A device and method for the continuous synthesis of 1,3,5-triisopropylbenzene based on microchannels

Abstract

The application provides a device and method for continuously synthesizing 1,3,5-triisopropylbenzene based on a microchannel, which uses alkylimidazole chloroaluminate ionic liquid as a catalyst, uses benzene and 2-halopropane as reaction raw materials, and uses a microchannel reactor to continuously and efficiently synthesize 1,3,5-triisopropylbenzene. The synthesis method fully utilizes the characteristics of the microchannel reactor in strengthening heat and mass transfer between fluids, makes the material flow in the microchannel form turbulent flow, realizes rapid micro-mixing of two materials, prevents local temperature from being too high by precise temperature control, strengthens the micro-reaction process, and can realize accurate control of the reaction temperature, reaction time and reactant ratio, thereby improving the utilization rate of the reaction raw materials and greatly improving the production efficiency. Moreover, the chloroaluminate ionic liquid can be separated and recovered by simple static phase separation after the reaction, and can be recycled. The synthesis method has the characteristics of continuous production, stable product quality, high mass transfer efficiency, mild reaction conditions, short reaction period, simple synthesis process and the like, conforms to the production concept of green, environmental protection, safety and high efficiency, and has a broad industrial development prospect.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis technology, and in particular to an apparatus and method for the continuous synthesis of 1,3,5-triisopropylbenzene based on microchannels. Background Technology

[0002] 1,3,5-Triisopropylbenzene, also known as mesitylene triisopropylbenzene or TIPB, is an important basic chemical raw material. As a multifunctional organic compound, it plays a vital role in the chemical industry, pharmaceutical field, and daily chemical products. In the chemical industry, 1,3,5-triisopropylbenzene is widely used as a high-boiling-point organic solvent, a plasticizer in plastic products, and as an intermediate in many chemical reactions. For example, 1,3,5-triisopropylbenzene is an essential raw material for the synthesis of phloroglucinol via the cumene process. In the pharmaceutical field, 1,3,5-triisopropylbenzene can be used as an active ingredient or excipient in drug synthesis, as a carrier in drug delivery systems, and also as a material in medical devices. In daily chemical products, 1,3,5-triisopropylbenzene is widely used in the manufacture of fragrances and flavorings, and as an ingredient in sunscreens and detergents.

[0003] The synthetic route of 1,3,5-triisopropylbenzene mainly involves the synthesis of benzene and alkylating agents (propylene, 2-halopropane, isopropanol) through a series of Friedel-Crafts alkylation reactions. Catalysts mainly include AlCl3, molecular sieves, and solid acids. Among these, the traditional catalyst anhydrous AlCl3 exhibits excellent catalytic performance in the reaction of benzene with 2-halopropane. However, the reaction is a heterogeneous process, producing large amounts of acidic hydrogen halide gas, resulting in a vigorous reaction. Furthermore, AlCl3 cannot be recovered and recycled, making continuous production difficult. Product quality is unstable. There are also serious environmental pollution problems. Molecular sieve catalysts, as an environmentally friendly catalyst, have been widely studied and exhibit high catalytic activity in the continuous gas-liquid-solid heterogeneous reaction of benzene and propylene. However, they are prone to carbon deposition leading to catalyst deactivation, and the required reaction conditions are relatively strict. When using activated clay as a catalyst for benzene and propylene, the reaction process requires an excessively high benzene-to-propylene ratio, resulting in significant waste and complex production processes. Therefore, there is an urgent need to explore a novel, green, and safe method for the continuous synthesis of 1,3,5-triisopropylbenzene. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide an apparatus and method for the continuous synthesis of 1,3,5-triisopropylbenzene based on microchannels. In a microchannel reactor, aluminochloroaluminate ionic liquid is used as a homogeneous catalyst to catalyze the continuous synthesis of 1,3,5-triisopropylbenzene from benzene and 2-halopropane. The synthesis method of the present invention features catalyst recyclability, continuous production, and... Stable product qualityWith high mass transfer efficiency, mild reaction conditions, short reaction cycle, and simple synthesis process, this invention enables precise control of reaction temperature, reaction time, and reactant ratio, improving the utilization rate of raw materials and significantly increasing production efficiency. It achieves efficient synthesis of the target product (1,3,5-triisopropylbenzene yield ≥90%) at full conversion. Specifically, the invention provides a microchannel-based continuous synthesis apparatus for 1,3,5-triisopropylbenzene. This apparatus is a microchannel reaction device, comprising a first raw material storage tank V101, a second raw material storage tank V102, a first filter F101, a second filter F102, a first plunger-type constant flow pump P101, a second plunger-type constant flow pump P102, a first one-way valve SV101, a second one-way valve SV102, a T-type micromixer MIX101, a microchannel reactor MR101, a reaction liquid receiving bottle V201, and a tail gas absorption bottle V301.

[0005] The microchannel reactor MR101 is placed in a constant temperature water bath with a temperature control of 35-65℃. The first raw material tank V101 is connected to the inlet end of the first plunger constant flow pump P101 via the first filter F101. The outlet end of the first plunger constant flow pump P101 is then connected to the first inlet end of the T-type micro mixer MIX101 via the first one-way valve SV101.

[0006] The second raw material tank V102 is connected to the inlet end of the second plunger constant flow pump P102 via the second filter F102, and the outlet end of the second plunger constant flow pump P102 is connected to the second inlet end of the T-type micro mixer MIX101 via the second one-way valve SV102.

[0007] The outlet of the T-type micro mixer MIX101 is connected to the inlet of the microchannel reactor MR101. The outlet of the microchannel reactor MR101 is connected to the inlet pipe of the reaction liquid receiving bottle V201. The gaseous products of the reaction liquid receiving bottle V201 are connected to the tail gas absorption bottle V301.

[0008] Furthermore, the first plunger-type constant flow pump P101 and the second plunger-type constant flow pump P102 monitor the flow rate of the reactants, the reaction pressure, and the reaction time, while the constant temperature water bath controls the reaction temperature.

[0009] Furthermore, the microchannel reactor is one of the following configurations: annular microchannel reactor, straight-tube microchannel reactor, or heart-shaped microchannel reactor. The MR101 microchannel reactor is made of polytetrafluoroethylene (PTFE) or 304 / 316 stainless steel, with a microchannel inner diameter of 1–6 mm and a microchannel length of 2–200 m. When the inner diameter and two-phase flow rate remain constant in the microchannel reactor, the residence time can be precisely controlled by changing the length of the micro-reaction channel.

[0010]

[0011] Furthermore, the first check valve SV101 and the second check valve SV102 prevent material back-mixing caused by pressure difference during the reaction process.

[0012] The present invention also provides a method for synthesizing 1,3,5-triisopropylbenzene using the microchannel-based continuous synthesis apparatus as described above, comprising the following steps:

[0013] Step SS1: Molecular sieves are added to benzene and 2-halopropane respectively for drying and dehydration treatment. 2-halopropane is one of 2-chloropropane and 2-bromopropane. The molecular sieve is one of sodium-type molecular sieves of 3A, 4A and 5A. The mixture is allowed to stand at room temperature for 24 hours for drying treatment.

[0014] Step SS2: The dehydrated benzene is loaded into the first raw material storage tank V101, and the chloroaluminate ionic liquid catalyst and 2-halopropane are loaded into the second raw material storage tank V102.

[0015] Step SS3: Benzene in the first raw material storage tank V101 and the mixture of chloroaluminate ionic liquid and 2-halopropane in the second raw material storage tank V102 are respectively transported to the T-type micro mixer MIX101 through the first plunger constant flow pump P101 and the second plunger constant flow pump P102. The reaction materials are mixed by collision flow at MIX101.

[0016] Step SS4: The mixed material enters the annular microchannel reactor MR101 for a continuous Friedel-Crafts reaction;

[0017] Step SS5: The reacted material enters the reaction liquid receiving bottle V201, where automatic gas-liquid separation occurs. The liquid product is allowed to stand in V201 to separate into layers. The upper organic phase consists of the reaction product and unreacted raw materials, while the lower layer is the ionic liquid catalyst. The gaseous product HBr is introduced into the tail gas absorption bottle V301 for absorption and treatment.

[0018] Furthermore, in step SS2, the feed molar ratio of benzene, 2-halopropane, and chloroaluminate ionic liquid is 1:(0.2-5):(0.02-0.5).

[0019] Furthermore, the 2-halopropane is specifically 2-bromopropane, and the Friedel-Crafts continuous reaction formula for benzene with 2-bromopropane in step SS4 is as follows:

[0020]

[0021] The reaction follows a multi-step, tandem Friedel-Crafts alkylation mechanism, yielding four substituted products: monosubstituted, disubstituted, trisubstituted, and tetrasubstituted. Among the trisubstituted products, 1,3,5-triisopropylbenzene is the target product.

[0022] The chloroaluminate ionic liquid catalyst in step SS2 includes one of the following: 1-methylimidazolium chloroaluminate ionic liquid, 1-ethylimidazolium chloroaluminate ionic liquid, 1-propylimidazolium chloroaluminate ionic liquid, and 1-butylimidazolium chloroaluminate ionic liquid.

[0023] In chloroaluminate ionic liquid catalysts, the catalytically active component is the chloroaluminate anion, while the cations 1-methylimidazolium, 1-ethylimidazolium, 1-propylimidazolium, and 1-butylimidazolium are used as precursors for the synthesis of chloroaluminate ionic liquids.

[0024] Furthermore, 1-methylimidazolium chloroaluminate ionic liquids include one of [C(2-16)MIm]Cl / (1-2.5)AlCl3 and C(2-16)MIm]Br / (1-2.5)AlCl3; 1-ethylimidazolium chloroaluminate ionic liquids include one of [C(2-16)EIm]Cl / (1-2.5)AlCl3 and C(2-16)EIm]Br / (1-2.5)AlCl3. One type; 1-propylimidazolium chloroaluminate ionic liquids include one of [C(2-16)PIm]Cl / (1-2.5)AlCl3 and C(2-16)PIm]Br / (1-2.5)AlCl3; 1-butylimidazolium chloroaluminate ionic liquids include one of [C(2-16)BIm]Cl / (1-2.5)AlCl3 and C(2-16)BIm]Br / (1-2)AlCl3.

[0025] Furthermore, in step SS3, the benzene feed flow rate is (1-100) ml / min.

[0026] Compared with the prior art, the advantages and positive effects of the present invention are:

[0027] (1) This invention fully utilizes the heat and mass transfer characteristics of microchannel reactors to enhance the flow of heat and mass between fluids, creating turbulent flow within the microchannels to achieve rapid micro-mixing of two material streams. Precise temperature control prevents localized overheating, thus enhancing the micro-reaction process and efficiently catalyzing the continuous synthesis of 1,3,5-triisopropylbenzene using Friedel-Crafts reactors. The microchannel reactor not only overcomes the limitations of existing batch reactors for the continuous production of 1,3,5-triisopropylbenzene... difficulty , Unstable product quality Low security performance Problems Furthermore, it can significantly shorten the reaction time. Under the same conditions, to achieve the same target product yield in a microchannel reactor and a batch reactor, the time required for traditional batch synthesis is approximately 8 to 10 times that of microchannel continuous flow synthesis. Moreover, due to the characteristics of microchannel reactors, the reaction can be scaled up several times without a scale-up effect, and continuous automated production is easily achieved. And the product quality is stable.It has broad prospects for industrial applications. ， It conforms to the production philosophy of safety and efficiency.

[0028] (2) This invention uses chloroaluminate ionic liquid as a catalyst, which not only has high catalytic activity and high selectivity for the target product 1,3,5-triisocyanate, but also requires no solvent, requires a small amount (approximately 10 mol%, determined by the feed molar ratio of benzene, 2-halopropane, and chloroaluminate ionic liquid), and the catalyst is easily settled and recovered after the reaction, exhibiting good cycle stability. This aligns with the green and environmentally friendly production concept.

[0029] (3) The yield and purity of 1,3,5-triisopropylbenzene of this invention are no less than those of traditional batch synthesis methods, achieving efficient synthesis of the target product at full conversion (1,3,5-triisopropylbenzene yield ≥90%). High-yield, high-quality continuous synthesis of 1,3,5-triisopropylbenzene can be achieved using only a simple reaction apparatus and process, and relatively low reaction conditions. It features a simple reaction process, high-efficiency and safe production, and mild reaction conditions. Furthermore, the molar ratio of benzene to 2-halopropane and the reaction temperature can be used to control product distribution and achieve the synthesis of different substituted products. Attached Figure Description

[0030] Figure 1 This is a flowchart of the method for continuous synthesis of 1,3,5-triisopropylbenzene based on microchannels in Examples 2-5;

[0031] Among them: first raw material storage tank V101, second raw material storage tank V102, first filter F101, second filter F102, first plunger constant flow pump P101, second plunger constant flow pump P102, first one-way valve SV101, second one-way valve SV102, T-type micro mixer MIX101, annular microchannel reactor MR101, reaction liquid receiving bottle V201 and tail gas absorption bottle V301. Detailed Implementation

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] The technical solution of the present invention will be further explained below with reference to implementation examples.

[0034] Example 1

[0035] This embodiment provides an apparatus for the continuous synthesis of 1,3,5-triisopropylbenzene based on microchannels. The apparatus is a microchannel reaction device, which includes a first raw material storage tank V101, a second raw material storage tank V102, a first filter F101, a second filter F102, a first plunger-type constant flow pump P101, a second plunger-type constant flow pump P102, a first one-way valve SV101, a second one-way valve SV102, a T-type micromixer MIX101, an annular microchannel reactor MR101, a reaction liquid receiving bottle V201, and a tail gas absorption bottle V301.

[0036] The annular microchannel reactor MR101 is placed in a constant temperature water bath with the temperature controlled at 35-65℃. The first raw material tank V101 is connected to the inlet end of the first plunger constant flow pump P101 via the first filter F101. The outlet end of the first plunger constant flow pump P101 is then connected to the first inlet end of the T-type micro mixer MIX101 via the first one-way valve SV101.

[0037] The second raw material tank V102 is connected to the inlet end of the second plunger constant flow pump P102 via the second filter F102, and the outlet end of the second plunger constant flow pump P102 is connected to the second inlet end of the T-type micro mixer MIX101 via the second one-way valve SV102.

[0038] The outlet of the T-type micro mixer MIX101 is connected to the inlet of the microchannel reactor MR101. The outlet of the microchannel reactor MR101 is connected to the inlet pipe of the reaction liquid receiving bottle V201. The gaseous products of the reaction liquid receiving bottle V201 are connected to the tail gas absorption bottle V301.

[0039] The first plunger-type constant flow pump P101 and the second plunger-type constant flow pump P102 monitor the flow rate of reactants, reaction pressure, and reaction time. A constant temperature water bath controls the reaction temperature. The annular microchannel reactor MR101 is made of polytetrafluoroethylene (PTFE) or 304 / 316 stainless steel, with a microchannel inner diameter of 1–6 mm and a microchannel length of 2–200 m. The first one-way valve SV101 and the second one-way valve SV102 prevent back-mixing of materials caused by pressure difference during the reaction.

[0040] Example 2

[0041] A method for synthesizing 1,3,5-triisopropylbenzene using a microchannel continuous synthesis apparatus includes the following steps:

[0042] Step SS1: Sodium-type 3A molecular sieves were added to benzene and 2-bromopropane respectively for drying and dehydration; the mixture was then allowed to stand at room temperature for 24 hours for further drying.

[0043] Step SS2: The dehydrated benzene is loaded into the first raw material storage tank V101, and the 1-methyl-3-butylimidazolium chloroaluminate ionic liquid catalyst and 2-bromopropane are loaded into the second raw material storage tank V102; the feed molar ratio of benzene, 2-bromopropane and 1-methyl-3-butylimidazolium chloroaluminate ionic liquid is 1:3.03:0.1;

[0044] Step SS3: Benzene in the first raw material storage tank V101 and the mixture of 1-methyl-3-butylimidazolium chloroaluminate ionic liquid and 2-bromopropane in the second raw material storage tank V102 are respectively transported to the T-type micro mixer MIX101 through the first plunger constant flow pump P101 and the second plunger constant flow pump P102. The mixture is stirred and mixed for 3 minutes under nitrogen protection, and the reaction materials are mixed by collision flow at MIX101.

[0045] Step SS4: The mixed material enters the microchannel reactor MR101 for a Friedel-Crafts continuous reaction; the annular microchannel reactor MR101 is placed in a constant temperature water bath at 45℃, and the theoretical residence time in the microchannel is 6.2 min;

[0046] Step SS5: The reacted material enters the reaction liquid receiving bottle V201, where automatic gas-liquid separation is performed. The liquid product is allowed to stand in V201 for 30 minutes to separate into layers and liquids. The upper organic phase consists of the reaction product and unreacted raw materials, while the lower layer is the ionic liquid catalyst. The gaseous product HBr is introduced into the tail gas absorption bottle V301 for absorption and treatment, resulting in a yield of 87.5% for 1,3,5-triisopropylbenzene at full conversion (benzene).

[0047] Example 3

[0048] This embodiment refers to Embodiment 2. The difference between this embodiment and Embodiment 2 is that the theoretical residence time in the microchannel in this embodiment is 14 min, and the yield of 1,3,5-triisopropylbenzene at full conversion (benzene) is 91.44%.

[0049] Example 4

[0050] This embodiment refers to Embodiment 2. The difference between this embodiment and Embodiment 2 is that the feed molar ratio of benzene, 2-bromopropane and 1-methyl-3-butylimidazolium chloroaluminate ionic liquid is 1:3.15:0.1, and the yield of 1,3,5-triisopropylbenzene at full conversion (benzene) is 91.25%.

[0051] Example 5

[0052] This embodiment refers to Embodiment 2. The difference between this embodiment and Embodiment 2 is that the feed molar ratio of benzene, 2-bromopropane and 1-methyl-3-butylimidazolium chloroaluminate ionic liquid is 1:3.25:0.1, and the yield of 1,3,5-triisopropylbenzene at full conversion (benzene) is 92.51%.

[0053] Example 6

[0054] This embodiment refers to Example 2, and tests the cyclic performance of the 1-methyl-3-butylimidazolium chloroaluminate ionic liquid catalyst. The lower layer ionic liquid catalyst obtained by layering and separating in step SS5 is recycled for catalytic reaction. During 5 cycles, the catalytic activity is stable, and the conversion rate and yield do not decrease significantly. The yield of the target product 1,3,5-triisopropylbenzene decreases by only 1.15%.

[0055] In summary, as demonstrated in Examples 2-6, aluminochloroaluminate ionic liquid, as a homogeneous catalyst, is readily applicable to the continuous flow reaction of benzene Friedel-Crafts alkylation using a microchannel reactor. It exhibits not only high catalytic activity and selectivity, but also solvent-free reaction, easily controllable reaction conditions, and easy sedimentation and recovery after reaction, demonstrating good cycle stability. It is a recyclable and green catalyst. Furthermore, the rapid micro-mixing of the reaction fluid within the microchannel reactor effectively shortens the reaction time, providing strong continuous reaction capability and facilitating scale-up experiments for practical production, thus showing broad industrial application prospects.

[0056] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for synthesizing 1,3,5-triisopropylbenzene using an apparatus based on continuous microchannel synthesis, characterized in that, Includes the following steps: step SS1: Molecular sieves were added to benzene and 2-halopropane respectively for drying and dehydration; Step SS2: The dehydrated benzene is loaded into the first raw material storage tank, and the chloroaluminate ionic liquid catalyst and 2-halopropane are loaded into the second raw material storage tank; Step SS3: Benzene in the first raw material storage tank, and the mixture of chloroaluminate ion liquid and 2-halopropane in the second raw material storage tank are respectively transported to the T-type micro mixer through the first plunger constant flow pump and the second plunger constant flow pump. The reaction materials are mixed by collision flow at the T-type micro mixer. Step SS4: The mixed material enters the microchannel reactor for a continuous Friedel-Crafts reaction; Step SS5: The reacted material enters the reaction liquid receiving bottle, where automatic gas-liquid separation is performed. The liquid product is allowed to stand and separate into layers, while the gaseous product is introduced into the tail gas absorption bottle for absorption and treatment. The apparatus for the continuous synthesis of 1,3,5-triisopropylbenzene based on microchannels is a microchannel reaction apparatus, which includes a first raw material storage tank, a second raw material storage tank, a first filter, a second filter, a first plunger constant flow pump, a second plunger constant flow pump, a first one-way valve, a second one-way valve, a T-type micromixer, a microchannel reactor, a reaction liquid receiving bottle, and a tail gas absorption bottle. The microchannel reactor is placed in a constant temperature water bath with the temperature controlled at 35-65℃. The first raw material tank is connected to the inlet end of the first plunger constant flow pump through the first filter. The outlet end of the first plunger constant flow pump is then connected to the first inlet end of the T-type micro mixer through the first check valve. The second raw material tank is connected to the inlet of the second plunger constant flow pump via the second filter, and the outlet of the second plunger constant flow pump is connected to the second inlet of the T-type micro mixer via the second check valve. The outlet of the T-type micro mixer is then connected to the inlet of the microchannel reactor, the outlet of the microchannel reactor is connected to the inlet pipe of the reaction liquid receiving bottle, and the gaseous products of the reaction liquid receiving bottle are connected to the tail gas absorption bottle. The microchannel reactor is one of the following configurations: annular microchannel reactor, straight tube microchannel reactor, and heart-shaped microchannel reactor; Chloroaluminate ionic liquid catalysts include one of the following: 1-methylimidazolium chloroaluminate ionic liquid, 1-ethylimidazolium chloroaluminate ionic liquid, 1-propylimidazolium chloroaluminate ionic liquid, and 1-butylimidazolium chloroaluminate ionic liquid.

2. The method according to claim 1, characterized in that, The first and second plunger constant flow pumps monitor the flow rate of the reactants, the reaction pressure, and the reaction time, while the constant temperature water bath controls the reaction temperature.

3. The method according to claim 1, characterized in that, The microchannel reactor is made of polytetrafluoroethylene (PTFE) or 304 / 316 stainless steel, with an inner diameter of 1~6mm and a length of 2~200m.

4. The method according to claim 1, characterized in that, The first and second check valves prevent material back-mixing caused by pressure difference during the reaction.

5. The method according to claim 1, characterized in that: In step SS2, the feed molar ratio of benzene, 2-halopropane, and chloroaluminate ionic liquid is 1:(0.2~5):(0.02~0.5), and 2-halopropane is one of 2-chloropropane and 2-bromopropane.

6. The method according to claim 1, characterized in that: 2-Hylopropane specifically refers to 2-bromopropane. The Friedel-Crafts continuous reaction formula for benzene and 2-bromopropane in step SS4 is as follows: 。 7. The method according to claim 1, characterized in that: In step SS3, the benzene feed flow rate is (1~100) ml / min.

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