A continuous recycling process and system for the hydroformylation of higher alkenes

Abstract

A continuous cycle process and system for high carbon olefin hydroformylation, the method comprising the following steps: mixing a catalyst aqueous solution and an olefin to obtain a first mixture, the catalyst aqueous solution comprising a rhodium catalyst, a ligand and an aqueous solution of azomethylnitrone; under a first synthesis gas pressure, the first mixture is subjected to a hydroformylation reaction to obtain a first reaction liquid; after the first reaction liquid is separated into phases, a first aqueous phase containing the catalyst aqueous solution and a first organic phase containing a crude aldehyde are obtained; the first aqueous phase is returned to the first mixture for continuous reaction, and the first organic phase is treated to obtain a hydroformylation reaction product. The aqueous solution of azomethylnitrone is used as a solvent in the present application, which can improve the hydroformylation reaction rate of long-chain olefins and make the reaction conditions more mild. After the hydroformylation reaction is completed, the catalyst phase and the product phase can be better separated, and the separated catalyst aqueous solution can be used in the hydroformylation reaction again, effectively reducing the cost of the reaction.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of olefin hydroformylation, and in particular to a continuous circulation reaction process for high-carbon olefin hydroformylation and a continuous circulation reaction system. BACKGROUND

[0002] Olefin hydroformylation refers to a process of synthesizing an aldehyde with one more carbon from an olefin and synthesis gas (CO / H2) as substrates under the action of a catalyst. In the olefin hydroformylation reaction, a rhodium catalyst is widely used in industrial devices due to its excellent catalytic activity and selectivity. However, the high price of the rhodium catalyst requires that the separation, recovery, and recycling of the rhodium catalyst be addressed in industrial applications to reduce the production cost of the olefin hydroformylation reaction.

[0003] A water-soluble rhodium phosphine catalyst is a promising strategy for solving the problems of catalyst separation and recycling. For example, the successful application of a water-soluble rhodium phosphine complex in the industrial production of butyraldehyde by propylene hydroformylation (RCH-RP process) shows that the introduction of a water-soluble rhodium phosphine complex catalyst into a water / organic two-phase olefin hydroformylation reaction can effectively solve the problem of difficult separation of products and catalysts in a homogeneous catalytic system, and realize the continuous separation and recycling of the catalyst.

[0004] However, the existing water-soluble rhodium phosphine catalytic olefin hydroformylation reaction is mainly aimed at low-carbon olefins such as propylene. For high-carbon olefins (>C5), due to their poor water miscibility, the water-soluble rhodium phosphine catalytic high-carbon olefin hydroformylation reaction has a slow reaction rate, requires a higher reaction temperature, and has a larger amount of rhodium ligand loss, which makes the industrialization process of the water-soluble rhodium phosphine catalytic high-carbon olefin hydroformylation reaction difficult. SUMMARY

[0005] An object of the present application is to provide a continuous circulation process for high-carbon olefin hydroformylation, which uses nitrogen-methyl pyrrolidone that is miscible with water and olefins as a cosolvent, can effectively improve the reaction rate of long-chain olefin hydroformylation, and make the reaction conditions more mild. At the same time, the catalyst phase can be separated from the product phase and recycled for repeated use, effectively reducing the reaction cost and being conducive to industrial application.

[0006] The present application is implemented by the following technical solutions:

[0007] A continuous circulation process for high-carbon olefin hydroformylation includes the following steps:

[0008] Mixing a catalyst aqueous solution and an olefin to obtain a first mixture, wherein the catalyst aqueous solution includes a rhodium catalyst, a ligand, and an aqueous solution of nitrogen-methyl pyrrolidone;

[0009] Under the first syngas pressure, the first mixture undergoes a hydroformylation reaction to obtain a first reaction solution;

[0010] After phase separation, the first reaction solution yields a first aqueous phase containing an aqueous catalyst solution and a first organic phase containing crude aldehydes.

[0011] The first aqueous phase is returned to the first mixture to continue the reaction, and the first organic phase is processed to obtain the hydroformylation reaction product.

[0012] In this technical solution, the catalyst aqueous solution used includes a rhodium catalyst, a ligand, and an aqueous solution of N-methylpyrrolidone. N-methylpyrrolidone is also known as NMP. In the catalyst aqueous solution, NMP acts as a co-solvent, mediating mass transfer between the organic phase of the olefin and the aqueous phase containing the catalyst. This effectively increases the hydroformylation rate of long-chain olefins and makes the reaction conditions milder. Furthermore, NMP does not undergo side reactions with olefins, aldehydes, or acids.

[0013] In this technical solution, both the rhodium catalyst and the ligand can be existing water-soluble rhodium-phosphine catalysts and water-soluble phosphorus ligands. In some preferred embodiments, the rhodium catalyst is at least one selected from rhodium trichloride, rhodium acetate, rhodium nitrate, tris(triphenylphosphine tri-m-sulfonate)carbonyl rhodium, di(triphenylphosphine tri-m-sulfonate)carbonyl rhodium chloride, tris(triphenylphosphine tri-m-sulfonate) rhodium chloride, and acetylacetone carbonyl rhodium. In some preferred embodiments, the ligand is at least one selected from mono(m-sulfonate phenyl)diphenylphosphine, di(m-sulfonate phenyl)phenylphosphine, and tris(m-sulfonate phenyl)phosphine.

[0014] In this technical solution, the catalyst aqueous solution and olefin are mixed, and oxygen is replaced by a first syngas. A hydroformylation reaction is then carried out under the pressure of the first syngas to obtain a first reaction solution. Subsequently, the first reaction solution undergoes phase separation to obtain a first aqueous phase and a first organic phase. The first aqueous phase contains the catalyst aqueous solution and can be directly returned to the first mixture to continue the hydroformylation reaction. The first organic phase mainly contains crude aldehydes containing hydroformylation reaction products. These crude aldehydes are then processed in subsequent steps to obtain the hydroformylation reaction products.

[0015] In this technical solution, by using an aqueous solution of N-methylpyrrolidone as a solvent, the hydroformylation reaction rate of long-chain olefins can be increased and the reaction conditions can be made milder. At the same time, after the hydroformylation reaction is completed, the catalyst phase and the product phase can be better separated, eliminating the need for a complex separation process. The separated aqueous solution of catalyst can be reused in the hydroformylation reaction, effectively reducing the cost of the reaction.

[0016] In a preferred embodiment of the catalyst aqueous solution of the present invention, the mass concentration of N-methylpyrrolidone in the aqueous solution ranges from 30% to 90%.

[0017] As a co-solvent, a higher mass concentration of N-methylpyrrolidone in its aqueous solution promotes better miscibility between the organic and aqueous phases, thereby increasing the rate of hydroformylation. However, the inventors discovered that when the N-methylpyrrolidone content exceeds 90%, the increased solubility of both olefins and aldehydes in the aqueous phase makes separation between the catalyst phase (aqueous phase) and the product phase (organic phase) more difficult. For example, a 90% N-methylpyrrolidone aqueous solution can dissolve 24.5% of 1-nonanal. Furthermore, kinetic experiments revealed that when the mass concentration of N-methylpyrrolidone in the aqueous solution is below 30%, the initiation of the olefin hydroformylation reaction requires a certain induction period, which is caused by the mass transfer effect between the gas-liquid-liquid three-phase system. When the mass concentration of N-methylpyrrolidone is greater than 30%, the mass transfer resistance between the gas-liquid-liquid three-phase system can be eliminated to some extent, further improving the reaction efficiency. Therefore, in this technical solution, the mass concentration range of N-methylpyrrolidone is set to 30%–90%. In some preferred embodiments, the mass concentration range of N-methylpyrrolidone is 40%–80%, and more preferably, the mass concentration range of N-methylpyrrolidone is 60%–80%. Within this range, the catalyst phase and the product phase can be better separated, and the gas-liquid-liquid-three-phase interactions can be essentially eliminated, thereby significantly improving the catalytic activity.

[0018] In this technical solution, using a co-solvent to promote the miscibility of the aqueous and organic phases can effectively improve the reaction rate of long-chain olefins and obtain milder reaction conditions more suitable for industrial applications. However, compared with traditional solvents such as polyethylene glycol and methanol, more rhodium catalyst will be introduced into the product phase, for example, 2 ppm, resulting in the loss of rhodium catalyst.

[0019] Therefore, as a preferred embodiment of the present invention, the first organic phase after phase separation is further washed and extracted to reduce the loss of water-soluble rhodium catalyst.

[0020] The processing of the first organic phase includes the following steps:

[0021] The first organic phase was mixed with the ligand aqueous solution to obtain a second mixture;

[0022] Under the second syngas pressure, the second mixture reacts to obtain the second reaction liquid;

[0023] After the second reaction liquid is separated into two phases, a second aqueous phase and a second organic phase are obtained. The second aqueous phase is treated and returned to the first mixture to continue the reaction. The second organic phase is the product of the hydroformylation reaction.

[0024] Experiments revealed that directly washing the first organic phase with deionized water resulted in a low recovery rate of rhodium catalyst, indicating that the coordination form of rhodium lost to the first organic phase was not entirely hydrophilic, but rather possessed a degree of oleophilicity. Therefore, this technical solution employs a water-soluble ligand to alter the coordination form of rhodium under a second syngas atmosphere, restoring it to hydrophilicity, thereby enabling the recovery of the rhodium catalyst.

[0025] Specifically, the first organic phase after phase separation is mixed with an aqueous solution of the ligand to obtain a second mixture. The ligand used in the aqueous solution can be the same as or different from the water-soluble phosphorus ligand used in the hydroformylation reaction. In some preferred embodiments, the ligand is selected from at least one of mono(sodium phenyl)diphenylphosphine, di(sodium phenyl)phenylphosphine, and tri(sodium phenyl)phosphine; more preferably, the ligand is tri(sodium phenyl)phosphine.

[0026] After the addition of the ligand aqueous solution, the second mixture reacts under the pressure of the second syngas, causing a change in the coordination mode of the rhodium catalyst in the organic phase, resulting in a hydrophilic rhodium catalyst. Next, the second reaction solution undergoes phase separation, yielding a second aqueous phase and a second organic phase. The rhodium catalyst originally present in the organic phase dissolves in the second aqueous phase after the reaction, significantly reducing the amount of rhodium catalyst in the second organic phase. Finally, the second aqueous phase, after treatment, is returned to the first mixture for further reaction, achieving the recovery of the rhodium catalyst.

[0027] In this technical solution, taking advantage of the characteristics of the catalyst aqueous solution with N-methylpyrrolidone as a cosolvent, the first organic phase is further treated with a ligand aqueous solution, which changes the coordination mode of the lipophilic rhodium catalyst contained in the first organic phase, resulting in a hydrophilic rhodium catalyst. After phase separation, the hydrophilic rhodium catalyst enters the second aqueous phase and is finally returned to the first mixture for recycling. This significantly improves the recovery rate of the rhodium catalyst, reduces the entrainment of crude aldehydes and dissolved rhodium catalyst, and achieves a highly efficient and economical production process, which is beneficial to the industrialization of long-chain olefin hydroformylation reaction.

[0028] Furthermore, the concentration of the ligand in the aqueous ligand solution is 0.1% to 3.0%. Both excessively high and low concentrations of the ligand in the aqueous ligand solution can affect the coordination morphology of the rhodium catalyst. Experimental studies have shown that during extraction, the concentration of the ligand in the aqueous ligand solution is preferably 0.1% to 3.0%, more preferably 0.5% to 1.5%, to reduce the rhodium catalyst in the second organic phase to 24 ppb, thereby achieving efficient recovery of the rhodium catalyst.

[0029] Furthermore, the volume ratio of the first organic phase to the ligand aqueous solution is 1:1 to 1:3. After the ligand in the ligand aqueous solution coordinates with a small amount of rhodium in the first organic phase, a water-soluble rhodium-phosphine complex is formed. This rhodium-phosphine complex is insoluble in the first organic phase but soluble in the ligand aqueous solution. If the volume of the ligand aqueous solution is too low, the recovery rate of rhodium from the first organic phase will be low due to the low ligand content. However, if the volume of the ligand aqueous solution is too high, although it does not affect the recovery rate, the excessive ligand will not only increase production costs, but the subsequent concentration treatment of the excess ligand aqueous solution will also increase production energy consumption. Therefore, in this technical solution, the volume of the ligand aqueous solution needs to be greater than or equal to the volume of the first organic phase to further improve the rhodium recovery rate. Considering the amount of ligand used and processing energy consumption, the volume ratio of the first organic phase to the ligand aqueous solution is preferably set to 1:1 to 1:3.

[0030] Furthermore, in the second synthesis gas, the H2 / CO ratio is 0.5–2. Experiments revealed that the partial pressures of H2 and CO in the second synthesis gas also affect the recovery of rhodium from the crude aldehyde. When the H2 / CO ratio is 0.5–2, the rhodium content in the second organic phase will decrease to below 100 ppb. Preferably, when the partial pressure of H2 is 1, the rhodium content in the second organic phase decreases to below 40 ppb.

[0031] Furthermore, the pressure of the second syngas is 0.5–2.5 MPa. When the pressure of the second syngas is controlled at 0.5–2.5 MPa, the rhodium content in the second organic phase is 28–54 ppb, and the difference in rhodium recovery remains within a good range. Therefore, in some preferred embodiments, in order to further reduce production costs, the pressure of the second syngas is set to 0.5–1.0 MPa.

[0032] Furthermore, the second aqueous phase is treated by an evaporator, and the resulting recovered catalyst aqueous solution is returned to the first mixture, while the evaporated water is returned to the second mixture. After the second reaction liquid is separated into phases, the ligand aqueous solution in the second aqueous phase contains a large amount of water. Directly returning it to the first mixture would affect the hydroformylation reaction of the first mixture. Therefore, in this technical solution, most of the water in the second aqueous phase is removed by an evaporator to obtain a recovered catalyst aqueous solution, which is then added to the first mixture for the hydroformylation reaction. Simultaneously, the evaporated water is treated, for example, by adding ligands to form a ligand aqueous solution, and then added back to the second mixture, achieving recycling, reducing emissions, and further reducing the cost of the continuous recycling reaction process.

[0033] Another object of the present invention is to provide a continuous cycle system for the hydroformylation of high carbon olefins, the system comprising:

[0034] The first reactor is used for the hydroformylation reaction of an aqueous catalyst solution and an olefin under a first syngas pressure to obtain a first reaction solution, wherein the aqueous catalyst solution comprises an aqueous solution of a rhodium catalyst, a ligand, and an N-methylpyrrolidone.

[0035] A first phase separator is used to separate the first reaction liquid into a first aqueous phase and a first organic phase. The first phase separator includes a first outlet end and a second outlet end. The first outlet end is used to output the first aqueous phase to the first reactor, and the second outlet end is used to output the first organic phase.

[0036] In this technical solution, the first reactor can be at least one of a stirred tank reactor, a stirredless reactor, a packed tower, a jet loop reactor, and a pipeline reactor. The first reactor is used for the hydroformylation reaction of an aqueous catalyst solution and an olefin under a first syngas pressure, wherein the aqueous catalyst solution includes an aqueous solution of a rhodium catalyst, a ligand, and an N-methylpyrrolidone.

[0037] In some embodiments, the reaction time in the first reactor is 0.5 to 6 hours, preferably 1 to 5 hours, and more preferably 2 to 4 hours.

[0038] After the hydroformylation reaction is completed, the first reaction solution enters the first phase separator to separate into a first aqueous phase and a first organic phase. The first aqueous phase is pumped through the first outlet to the first reactor to continue the hydroformylation reaction as part of the catalyst aqueous solution. The first organic phase is discharged through the second outlet to the subsequent processing unit.

[0039] In some embodiments, the time for the first reaction liquid exiting the first reactor to undergo static phase separation in the first phase separator is 0.5 to 5 hours, preferably 1 to 3 hours.

[0040] Furthermore, the high-carbon olefin hydroformylation continuous cycle system also includes:

[0041] The second reactor is used to react the first organic phase and the ligand aqueous solution under the second syngas pressure to obtain the second reaction liquid;

[0042] The second phase separator is used to separate the second reaction liquid into a second aqueous phase and a second organic phase.

[0043] An evaporator for treating a second aqueous phase into a recovered catalyst aqueous solution and water, the evaporator including a third outlet end and a fourth outlet end, the third outlet end being used to output the recovered catalyst aqueous solution to the first reactor, and the fourth outlet end being used to output water to the container;

[0044] The container is used to prepare the ligand aqueous solution, adjust the concentration of the ligand aqueous solution, and output the ligand aqueous solution to the second reactor.

[0045] In this technical solution, the second reactor can be at least one of a stirred tank reactor, a non-stirred reactor, a packed tower, a jet loop reactor, and a pipeline reactor. The first organic phase, discharged from the second outlet of the first phase separator, enters the second reactor, mixes with the ligand aqueous solution, and reacts under the second syngas pressure to obtain the second reaction liquid. After static phase separation in the second phase separator, the upper second organic phase is collected to obtain the hydroformylation reaction product, while the lower second aqueous phase enters the evaporator. The evaporator removes most of the water from the second aqueous phase to obtain a recovered catalyst aqueous solution, which is recycled back to the first reactor via the third outlet. Simultaneously, the water separated by the evaporator is used as a solvent for preparing the ligand aqueous solution and input into a container. Water or ligand can be added to the container according to the required concentration of the ligand aqueous solution. After obtaining the desired concentration of the ligand aqueous solution, it is output to the second reactor. Alternatively, the separated water can be directly recycled back to the second reactor without adding any ligand.

[0046] The aforementioned equipment can improve the reaction rate of long-chain olefins, making the hydroformylation reaction conditions of long-chain olefins milder. It can also carry out the hydroformylation reaction with high activity and high selectivity under lower temperature and pressure conditions compared to traditional processes. Moreover, by setting up a second reactor and an evaporator, the rhodium catalyst in the first organic phase can be converted and recovered, minimizing the loss of rhodium and enabling the catalyst to be recycled for a long time at a lower cost, showing excellent prospects for industrial application.

[0047] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0048] 1. By using an aqueous solution of N-methylpyrrolidone as a solvent, this invention can improve the hydroformylation rate of long-chain olefins and make the reaction conditions milder. At the same time, after the hydroformylation reaction is completed, the catalyst phase and the product phase can be better separated, eliminating the need for a complex separation process. The separated aqueous solution of catalyst can be reused in the hydroformylation reaction, effectively reducing the cost of the reaction.

[0049] 2. In this invention, the mass concentration range of N-methylpyrrolidone is set to 30% to 90%, which allows for better phase separation between the catalyst phase and the product phase, while the gas-liquid-liquid-three-phase interaction can be largely eliminated, thereby significantly improving catalytic activity.

[0050] 3. This invention utilizes an aqueous solution of ligands to further treat the first organic phase, thereby changing the coordination morphology of the lipophilic rhodium catalyst contained in the first organic phase to obtain a hydrophilic rhodium catalyst, which enters the second aqueous phase after phase separation and is finally returned to the first mixture for recycling. This significantly improves the recovery rate of the rhodium catalyst, reduces the entrainment of crude aldehydes and dissolved rhodium catalyst, and achieves an efficient and economical production process, which is beneficial to the industrial progress of hydroformylation reaction of long-chain olefins.

[0051] 4. The continuous recycling process system of the present invention can improve the reaction rate of long-chain olefins, making the hydroformylation reaction conditions of long-chain olefins milder. Under lower temperature and pressure conditions compared with traditional processes, it can also carry out hydroformylation reactions with high activity and high selectivity. Moreover, by setting up a second reactor and an evaporator, the rhodium catalyst in the first organic phase can be converted and recovered, minimizing the loss of rhodium and enabling the catalyst to be recycled for a long time at a lower cost, which has excellent prospects for industrial application. Attached Figure Description

[0052] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0053] Figure 1 This is a flowchart of the continuous cycle process in a specific embodiment of the present invention;

[0054] Figure 2 This is a flowchart of the continuous cycle process in a specific embodiment of the present invention;

[0055] Figure 3 This is a schematic diagram of the continuous circulation system in a specific embodiment of the present invention;

[0056] The attached diagram shows the markings and corresponding component names:

[0057] 1-First reactor, 2-First phase separator, 3-Second reactor, 4-Second phase separator, 5-Evaporator, 6-Container;

[0058] 10-First reaction solution, 11-First aqueous phase, 12-First organic phase, 13-Ligand aqueous solution, 14-Second reaction solution, 15-Product, 16-Second aqueous phase, 17-Recovered catalyst aqueous solution, 18-Water. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0060] All raw materials used in this invention are not particularly limited in their source; they can be purchased commercially or prepared using conventional methods well-known to those skilled in the art. The purity of all raw materials used in this invention is not particularly limited; however, analytical grade or the purity requirements conventional in the field of olefin hydroformylation are preferred. All raw materials used in this invention have designations and abbreviations that are conventional in the art, and each designation and abbreviation is clearly defined within its relevant application. Those skilled in the art can obtain these materials from commercial sources or prepare them using conventional methods based on the designation, abbreviation, and corresponding application.

[0061] Example 1:

[0062] like Figure 1 The illustrated continuous cyclic process for hydroformylation of high-carbon olefins includes the following steps:

[0063] A first mixture is obtained by mixing an aqueous catalyst solution and an olefin, wherein the aqueous catalyst solution comprises an aqueous solution of a rhodium catalyst, a ligand, and an N-methylpyrrolidone.

[0064] Under the first syngas pressure, the first mixture undergoes a hydroformylation reaction to obtain a first reaction solution;

[0065] After phase separation, the first reaction solution yields a first aqueous phase containing an aqueous catalyst solution and a first organic phase containing crude aldehydes.

[0066] The first aqueous phase is returned to the first mixture to continue the reaction, and the first organic phase is processed to obtain the hydroformylation reaction product.

[0067] In some preferred embodiments, the rhodium catalyst is at least one selected from rhodium trichloride, rhodium acetate, rhodium nitrate, tris(triphenylphosphine tri-methylsulfonate)carbonyl rhodium hydride, di(triphenylphosphine tri-methylsulfonate)carbonyl rhodium chloride, tris(triphenylphosphine tri-methylsulfonate) rhodium chloride, and acetylacetone carbonyl rhodium.

[0068] In some preferred embodiments, the ligand is at least one of mono(sodium m-sulfonate phenyl)diphenylphosphine, di(sodium m-sulfonate phenyl)phenylphosphine, and tri(sodium m-sulfonate phenyl)phosphine.

[0069] In one or more embodiments, the volume ratio of the catalyst aqueous solution to the olefin is 1:1 to 6:1. If there is too much catalyst aqueous solution, the olefin will dissolve and form a homogeneous phase; if there is too little catalyst aqueous solution, the reaction efficiency will be low. Preferably, the volume ratio of the catalyst aqueous solution to the olefin is 2:1 to 4:1.

[0070] In one or more embodiments, the pressure of the first synthesis gas for the hydroformylation reaction is 0.5 to 3.5 MPa, preferably 1.5 to 2.5 MPa.

[0071] In one or more embodiments, the first synthesis gas comprises hydrogen and carbon monoxide, wherein the volume ratio of hydrogen to carbon monoxide is 1.0 to 2.0, preferably, the volume ratio of hydrogen to carbon monoxide is 1.01 to 1.1.

[0072] In one or more embodiments, the hydroformylation reaction is carried out at a temperature of 60–120°C, preferably 70–110°C, and more preferably 85–105°C.

[0073] In one or more embodiments, the content of rhodium catalyst in the aqueous catalyst solution is 20–300 ppm, preferably 30–150 ppm. The concentration of water-soluble phosphorus ligand is 3%–15%, preferably 7%–12%, to obtain higher reaction efficiency.

[0074] In some preferred embodiments, the mass concentration of N-methylpyrrolidone in the aqueous solution ranges from 30% to 90%. In some preferred embodiments, the mass concentration of N-methylpyrrolidone ranges from 40% to 80%, and more preferably, the mass concentration of N-methylpyrrolidone ranges from 60% to 80%. Within this range, the catalyst phase and the product phase can be better separated, and the gas-liquid-liquid three-phase interactions can be essentially eliminated, thereby significantly improving the catalytic activity.

[0075] Example 2:

[0076] Based on Example 1, such as Figure 2 As shown, the processing method for the first organic phase includes the following steps:

[0077] The first organic phase was mixed with the ligand aqueous solution to obtain a second mixture;

[0078] Under the second syngas pressure, the second mixture reacts to obtain the second reaction liquid;

[0079] After the second reaction liquid is separated into two phases, a second aqueous phase and a second organic phase are obtained. The second aqueous phase is treated and returned to the first mixture to continue the reaction. The second organic phase is the product of the hydroformylation reaction.

[0080] In this embodiment, taking advantage of the characteristics of the catalyst aqueous solution with N-methylpyrrolidone as a cosolvent, the first organic phase is further treated with a ligand aqueous solution, which changes the coordination mode of the lipophilic rhodium catalyst contained in the first organic phase, resulting in a hydrophilic rhodium catalyst. After phase separation, the hydrophilic rhodium catalyst enters the second aqueous phase and is finally returned to the first mixture for recycling. This significantly improves the recovery rate of the rhodium catalyst, reduces the entrainment of crude aldehydes and dissolved rhodium catalyst, and achieves an efficient and economical production process, which is beneficial to the industrialization of long-chain olefin hydroformylation reaction.

[0081] In some preferred embodiments, the concentration of the ligand in the aqueous solution is 0.1% to 3.0%, more preferably 0.5% to 1.5%.

[0082] In some preferred embodiments, the volume ratio of the first organic phase to the ligand aqueous solution is 1:1 to 1:3.

[0083] In some preferred embodiments, the partial pressure of H2 in the second synthesis gas is 1–2 MPa. Preferably, the partial pressure of H2 is 1.5 MPa, and the rhodium content in the second organic phase is reduced to below 40 ppb.

[0084] In some preferred embodiments, the pressure of the second synthesis gas is 0.5–2.5 MPa. In one or more embodiments, to further reduce production costs, the pressure of the second synthesis gas is set to 0.5–1.0 MPa.

[0085] In some preferred embodiments, the second aqueous phase is treated by an evaporator, and the resulting recovered catalyst aqueous solution is returned to the first mixture, while the evaporated water is returned to the second mixture. In this embodiment, most of the water in the second aqueous phase is removed by an evaporator to obtain a recovered catalyst aqueous solution, which is then added to the first mixture for hydroformylation. Simultaneously, the evaporated water is treated, for example, by adding ligands to form a ligand aqueous solution, and then added back to the second mixture, achieving recycling, reducing emissions, and further lowering the cost of the continuous recycling reaction process.

[0086] Example 3:

[0087] Based on the above embodiments, such as Figure 3 A continuous cycle system for hydroformylation of high-carbon olefins is shown, comprising:

[0088] First reactor 1 is used for hydroformylation of catalyst aqueous solution and olefin under first synthesis gas pressure to obtain first reaction solution, wherein the catalyst aqueous solution includes an aqueous solution of rhodium catalyst, ligand and N-methylpyrrolidone;

[0089] The first phase separator 2 is used to separate the first reaction liquid into a first aqueous phase and a first organic phase. The first phase separator 2 includes a first outlet end and a second outlet end. The first outlet end is used to output the first aqueous phase to the first reactor 1, and the second outlet end is used to output the first organic phase.

[0090] In some preferred embodiments, the high-carbon olefin hydroformylation continuous cycle system further includes:

[0091] The second reactor 3 is used to react the first organic phase and the ligand aqueous solution under the second syngas pressure to obtain the second reaction liquid;

[0092] The second phase separator 4 is used to separate the second reaction liquid into a second aqueous phase and a second organic phase;

[0093] Evaporator 5 is used to process the second aqueous phase into a recovered catalyst aqueous solution and water. Evaporator 5 includes a third outlet end and a fourth outlet end. The third outlet end is used to output the recovered catalyst aqueous solution to the first reactor 1, and the fourth outlet end is used to output water to the container 6.

[0094] Container 6 is used to prepare ligand aqueous solution, adjust the concentration of ligand aqueous solution, and output the ligand aqueous solution to the second reactor 3.

[0095] In one or more embodiments, the temperature of the second reactor is 50–110°C, preferably 60–100°C. In some preferred embodiments, the residence time of the first organic phase and the ligand aqueous solution in the second reactor is 0.5–2 hours, and the static phase separation time of the second phase separator is 0.5–3 hours, preferably 1–2 hours.

[0096] This embodiment can improve the reaction rate of long-chain olefins, making the hydroformylation reaction conditions of long-chain olefins milder. It can also carry out the hydroformylation reaction with high activity and high selectivity under lower temperature and pressure conditions compared with traditional processes. Moreover, by setting up a second reactor and an evaporator, the rhodium catalyst in the first organic phase can be converted and recovered, minimizing the loss of rhodium and enabling the catalyst to be recycled for a long time at a lower cost, which has excellent prospects for industrial application.

[0097] Example 4:

[0098] In this embodiment, 1-decene was used as the raw material olefin for hydroformylation reaction. The mass concentration of the aqueous solution of N-methylpyrrolidone was changed to test the effect of different mass concentrations of N-methylpyrrolidone on the reaction activity.

[0099] The reactor had a volume of 50 mL and was magnetically stirred. The reactor contained 10 mL of 1-decene and 30 mL of aqueous phase, which included [Rh] = 150 μg / mL, TPPTS / Rh = 60, N-methylpyrrolidone, and water. The rhodium catalyst was tris(triphenylphosphine tri-m-sulfonate)carbonyl rhodium, and the TPPTS ligand was tris(m-m-sulfonate phenyl)phosphine. The reaction temperature was 95 °C, the reaction time was 1 hour, the syngas pressure was 2.5 MPa, and the syngas composition was H2 / CO = 1.0–1.1.

[0100] The experimental results are shown in Table 1. Increasing the amount of NMP added to the catalyst aqueous solution effectively improves the catalytic activity. With the addition of 80% NMP, the conversion of 1-decene reaches 98.3% after 30 minutes, and the selectivity for aldehydes reaches 97.3%. The isomerization, hydrogenation, and hydrogenation of aldehydes are all very low, below 2%. Therefore, in some preferred embodiments, the mass concentration range of NMP is preferably 60%–80%, depending on the feed olefin.

[0101] Table 1:

[0102]

[0103]

[0104] Example 5:

[0105] In this embodiment, the hydroformyl oxidation reactivity of various long-chain olefins was tested.

[0106] The reactor has a volume of 50 mL and is magnetically stirred at 800 rpm. The reactor contains 10 mL of the raw olefin and 30 mL of aqueous phase, which comprises [Rh] = 150 μg / mL, TPPTS / Rh = 60, 80% N-methylpyrrolidone, and 20% water. The rhodium catalyst is tris(triphenylphosphine tri-m-sulfonate)carbonyl rhodium hydride, and the TPPTS ligand is tris(m-sulfonate phenyl)phosphine. The syngas pressure is 2.5 MPa, and the syngas composition is H2 / CO = 1.0–1.1.

[0107] The experimental results are shown in Table 2. The conversion rates of α-olefins from octene to octadecene were all high. Octadecene, in particular, achieved a conversion rate of approximately 85% even at a relatively low temperature of 105℃ for 1 hour. With appropriately extended reaction time, the conversion rate could reach over 95%. Other special olefins, such as styrene and dicyclopentadiene, also exhibited good reactivity. This indicates that using N-methylpyrrolidone as a co-solvent in an aqueous catalyst solution can significantly improve the hydroformylation rate of long-chain olefins and make the reaction conditions more moderate.

[0108] Table 2:

[0109]

[0110]

[0111] Example 6:

[0112] This example tested the effect of rhodium concentration on the hydroformylation reaction activity. The reactor volume was 50 mL, and a magnetic stirrer was used at 800 rpm. The reactor contained 10 mL of 1-nonene and 30 mL of aqueous phase, which consisted of [Rh] = 150 μg / mL, TPPTS / Rh = 60, 80% N-methylpyrrolidone, and 20% water. The rhodium catalyst was tris(triphenylphosphine tri-m-sulfonate sodium)carbonyl rhodium, and the ligand TPPTS was tris(m-sulfonate sodium phenyl)phosphine. The reaction temperature was 90 °C, the reaction time was 1 hour, the syngas pressure was 2.5 MPa, and the syngas composition was H2 / CO = 1.0–1.1.

[0113] Table 3:

[0114]

[0115] The experimental results are shown in Table 3. When the rhodium concentration increased from 30 μg / mL to 300 μg / mL, the conversion rate remained above 95% after 1 hour of reaction. The conversion rate increased slightly with increasing rhodium concentration, while the selectivity and N / I ratio of the aldehydes remained relatively unchanged. This indicates that the hydroformylation reaction of long-chain olefins can be carried out with a lower rhodium concentration, which is beneficial for reducing rhodium loss, lowering reaction costs, and improving reaction cycle capacity.

[0116] Example 7:

[0117] This embodiment tested the effect of the first syngas pressure on the hydroformylation reaction activity of long-chain olefins. The reactor volume was 50 mL, and a magnetic stirrer was used at a speed of 800 rpm. The reactor contained 10 mL of 1-octene and 30 mL of aqueous phase, which consisted of [Rh] = 150 μg / mL, TPPTS / Rh = 60, 80% N-methylpyrrolidone, and 20% water. The rhodium catalyst was tris(triphenylphosphine tri-m-sulfonate)carbonyl rhodium, and the ligand TPPTS was tris(m-sulfonate phenyl)phosphine. The reaction temperature was 85 °C, the reaction time was 1 hour, and the syngas composition was H2 / CO = 1.0–1.1.

[0118] The experimental results are shown in Table 4. When the reaction pressure is between 0.5 MPa and 3.0 MPa, the hydroformylation of 1-octene exhibits good reactivity, with a conversion rate remaining above 96%. The selectivity for the aldehyde and the N / I ratio are also good. The N / I ratio increases slightly with increasing reaction pressure, but the increase is not significant. Therefore, the catalyst aqueous solution in this embodiment can make the reaction conditions for long-chain olefins more moderate, and the pressure of the first syngas can be reduced to at most 0.5 MPa, which is beneficial for reducing the cost of the recycling reaction and improving safety.

[0119] Table 4:

[0120]

[0121] Example 8:

[0122] In this embodiment, 1-octene was used as the raw material olefin, and a 1L reactor continuous catalytic test was conducted.

[0123] Specifically, the feed rate for 1-octene was 2.5 mL / min, the feed rate for aqueous phase was 6 mL / min, the syngas pressure was 2.5 MPa, the reactor was a 1 L vessel, the overflow volume of the reactor was 700 mL, 540 mL of aqueous phase was added to the reactor, and 300 mL of aqueous phase was added to the phase separator. The aqueous phase composition was: [Rh] = 150 μg / mL, TPPTS / Rh = 60, 80% NMP, 20% water, and the rhodium catalyst was tris(triphenylphosphine tri-m-sulfonate sodium)carbonyl rhodium hydride. The average residence time was approximately 85 min. The reaction temperature was 85 °C, the syngas composition was H2 / CO = 1.0–1.1, and the inlet gas flow rate was CO / 1-octene = 0.9–1.0. After the reaction was complete, the composition of the first organic phase in the first phase separator was analyzed.

[0124] The experimental results are shown in Table 5. The hydroformyl reaction was cycled for 240 hours, and the conversion rate of aldehyde remained at about 85%. The selectivity and positive-to-negative ratio of aldehyde remained basically stable, indicating that the catalytic activity of the catalyst aqueous solution could be well maintained.

[0125] Table 5:

[0126]

[0127] Example 9:

[0128] In this embodiment, the rhodium catalyst in crude aldehyde was tested by washing and recovering it using a ligand aqueous solution in a second reactor.

[0129] The reaction conditions were: 30 mL of TPPTS aqueous solution, 10 mL of crude aldehyde, magnetic stirring at room temperature (20℃~30℃) at 800 rpm for 1 h, followed by phase separation, and analysis of the rhodium content in the upper layer of crude aldehyde.

[0130] The rhodium content in the crude aldehyde before water washing was 215 ppb. The experimental results are shown in Table 6. Even with the addition of ligands, simple water washing at room temperature resulted in a rhodium recovery efficiency of less than 10%. Extending the stirring time to 24 hours did not significantly change the recovery efficiency. This indicates that the rhodium catalyst lost into the first organic phase was not due to incomplete phase separation, but rather a change in coordination morphology, with the rhodium becoming lipophilic and dissolving in the crude aldehyde.

[0131] Table 6:

[0132]

[0133] Example 10:

[0134] In this embodiment, the recovery rate of rhodium from crude aldehyde was increased by adjusting the temperature and gas atmosphere for rhodium recovery and utilizing the ligand aqueous solution.

[0135] Specifically, the reactor volume was 50 mL, and a magnetic stirrer was used at 800 rpm. 10 mL of crude aldehyde was washed with 30 mL of 1.0% TPPTS aqueous solution. The pressure of the second syngas was 2.5 MPa, and the composition of the second syngas was H2 / CO = 1.0–1.1. After reacting for 1 hour, phase separation was performed, and the rhodium content of the upper layer of crude aldehyde was analyzed. Before water washing, the rhodium content in the crude aldehyde was 215 ppb. The washing results are shown in Table 7.

[0136] Table 7:

[0137]

[0138] As shown in Table 7, the rhodium recovery rate under a syngas atmosphere is significantly higher than that under a N2 atmosphere. Under a syngas atmosphere, with a reaction temperature above 70℃ and extraction for 1 hour, the rhodium content in the crude aldehyde can be reduced to below 50 ppb. Therefore, using a ligand aqueous solution under syngas pressure at a temperature of 60–80℃ can effectively improve the rhodium recovery rate from crude aldehyde.

[0139] Example 11:

[0140] This embodiment explores the effect of different ligand concentrations in the ligand aqueous solution on the recovery of rhodium from crude aldehyde.

[0141] Specifically, the reactor volume was 50 mL, and a magnetic stirrer was used at a speed of 800 rpm. 10 mL of crude aldehyde was washed with 30 mL of TPPTS aqueous solution of different concentrations. The pressure of the second syngas was 2.5 MPa, and the composition of the second syngas was H2 / CO = 1.0–1.1. The reaction temperature was 80 °C. After one hour of reaction, the phases were separated, and the rhodium content in the upper layer of crude aldehyde was analyzed. Before water washing, the rhodium content in the crude aldehyde was 215 ppb. The experimental results are shown in Table 8.

[0142] Table 8:

[0143]

[0144] Therefore, it can be seen that in the ligand aqueous solution, the recovery rate of rhodium also decreases to some extent as the concentration of the ligand decreases. Thus, in some preferred embodiments, to ensure the recovery rate of rhodium, a better ligand concentration is 0.5% to 1.5%.

[0145] Example 12:

[0146] This embodiment explores the effect of the pressure of the second synthesis gas on the recovery of rhodium from crude aldehyde.

[0147] Specifically, the reactor volume was 50 mL, and magnetic stirring was used at 800 rpm. 10 mL of crude aldehyde was washed with 30 mL of 0.5% TPPTS aqueous solution. The composition of the second synthesis gas was H2 / CO = 1.0–1.1, and the reaction temperature was 80 °C. After one hour of reaction, phase separation was performed, and the rhodium content of the upper layer of crude aldehyde was analyzed. Before water washing, the rhodium content in the crude aldehyde was 215 ppb. The experimental results are shown in Table 9.

[0148] Table 9:

[0149]

[0150] As shown in Table 9, the extraction results are basically consistent when the pressure of the second syngas is in the range of 0.5 MPa to 2.5 MPa. Therefore, the entire extraction process can be controlled at a lower pressure. For example, in some preferred embodiments, the pressure of the second syngas is set to 0.5 to 1.0 MPa.

[0151] Example 13:

[0152] This embodiment explores the effect of different compositions of the second synthesis gas on the recovery of rhodium from crude aldehydes.

[0153] Specifically, the reaction vessel volume was 50 mL, and magnetic stirring was used at a speed of 800 rpm. 10 mL of crude aldehyde was washed with 30 mL of 0.5% TPPTS aqueous solution. The total pressure of the second synthesis gas was 3.0 MPa. Extraction was performed under different partial pressures of H2 and CO, and the reaction temperature was 80 °C. After one hour of reaction, the phases were separated, and the rhodium content in the upper layer of crude aldehyde was analyzed. Before water washing, the rhodium content in the crude aldehyde was 215 ppb. The experimental results are shown in Table 10.

[0154] Table 10:

[0155]

[0156] Therefore, it is evident that the rhodium recovery rate is not high when the partial pressure of H2 or CO is too high. Thus, in some preferred embodiments, the partial pressure of H2 is 1 to 2 MPa, and more preferably, the partial pressure of H2 or CO is 1.5 MPa, i.e., H2 / CO = 1.0, when the rhodium recovery efficiency is the highest.

[0157] Example 14:

[0158] In this embodiment, a second reactor, a second phase separator, an evaporator, and a container are used to recover the rhodium catalyst in the first organic phase.

[0159] The reaction conditions were as follows: crude aldehyde (first organic phase) feed rate 2 mL / min, aqueous phase feed rate 6 mL / min, second syngas feed rate 50 mL / min, H2 / CO ratio in the second syngas = 1.0–1.1, pressure 2.5 MPa, 1 L reactor, overflow volume 700 mL, 540 mL aqueous phase added to the reactor, and 300 mL aqueous phase added to the phase separator (1% TPPTS aqueous solution). The extraction temperature was 90℃, and the average residence time was approximately 90 min. The rhodium content in the crude aldehyde was 215 ppb. After extraction, the rhodium content in the oil phase from the phase separator was analyzed. The extraction results are shown in Table 11.

[0160] Table 11:

[0161]

[0162]

[0163] This shows that after the entire recycling process ran continuously for 240 hours, the rhodium content in the recovered crude aldehyde was consistently below 100 ppb. The slight decrease in the later recovery volume was mainly due to the partial oxidation of ligands within the system.

[0164] The terms "first," "second," etc., used in this document (e.g., first reactor, second reactor, first phase separator, second phase separator, etc.) are merely for clarity of description and are not intended to restrict any order or emphasize importance. Furthermore, the term "connection" used herein, unless otherwise specified, can refer to a direct connection or an indirect connection via other components.

[0165] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A continuous cyclic process for the hydroformylation of high-carbon olefins, characterized in that, Includes the following steps: A first mixture is obtained by mixing an aqueous catalyst solution and an olefin, wherein the aqueous catalyst solution comprises an aqueous solution of a rhodium catalyst, a ligand, and an N-methylpyrrolidone, wherein the mass concentration of the N-methylpyrrolidone in the aqueous solution ranges from 30% to 90%. Under the first syngas pressure, the first mixture undergoes a hydroformylation reaction to obtain a first reaction solution; After phase separation, the first reaction solution yields a first aqueous phase containing an aqueous catalyst solution and a first organic phase containing crude aldehydes. The first aqueous phase is returned to the first mixture to continue the reaction, and the first organic phase is treated to obtain the hydroformylation reaction product; The processing of the first organic phase includes the following steps: The first organic phase is mixed with an aqueous solution of the ligand to obtain a second mixture, wherein the concentration of the ligand in the aqueous solution is 0.5% to 3.0%. Under a second syngas pressure, the second mixture reacts to obtain a second reaction liquid. In the second syngas, the H2 / CO ratio is 0.5~2, and the pressure of the second syngas is 0.5~2.5 MPa. After the second reaction liquid is separated into two phases, a second aqueous phase and a second organic phase are obtained. The second aqueous phase is treated and returned to the first mixture to continue the reaction. The second organic phase is the product of the hydroformylation reaction.

2. The continuous cyclic process for hydroformylation of high-carbon olefins according to claim 1, characterized in that, The volume ratio of the first organic phase to the ligand aqueous solution is 1:1 to 1:

3.

3. The continuous cyclic process for hydroformylation of high-carbon olefins according to claim 1, characterized in that, The second aqueous phase is processed by an evaporator, and the resulting recovered catalyst aqueous solution is returned to the first mixture, while the evaporated water is returned to the second mixture.

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