reactor outlets is respectively limited to two high points of selectivity, and according to parameters such as selectivity design reactor volume, the third reactor is used to solve the tailing problem, and the conversion rate and selectivity of the reaction can be greatly improved.

[0007] On the other hand, the present invention also provides a method for preparing 4-hydroxybutyraldehyde by continuous hydroformylation of allyl alcohol using the above-mentioned device. Under the action of rhodium catalyst, the conversion rate of the obtained product is above 99.5%, the selectivity is above 95%, and the mass ratio of 4-hydroxybutyraldehyde to 2-methyl-3-hydroxypropionaldehyde contained in the product is above 20.

[0008] Furthermore, in the above-mentioned continuous hydroformylation process, the present invention also preferably adopts an organic polymer-supported rhodium catalyst, by adding triphenylphosphine during the process of melt-molding the organic polymer carrier, and adding an organic acid during the bonding process between the metal bond of rhodium and the carbon-carbon double bond in the organic polymer, the organic acid can strengthen the bonding effect of the two chemical bonds and increase the active sites of the catalyst. The catalyst selected by the present invention can not only increase the catalytic effect of the rhodium catalyst, further improve the conversion rate and selectivity, but also overcome the disadvantages of easy loss and deactivation of homogeneous catalysts.

[0009] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0010] The present invention provides a device for preparing 4-hydroxybutyraldehyde by continuous hydroformylation of allyl alcohol, comprising a first reactor, a second reactor, and a third reactor which are arranged in sequence;

[0011] The first reactor is provided with a gas phase pipeline at the top connected to the second reactor, and a liquid phase pipeline at the bottom connected to the second reactor;

[0012] The second reactor is provided with a gas phase pipeline at the top connected to the third reactor, and a liquid phase pipeline at the bottom connected to the third reactor;

[0013] The top of the third reactor is provided with a gas phase pipeline connected to the first reactor;

[0014] The first reactor is connected with a liquid phase feed pipeline;

[0015] A synthesis gas feed pipeline is connected to the gas phase pipeline connected to the third reactor at the top of the second reactor;

[0016] A liquid product outlet is provided at the upper portion of the third reactor.

[0017] In the present invention, further, a gas compressor is arranged on the gas phase pipeline connected to the third reactor at the top of the second reactor, and the synthesis gas feed pipeline is merged into the gas phase pipeline and then enters the gas compressor together.

[0018] In the present invention, further, a liquid phase delivery pump is arranged on the liquid phase pipeline connecting the bottom of the second reactor with the third reactor.

[0019] In the present invention, further, the first reactor and the second reactor are kettle reactors, and the third reactor is a multi-stage bubble tower reactor;

[0020] Preferably, the number of stages of the multi-stage bubble tower reactor is 6-16, preferably 9-13.

[0021] In the present invention, further, the height-to-diameter ratio of the first reactor and the second reactor is 1-1.5, preferably 1.2-1.3;

[0022] The height-to-diameter ratio of the third reactor is 3-15, preferably 6-10.

[0023] In the present invention, further, the first reactor and the second reactor are both provided with a stirring paddle, a gas distributor and a heat transfer coil; the stirring paddle is driven by a motor and works together with the gas distributor and the heat transfer coil to achieve good mixing of the gas phase and the liquid phase in the reactor, achieve uniform distribution of the gas and be used for heat transfer in the reactor;

[0024] Preferably, the ratio of the diameter of the stirring paddle to the diameter of the reactor is 0.15-0.55, preferably 0.3-0.4;

[0025] Preferably, the ratio of the diameter of the gas distributor to the diameter of the reactor is 0.1-0.45, preferably 0.25-0.3;

[0026] Preferably, the ratio of the diameter of the heat transfer coil to the diameter of the reactor is 0.01-0.05, preferably 0.03-0.035.

[0027] In the present invention, further, a gas distributor, a porous sieve plate and a heat transfer coil are provided inside the third reactor to reduce liquid phase backmixing in the reactor and realize gas redispersion and reactor heat transfer;

[0028] Preferably, the ratio of the diameter of the gas distributor to the diameter of the reactor is 0.5-0.9, preferably 0.6-0.8;

[0029] Preferably, the porous sieve plates are 5-15 in number, preferably 8-12 in number, and have an opening rate of 0.5-5%, preferably 1-2%;

[0030] Preferably, the ratio of the diameter of the heat transfer coil to the diameter of the reactor is 0.01-0.05, preferably 0.03-0.035.

[0031] In the present invention, further, a solid-liquid separation system is provided inside the third reactor, and the solid-liquid separation system is composed of a vertical draft tube and an annular flow stabilizing plate concentrically arranged around the vertical draft tube;

[0032] The vertical draft tube is in the shape of an inverted funnel, and the lower edge of the conical funnel is in close contact with the inner wall of the third reactor;

[0033] The annular flow stabilizing plate is fixed on the conical bucket of the vertical guide tube;

[0034] Preferably, the annular flow stabilizer is also provided with an annular guide plate on the upper edge. Those skilled in the art can design it in a manner known in the prior art, or arbitrarily select its specific shape, position, etc. according to actual needs. The present invention is not particularly limited. For example, it can be designed as follows: Figure 5 The structure setup shown.

[0035] Preferably, the number of the annular flow stabilizers is 1-5, preferably 2-4, and the height of the annular flow stabilizers decreases from the guide tube to the inner wall of the third reactor;

[0036] The solid-liquid separation system is located above the sieve plate in the third reactor to separate the catalyst from the reaction liquid. The catalyst can be recovered and used in the first reactor after being taken out. The reaction liquid is taken out from the upper liquid phase product outlet through the pipeline and enters the downstream application.

[0037] The arrangement of the stirring paddle, gas distributor and heat transfer coil inside the first reactor and the second reactor of the present invention, as well as the arrangement of the gas distributor, porous sieve plate and heat transfer coil inside the third reactor are all conventional technical means in the art. Those skilled in the art can design them in a manner known in the prior art, or arbitrarily select their shapes, positions, etc. according to actual needs, and the present invention has no special limitation; for example, in a bubble tower, the gas distributor is generally located at the tangent line of the bottom lower head, and the porous sieve plates are generally evenly distributed in the axial position of the bubble tower according to the number; the heat transfer coil is usually arranged close to the reactor wall;

[0038] Preferably, in the third reactor, an interstage heat exchange method is adopted, and preferably a group of heat transfer coils are arranged every one or more layers of porous sieve plates. For example, heat is transferred by heat transfer coils in the first stage, no heat transfer coils are arranged in the second stage, and heat transfer coils are arranged in the third stage, and so on.

[0039] In the present invention, further, the volumes of the first reactor and the second reactor are determined according to the theoretical conversion rates of the two reactors, respectively. Specifically, the volumes of the first reactor and the second reactor are calculated by formula (1):

[0040]

[0041] V R : Volume of the reactor, m 3 ;

[0042] V0: Material volume flow rate, m 3 / h;

[0043] x A : Theoretical conversion rate of raw materials in the first reactor (x A1 ) or the theoretical conversion rate in the second reactor (x A2 ), %;

[0044] C: Catalyst content in the material, wt%;

[0045] Furthermore, in the reaction process of preparing 4-hydroxybutyraldehyde by hydroformylation of allyl alcohol, there are two high points in selectivity, the theoretical conversion rate of the raw material in the first and second reactors, that is, x A The theoretical conversion rate (x A1 ) corresponds to the first high point of selectivity, and the theoretical conversion rate of the second reactor (x A2 ) corresponds to the second high point of selectivity;

[0046] Preferably, the conversion rates corresponding to the two high points of selectivity in the reaction process of preparing 4-hydroxybutyraldehyde by hydroformylation of allyl alcohol are both in the range of 45-80%, that is, the theoretical conversion rate of the raw material in the first reactor or the second reactor is 45-80%, for example 50%, 80%.

[0047] Preferably, the two high points of the selectivity can be determined by those skilled in the art according to any achievable method disclosed in the prior art. In some specific examples of the present invention, the method is as follows: at the start of the reaction of preparing 4-hydroxybutyraldehyde by hydroformylation of allyl alcohol, the change of conversion rate and selectivity over time is recorded, and a relationship diagram between conversion rate and selectivity is drawn, thereby obtaining two high points of the selectivity. It should be noted that in the relationship diagram, the second high point is relative to the total conversion rate of the raw material (x 总 ), the conversion rate in the second reactor (x A2 ) needs to be converted, and the conversion method can adopt a conventional method. For example, the present invention specifically adopts the following formula to calculate:

[0048]

[0049] Similarly, the maximum conversion rate expected to be achieved at the outlet of the third reactor is also relative to the total conversion rate of the raw materials (x 总 ), and then the conversion rate (x) inside the third reactor is calculated. A3 , theoretical conversion rate), which can be calculated by conventional methods, for example, the present invention specifically uses the following formula to calculate:

[0050] x 总 =x A1 +(1-x A1 )x A2 +(1-x A1 )x A2 x A3 .

[0051] The reaction of preparing 4-hydroxybutyraldehyde by hydroformylation of allyl alcohol can adopt any achievable method disclosed in the prior art, and the present invention has no special requirements. It is preferred to adopt the same reaction system as the device developed by the present invention in subsequent practical applications; the method preferably adopted in the example of the present invention is: in the presence of a catalyst (such as a commercially available rhodium catalyst or the preferred organic polymer-supported rhodium catalyst described below), the raw material allyl alcohol and synthesis gas are subjected to a hydroformylation reaction in a toluene solvent, and sampling and analysis are performed every 5-15 minutes, for example, 10 minutes, to test the conversion rate and selectivity;

[0052] For example, drawing Figure 1The reaction of preparing 4-hydroxybutyraldehyde by hydroformylation of allyl alcohol is as follows: 50 g of allyl alcohol, 200 g of toluene, and 0.5 g of organic polymer-supported rhodium catalyst are added to a 500 ml reactor (conventional reactor, no special requirements for the structure), and then the reactor is heated to 80°C, synthesis gas is introduced for hydroformylation reaction and timing is started, sampling is performed every 10 minutes, and a graph is drawn according to the sampling results. Figure 1 The relationship between the conversion rate of raw material allyl alcohol and the selectivity of product 4-hydroxybutyraldehyde over time is shown. It is found that the selectivity of product 4-hydroxybutyraldehyde has two high points, both around 98%, and the corresponding raw material allyl alcohol conversion rates are around 50% and 75%, respectively.

[0053] In the present invention, further, the reactor volume of the third reactor is calculated by formula (2):

[0054] V R =-CV0ln (1-x A3 ) (2),

[0055] V R : Volume of the reactor, m 3 ;

[0056] V0: Material volume flow rate, m 3 / h;

[0057] x A3 : The theoretical conversion rate of the raw material in the third reactor;

[0058] C: Catalyst content in the material, wt%;

[0059] Furthermore, the theoretical conversion rate x of the raw material in the third reactor is A3 The theoretical conversion rate in the third reactor is about 75-99%. The theoretical conversion rate in the third reactor is calculated based on the maximum conversion rate expected to be achieved based on the total conversion rate of the raw materials. The expected maximum conversion rate can be set by the R&D personnel. It is generally set above 99% based on engineering scale-up and economic considerations. The theoretical conversion rate in the third reactor calculated is x A3 The range is about 75-99%.

[0060] In the present invention, further, the heat exchange area of ​​the heat transfer coils in the first reactor and the second reactor needs to be determined according to the theoretical conversion rate of the reactor. Specifically, the heat exchange area of ​​the heat transfer coils is calculated by formula (3):

[0061]

[0062] A: Heat exchange area of ​​the heat transfer coil of the first reactor or the second reactor, m 2 ;

[0063] V0: Material volume flow rate, m 3 / h;

[0064] V g : superficial gas velocity in the first reactor or the second reactor, m / h;

[0065] x A : Theoretical conversion rate of the raw material in the first reactor or the second reactor.

[0066] The superficial gas velocity is determined by the amount of gas introduced into the reactor (Q, m 3 / h) divided by the reactor cross-sectional area (m 2 ) obtained that the superficial gas velocity in the first reactor and the second reactor in the present invention is about 18-54m / h.

[0067] The present invention also provides a method for preparing 4-hydroxybutyraldehyde by continuous hydroformylation of allyl alcohol, the method adopts the above reaction device, and the steps include:

[0068] 1) A mixed solution of allyl alcohol, rhodium catalyst and toluene is transported to the first reactor through a liquid phase feed pipeline, and unreacted synthesis gas from the third reactor is transported to the first reactor through a gas phase pipeline. Under the action of the catalyst, allyl alcohol and the synthesis gas undergo a hydroformylation reaction, and the gas phase and liquid phase after the reaction enter the second reactor through a gas phase pipeline and a liquid phase pipeline respectively;

[0069] 2) The gas phase and liquid phase entering the second reactor continue to undergo hydroformylation reaction, the gas phase after the reaction is combined with the fresh synthesis gas from the synthesis gas feed pipeline through the gas phase pipeline, and preferably after being compressed by a gas compressor, enters the third reactor, and the liquid phase after the reaction passes through the liquid phase pipeline, and preferably enters the third reactor via a liquid phase delivery pump;

[0070] 3) The gas phase and liquid phase entering the third reactor continue to undergo hydroformylation reaction, and the unreacted synthesis gas is transported to the first reactor through the gas phase pipeline to continue to participate in the reaction, and the liquid phase product 4-hydroxybutyraldehyde is produced from the upper liquid phase product outlet.

[0071] In step 1), in the mixed solution of allyl alcohol, catalyst and toluene, the catalyst concentration is 1-4wt%, preferably 2-3wt%, and the allyl alcohol concentration is 5-50wt%, preferably 30-40wt%;

[0072] In step 1), the rhodium catalyst is a supported rhodium catalyst, which may be a rhodium catalyst known in the prior art or a modified rhodium catalyst, which may be purchased commercially or prepared in-house. The present invention has no particular requirements, and in some examples, an organic polymer-supported rhodium catalyst is preferably used;

[0073] The organic polymer-supported rhodium catalyst comprises an active component rhodium and an organic polymer carrier, wherein the content of the active component rhodium is 0.5-20wt%, preferably 5-10wt%.

[0074] Preferably, the organic polymer carrier is selected from an organic polymer containing triphenylphosphine, wherein the content of triphenylphosphine is 2-5wt%; the polymer is any one of polyethylene, polypropylene, polyvinyl alcohol or a combination of at least two thereof.

[0075] Preferably, the density of the organic polymer carrier is 0.9-0.95 kg / m 3 , particle size is 0.1-10um, pore size is 5-10nm, specific surface area is 2500-3000m 2 / m 3 , porosity 55-60%;

[0076] The organic polymer containing triphenylphosphine is prepared by conventional methods in the art without special requirements. For example, in some examples, the preparation method includes: mixing the polymer with triphenylphosphine under inert gas, reacting at 150-180° C. for 0.5-5 h, and washing to obtain the organic polymer containing triphenylphosphine.

[0077] The organic polymer-supported rhodium catalyst can be prepared by the existing technology by loading the active component, preferably by impregnation, and more preferably, 0.5-2 wt% of an organic acid (such as isooctanoic acid, butyric acid, isononanoic acid) is added to the impregnation solution during the impregnation process. For example, the specific method used in some examples is:

[0078] The organic polymer carrier is added to an aqueous solution containing rhodium metal salt for impregnation, 0.5-2wt% of organic acid is added to the impregnation solution, and after reaching adsorption equilibrium, the organic polymer-supported rhodium catalyst is obtained through filtering, drying, roasting, activation, etc.

[0079] The organic polymer-supported rhodium catalyst preferably used in the present invention has an auxiliary agent triphenylphosphine added thereto during the carrier melt molding process, thereby achieving the combination between the auxiliary agent and the carrier. In addition, an organic acid is added during the bonding process between the carbon-carbon double bond in the organic polymer and the catalyst rhodium metal, and the organic acid is selected from butyric acid, isooctanoic acid, isononanoic acid, etc., but is not limited to the above organic acids. The addition of the organic acid can strengthen the bonding effect between the metal bond and the carbon-carbon double bond and increase the effective active sites of the catalyst.

[0080] In step 1), the hydroformylation reaction temperature is 75-85° C., preferably 78-83° C., the pressure is 1.1-1.3 MPaG, preferably 1.15-1.25 MPaG, and the residence time is 40-120 min, preferably 50-100 min.

[0081] In step 2), the hydroformylation reaction temperature is 75-85° C., preferably 78-83° C., the pressure is 0.8-1.0 MPaG, preferably 0.85-0.95 MPaG, and the residence time is 40-120 min, preferably 50-100 min.

[0082] In step 3), the hydroformylation reaction temperature is 75-85° C., preferably 78-83° C., the pressure is 1.4-1.6 MPaG, preferably 1.45-1.55 MPaG, and the residence time is 100-300 min, preferably 150-250 min.

[0083] In step 2), the fresh synthesis gas input from the synthesis gas feed pipeline is used in an amount to maintain the molar ratio of synthesis gas to allyl alcohol in the system within the required range, which is a conventional operation in the art and can be calculated by technicians according to actual needs.

[0084] The volume ratio of hydrogen to carbon monoxide in the synthesis gas is 1:0.8-1.2, preferably 1:0.95-1.05.

[0085] In step 3), inside the third reactor, the catalyst and the reaction liquid are separated by a solid-liquid separation system. After separation, the liquid product 4-hydroxybutyraldehyde is extracted from the upper liquid product outlet. The catalyst is deposited at the bottom of the solid-liquid separation system and is extracted from the bottom of the solid-liquid separation system and can be recycled for use in the first reactor.

[0086] In the method of the present invention, the liquid phase material in the first reactor is transported with the pressure difference between the first reactor and the second reactor as the driving force for the liquid phase material and the gas phase material.

[0087] In the method of the present invention, the temperature of the material in the third reactor is controlled by an inter-stage heat exchange method. In the first stage, heat is transferred by a heat transfer coil to reduce the material temperature to the reaction temperature while removing the reaction heat. No heat transfer coil is provided in the second stage, and the material is heated by utilizing the reaction exotherm. An internal coil is provided in the third stage to transfer heat and reduce the temperature, and so on. This inter-stage heat exchange method can save cooling water.

[0088] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0089] The present invention utilizes the fact that there are two selectivity high points in the reaction of allyl alcohol and synthesis gas, adopts a reaction device composed of two continuous reactors and a bubbling tower, controls the conversion rates of the first two reactors at the selectivity high point, and the third bubbling tower reactor is used to reduce the reaction time of the tailing section. This device can reduce the reaction liquid phase volume while improving the selectivity of the reaction, thereby increasing the economic efficiency of the device.

[0090] In the present invention, the synthesis gas is fed into the third reactor first, and then enters the first reactor and the second reactor in sequence after a small amount of consumption in the third reactor. Since the consumption of synthesis gas in the third reactor is small, but the amount of gas required to ensure mixing in the reactor is relatively high, this intake method can greatly reduce the inventory of synthesis gas in the reaction system compared to the method in which the synthesis gas first enters the first reactor, then the second reactor, and finally the third reactor, thereby reducing the operating cost of the gas compressor; in the present invention, the third reactor uses an inter-stage heat transfer method to control the reaction temperature, which can reduce the amount of heat transfer medium while ensuring the reaction effect. In the present invention, a solid-liquid separation system is further arranged inside the third reactor, and gravity is used to separate the catalyst from the reaction liquid, thereby realizing online recovery of the catalyst.

[0091] The invention uses allyl alcohol as a raw material and reacts with synthesis gas to produce 4-hydroxybutyraldehyde through hydroformylation reaction under the action of a rhodium catalyst, and the reaction process is a continuous operation. The rhodium catalyst of the invention preferably adopts an organic polymer-supported rhodium catalyst, and an organic acid is used in the preparation process to strengthen the bonding between the metal bond and the carbon-carbon double bond, thereby overcoming the disadvantages of easy loss and deactivation of the homogeneous catalyst and enhancing the reaction effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0092] Figure 1 The conversion rate and selectivity of allyl alcohol hydroformylation reaction change with time;

[0093] Figure 2 This is a schematic diagram of the device flow of Example 1 of the present invention;

[0094] In the figure: 1, the first reactor, 2, the second reactor, 3, the third reactor, 4, the gas phase pipeline (the first and second reactors are connected by gas to each other), 5, the liquid phase pipeline (the first and second reactors are connected by liquid to each other, 6, the gas phase pipeline (the second and third reactors are connected by gas to each other), 7, the liquid phase pipeline (the second and third reactors are connected by liquid to each other), 8, the liquid phase delivery pump, 9, the gas phase pipeline (the third reactor and the first reactor are connected by gas to each other), 10, the liquid phase feed pipeline, 11, the synthesis gas feed pipeline, 12, the gas compressor, 13, the liquid phase product outlet,

[0095] Figure 3 Schematic diagram of the internal structure of the first and second reactors;

[0096] In the figure: 1 / 2, first reactor / second reactor, 101 / 201, stirring paddle, 102 / 202, gas distributor, 103 / 203, heat transfer coil;

[0097] Figure 4 Schematic diagram of the internal structure of the third reactor;

[0098] In the figure: 3, third reactor, 301, gas distributor, 302, porous sieve plate, 303, heat transfer coil, 304, solid-liquid separation system;

[0099] Figure 5 Schematic diagram of the structure of the solid-liquid separation system in the third reactor (a) and schematic diagram of the material flow (b);

[0100] In the figure: 3041, vertical guide tube, 3042, annular flow stabilizer, 3043, guide plate. DETAILED DESCRIPTION

[0101] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0102] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0103] In the description of the present invention, it should be noted that the terms "top", "bottom", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0104] Unless otherwise clearly specified and limited, the terms "disposed", "connected", "connected", "fixed", and "closely connected" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0105] The sources of the main raw materials used in the examples and comparative examples of the present invention are as follows. The remaining raw materials are all common commercially available products unless otherwise specified:

[0106] Allyl alcohol: Merck, product number: 452491;

[0107] Polypropylene: Merck, product number: GF00254944;

[0108] Triphenylphosphine: Aladdin, product number: T104475;

[0109] Rhodium salt (RhCl3·3H2O): Beijing Coupling Technology Co., Ltd., product number: 01012204;

[0110] Rhodium catalyst B: alumina-supported rhodium catalyst, Shaanxi Kaida Chemical Co., Ltd.;

[0111] Rhodium catalyst A (rhodium catalyst supported by organic polymer), prepared by:

[0112] 1) In a nitrogen environment, polypropylene and triphenylphosphine were fully mixed, reacted at 150°C under normal pressure for 3 hours, and washed with water to obtain an organic polymer carrier with a triphenylphosphine content of 3 wt% and a density of 0.95 kg / m 3 , particle size is 0.1-10um, pore size is 5-8nm, specific surface area is 3000m 2 / m 3 , porosity 60%;

[0113] 2) The organic polymer carrier is added to a 10wt% RhCl3·3H2O aqueous solution for impregnation, 1wt% isooctanoic acid is added to the impregnation solution, and after rhodium reaches adsorption equilibrium on the carrier, the excess solution is filtered out, and the organic polymer-supported rhodium catalyst is obtained through drying, roasting and activation steps, and the content of active component rhodium is 5wt%.

[0114] draw Figure 1 :

[0115] The reaction of preparing 4-hydroxybutyraldehyde by hydroformylation of allyl alcohol is as follows: 50 g of allyl alcohol, 200 g of toluene, and 0.5 g of rhodium catalyst A are added to a 500 ml reactor, and then the reactor is heated to 80°C, and synthesis gas (the molar ratio of synthesis gas to raw material allyl alcohol is 1:1) is introduced, the pressure is 1 MPaG, the hydroformylation reaction is carried out and the timing is started, and samples are taken every 10 minutes. According to the sampling results, a graph is drawn as follows: Figure 1 The relationship between the conversion rate of raw material allyl alcohol and the selectivity of product 4-hydroxybutyraldehyde over time is shown (the selectivity of product 4-hydroxybutyraldehyde has two high points both at about 98%, and the corresponding raw material allyl alcohol conversion rates are about 50% and 75%, respectively);

[0116] Figure 1 Method analysis: The total volume of the liquid phase is 500 ml, the catalyst concentration in the reaction system is 2wt%, the precious metal rhodium content in the catalyst is 5wt%, the rhodium stock in the entire reaction system is 0.5g, and based on the current rhodium price of RMB 3 million / kg, the investment in the reaction system catalyst is close to RMB 1,500.

[0117] The main testing instrument used in the examples and comparative examples of the present invention is Shimadzu gas chromatograph, model Nexis GC-2030.

[0118] Example 1

[0119] A device for preparing 4-hydroxybutyraldehyde by continuous hydroformylation of allyl alcohol (such as Figure 2 As shown), comprising a first reactor 1 (as Figure 3 As shown), the second reactor 2 (as Figure 3 As shown), the third reactor 3 (as Figure 4 shown);

[0120] The top of the first reactor 1 is provided with a gas phase pipeline 4 connected to the second reactor 2, and the bottom is provided with a liquid phase pipeline 5 connected to the second reactor 2;

[0121] A gas phase pipeline 6 is provided on the top of the second reactor 2 and connected to the third reactor 3 , and a liquid phase pipeline 7 is provided on the bottom of the second reactor 2 and connected to the third reactor 3 , wherein a liquid phase delivery pump 8 is provided on the liquid phase pipeline 7 .

[0122] A gas phase pipeline 9 is provided at the top of the third reactor 3 and is connected to the first reactor 1;

[0123] The first reactor 1 is connected to a liquid phase feed pipeline 10;

[0124] A synthesis gas feed pipeline 11 is connected to the gas phase pipeline 6 connected to the third reactor 3 at the top of the second reactor 2;

[0125] A gas compressor 12 is provided on the gas phase pipeline 6 connected to the third reactor 3 at the top of the second reactor 2 , and the synthesis gas feed pipeline 11 is merged into the gas phase pipeline 6 and enters the gas compressor 12 together.

[0126] A liquid product outlet 13 is provided at the upper portion of the third reactor 3 .

[0127] The first reactor 1 and the second reactor 2 are kettle reactors, and the third reactor is a multi-stage bubble tower reactor having ten stages.

[0128] The height-to-diameter ratio of the first reactor 1 and the second reactor 2 is 1.2; the height-to-diameter ratio of the third reactor 3 is 9.

[0129] The first reactor 1 and the second reactor 2 are both provided with a stirring paddle 101 / 201, a gas distributor 102 / 202 and a heat transfer coil 103 / 203; wherein: the ratio of the diameter of the stirring paddle 101 / 201 to the diameter of the reactor 1 / 2 is 0.35; the ratio of the diameter of the gas distributor 102 / 202 to the diameter of the reactor 1 / 2 is 0.25; the ratio of the diameter of the heat transfer coil 103 / 203 to the diameter of the reactor 1 / 2 is 0.03.

[0130] The third reactor 3 is provided with a gas distributor 301, a porous sieve plate 302, a heat transfer coil 303, and a solid-liquid separation system 304 (such as Figure 5 As shown); wherein: the ratio of the diameter of the gas distributor 301 to the diameter of the reactor 3 is 0.8; the number of the porous sieve plates 302 is 10, and the opening rate is 1.5%; the ratio of the diameter of the heat transfer coil 303 to the reactor 3 is 0.03.

[0131] The solid-liquid separation system 304 is composed of a vertical guide tube 3041 and an annular flow stabilizing plate 3042 concentrically arranged around the vertical guide tube 3041;

[0132] The vertical flow guide tube 3041 is in the shape of an inverted funnel, and the lower edge of its conical bucket is in close contact with the inner wall of the third reactor 3; there are three annular flow stabilizers 3042 fixed on the conical bucket of the vertical flow guide tube, and the height of the annular flow stabilizers decreases successively from the flow guide tube to the inner wall of the third reactor 3; a circle of annular flow guide plates 3043 are also provided on the upper edge of the outer walls of the two internal annular flow stabilizers.

[0133] Example 2

[0134] 4-Hydroxybutyraldehyde was prepared by continuous hydroformylation of allyl alcohol using the reaction apparatus of Example 1:

[0135] The volumes of the first reactor and the second reactor are calculated by formula (1):

[0136]

[0137] Among them, the values ​​of each parameter are: V0 = 50m 3 / h,x A1 =50%,x A2 =50% (by Figure 1 Determine), C = 2wt%; Calculate: the volume of the first reactor V R1 =50m 3 ; Second reactor volume V R2 =50m 3 .

[0138] The volume of the third reactor is calculated by formula (2):

[0139] V R =-CV0ln (1-x A3 ) (2),

[0140] Among them, the values ​​of each parameter are: V0 = 50m 3 / h,x A3 96%, C = 2wt%;

[0141] Calculated: The volume of the third reactor V R3 =322m 3 .

[0142] The heat exchange area of ​​the coils in the first reactor and the second reactor is calculated by formula (3):

[0143]

[0144] Among them, the values ​​of each parameter are: V0 = 50m 3 / h,x A1 =50%,x A2 =50% (by Figure 1 Determine), superficial gas velocity Vg = 36m / h;

[0145] Calculated: The heat exchange area of ​​the coil in the first reactor is A1 = 70m 2 ; Heat exchange area of ​​the coil in the second reactor A2 = 70m 2 .

[0146] It should be noted that in the above calculation process, Figure 1 The second highest point, that is, the conversion rate after the outlet of the second reactor is 75%. This conversion rate is relative to the total conversion rate of the raw material. This conversion rate corresponds to the conversion rate x in the second reactor. A2 (theoretical conversion rate) should also be 50% after conversion; similarly, the maximum conversion rate expected to be achieved at the outlet of the third reactor (i.e., the total conversion rate of raw materials) is specified to be 99%, and the conversion rate (theoretical conversion rate) inside the third reactor is calculated to be 96%, that is, x in formula (2) A3 96%;

[0147] In formula (3), Vg is the superficial gas velocity, which can be calculated by conventional methods, for example, Vg = gas flow rate into the reactor / reactor cross-sectional area. Take the calculation of Vg of the first reactor as an example:

[0148] Known V R1 =50m 3 , according to the height-to-diameter ratio of reactor 1.2, the reactor diameter is determined to be 4m;

[0149] The fresh syngas feed into the third reactor is about 600m 3 / h, and the raw material consumption in the third reactor is about 24% (total conversion rate 99% - second reactor outlet conversion rate 75%), that is, the amount of synthesis gas entering the first reactor is about 450m 3 / h;

[0150] Among them, the fresh synthesis gas feed volume of the third reactor is about 600m 3 / h is calculated by the following method: the feed volume flow rate V0 is 50m 3 / h, the density of toluene is about 800kg / m 3 , the concentration of allyl alcohol in the solution is 30wt%, and the mass flow rate of allyl alcohol in the feed can be calculated to be 50*0.8*0.3*1000=12000kg / h, which is converted into a molar flow rate of 12000 / 58=207kmol / h. 1mol of allyl alcohol consumes 1mol of H2 and 1mol of CO, that is, the theoretical consumption of synthesis gas is 414kmol / h. According to the ideal gas state equation, the volume flow rate is 207*2*22.4=9275Nm 3 / h, the pressure in the three reactors is 1.5MPa, that is, the volume flow rate in the three reactors is 9275 / 15, about 600m 3 / h.

[0151] The calculated apparent gas velocity Vg = 450 / (0.25*3.14*4^2), which is about 36m / h.

[0152] According to the above calculation results, the total volume of liquid phase in the three reactors of this embodiment is 422m 3 The catalyst concentration in the reaction system is 2wt%, the precious metal rhodium content in the catalyst is 5wt%, and the entire reaction system (with a volume flow rate of 50m 3 / h) has a rhodium stock of 422kg. Based on the current rhodium price of RMB 3 million / kg, the investment in the catalyst of the reaction system is close to RMB 1.3 billion.

[0153] The specific steps of the preparation process are:

[0154] 1) Volume flow rate is 50m 3 / h of a mixed solution of allyl alcohol, catalyst A and toluene (in the mixed solution, the concentration of catalyst A is 2wt% and the concentration of allyl alcohol is 30wt%) is transported to the first reactor 1 through a liquid phase feed pipeline 10, and at the same time, the unreacted synthesis gas from the third reactor 3 is transported to the first reactor 1 through a gas phase pipeline 9. Under the action of catalyst A, allyl alcohol and the synthesis gas undergo a hydroformylation reaction at 80°C and a pressure of 1.2MPa. The reaction residence time is 60min. The gas phase and liquid phase after the reaction enter the second reactor 2 through a gas phase pipeline 4 and a liquid phase pipeline 5 respectively;

[0155] 2) The gas phase and liquid phase entering the second reactor 2 continue to undergo hydroformylation reaction at 80°C and a pressure of 0.9 MPa. The reaction residence time is 60 min. The gas phase after the reaction passes through the gas phase pipeline 6 and the volume flow rate from the synthesis gas feed pipeline 11 is 600 m 3 / h of fresh synthesis gas is combined and compressed by a gas compressor 12 before entering the third reactor 3. The liquid phase after the reaction passes through a liquid phase pipeline 7 and enters the third reactor 3 through a liquid phase delivery pump 8;

[0156] 3) The gas phase and liquid phase entering the third reactor 3 continue to undergo hydroformylation reaction at 80° C. and a pressure of 1.5 MPa, with a reaction residence time of 390 min. The unreacted synthesis gas is transported to the first reactor 1 through the gas phase pipeline 9 to continue to participate in the reaction, and the liquid product 4-hydroxybutyraldehyde is produced from the upper liquid phase product outlet 13.

[0157] Inside the third reactor 3 , the catalyst A is separated from the reaction liquid by the solid-liquid separation system 304 , and the catalyst can be recovered and used in the first reactor 1 after being taken out.

[0158] Sampling analysis after 20 hours of reaction: the actual conversion rate in the first reactor was 50.5%, the selectivity was 98%, the conversion rate in the second reactor was 49.5%, the selectivity was 98%, the conversion rate in the third reactor was 96%, the selectivity was 95%; no rhodium was detected in the reaction liquid at the outlet of the liquid phase product of the third reactor;

[0159] After three reactors, the total conversion rate was 99% and the selectivity was 95%.

[0160] After the reaction was continued for 1000 hours, sampling and analysis showed that the actual conversion rate in the first reactor was 50%, and the selectivity was 98.5%, the conversion rate in the second reactor was 50%, and the selectivity was 97%, and the conversion rate in the third reactor was 96%, and the selectivity was 95.5%. No rhodium was detected in the reaction liquid at the outlet of the liquid phase product of the third reactor.

[0161] After three reactors, the total conversion rate was 99% and the selectivity was 95%.

[0162] Example 3

[0163] The continuous hydroformylation of allyl alcohol to prepare 4-hydroxybutyraldehyde uses the reaction apparatus of Example 1:

[0164] The volumes of the first reactor and the second reactor are calculated by formula (1), wherein the values ​​of the parameters are different from those in Example 2 only in that V0 = 100 m 3 / h, calculated as: volume V of the first reactor R1 =100m 3 ; Second reactor volume V R2 =100m 3 Calculated by formula (2)

[0165] The volume of the third reactor, wherein the values ​​of each parameter differ from those in Example 2 only in that x A3 is 99%, calculated as: the volume of the third reactor V R3 =920m 3 .

[0166] The heat exchange area of ​​the coils in the first reactor and the second reactor is calculated by formula (3), where the values ​​of each parameter are V0 = 100m 3 / h,x A =50%,75%(by Figure 1 Determined), Vg = 46m / h, calculated: the heat exchange area of ​​the coil in the first reactor is A1 = 109m 2 ; Heat exchange area of ​​the coil in the second reactor A2 = 109m 2 .

[0167] According to the above calculation results, the total volume of liquid phase in the three reactors of this embodiment is 1120m 3 The catalyst concentration in the reaction system is 2wt%, the precious metal rhodium content in the catalyst is 5wt%, and the rhodium stock of the entire reaction system is 1120kg. Based on the current rhodium price of RMB 3 million / kg, the investment in the catalyst of the reaction system is close to RMB 3.36 billion. The specific steps of the preparation process are:

[0168] 1) Volume flow rate is 100m 3 / h of a mixed solution of allyl alcohol, catalyst A and toluene (in the mixed solution, the concentration of catalyst A is 3wt% and the concentration of allyl alcohol is 35wt%) is transported to the first reactor 1 through a liquid phase feed pipeline 10, and at the same time, the unreacted synthesis gas from the third reactor 3 is transported to the first reactor 1 through a gas phase pipeline 9. Under the action of catalyst A, allyl alcohol and the synthesis gas undergo a hydroformylation reaction at 85°C and a pressure of 1.25MPa. The reaction residence time is 60min. The gas phase and liquid phase after the reaction enter the second reactor 2 through a gas phase pipeline 4 and a liquid phase pipeline 5 respectively;

[0169] 2) The gas phase and liquid phase entering the second reactor 2 continue to undergo hydroformylation reaction at 85°C and a pressure of 0.95 MPa. The reaction residence time is 60 min. The gas phase after the reaction passes through the gas phase pipeline 6 and the volume flow rate from the synthesis gas feed pipeline 11 is 600 m 3 / h of fresh synthesis gas is combined and compressed by a gas compressor 12 before entering the third reactor 3. The liquid phase after the reaction passes through a liquid phase pipeline 7 and enters the third reactor 3 through a liquid phase delivery pump 8;

[0170] 3) The gas phase and liquid phase entering the third reactor 3 continue to undergo hydroformylation reaction at 85° C. and a pressure of 1.55 MPa, with a reaction residence time of 550 min. The unreacted synthesis gas is transported to the first reactor 1 through the gas phase pipeline 9 to continue to participate in the reaction, and the liquid product 4-hydroxybutyraldehyde is produced from the upper liquid phase product outlet 13.

[0171] Inside the third reactor 3 , the catalyst A is separated from the reaction liquid by the solid-liquid separation system 304 , and the catalyst can be recovered and used in the first reactor 1 after being taken out.

[0172] Sampling analysis after 20 hours of reaction: the actual conversion rate in the first reactor was 52%, the selectivity was 98%, the conversion rate in the second reactor was 48%, the selectivity was 98%, the conversion rate in the third reactor was 98%, the selectivity was 95%; no rhodium was detected in the reaction liquid at the outlet of the liquid phase product of the third reactor;

[0173] After three reactors, the total conversion rate was 99.5% and the selectivity was 95%.

[0174] After the reaction was continued for 1000 hours, sampling and analysis showed that the actual conversion rate in the first reactor was 51%, and the selectivity was 98%, the conversion rate in the second reactor was 49%, and the selectivity was 98%, and the conversion rate in the third reactor was 96%, and the selectivity was 95%. No rhodium was detected in the reaction liquid at the outlet of the liquid phase product of the third reactor.

[0175] After three reactors, the total conversion rate was 99% and the selectivity was 95%.

[0176] Example 4

[0177] The method of Example 2 is referred to, except that catalyst A is replaced by catalyst B. Unless otherwise specified, other operations remain unchanged.

[0178] After replacement, the concentration of catalyst B in the reaction system is 3wt%, the content of precious metal rhodium in the catalyst is 8wt%, and the rhodium stock of the entire reaction system is 1013kg. Based on the current rhodium price of RMB 3 million / kg, the investment in the reaction system catalyst is close to RMB 3.12 billion.

[0179] Sampling analysis after 20 hours of reaction: the actual conversion rate in the first reactor was 45%, the selectivity was 95%, the conversion rate in the second reactor was 45%, the selectivity was 95%, the conversion rate in the third reactor was 90%, the selectivity was 90%; no rhodium was detected in the reaction liquid at the outlet of the liquid phase product of the third reactor;

[0180] After three reactors, the total conversion rate was 97% and the selectivity was 93%.

[0181] After the reaction was continued for 1000 hours, sampling and analysis showed that the actual conversion rate in the first reactor was 40%, and the selectivity was 95%, the conversion rate in the second reactor was 40%, and the selectivity was 95%, and the conversion rate in the third reactor was 80%, and the selectivity was 90%; the rhodium content in the reaction liquid at the outlet of the liquid phase product of the third reactor was 20 ppm;

[0182] After three reactors, the total conversion rate was 93% and the selectivity was 93%.

[0183] Comparative Example 1

[0184] Referring to the method of Example 2, 4-hydroxybutyraldehyde was prepared by continuous hydroformylation of allyl alcohol, using the reaction apparatus of Example 1, except that the third reactor in this comparative example was still a kettle reactor.

[0185] The calculation formula of the third reactor size is obtained by (1):

[0186]

[0187] Among them, the values ​​of each parameter are: V0 = 50m 3 / h,x A It is specified as 96%, C = 2wt%;

[0188] Calculated: The volume of the third reactor V R3 =1200m 3 .

[0189] The total volume of liquid phase in the three reactors of this comparative example is 1300m 3 The catalyst concentration in the reaction system is 2wt%, the precious metal rhodium content in the catalyst is 5wt%, and the rhodium stock in the entire reaction system is 1266kg. Based on the current rhodium price of RMB 3 million / kg, the investment in the reaction system catalyst is close to RMB 3.9 billion.

[0190] Comparative Example 2

[0191] 4-Hydroxybutyraldehyde was prepared by continuous hydroformylation of allyl alcohol according to the method of Example 2, except that the second reactor was omitted from the reaction apparatus of Example 1, and only the first reactor and the third reactor were used.

[0192] The total liquid volume in the two reactors is 372m 3 The catalyst concentration in the reaction system is 2wt%, the precious metal rhodium content in the catalyst is 5wt%, and the rhodium stock in the entire reaction system is 372kg. Based on the current rhodium price of RMB 3 million / kg, the investment in the reaction system catalyst is close to RMB 1.1 billion.

[0193] 1) Volume flow rate is 50m 3 / h of a mixed solution of allyl alcohol, catalyst A and toluene (in the mixed solution, the concentration of catalyst A is 2wt% and the concentration of allyl alcohol is 30wt%) is transported to the first reactor 1 through a liquid phase feed pipeline 10, and at the same time, unreacted synthesis gas from the third reactor 3 is transported to the first reactor 1 through a gas phase pipeline 9. Under the action of catalyst A, allyl alcohol and synthesis gas undergo a hydroformylation reaction at 80°C and a pressure of 1.2MPa. The reaction residence time is 60min. The gas phase and liquid phase after the reaction enter the third reactor through a gas phase pipeline and a liquid phase pipeline respectively;

[0194] 3) The gas phase and liquid phase entering the third reactor 3 continue to undergo hydroformylation reaction at 80° C. and a pressure of 1.5 MPa, with a reaction residence time of 390 min. The unreacted synthesis gas is transported to the first reactor 1 through the gas phase pipeline 9 to continue to participate in the reaction, and the liquid product 4-hydroxybutyraldehyde is produced from the upper liquid phase product outlet 13.

[0195] Sampling analysis after 20 hours of reaction: the actual conversion rate in the first reactor was 50%, the selectivity was 98%, and the conversion rate in the third reactor was 96%, the selectivity was 90%;

[0196] After two reactors, the total conversion was 98% and the selectivity was 92%.

[0197] Comparative Example 3

[0198] 4-Hydroxybutyraldehyde was prepared by continuous hydroformylation of allyl alcohol according to the method of Example 2, except that the solid-liquid separation device was omitted in the third reactor of the reaction apparatus of Example 1, and other operations and parameters remained unchanged.

[0199] Since no solid-liquid separation system was set up, the catalyst content in the extracted product was 2wt%.

[0200] Sampling analysis after 20 hours of reaction: the actual conversion rate in the first reactor was 25%, the selectivity was 98%, the conversion rate in the second reactor was 25%, the selectivity was 98%, the conversion rate in the third reactor was 50%, the selectivity was 95%; the catalyst was detected in the reaction liquid at the outlet of the liquid product of the third reactor, and the catalyst content was 2wt%;

[0201] After three reactors, the total conversion was 72% and the selectivity was 95%.

[0202] After 1000h of reaction, the actual conversion rate in the first reactor was 5%, and the selectivity was 98%. The conversion rate in the second reactor was 5%, and the selectivity was 98%. The conversion rate in the third reactor was 20%, and the selectivity was 95%.

[0203] Catalyst was detected, with a catalyst content of 2 wt%;

[0204] After three reactors, the total conversion rate was 28% and the selectivity was 95%. As the catalyst was constantly lost, the conversion rate of the system continued to decline.

Claims

1. A device for preparing 4-hydroxybutyraldehyde by continuous hydroformylation of allyl alcohol, characterized in that: It comprises a first reactor, a second reactor and a third reactor which are arranged in sequence; The first reactor is provided with a gas phase pipeline at the top connected to the second reactor, and a liquid phase pipeline at the bottom connected to the second reactor; The second reactor is provided with a gas phase pipeline at the top connected to the third reactor, and a liquid phase pipeline at the bottom connected to the third reactor; The top of the third reactor is provided with a gas phase pipeline connected to the first reactor; The first reactor is connected with a liquid phase feed pipeline; A synthesis gas feed pipeline is connected to the gas phase pipeline connected to the third reactor at the top of the second reactor; The third reactor is provided with a liquid product outlet at the upper portion; The first reactor and the second reactor are kettle reactors, and the third reactor is a multi-stage bubble tower reactor; In the reaction process of preparing 4-hydroxybutyraldehyde by hydroformylation of allyl alcohol, there are two high points in selectivity, and the theoretical conversion rates of the raw materials in the first and second reactors are respectively limited to the two high points of selectivity, wherein the theoretical conversion rate of the first reactor corresponds to the first high point of selectivity, and the theoretical conversion rate of the second reactor corresponds to the second high point of selectivity.

2. The device according to claim 1, characterized in that A gas compressor is arranged on the gas phase pipeline connected to the third reactor at the top of the second reactor, and the synthesis gas feed pipeline is merged into the gas phase pipeline and enters the gas compressor together.

3. The device according to claim 1, characterized in that A liquid phase delivery pump is arranged on the liquid phase pipeline connected to the third reactor at the bottom of the second reactor.

4. The device according to claim 1, characterized in that The multi-stage bubble tower reactor has 6-16 stages.

5. The device according to claim 4, characterized in that The multi-stage bubble tower reactor has 9-13 stages.

6. The device according to claim 1, characterized in that The height-to-diameter ratio of the first reactor and the second reactor is 1-1.

5.

7. The device according to claim 6, characterized in that The height-to-diameter ratio of the first reactor and the second reactor is 1.2-1.

3.

8. The device according to claim 1, characterized in that The height-to-diameter ratio of the third reactor is 3-15.

9. The device according to claim 8, characterized in that The height-to-diameter ratio of the third reactor is 6-10.

10. The device according to claim 1, characterized in that The first reactor and the second reactor are both provided with a stirring blade, a gas distributor and a heat transfer coil; and / or The third reactor is provided with a gas distributor, a porous sieve plate and a heat transfer coil.

11. The device according to claim 10, characterized in that The ratio of the diameter of the stirring paddle to the diameter of the reactor is 0.15-0.

55.

12. The device according to claim 11, characterized in that The ratio of the diameter of the stirring paddle to the diameter of the reactor is 0.3-0.

4.

13. The device according to claim 10, characterized in that The ratio of the diameter of the gas distributor to the diameter of the reactor is 0.1-0.

45.

14. The device according to claim 13, characterized in that The ratio of the diameter of the gas distributor to the diameter of the reactor is 0.25-0.

3.

15. The device according to claim 10, characterized in that The ratio of the diameter of the heat transfer coil to the diameter of the reactor is 0.01-0.

05.

16. The device according to claim 15, characterized in that The ratio of the diameter of the heat transfer coil to the diameter of the reactor is 0.03-0.

035.

17. The device according to claim 10, characterized in that The ratio of the diameter of the gas distributor to the diameter of the reactor is 0.5-0.

9.

18. The device according to claim 17, characterized in that The ratio of the diameter of the gas distributor to the diameter of the reactor is 0.6-0.

8.

19. The device according to claim 10, characterized in that The porous sieve plates are present in a quantity of 5 to 15 and have an opening rate of 0.5 to 5%.

20. The device according to claim 19, characterized in that The porous sieve plates are 8-12 in number and have an opening rate of 1-2%.

21. The device according to claim 10, characterized in that The ratio of the diameter of the heat transfer coil to the diameter of the reactor is 0.01-0.

05.

22. The device according to claim 21, characterized in that The ratio of the diameter of the heat transfer coil to the diameter of the reactor is 0.03-0.

035.

23. The device according to claim 10, characterized in that In the third reactor, a group of heat transfer coils is arranged every two layers of porous sieve plates.

24. The device according to claim 1, characterized in that A solid-liquid separation system is provided inside the third reactor, and the solid-liquid separation system is composed of a vertical draft tube and an annular flow stabilizing plate concentrically arranged around the vertical draft tube; The vertical draft tube is in the shape of an inverted funnel, and the lower edge of the conical funnel is in close contact with the inner wall of the third reactor; The annular flow stabilizing plate is fixed on the conical bucket of the vertical guide tube; The solid-liquid separation system is located above the sieve plate in the third reactor.

25. The device according to claim 24, characterized in that The upper edge of the annular flow stabilizing plate is also provided with a circle of annular flow guide plates.

26. The device according to claim 24, characterized in that The number of the annular flow stabilizing plates is 1-5, and the heights of the annular flow stabilizing plates decrease gradually from the guide tube to the inner wall of the third reactor.

27. The device according to claim 26, characterized in that The number of the annular flow stabilizing plates is 2-4.

28. The device according to claim 1, characterized in that The volumes of the first reactor and the second reactor are calculated by formula (1): V R : Volume of the reactor, m 3 ; V0: Material volume flow rate, m 3 / h; x A : Theoretical conversion rate of raw materials in the first reactor (x A1 ) or the theoretical conversion rate in the second reactor (x A2 ), %; C: Catalyst content in the material, wt%.

29. The device according to claim 1, characterized in that The reactor volume of the third reactor is calculated by formula (2): V R =-CV0ln(1-x A3 ) (2), V R : Volume of the reactor, m 3 ; V0: Material volume flow rate, m 3 / h; x A3 : The theoretical conversion rate of the raw material in the third reactor; C: Catalyst content in the material, wt%; The theoretical conversion rate of the raw material in the third reactor (x A3 ) is 75-99%.

30. The device according to claim 10, characterized in that The heat transfer area of ​​the heat transfer coil is calculated by formula (3): A: Heat exchange area of ​​the heat transfer coil of the first reactor or the second reactor, m 2 ; V0: Material volume flow rate, m 3 / h; V g : superficial gas velocity in the first reactor or the second reactor, m / h; x A : Theoretical conversion rate of the raw material in the first reactor or the second reactor.

31. A method for preparing 4-hydroxybutyraldehyde by continuous hydroformylation of allyl alcohol, the method using the apparatus according to any one of claims 1 to 30, the steps comprising: 1) A mixed solution of allyl alcohol, rhodium catalyst and toluene is transported to the first reactor through a liquid phase feed pipeline, and unreacted synthesis gas from the third reactor is transported to the first reactor through a gas phase pipeline. Under the action of the catalyst, allyl alcohol and the synthesis gas undergo a hydroformylation reaction, and the gas phase and liquid phase after the reaction enter the second reactor through a gas phase pipeline and a liquid phase pipeline respectively; 2) The gas phase and liquid phase entering the second reactor continue to undergo hydroformylation reaction, the gas phase after the reaction is combined with the fresh synthesis gas from the synthesis gas feed pipeline through the gas phase pipeline, and after being compressed by the gas compressor, enters the third reactor, and the liquid phase after the reaction passes through the liquid phase pipeline and enters the third reactor through the liquid phase delivery pump; 3) The gas phase and liquid phase entering the third reactor continue to undergo hydroformylation reaction, and the unreacted synthesis gas is transported to the first reactor through the gas phase pipeline to continue to participate in the reaction, and the liquid phase product 4-hydroxybutyraldehyde is produced from the upper liquid phase product outlet.

32. The method according to claim 31, characterized in that In step 1), in the mixed solution of allyl alcohol, catalyst and toluene, the catalyst concentration is 1-4wt% and the allyl alcohol concentration is 5-50wt%; In step 1), the rhodium catalyst is a supported rhodium catalyst.

33. The method according to claim 32, characterized in that In the mixed solution of allyl alcohol, catalyst and toluene, the concentration of catalyst is 2-3wt% and the concentration of allyl alcohol is 30-40wt%.

34. The method according to claim 32, characterized in that The rhodium catalyst is an organic polymer-supported rhodium catalyst; The organic polymer-supported rhodium catalyst comprises an active component rhodium and an organic polymer carrier, wherein the content of the active component rhodium is 0.5-20wt%.

35. The method according to claim 34, characterized in that The content of the active component rhodium is 5-10wt%.

36. The method according to claim 34, characterized in that The organic polymer carrier is selected from an organic polymer containing triphenylphosphine, wherein the content of triphenylphosphine is 2-5wt%; the polymer is any one of polyethylene, polypropylene and polyvinyl alcohol or a combination of at least two thereof.

37. The method according to claim 34, characterized in that The density of the organic polymer carrier is 0.9-0.95 kg / m 3 , particle size is 0.1-10um, pore size is 5-10nm, specific surface area is 2500-3000m 2 / m 3 , porosity 55-60%.

38. The method according to claim 34, characterized in that The active component of the organic polymer-supported rhodium catalyst is supported by an impregnation method.

39. The method according to claim 38, characterized in that In the impregnation process, 0.5-2 wt % of organic acid is added to the impregnation solution.

40. The method according to claim 39, characterized in that The organic acid is selected from isooctanoic acid, butyric acid and isononanoic acid.

41. The method according to claim 31, characterized in that In step 1), the hydroformylation reaction temperature is 75-85°C, the pressure is 1.1-1.3 MPaG, and the residence time is 40-120 min; In step 2), the hydroformylation reaction temperature is 75-85°C, the pressure is 0.8-1.0 MPaG, and the residence time is 40-120 min; In step 3), the hydroformylation reaction temperature is 75-85°C, the pressure is 1.4-1.6MPaG, and the residence time is 100-300min; The volume ratio of hydrogen to carbon monoxide in the synthesis gas is 1:0.8-1.

2.

42. The method according to claim 41, characterized in that In step 1), the hydroformylation reaction temperature is 78-83° C., the pressure is 1.15-1.25 MPaG, and the residence time is 50-100 min.

43. The method according to claim 41, characterized in that In step 2), the hydroformylation reaction temperature is 78-83° C., the pressure is 0.85-0.95 MPaG, and the residence time is 50-100 min.

44. The method according to claim 41, characterized in that In step 3), the hydroformylation reaction temperature is 78-83° C., the pressure is 1.45-1.55 MPaG, and the residence time is 150-250 min.

45. The method according to claim 41, characterized in that In step 3), the volume ratio of hydrogen to carbon monoxide in the synthesis gas is 1:0.95-1.05.

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