Continuous production method and device of isobutylbenzene

Abstract

The invention belongs to the technical field of organic synthesis, and particularly relates to a continuous production method and device of isobutylbenzene. The continuous production method comprises the steps that a raw material A and a raw material B are continuously introduced into a reactor for a side chain alkylation reaction, the raw material A comprises methylbenzene and a catalyst, the raw material B comprises propylene, obtained reaction liquid containing isobutylbenzene is continuously discharged and subjected to solid-liquid separation, solid and first feed liquid are obtained, and the solid is the recycled catalyst and is reused; carrying out first rectification on the first feed liquid to obtain second feed liquid and a first gas component; the first gas component is recycled propylene; carrying out second rectification on the second feed liquid to obtain third feed liquid and a second gas component; the second gas component is recycled methylbenzene; and carrying out third rectification and liquefaction on the third feed liquid to obtain isobutylbenzene. Compared with a traditional kettle type production process, the method has the advantages that the reaction pressure is low, the reaction temperature is easy to adjust, side reactions are reduced, and the method is more efficient and stable.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a continuous production method and device for isobutylbenzene. Background Art

[0002] Ibuprofen is a nonsteroidal anti-inflammatory drug with peripheral and central analgesic effects. It has been proven that ibuprofen is an extremely effective antipyretic and analgesic drug for both adults and children, and it has few side effects. Isobutylbenzene is an important substance in the production of ibuprofen, with a general structural formula of C 6 H 5 -CH 2 -CH(CH 3 ) 2 It is a colorless liquid, insoluble in water, soluble in organic solvents such as ethanol and ether, has an aromatic smell, and a boiling point of about 170-172°C.

[0003] At present, the production method of isobutylbenzene is a batch reaction in a kettle. First, toluene, liquid propylene and catalyst are added to a batch reactor at one time and mixed, and then heated to carry out side chain alkylation reaction to obtain isobutylbenzene. After the reaction is completed, the material is unloaded, and the whole process has obvious discontinuity and periodicity. The production efficiency of this traditional technology is relatively low, and the output per unit time is low; the process control is difficult and prone to fluctuations, and it is difficult to maintain the same quality of different batches of products. The stability of product quality is poor and it is not suitable for large-scale production; and the performance in equipment utilization and energy consumption is not ideal, which will cause waste of resources and increase costs. Moreover, the recovery of catalysts and raw materials is relatively difficult, and the raw material conversion rate is low, usually only about 40%. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a continuous production method and device for isobutylbenzene. The continuous production method for isobutylbenzene provided by the present invention has high raw material conversion rate, less impurities generated during the reaction process, and high product yield.

[0005] The present invention provides a continuous production method of isobutylbenzene, comprising the following steps:

[0006] Continuously introducing raw material A and raw material B into a reactor for side chain alkylation reaction to obtain a reaction liquid containing isobutylbenzene; the raw material A comprises toluene and a catalyst, and the raw material B comprises propylene;

[0007] The isobutylbenzene-containing reaction liquid is continuously discharged for solid-liquid separation to obtain a solid and a first liquid, wherein the solid includes a recovered catalyst and is reused for a side chain alkylation reaction;

[0008] The first feed liquid is subjected to a first distillation to obtain a second feed liquid and a first gas component; the first gas component is mainly recovered propylene, which is reused for side chain alkylation reaction;

[0009] The second feed liquid is subjected to a second distillation to obtain a third feed liquid and a second gas component; the second gas component is mainly recovered toluene, which is reused for the side chain alkylation reaction;

[0010] The third feed liquid is subjected to a third distillation, and the obtained third gas component is liquefied to obtain isobutylbenzene.

[0011] Preferably, the catalyst is a mixture of alkali metal and alkali metal carbonate, and the mass ratio of alkali metal to alkali metal carbonate in the catalyst is 0.5-1.5:1-3.

[0012] Preferably, the mass ratio of toluene to catalyst is 95-99.5:0.5-5.

[0013] Preferably, the molar ratio of propylene to toluene is 4-9:1-5.

[0014] Preferably, the temperature of the side chain alkylation reaction is 165-255°C.

[0015] Preferably, the pressure of the side chain alkylation reaction is 1 to 5 MPa.

[0016] Preferably, the residence time of the raw material A and the raw material B is 15 to 30 minutes.

[0017] The present invention also provides a continuous production device for isobutylbenzene, comprising a reaction kettle;

[0018] A first storage tank and a second storage tank respectively connected to the feed port of the reactor;

[0019] a hydrocyclone separator connected to the discharge port of the reactor;

[0020] a first distillation tower connected to the overflow outlet of the hydrocyclone, the underflow outlet of the hydrocyclone being connected to the reactor;

[0021] A second distillation tower connected to the bottom discharge port of the first distillation tower, wherein the top discharge port of the first distillation tower is connected to the first storage tank;

[0022] A third distillation tower is connected to the bottom discharge port of the second distillation tower, and the top discharge port of the second distillation tower is connected to the second storage tank.

[0023] Preferably, a delivery pump is connected between the discharge port of the reactor and the hydrocyclone separator.

[0024] Preferably, a first compressor is connected between the top discharge port of the first distillation tower and the first storage tank; and a second compressor is connected between the top discharge port of the second distillation tower and the second storage tank.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The invention provides a continuous production method of isobutylbenzene, comprising the following steps: continuously introducing raw materials A and raw materials B into a reactor for side chain alkylation reaction to obtain a reaction liquid containing isobutylbenzene, wherein the raw materials A include toluene and a catalyst, and the raw materials B include propylene; continuously discharging the reaction liquid containing isobutylbenzene, performing solid-liquid separation to obtain a solid and a first feed liquid, wherein the solid includes a recovered catalyst and is reused in the side chain alkylation reaction; performing a first distillation on the first feed liquid to obtain a second feed liquid and a first gas component, wherein the first gas component is mainly recovered propylene and is reused in the side chain alkylation reaction; performing a second distillation on the second feed liquid to obtain a third feed liquid and a second gas component, wherein the second gas component is mainly recovered toluene and is reused in the side chain alkylation reaction; performing a third distillation on the third feed liquid, and liquefying the obtained third gas component to obtain isobutylbenzene.

[0027] The continuous production method of isobutylbenzene of the present invention realizes uninterrupted operation of the reaction process through continuous feeding and discharging operations, can reduce the occurrence of side reactions such as self-polymerization of propylene, and reduce the generation of impurities. In addition, the continuous production method of the present invention can recover unreacted propylene and toluene in the rectification system after the reaction, and recycle the unreacted raw materials, which can improve the raw material conversion rate and product yield, significantly improve the resource utilization rate, and reduce the waste of raw materials.

[0028] The present invention adopts a continuous synthesis method, and the reaction time can be precisely controlled, which is conducive to controlling the reaction time, controlling the feeding and discharging time, reducing the amount of impurities generated, and thus improving the purity and yield of isobutylbenzene. The present invention ensures that the reactants react fully and reduces the discharge of unreacted raw materials by reasonably controlling the residence time, temperature, pressure and catalyst dosage of the reactants.

[0029] The present invention realizes the continuity of the production process, effectively improves the production efficiency, shortens the production cycle, and can quickly and massively supply the market demand. At the same time, the continuous and stable reaction environment is conducive to the precise control of the reaction conditions, thereby ensuring that the product quality achieves a high degree of consistency and stability. It is of great significance in terms of resource utilization efficiency and energy conservation, and can reduce production costs and environmental impact. The present invention brings a new revolution to the production of isobutylbenzene, and promotes the development of related industries in a more efficient, high-quality and sustainable direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 Schematic diagram of the equipment for continuous production of isobutylbenzene in the embodiment; wherein S01-propylene storage tank, S02-toluene storage tank, R01-isobutylbenzene synthesis reactor, P01-transfer pump, F01-hydrocyclone separator, T01-distillation tower 1, T02-distillation tower 2, T03-distillation tower 3, C01-compressor 1, C02-compressor 2;

[0032] Figure 2 This is a graph showing the effects of different catalyst dosages, reaction temperatures, reaction pressures and residence times on product yields. DETAILED DESCRIPTION

[0033] The present invention provides a continuous production method of isobutylbenzene, comprising the following steps:

[0034] Continuously introducing raw material A and raw material B into a reactor for side chain alkylation reaction to obtain a reaction liquid containing isobutylbenzene; the raw material A comprises toluene and a catalyst, and the raw material B comprises propylene;

[0035] The isobutylbenzene-containing reaction liquid is continuously discharged for solid-liquid separation to obtain a solid and a first liquid, wherein the solid includes a recovered catalyst and is reused for a side chain alkylation reaction;

[0036] The first feed liquid is subjected to a first distillation to obtain a second feed liquid and a first gas component; the first gas component is mainly recovered propylene, which is reused for side chain alkylation reaction;

[0037] The second feed liquid is subjected to a second distillation to obtain a third feed liquid and a second gas component; the second gas component is mainly recovered toluene, which is reused for the side chain alkylation reaction;

[0038] The third feed liquid is subjected to a third distillation, and the obtained third gas component is liquefied to obtain isobutylbenzene.

[0039] In the present invention, unless otherwise specified, the materials and equipment used are commercially available products in the art.

[0040] The present invention continuously introduces raw material A and raw material B into a reactor for side chain alkylation reaction to obtain a reaction liquid containing isobutylbenzene; the raw material A comprises toluene and a catalyst, and the raw material B comprises propylene.

[0041] In the present invention, the catalyst is preferably a mixture of alkali metal and alkali metal carbonate, specifically a mixture of potassium and sodium carbonate, or a mixture of sodium and potassium carbonate; the mass ratio of alkali metal to alkali metal carbonate in the catalyst is preferably 0.5-1.5:1-3, more preferably 0.8:1.2.

[0042] In the present invention, the mass ratio of toluene to catalyst is preferably 95-99.5:0.5-5, more preferably 96-99:1-4, specifically 99:1, 98:2 or 97:3. The content of catalyst in the raw material A is preferably 1wt%-3wt%, specifically 1wt%, 2wt% or 3wt%.

[0043] In the present invention, the molar ratio of propylene to toluene is preferably 4-9:1-5, specifically 1:1.

[0044] In the present invention, the temperature of the side chain alkylation reaction is preferably 165-255°C, more preferably 180-250°C, specifically 180°C, 190°C, 195°C, 200°C, 210°C, 225°C, 240°C or 250°C.

[0045] In the present invention, the pressure of the side chain alkylation reaction is preferably 1-5 MPa, specifically 2 MPa, 3 MPa, 4 MPa or 5 MPa.

[0046] In the present invention, the residence time of the raw materials A and B is preferably 15 to 30 minutes, specifically 20 minutes or 25 minutes.

[0047] After obtaining the reaction liquid containing isobutylbenzene, the present invention continuously discharges the reaction liquid containing isobutylbenzene, performs solid-liquid separation, and obtains a solid and a first liquid. The solid includes a recovered catalyst, which is reused for the side chain alkylation reaction.

[0048] In the present invention, the purpose of the solid-liquid separation is to separate the catalyst from the feed liquid, and then to recover the catalyst and reuse it in the side chain alkylation reaction.

[0049] The present invention performs a first distillation on the first feed liquid to obtain a second feed liquid and a first gas component; the first gas component is mainly recovered propylene, which is reused for side chain alkylation reaction.

[0050] In the present invention, the distillation tower pressure used in the first distillation is preferably 3.5 MPa, the tower top temperature is preferably 90-100°C, and the tower bottom temperature is preferably 105-115°C. The temperature and pressure of the first distillation can gasify propylene (the boiling point of propylene at 3.5 MPa is about 95°C), while other components are still retained in the feed liquid, thereby achieving the separation of propylene. After the first distillation, it is preferred that the first gas component obtained is liquefied.

[0051] The present invention performs a second distillation on the second feed liquid to obtain a third feed liquid and a second gas component; the second gas component is mainly recovered toluene, which is reused for the side chain alkylation reaction.

[0052] In the present invention, the top temperature of the distillation tower used in the second distillation is preferably 110-115° C., and the bottom temperature is preferably 120-130° C. The temperature of the second distillation can gasify toluene (the boiling point of toluene at normal pressure is about 110.6° C.), while other components are still retained in the remaining liquid, thereby achieving the separation of toluene. After the second distillation, the second gas component obtained is preferably liquefied.

[0053] The present invention performs a third distillation on the third feed liquid, and liquefies the obtained third gas component to obtain isobutylbenzene.

[0054] In the present invention, the top temperature of the distillation tower used in the third distillation is preferably 165-170° C., and the bottom temperature is preferably 175-185° C. The temperature of the third distillation can vaporize isobutylbenzene (the boiling point of isobutylbenzene is about 169° C. at normal pressure), while other high-boiling impurities are still retained in the remaining liquid, thereby achieving separation of isobutylbenzene.

[0055] The present invention also provides a continuous production device for isobutylbenzene, comprising a reaction kettle;

[0056] A first storage tank and a second storage tank respectively connected to the feed port of the reactor;

[0057] a hydrocyclone separator connected to the discharge port of the reactor;

[0058] a first distillation tower connected to the overflow outlet of the hydrocyclone, the underflow outlet of the hydrocyclone being connected to the reactor;

[0059] A second distillation tower connected to the bottom discharge port of the first distillation tower, wherein the top discharge port of the first distillation tower is connected to the first storage tank;

[0060] A third distillation tower is connected to the bottom discharge port of the second distillation tower, and the top discharge port of the second distillation tower is connected to the second storage tank.

[0061] In the present invention, the reactor is used for the synthesis of isobutylbenzene, the first storage tank is used for storing propylene, and the second storage tank is used for storing toluene.

[0062] In the present invention, a delivery pump is preferably connected between the discharge port of the reactor and the hydrocyclone separator to deliver the material. The function of the hydrocyclone separator is to separate the feed liquid from the catalyst, and the catalyst is reused to catalyze the synthesis of isobutylbenzene.

[0063] In the present invention, a first compressor is preferably connected between the top discharge port of the first distillation tower and the first storage tank for liquefying propylene; a second compressor is preferably connected between the top discharge port of the second distillation tower and the second storage tank for liquefying toluene.

[0064] In order to further illustrate the present invention, the continuous production method and device of isobutylbenzene provided by the present invention are described in detail below in conjunction with the accompanying drawings and examples, but they should not be construed as limiting the scope of protection of the present invention.

[0065] In Examples 1 to 3 of the present invention, the composition of raw material A includes: 98 wt% toluene, 0.8 wt% potassium and 1.2 wt% sodium carbonate, wherein potassium and sodium carbonate are catalysts; raw material B: propylene; the capacity of the synthesis reactor is 5000 L.

[0066] In the embodiment of the present invention, the device used is as follows Figure 1 As shown, S01-propylene storage tank, S02-toluene storage tank, R01-isobutylbenzene synthesis reactor, P01-transfer pump, F01-hydrocyclone separator, T01-distillation tower 1, T02-distillation tower 2, T03-distillation tower 3, C01-compressor 1, C02-compressor 2.

[0067] Example 1

[0068] according to Figure 1The equipment is installed and debugged, and toluene and catalyst are mixed (the content of catalyst in the mixed liquid is 2wt%) as raw material A, and propylene is used as raw material B, and transported to the synthesis reactor (R01), and the feeding ratio of toluene to propylene is 1:1. When the reactor is half full, the temperature in the synthesis reactor is heated to 195°C using heat transfer oil, and the reaction begins in the reactor. The pressure in the synthesis reactor is 3MPa. After 30 minutes of reaction, the feeding and discharging of the synthesis reactor are opened at the same time, and the material residence time is 30 minutes. The material at the discharge port is sent to the hydrocyclone (F01) through a delivery pump (P01). After the material enters the hydrocyclone, the catalyst and the feed liquid are separated, and then the catalyst is recycled and utilized for the second time. The feed liquid is sent to distillation tower 1 (T01), the operating pressure of distillation tower 1 is 3.5MPa, the top temperature is 90-100℃, and the bottom temperature is 105-115℃. The propylene with the lowest boiling point in the feed liquid is extracted from the top of the tower, liquefied by compressor (C01), and then recovered to propylene storage tank (S01) for reuse. The remaining part of the feed liquid is sent to distillation tower 2 (T02), the top temperature of distillation tower 2 is 110-115℃, and the bottom temperature is 120-130℃. The toluene in the feed liquid is extracted from the top of the tower, liquefied by compressor (C02), and then recovered to toluene storage tank (S02) for reuse. The remaining liquid is sent to distillation tower 3 (T03) to separate isobutylbenzene and high-boiling impurities. The top temperature of distillation tower 3 is 165-170°C, and the bottom temperature is 175-185°C. Finally, isobutylbenzene product is obtained at the top of T03. The reaction is carried out for 8 hours in total.

[0069] In this embodiment, the toluene conversion rate is 72%, and the isobutylbenzene yield is 39.5%.

[0070] Example 2

[0071] The difference from Example 1 is that the temperature inside the synthesis reactor is heated to 210° C. and the pressure inside the synthesis reactor is 5 MPa.

[0072] In this embodiment, the toluene conversion rate is 60.5%, and the isobutylbenzene yield is 35.2%.

[0073] Example 3

[0074] The difference from Example 1 is that the temperature inside the synthesis reactor is heated to 180° C. and the pressure inside the synthesis reactor is 1 MPa.

[0075] In this embodiment, the toluene conversion rate is 48.6%, and the isobutylbenzene yield is 33.6%.

[0076] The combination of appropriate temperature and medium pressure in Example 1 provides the highest conversion rate and yield, indicating that the higher the temperature and pressure, the better the reaction. By comparing the three examples, it can be seen that the combination of medium temperature and medium pressure has the best effect, while the effects of too high temperature and pressure (Example 2) and lower temperature and pressure (Example 3) are poor.

[0077] Example 4

[0078] An orthogonal experiment was conducted to investigate the effects of reaction temperature, reaction pressure, catalyst dosage (the mass ratio of potassium and sodium carbonate was maintained at 2:3), and material residence time on the synthesis of isobutylbenzene. Except for the variables in the table, the other conditions were the same as those in Example 1. The setting conditions and results are shown in Tables 1 and 2:

[0079] Table 1 Effect of reaction temperature and reaction pressure on the synthesis of isobutylbenzene

[0080]

[0081]

[0082] Table 2 Effect of catalyst dosage and residence time on the synthesis of isobutylbenzene

[0083]

[0084] The effects of different catalyst dosages, reaction temperatures, reaction pressures and residence times on product yields are shown in the table below. Figure 2 As shown. It can be seen that with the increase of the amount of catalyst, the product yield gradually increases. When the catalyst content in raw material A reaches 2wt%, the product yield reaches the highest, and then as the catalyst content increases, the product yield begins to decline. With the increase of reaction temperature, the product yield gradually increases. When the reaction temperature reaches 195°C, the product yield reaches the highest, and then as the reaction temperature increases, the product yield begins to decline. With the increase of reaction pressure, the product yield gradually increases. When the reaction pressure reaches 3MPa, the product yield reaches the highest, and then as the reaction pressure increases, the product yield begins to decline. With the increase of residence time, the product yield gradually increases. When the residence time exceeds 30 minutes, the yield increases slowly, so the optimal residence time is determined to be 30 minutes.

[0085] Compared with the existing intermittent production technology of isobutylbenzene, the continuous autoclave production adopted by the present invention has significant advantages. The existing intermittent production technology has problems such as discontinuous operation, relatively low efficiency, cumbersome process and difficulty in precise control. The continuous autoclave production of the present invention realizes an uninterrupted process, improves production efficiency and output, and can more accurately control various process parameters to ensure the stability and consistency of product quality. Through the continuous production mode, the pause and conversion time of the intermediate links are effectively reduced, the overall production efficiency is greatly improved, and many disadvantages of the existing intermittent production technology are successfully solved. The present invention adopts continuous production, the reaction pressure is lower than the traditional intermittent reaction pressure, and the unreacted raw materials can be recycled and reused.

[0086] Although the above-mentioned embodiments have made a detailed description of the present invention, they are only some embodiments of the present invention, rather than all embodiments. People can also obtain other embodiments based on the embodiments of the present invention without creative work, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A continuous production method of isobutylbenzene, characterized in that: The following steps are involved: Continuously introducing raw material A and raw material B into a reactor for side chain alkylation reaction to obtain a reaction liquid containing isobutylbenzene; the raw material A comprises toluene and a catalyst, and the raw material B comprises propylene; The isobutylbenzene-containing reaction liquid is continuously discharged for solid-liquid separation to obtain a solid and a first liquid, wherein the solid includes a recovered catalyst and is reused for a side chain alkylation reaction; The first feed liquid is subjected to a first distillation to obtain a second feed liquid and a first gas component; the first gas component is mainly recovered propylene, which is reused for side chain alkylation reaction; The second feed liquid is subjected to a second distillation to obtain a third feed liquid and a second gas component; the second gas component is mainly recovered toluene, which is reused for the side chain alkylation reaction; The third feed liquid is subjected to a third distillation, and the obtained third gas component is liquefied to obtain isobutylbenzene.

2. The continuous production method according to claim 1, characterized in that: The catalyst is a mixture of alkali metal and alkali metal carbonate, and the mass ratio of alkali metal to alkali metal carbonate in the catalyst is 0.5-1.5:1-3.

3. The continuous production method according to claim 1 or 2, characterized in that: The mass ratio of toluene to catalyst is 95-99.5:0.5-5.

4. The continuous production method according to claim 1, characterized in that: The molar ratio of propylene to toluene is 4-9:1-5.

5. The continuous production method according to claim 1, characterized in that: The temperature of the side chain alkylation reaction is 165-255°C.

6. The continuous production method according to claim 1 or 5, characterized in that: The pressure of the side chain alkylation reaction is 1-5 MPa.

7. The continuous production method according to claim 1, characterized in that: The residence time of the raw material A and the raw material B is 15 to 30 minutes.

8. A continuous production device for isobutylbenzene, characterized in that: including a reaction kettle; A first storage tank and a second storage tank respectively connected to the feed port of the reactor; a hydrocyclone separator connected to the discharge port of the reactor; a first distillation tower connected to the overflow outlet of the hydrocyclone, the underflow outlet of the hydrocyclone being connected to the reactor; A second distillation tower connected to the bottom discharge port of the first distillation tower, wherein the top discharge port of the first distillation tower is connected to the first storage tank; A third distillation tower is connected to the bottom discharge port of the second distillation tower, and the top discharge port of the second distillation tower is connected to the second storage tank.

9. The continuous production device according to claim 8, characterized in that: A delivery pump is also connected between the discharge port of the reactor and the hydrocyclone separator.

10. The continuous production device according to claim 8 or 9, characterized in that: A first compressor is also connected between the top discharge port of the first distillation tower and the first storage tank; a second compressor is also connected between the top discharge port of the second distillation tower and the second storage tank.

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