Method and system for preparing valeraldehyde from 1-butene
By improving the catalyst preparation and separation process, the problems of complex separation process and high energy consumption in the existing pentanal production have been solved, realizing efficient pentanal production and improving product purity and yield.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-23
- Publication Date
- 2026-04-10
AI Technical Summary
In the existing pentanal production process, the product separation process is complex, the operating pressure decreases and then increases, resulting in high energy consumption, and traditional catalysts pose an environmental pollution risk.
An improved catalyst preparation method and separation process were adopted, including the preparation of rhodium-based catalysts using poly(styrene-4-chloromethylstyrene) and sodium iodide and diphenylphosphine chloride, and the separation of pentanal by flash separator and double-tower distillation operation, which simplifies the process and reduces energy consumption.
This simplified the product separation process, reduced energy consumption, and improved the purity and yield of pentanal.
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Figure CN121824285A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of petrochemical industry, and particularly relates to a method and system for preparing pentanal from 1-butene. BACKGROUND
[0002] Pentanal is an important organic chemical raw material, and its downstream products are widely distributed, mainly in the fields of perfumes and plasticizers. In the field of perfumes, pentanal is used as a reaction raw material to generate dihydrojasmone acid methyl ester, which is an excellent substitute for natural jasmine oil. In the field of plasticizers, due to the influence of policy, the use of traditional plasticizer DOP is gradually decreasing, and the demand for high-quality substitute DPHP is rapidly rising, which leads to a market gap in 2-PH, and the core of producing 2-PH is the production of pentanal. In other fields, pentanal is also an important organic synthesis intermediate, which can be hydrogenated to generate n-pentanol, oxidized to generate n-pentanoic acid, and aminated to generate n-pentylamine.
[0003] In the existing pentanal production process, there are mainly three methods: n-pentanol oxidation method, biomimetic synthesis method and butene hydroformylation synthesis method. The n-pentanol oxidation method refers to the oxidation of pentanol to pentanal under the action of a catalyst in a gas phase or a liquid phase. However, the value of pentanol is higher than that of pentanal, so the economic benefit of this process is poor, it is only applied to small-batch production in the laboratory, and is not suitable for industrial mass production. In addition, the catalyst required for the oxidation of n-pentanol is often a heavy metal chromium-based catalyst, which can easily cause environmental pollution problems. The biomimetic synthesis method is a new method for synthesizing n-pentanal, which uses biological enzymes to synthesize pentanal from n-butyl bromide, o-phenylenediamine and formic acid as initial raw materials in one step. This process has mild process conditions, simple equipment and high yield. However, this process is still in the research and development stage, and problems such as enzyme stability and process optimization have not been solved. The butene hydroformylation synthesis method is the only industrialized method for producing pentanal. This method uses a large amount of C4 hydrocarbon by-products of petroleum and coal chemical industry as raw materials, and reacts with synthesis gas under the action of a catalyst to generate pentanal. According to the different catalysts, it can be divided into a cobalt catalyst system process and a rhodium catalyst system process.
[0004] In the currently industrialized rhodium catalyst process, the separation of the catalyst and the reaction product adopts a two-stage falling film evaporator, the first-stage falling film evaporator operates at a pressure of 0.15 MPaG, and the second-stage falling film evaporator operates in a vacuum state; the separation of the crude pentanal and butene adopts a synthesis gas stripping process, and the stripping tower operates at a pressure of 1.7 MPaG. This process has the problems of complex product separation process and high energy consumption due to the first decrease and then increase of the operating pressure. SUMMARY
[0005] In order to solve the problems in the prior art, the application provides a method and system for preparing pentanal from 1-butene.
[0006] A method for preparing pentanal from 1-butene, which comprises: introducing the 1-butene synthesis gas purified by a purification unit I into a hydroformylation reaction unit II to react, introducing the reaction mixture containing pentanal obtained by the reaction into a catalyst separation unit III to separate, introducing the gaseous mixture containing pentanal obtained by the separation into a product separation unit IV, and separating pentanal by double-tower rectification operation in the product separation unit IV.
[0007] In the above method, the liquid mixture containing catalyst in the catalyst separation unit III is returned to the hydroformylation reaction unit II to continue to participate in the reaction.
[0008] In the above method, the components of the 1-butene synthesis gas are hydrogen and carbon monoxide, and the molar ratio of hydrogen to CO is 0.9-1.1.
[0009] In the above method, the catalyst used in the hydroformylation reaction unit II is prepared by the following method:
[0010] (1) adding poly(4-chloromethylstyrene-styrene) into a potassium carbonate solution to react, and then filtering, washing and drying in sequence to obtain intermediate A;
[0011] (2) mixing intermediate A, sodium iodide and diphenylphosphine chloride to react, and then washing and drying to obtain intermediate B;
[0012] (3) immersing intermediate B in a solution of dicarbonyl rhodium dimer to obtain a supported catalyst.
[0013] In some specific technical solutions, the catalyst is prepared by the following method:
[0014] (1) adding poly(4-chloromethylstyrene-styrene) into a basic solution to hydrolyze, to obtain intermediate A; the molar ratio of poly(4-chloromethylstyrene-styrene) to the basic solution is 1:(2-10);
[0015] (2) mixing intermediate A, sodium iodide and diphenylphosphine chloride to obtain intermediate B; the molar ratio of intermediate A, sodium iodide and diphenylphosphine chloride is 1:(2-10):(2-8).
[0016] In the above method for preparing the catalyst, the basic solution in step (1) is at least one of potassium hydroxide, sodium hydroxide, sodium carbonate and potassium carbonate.
[0017] In the above method for preparing the catalyst, the reaction temperature during hydrolysis in step (1) is 50-120℃, and the reaction time is 6-18h.
[0018] In the preparation method of the catalyst, the disubstituted chlorophosphine in step (2) is one of diphenylchlorophosphine, di-p-tolylchlorophosphine, bis(2,4,6-trimethylphenyl)chlorophosphine and bis(3,5-dimethyl-4-methoxyphenyl)chlorophosphine.
[0019] In the preparation method of the catalyst, the reaction temperature in step (2) is 25-100 DEG C, and the reaction time is 2-16 h.
[0020] In the method, the reaction operation temperature of the hydroformylation reaction unit is 80-120 DEG C, and the operation pressure is 2-2.5 MPaG.
[0021] In the method, the equipment adopted by the catalyst separation unit III is a flash separator, the operation pressure is 0.03-0.08 MPaG, and the operation temperature is 110-115 DEG C.
[0022] In the method, the product separation unit IV comprises 1# column rectification and 2# column rectification, the overhead operation temperature of the 1# column rectification is 90-101 DEG C, the overhead operation pressure is 0.03-0.04 MPaG, and the overall pressure drop of the column is less than 10 kPa; the overhead operation temperature of the 2# column rectification is 95-107 DEG C, the overhead operation pressure is 0.01-0.02 MPaG, and the overall pressure drop of the column is less than 10 kPa.
[0023] In the method, the content of sulfur, chlorine, oxygen and carbonyl metal in the purified 1-butene and synthesis gas in step (1) is less than or equal to 2 ppm.
[0024] In some specific technical solutions, the catalyst separation adopts a flash separator with an internal hot water heater, the operation pressure is 0.05 MPaG, and the separation operation temperature is 110-115 DEG C.
[0025] The present application has the advantages of solving the problems of complex product separation process and high energy consumption of the operation pressure which is first reduced and then increased. BRIEF DESCRIPTION OF DRAWINGS
[0026] Figure 1 is a process flow diagram of the present application;
[0027] In the figure, I. raw material purification unit, II. hydroformylation reaction unit, III. catalyst separation unit, IV. product separation unit. DETAILED DESCRIPTION
[0028] The present application will be further described below in conjunction with examples, but the protection scope of the present application is not limited thereto:
[0029] The preparation method of the rhodium-based catalyst in the examples is as follows:
[0030] (1) poly(styrene-4-chloromethylstyrene) (manufacturer: Sigma-Aldrich, product number: 659177) is added to a potassium carbonate solution, the reaction temperature is 100°C, the reaction time is 10h, filtration, washing with deionized water, drying at 120°C for 24h, to obtain intermediate A, the molar ratio of poly(styrene-4-chloromethylstyrene) to basic solution is 1:2;
[0031] (2) intermediate A is added to a round-bottom flask, then sodium iodide, diphenyl chlorophosphine, solvent acetonitrile, the reaction temperature is 80°C, the reaction time is 12h, filtration at room temperature, washing the product with n-hexane, then drying at 120°C for 24h to obtain intermediate B, the molar ratio of intermediate A, sodium iodide, disubstituted chlorophosphine is 1:6:6;
[0032] (3) intermediate B is immersed in a toluene solution of dicarbonyl rhodium dimer with a concentration of 2mol / L, the immersion temperature is 60°C, the immersion time is 4h, after immersion, methanol is used for washing, drying at 70°C for 72h to obtain a supported catalyst, the loading of intermediate B is 1%.
[0033] As Figure 1 , the process system for preparing pentanal from 1-butene includes a raw material purification unit I, a hydroformylation reaction unit II, a catalyst separation unit III, and a product separation unit IV.
[0034] 1-butene and synthesis gas enter the raw material purification unit I, and after removing sulfur, chlorine, oxygen, and carbonyl metals, they enter the hydroformylation reaction unit II, where an exothermic reaction occurs under the action of a rhodium-based catalyst to obtain a reaction mixture containing pentanal. The heat released during the reaction is removed by circulating water. The reaction mixture is subjected to micro-positive pressure separation in the catalyst separation unit III, and the gas-phase mixture containing pentanal obtained by evaporation through hot water heating enters the product separation unit IV. The remaining liquid-phase mixture containing catalyst returns to the hydroformylation reaction unit II. In the product separation unit IV, qualified liquid-phase pentanal products and heavy component by-products are obtained through double-tower micro-positive pressure rectification operation.
[0035] The reaction operation temperature of the hydroformylation reaction unit is 100°C, and the operation pressure is 2.2MPaG.
[0036] The catalyst separation unit III uses a flash separator, the operation pressure is 0.05MPaG, and the operation temperature is 110-115°C.
[0037] The product separation unit IV includes 1# column rectification and 2# column rectification, the overhead operating temperature of the 1# column rectification is 90~101℃, the overhead operating pressure is 0.03~0.04 MPaG, and the overall pressure drop of the column is less than 10kPa; the overhead operating temperature of the 2# column rectification is 95~107℃, the overhead operating pressure is 0.01~0.02 MPaG, and the overall pressure drop of the column is less than 10kPa.
[0038] Application case:
[0039] 1100kg / h of 1-butene and 580kg / h of synthesis gas from outside enter the raw material purification unit I, and the sulfur, chlorine, oxygen and carbonyl metal contained in the raw material are purified to less than 1ppm, and then enter the hydroformylation reaction unit II, and the exothermic reaction occurs under the action of rhodium-based catalyst to obtain a reaction mixture containing valeraldehyde, the reaction operating temperature is 100℃, and the operating pressure is 2.2MPaG. 3307kg / h of the reaction mixture enters the catalyst separation unit III, and is separated under micro-positive pressure in the flash separator (operating pressure 0.05 MPaG, operating temperature 113℃), the hot water operating temperature is 120℃, 1611kg / h of the gas phase mixture containing valeraldehyde enters the product separation unit IV, and the remaining 1696kg / h of the liquid phase mixture containing catalyst returns to the hydroformylation reaction unit II. In the product separation unit IV, through 1# column rectification operation (the overhead operating temperature of the 1# column rectification is 95~98℃, the overhead operating pressure is 0.04 MpaG, and the overall pressure drop of the column is less than 10kPa), 1467kg / h of crude valeraldehyde is obtained at the bottom of the column, and 144kg / h of light components containing synthesis gas butene is obtained at the top of the column and returned to the hydroformylation reaction unit II; the crude valeraldehyde is subjected to 2# column rectification operation (the overhead operating temperature of the 2# column rectification is 95~98℃, the overhead operating pressure is 0.02 MpaG, and the overall pressure drop of the column is less than 10kPa), 1409kg / h of qualified valeraldehyde product is obtained at the top of the column, and 58kg / h of heavy components is obtained at the bottom of the column. (The purity of valeraldehyde product is ≥99.5%, and the product yield is ≥83%).
Claims
1. A method for producing pentanal from 1-butene, characterized in that, The method involves 1-butene synthesis gas purified by purification unit I entering hydroformylation reaction unit II for reaction. The resulting reaction mixture containing pentanal enters catalyst separation unit III for separation, and the resulting gaseous mixture containing pentanal enters product separation unit IV. In product separation unit IV, pentanal is separated by a double-tower distillation operation.
2. The method according to claim 1, characterized in that, The liquid mixture containing the catalyst in catalyst separation unit III is returned to hydroformylation reaction unit II to continue participating in the reaction.
3. The method according to claim 1, characterized in that, The components of 1-butene synthesis gas are hydrogen and carbon monoxide, with a molar ratio of hydrogen to CO of 0.9-1.
1.
4. The method according to claim 1, characterized in that, The catalyst used in hydroformylation reaction unit II was prepared by the following method: (1) Poly(styrene-4-chloromethylstyrene) was added to potassium carbonate solution for reaction. After the reaction was completed, the mixture was filtered, washed and dried to obtain intermediate A. (2) Intermediate A, sodium iodide and diphenylphosphine chloride were mixed and reacted. After the reaction was completed, the mixture was washed and dried to obtain intermediate B. (3) Immerse intermediate B in a solution of dicarbonyl rhodium dimer to obtain a supported catalyst.
5. The method according to claim 3, characterized in that, The hydroformylation reaction unit operates at a temperature of 80~120℃ and a pressure of 2~2.5MPaG.
6. The method according to claim 1, characterized in that, The catalyst separation unit III uses a flash separator with an operating pressure of 0.03~0.08 MPaG and an operating temperature of 110-115℃.
7. The method according to claim 3, characterized in that, Product separation unit IV includes distillation column #1 and distillation column #2. The operating temperature at the top of distillation column #1 is 90~101℃, the operating pressure at the top of the column is 0.03~0.04 MPaG, and the overall pressure drop of the column is less than 10 kPa. The operating temperature at the top of distillation column #2 is 95~107℃, the operating pressure at the top of the column is 0.01~0.02 MPaG, and the overall pressure drop of the column is less than 10 kPa.