A system and method for producing isononyl alcohol

Abstract

This invention discloses a system and method for preparing isononol. The method of this invention involves directly introducing the product into a hydrogenation reactor after the carbonyl synthesis reaction. Utilizing the hydrogenation function of the carbonyl synthesis catalyst (which has both catalytic carbonyl synthesis and catalytic hydrogenation functions), the process parameters of temperature and pressure are adjusted, and hydrogen gas is bubbled in to hydrogenate isononaldehyde to isononol. This avoids the problem of difficult separation of isononaldehyde (which is easily polymerized and oxidized at high temperatures) from the catalyst in traditional processes.

Description

Technical Field

[0001] This invention relates to the field of octene carbonyl synthesis to isononol technology, and particularly to a system and method for preparing isononol. Background Technology

[0002] Isononol (INA) is primarily used in the production of high molecular weight phthalate plasticizers such as diisononyl phthalate (DINP). With increasing market acceptance of the safety of DINP, its demand is rapidly growing as an environmentally friendly alternative to low molecular weight phthalate plasticizers such as dioctyl phthalate (DOP), and it is widely used in industries such as automotive, cable, flooring, and construction.

[0003] Currently, my country has limited varieties of plasticizer alcohols, including only n-butanol, isobutanol, and octanol. Other plasticizer alcohols such as isononol, isodecanol, and 2-propylheptanol are produced in small quantities, and market demand is primarily met through imports. Europe has completely banned the use of DOP, DBP, and BBP plasticizers in children's plastic toys, and the United States has permanently banned the production and sale of children's products containing more than 0.1% DOP, DBP, and BBP by mass. Although the fate of DOP in developing countries is still uncertain, the trend of DOP being replaced by other, better-performing plasticizers is irreversible. It is foreseeable that the future development prospects of DINP are optimistic. As the world's largest toy exporter, China has a promising DINP market, and China should accelerate the pace of plasticizer product structure adjustment.

[0004] Currently, the preparation of isononol involves two main steps: the first step is the hydroformylation of octene to generate isononal, and the second step is the hydrogenation reduction of isononal to obtain isononol. Separating the isononal generated in the first step from the catalyst is challenging. At high separation temperatures, isononal readily polymerizes; at low separation temperatures, vacuum distillation is required. A small amount of air entering the system will cause isononal to be oxidized to isonononic acid. Accumulation of isonononic acid in the carbonyl synthesis reaction system can lead to reactor corrosion. When isonononic acid is introduced into the isononol system, it will undergo esterification with isononol, generating byproducts.

[0005] Patent CN201911353572.7 discloses a method and system for the co-production of isononanol and C8 alkane. The process involves carbonyl synthesis followed by hydrogenation, and it is necessary to separate the carbonyl synthesis catalyst from isononanol.

[0006] Patent CN201911220649.3 discloses a method for preparing isononol from mixed octene, which also uses carbonyl synthesis followed by hydrogenation, requiring the separation of the carbonyl synthesis catalyst from isononol. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies by providing a system and method for preparing isononol.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] The first aspect of the present invention is to provide a system for preparing isononol, comprising a carbonyl synthesis reactor, a hydrogenation reactor, a catalyst separator, a C8 removal tower, a light removal tower, and a heavy removal tower connected in sequence by pipelines. The bottom outlet of the catalyst separator is connected to the carbonyl synthesis reactor through a catalyst circulation pipeline. The carbonyl synthesis reactor and the hydrogenation reactor use the same catalyst, which is a heterogeneous rhodium metal catalyst.

[0010] A second aspect of the present invention is to provide a method for preparing isononol, using the above-described system for preparing isononol, comprising the following steps:

[0011] Octene is mixed with catalyst separated from the catalyst separator and then fed into the carbonyl synthesis reactor. Synthesis gas is simultaneously bubbled into the bottom of the carbonyl synthesis reactor. Octene reacts with the synthesis gas in the carbonyl synthesis reactor to produce isononanal. The reaction solution then enters the hydrogenation reactor and hydrogen is bubbled in. Isononanal is reacted into isononol in the hydrogenation reactor, and unreacted octene is also hydrogenated to nonane. The mixture is then sent to the catalyst separator, where the catalyst is separated from isononol and nonane. The catalyst is recycled back to the carbonyl synthesis reactor. The separated isononol and octane are sent to a C8 stripper. Nonane is separated from the top of the C8 stripper, and the bottom material is sent to a light component stripper. Light components are separated from the top of the light component stripper, and the bottom material is sent to a heavy component stripper. Isononol is separated from the top of the heavy component stripper, and heavy components are separated from the bottom of the heavy component stripper.

[0012] Furthermore, the catalyst has both catalytic carbonyl synthesis and catalytic hydrogenation functions.

[0013] Furthermore, the temperature and pressure of the hydrogenation reactor are both higher than those of the carbonyl synthesis reactor.

[0014] Furthermore, the reaction pressure of the carbonyl synthesis reactor is 100-110 kg, and the temperature is 90-100℃.

[0015] Furthermore, the hydrogenation reactor operates at a reaction pressure of 150-160 kg and a temperature of 120-130 °C.

[0016] Furthermore, before being fed into the catalyst separator, the hydrogenation reaction liquid in the hydrogenation reactor is first fed into a primary flash tank, and the released gas from the flash is sent into the fuel gas pipeline network.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] The method for preparing isononanol of this invention involves directly feeding the product into a hydrogenation reactor after the carbonyl synthesis reaction. Utilizing the hydrogenation function of the carbonyl synthesis catalyst (which catalyzes both carbonyl synthesis and hydrogenation), the process parameters of temperature and pressure are adjusted, and hydrogen gas is bubbled in to hydrogenate isononanaldehyde to isononanol. This method avoids the difficulty of separating isononanaldehyde from the catalyst in traditional processes (isononanaldehyde has a high boiling point, and separation at atmospheric pressure easily leads to polymerization; therefore, vacuum distillation is required for separation, but air inevitably leaks in during this process. When isononanaldehyde encounters air, it is oxidized to isononanoic acid, which corrodes the equipment. Furthermore, isononanoic acid has a higher boiling point than isononanaldehyde and will remain in the catalyst solution, affecting catalyst activity. Therefore, this invention avoids the problem of difficult separation between isononanaldehyde and the catalyst). Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the system for preparing isononol according to the present invention;

[0020] The reference numerals in the attached figures are:

[0021] 1-Carbonyl synthesis reactor; 2-Hydrogenation reactor; 3-Catalyst separation tank; 4-C8 removal tower; 5-Light component removal tower; 6-Heavy component removal tower. Detailed Implementation

[0022] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings to enable a better understanding of the invention. However, the following embodiments do not limit the scope of the invention.

[0023] refer to Figure 1 This invention discloses a system for preparing isononanol, comprising a carbonyl synthesis reactor 1, a hydrogenation reactor 2, a catalyst separation tank 3, a C8 removal tower 4, a light removal tower 5, and a heavy removal tower 6 connected in sequence by pipelines. The bottom outlet of the catalyst separation tank 3 is connected to the carbonyl synthesis reactor 1 through a catalyst circulation pipeline. The same catalyst is used in both the carbonyl synthesis reactor 1 and the hydrogenation reactor 2. The catalyst is a heterogeneous rhodium metal catalyst.

[0024] This invention also discloses a method for preparing isononol, comprising the following steps:

[0025] Octene is mixed with catalyst separated from catalyst separator 3 and then enters carbonyl synthesis reactor 1. Synthesis gas is simultaneously blown into the bottom of carbonyl synthesis reactor 1. Octene reacts with synthesis gas in carbonyl synthesis reactor 1 to produce isononanal. The reaction liquid then enters hydrogenation reactor 2 and hydrogen is blown in. Isononanal is reacted to isononol in hydrogenation reactor 2. At the same time, unreacted octene is also hydrogenated to nonane. The mixture is then sent to catalyst separator 3. The catalyst is separated from isononol and nonane. The catalyst is recycled back to carbonyl synthesis reactor 1. The separated isononol and octane are sent to C8 stripper 4. Nonane is separated from the top of C8 stripper 4. The bottom material is sent to light component stripper 5. Light component is separated from the top of light component stripper 5. The bottom material is sent to heavy component stripper 6. Isononol product is separated from the top of heavy component stripper 6. Heavy component is separated from the bottom of heavy component stripper 6.

[0026] The aforementioned catalyst possesses both catalytic carbonyl synthesis and catalytic hydrogenation functions. In experiments, this invention revealed that during the carbonyl synthesis reaction, the reactor outlet not only contains isononanal, but isononanal also undergoes partial hydrogenation to generate isononol. The carbonyl synthesis catalyst not only performs carbonyl synthesis, but its rhodium metal catalyst also exhibits hydrogenation capabilities. Experiments showed that at the end of the carbonyl synthesis reaction, raising the reaction temperature resulted in isononanal being hydrogenated by rhodium metal to isononol. Based on the hydrogenation characteristic of the rhodium metal catalyst observed in small-scale experiments, and addressing the difficulty in separating the carbonyl synthesis catalyst and isononanal in the isononol unit, this invention develops a new process for isononol generation. This process circumvents the difficulty of isononanal separation and simplifies the process flow.

[0027] Example 1

[0028] 5940 kg / h of octene, along with 2970 kg of circulating catalyst solution from the catalyst separator and 1470 kg of syngas, enters the carbonyl synthesis reactor. The carbonyl synthesis reactor is a three-stage, fully mixed-tank reactor with external circulation for heat removal. The reaction pressure is 100 kg / h, the temperature is 90°C, and the catalyst is a heterogeneous rhodium metal catalyst. The carbonyl synthesis reaction of octene and syngas produces isononanal. After the reaction, the product is pumped into the hydrogenation reactor, which operates at 120°C and 150 kg / h, with hydrogen gas introduced. Unreacted octene reacts with hydrogen to hydrogenate octane, and isononanal reacts with hydrogen to hydrogenate isononyl alcohol. The hydrogenation reaction is exothermic and uses external circulation for heat removal. After hydrogenation, the pressure is reduced to 5 kg / h before entering the first-stage flash tank. Figure 1 (Not shown in the text) 261 kg / h of release gas is flashed out and sent to the fuel gas pipeline network, and 10259 kg / h of the bottom liquid is sent to the catalyst separator. The catalyst separator operates under negative pressure at an operating pressure of 10 kPa. The bottom of the bottom is forced to circulate and reboil to evaporate. 7283 kg / h of octane and isononol is obtained at the top of the column, and 2975 kg / h of catalyst solvent is obtained at the bottom of the column and sent back to the carbonyl synthesis reactor.

[0029] A mixture of octane and isononol is fed into a C8 removal tower, which is operated under vacuum with a top operating pressure of 20 kPaA. Approximately 72.8 kg / h of non-condensable vapors at the top are removed by a vacuum pump, and 655.2 kg / h of octane is sent off-site. The bottom temperature is 147 degrees Celsius, and 6551 kg / h of bottom liquid is sent to a light component removal tower, which is also a vacuum tower with a top pressure of 10 kPaA and an operating temperature of 99 degrees Celsius. 114 kg / h of light components is obtained and sent to a residue tank. The bottom temperature is 134 degrees Celsius, and 6437 kg / h of bottom liquid is obtained and sent to a heavy component removal tower. The heavy component removal tower operates at a pressure of 5 kPaA. 6307 kg / h of isononol at 109 degrees Celsius is obtained at the top and sent off-site as a product. 129 kg / h of heavy components at 113 degrees Celsius is obtained at the bottom and sent to a residue tank off-site.

[0030] The above description is merely a preferred embodiment of the present invention and does not limit the implementation and protection scope of the present invention. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the content of the present invention specification and drawings should be included within the protection scope of the present invention.

Claims

1. A method for preparing isononol, characterized in that, The system for preparing isononol comprises a carbonyl synthesis reactor (1), a hydrogenation reactor (2), a catalyst separator (3), a C8 removal tower (4), a light removal tower (5), and a heavy removal tower (6) connected in sequence by pipelines. The bottom outlet of the catalyst separator (3) is connected to the carbonyl synthesis reactor (1) through a catalyst circulation pipeline. The same catalyst is used in the carbonyl synthesis reactor (1) and the hydrogenation reactor (2). The catalyst is a heterogeneous rhodium metal catalyst. The method includes the following steps: Octene is mixed with the catalyst separated from the catalyst separator (3) and then enters the carbonyl synthesis reactor (1). Synthesis gas is simultaneously blown into the bottom of the carbonyl synthesis reactor (1). Octene and synthesis gas react in the carbonyl synthesis reactor (1) to generate isononal. Then the reaction liquid enters the hydrogenation reactor (2) and hydrogen is blown in. Isononal is reacted into isononol in the hydrogenation reactor (2). At the same time, unreacted octene is also hydrogenated into octane and then sent to the catalyst separator (3). The catalyst is separated from isononol and octane. The catalyst is recycled back to the carbonyl synthesis reactor (1). The separated isononol and octane are sent to the C8 removal tower (4). Octane is separated from the top of the C8 removal tower (4). The bottom material is sent to the light component removal tower (5). Light components are separated from the top of the light component removal tower (5). The bottom material is sent to the heavy component removal tower (6). Isononol product is separated from the top of the heavy component removal tower (6). Heavy components are separated from the bottom of the heavy component removal tower (6). The catalyst has both catalytic carbonyl synthesis and catalytic hydrogenation functions; the reaction pressure of the carbonyl synthesis reactor (1) is 100-110 kg and the temperature is 90-100℃; the reaction pressure of the hydrogenation reactor (2) is 150-160 kg and the temperature is 120-130℃.

2. The method for preparing isononol according to claim 1, characterized in that, Before being fed into the catalyst separator (3), the hydrogenation reaction liquid in the hydrogenation reactor (2) is first sent into the first-stage flash tank, and the released gas from the flash is sent into the fuel gas pipeline.

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