Method for preparing isononanal through hydroformylation of isooctene

Abstract

The invention discloses a method for preparing isononanal through hydroformylation of isooctene, and belongs to the technical field of petrochemical engineering. The method comprises the following steps: feeding isooctene and synthesis gas from the outside into a raw material purification unit I, and removing sulfur, chlorine, oxygen and carbonyl metal to obtain purified isooctene and synthesis gas; under the catalytic action of a rhodium catalyst, the purified isooctene and synthesis gas enter a hydroformylation reaction unit II for reaction, and a reaction mixture containing isononanal is obtained; the reacted mixture enters a catalyst separation unit III to obtain a gas-phase mixture containing isononanal, the gas-phase mixture enters a product separation unit IV, and a liquid-phase mixture containing a catalyst returns to the hydroformylation reaction unit II; and a liquid-phase isononanal product and a byproduct containing isooctane and isooctene are obtained in a product separation unit IV and are respectively sent to the outside. The method solves the problems that the rhodium catalyst system has many heavy components, the catalyst and the product are difficult to separate, and the catalyst is easy to inactivate.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of petroleum chemical industry, and relates to a method for preparing iso-nonylaldehyde through iso-octene hydroformylation. BACKGROUND

[0002] The reaction of olefins and synthesis gas to add one carbon aldehyde compound is called hydroformylation, and the initial raw material is generally obtained from petroleum cracking products, which is abundant and cheap. Now, the reaction has become one of the most important reactions for producing aldehyde compounds, which realizes the rational use of resources and creates more valuable additional products.

[0003] In the existing hydroformylation process for preparing aldehyde, there are mainly two mainstream processes: a cobalt catalyst system process and a rhodium catalyst system process. Due to the low activity of cobalt catalyst, many by-products, harsh reaction conditions, high energy consumption and other shortcomings, rhodium catalyst gradually becomes the research focus of the olefin hydroformylation reaction. However, in the hydroformylation reaction process of high-carbon olefins with C6 or more as raw materials, due to the high boiling point of high-carbon aldehyde product, the temperature required for the separation of product aldehyde and catalyst is high, which leads to the problems of intensified aldehyde condensation by-product, increased heavy components, rhodium catalyst reaching the decomposition and deactivation temperature, and difficult separation of catalyst and product. Due to the existence of the problems, the production technology of high-carbon olefins for preparing aldehyde in China is still basically in the laboratory stage, and there is no report on the technology that can successfully realize industrialization. SUMMARY

[0004] In order to solve the problems in the prior art, the application provides a method and system for preparing iso-nonylaldehyde through iso-octene hydroformylation, and successfully realizes industrial application.

[0005] The purpose of the application can be achieved by the following technical solutions.

[0006] A method for preparing iso-nonylaldehyde through iso-octene hydroformylation, which comprises the following steps:

[0007] (1) Iso-octene and synthesis gas from outside enter a raw material purification unit I, and after removing sulfur, chlorine, oxygen and carbonyl metal, purified iso-octene and synthesis gas are obtained;

[0008] (2) Under the catalysis of a rhodium catalyst, the purified iso-octene and synthesis gas enter a hydroformylation reaction unit II to react, and a reaction mixture containing iso-nonylaldehyde is obtained;

[0009] (3) The reaction mixture enters a catalyst separation unit III, a gas-phase mixture containing iso-nonylaldehyde enters a product separation unit IV, and a liquid-phase mixture containing catalyst returns to the hydroformylation reaction unit II;

[0010] (4) The liquid phase iso-nonylaldehyde product and iso-octane iso-octene containing by-product obtained in the product separation unit IV are sent out of the system.

[0011] In the above method, the mass ratio of iso-octene to synthesis gas in step (1) is 1:1-3:1, and the synthesis gas is hydrogen and carbon monoxide in a molar ratio of 0.9-1.1:1.

[0012] In the above method, the content of sulfur, chlorine, oxygen and carbonyl metal in the purified iso-octene and synthesis gas in step (1) is less than or equal to 2 ppm.

[0013] In the above method, the reaction temperature in step (2) is 75-95℃, and the reaction pressure is 900-1200 kPaA.

[0014] In the above method, the separation operation in the catalyst separation unit III in step (3) is carried out by using a flash separator, and the operation pressure is 2-20 kPaA and the operation temperature is 80-120℃.

[0015] In the above method, the product separation operation in the product separation unit IV in step (3) is carried out at a pressure of 2-20 kPaA.

[0016] In the above method, the catalyst used in the hydroformylation reaction unit II is prepared by the following method:

[0017] (1) The poly(4-chloromethylstyrene-styrene) is added to a potassium carbonate solution for reaction, and after the reaction is completed, filtration, washing and drying are sequentially carried out to obtain intermediate A;

[0018] (2) Intermediate A, sodium iodide and diphenyl chlorophosphine are mixed for reaction, and after the reaction is completed, washing and drying are carried out to obtain intermediate B;

[0019] (3) Intermediate B is immersed in a solution of dicarbonyl rhodium dimer to obtain a supported catalyst.

[0020] In some specific technical solutions, the catalyst is prepared by the following method:

[0021] (1) The poly(4-chloromethylstyrene-styrene) is added to a basic solution for hydrolysis to obtain intermediate A, and the molar ratio of the poly(4-chloromethylstyrene-styrene) to the basic solution is 1:(2-10);

[0022] (2) Intermediate A, sodium iodide and disubstituted chlorophosphine are reacted to obtain intermediate B; the molar ratio of intermediate A, sodium iodide and disubstituted chlorophosphine is 1:(2-10):(2-8).

[0023] In the preparation method of the catalyst, the alkaline solution in step (1) is at least one of potassium hydroxide, sodium hydroxide, sodium carbonate, and potassium carbonate.

[0024] In the preparation method of the catalyst, the reaction temperature during hydrolysis in step (1) is 50-120°C, and the reaction time is 6-18h.

[0025] 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.

[0026] In the preparation method of the catalyst, the reaction temperature in step (2) is 25-100°C, and the reaction time is 2-16h.

[0027] The beneficial effects of the present application are as follows:

[0028] The catalytic reaction system can realize a conversion rate of isooctene of up to 98.5%, a selectivity of up to 96.7%, and a product yield of isononyl aldehyde of up to 84% under the action of a rhodium catalyst. The problems of a large amount of heavy components in the rhodium catalyst system, difficult separation of the catalyst and the product, and easy deactivation of the catalyst are solved, and the industrial application of isooctene hydroformylation to isononyl aldehyde is realized. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a process flow diagram of the present application.

[0030] In the figure, I. raw material purification unit, II. hydroformylation reaction unit, III. catalyst separation unit, IV. product separation unit. DETAILED DESCRIPTION

[0031] The present application will be further described below in conjunction with examples, but the scope of protection of the present application is not limited thereto:

[0032] The preparation method of the rhodium catalyst in Example 1 is as follows:

[0033] (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, and drying at 120°C for 24h to obtain intermediate A, the molar ratio of poly(styrene-4-chloromethylstyrene) to alkaline solution is 1:2;

[0034] (2) Intermediate A was added into a round bottom flask, then sodium iodide, diphenylphosphine chloride, solvent acetonitrile were added, the reaction temperature was 80°C, the reaction time was 12h, the product was washed with n-hexane at room temperature, then dried at 120°C for 24h to obtain intermediate B, the molar ratio of intermediate A, sodium iodide, disubstituted phosphine chloride was 1:6:6;

[0035] (3) Intermediate B was immersed in a toluene solution of dicarbonyl rhodium dimer with a concentration of 2 mol / L, the immersion temperature was 60°C, the immersion time was 4h, after immersion, methanol was used for washing, and drying was carried out at 70°C for 72h to obtain a supported catalyst, the loading amount of intermediate B was 1%.

[0036] Example 1

[0037] As Figure 1 , the process flow of the present application is as follows: the process system for preparing iso-nonylaldehyde by hydroformylation of iso-octene includes a raw material purification unit I, a hydroformylation reaction unit II, a catalyst separation unit III, and a product separation unit IV.

[0038] 1200kg / h of iso-octene and 600kg / h of synthesis gas (molar ratio of hydrogen and carbon monoxide is 1:1) from outside the system 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 2ppm, and then enter the hydroformylation reaction unit II, and an exothermic reaction occurs under the action of a rhodium-based catalyst to obtain a reaction mixture containing iso-nonylaldehyde, the reaction operating temperature is 80°C, and the operating pressure is 1100 kPaA. 3400kg / h of the reaction mixture enters the catalyst separation unit III, and is separated under negative pressure in a flash separator (operating pressure is 18 kPaA, operating temperature is 111°C), the hot water operating temperature is 130°C, 1600kg / h of a gas-phase mixture containing iso-nonylaldehyde enters the product separation unit IV, and the remaining 1900kg / h of a liquid-phase mixture containing catalyst returns to the hydroformylation reaction unit II. In the product separation unit IV, 1300kg / h of qualified iso-nonylaldehyde product and 240kg / h of by-product containing iso-octane and iso-octene are obtained by negative pressure rectification operation (operating pressure is 18 kPaA). (The purity of the iso-nonylaldehyde product is ≥99%, and the product yield is ≥84%)

[0039] Comparative Example 1

[0040] 1200 kg / h of isooctene and 600 kg / h of syngas from outside the facility enter the feed purification unit I, where sulfur, chlorine, oxygen, and carbonyl metals in the feed are purified to less than 2 ppm. The feed then enters the hydroformylation reaction unit II, where an exothermic reaction occurs under the action of the rhodium-based catalyst described in ZL200410009950.7, yielding a reaction mixture containing isononanal. The reaction operation temperature is 80°C, and the operating pressure is 1100 kPaA. 3400 kg / h of the reaction mixture enters the catalyst separation unit III, where it undergoes negative pressure separation in a flash separator (operating pressure 18 kPaA, operating temperature 111°C). The hot water operation temperature is 130°C, yielding a 1600 kg / h gaseous mixture containing isononanal, which enters the product separation unit IV. The remaining 1900 kg / h liquid mixture containing the catalyst is returned to the hydroformylation reaction unit II. In product separation unit IV, a negative pressure distillation operation (operating pressure 18 kPaA) yielded 824 kg / h of qualified isononal and 716 kg / h of isooctane-containing isooctene byproducts, with a product yield of 51%.

Claims

1. A method for the hydroformylation of isooctene to prepare isononal, characterized in that, The method includes the following steps: (1) Isooctene and syngas from outside the boundary enter the raw material purification unit I, and after removing sulfur, chlorine, oxygen and carbonyl metal, purified isooctene and syngas are obtained; (2) Under the catalysis of rhodium catalyst, the purified isooctene and syngas enter the hydroformylation reaction unit II to react and obtain a reaction mixture containing isononanal; (3) The mixture after the reaction enters the catalyst separation unit III, and the gas phase mixture containing isononanal enters the product separation unit IV. The liquid phase mixture containing the catalyst is returned to the hydroformylation reaction unit II. (4) Liquid isononal product and isooctane-containing isooctene byproduct are obtained in product separation unit IV and sent to the outside world respectively.

2. The method according to claim 1, characterized in that, In step (1), the mass ratio of isooctene to syngas is 1:1 to 3:1, and the syngas is hydrogen and carbon monoxide in a molar ratio of 0.9 to 1.1:

1.

3. The method according to claim 1, characterized in that, In step (1), the content of sulfur, chlorine, oxygen and carbonyl metal in the purified isooctene and synthesis gas is less than or equal to 2 ppm.

4. The method according to claim 1, characterized in that, The rhodium catalyst in step (2) 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 1, characterized in that, In step (2), the reaction temperature is 75-95℃ and the reaction pressure is 900-1200kPaA.

6. The method according to claim 1, characterized in that, In step (3), the equipment used for the separation operation in catalyst separation unit III is a flash separator, with an operating pressure of 2-20 kPaA and an operating temperature of 80-120℃.

7. The method according to claim 1, characterized in that, In step (3), the product separation unit IV operates at a pressure of 2-20 kPaA.

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