Micro-reaction equipment and method for preparing 2-nitro-4-methylsulfonyl toluene

文档序号:1928772 发布日期:2021-12-07 浏览:13次 中文

阅读说明:本技术 一种制备2-硝基-4-甲砜基甲苯的微反应设备和方法 (Micro-reaction equipment and method for preparing 2-nitro-4-methylsulfonyl toluene ) 是由 陈桂光 谢振强 王成金 孙中亮 于 2021-05-24 设计创作,主要内容包括:本发明涉及一种制备2-硝基-4-甲砜基甲苯的微反应设备和方法。该设备包括进料装置、微反应装置和物料收集装置,所述进料装置与所述微反应装置连通,所述微反应装置与物料收集装置连通,所述微反应装置包括微反应器,所述微反应器为微分散型反应器,包括分散相进口、连续相进口、分散相通路、分散介质膜、连续相通路、混合通路和反应液通路,所述浓硝酸通过分散相通路以及分散介质膜分散为微小液滴并进入混合通路,所述原料液通过连续相通路进入混合通路,在混合通路与浓硝酸充分混合,并在微反应装置内完成硝化反应生成反应产物。本申请的方案具有酸用量低、物料滞留量小、反应效率高、易放大、安全可靠等优势。(The invention relates to a micro-reaction device and a method for preparing 2-nitro-4-methylsulfonyl toluene. The equipment comprises a feeding device, a micro-reaction device and a material collecting device, wherein the feeding device is communicated with the micro-reaction device, the micro-reaction device is communicated with the material collecting device, the micro-reaction device comprises a micro-reactor, the micro-reactor is a micro-dispersion reactor and comprises a dispersion phase inlet, a continuous phase inlet, a dispersion phase passage, a dispersion medium film, a continuous phase passage, a mixing passage and a reaction liquid passage, the concentrated nitric acid is dispersed into micro droplets through the dispersion phase passage and the dispersion medium film and enters the mixing passage, the raw material liquid enters the mixing passage through the continuous phase passage, is fully mixed with the concentrated nitric acid in the mixing passage, and finishes nitration reaction in the micro-reaction device to generate a reaction product. The scheme of the application has the advantages of low acid consumption, small material retention, high reaction efficiency, easiness in amplification, safety, reliability and the like.)

1. A micro-reaction device for preparing 2-nitro-4-methylsulfonyl toluene is characterized in that: the equipment comprises a feeding device, a micro-reaction device and a material collecting device, wherein the feeding device is communicated with the micro-reaction device, the micro-reaction device is communicated with the material collecting device and comprises a micro-reactor, the micro-reactor is a micro-dispersion reactor and comprises a dispersion phase inlet, a continuous phase inlet, a dispersion phase passage, a dispersion medium film, a continuous phase passage, a mixing passage and a reaction liquid passage, concentrated nitric acid is pumped to the dispersion phase inlet, methylsulfonyl toluene and concentrated sulfuric acid are mixed to obtain a raw material liquid which is pumped to the continuous phase inlet, the concentrated nitric acid is dispersed into micro-droplets through the dispersed phase passage and the dispersed medium film and enters the mixing passage, the raw material liquid enters the mixing passage through the continuous phase passage, fully mixing with concentrated nitric acid in the mixing passage, and completing nitration reaction in the micro-reaction device to generate reaction products.

2. The micro-reaction device for preparing 2-nitro-4-methylsulfonyltoluene according to claim 1, wherein: the micro-reaction device also comprises a first-stage pipeline reactor and a multi-stage pipeline reactor which are connected with the micro-reactor; the discharge port of the microreactor is communicated with the feed port of the first-stage pipeline reactor, and the discharge port of the multi-stage pipeline reactor is communicated with the material collecting device.

3. The micro-reaction device for preparing 2-nitro-4-methylsulfonyltoluene according to claim 1, wherein: the micro-reaction device also comprises a primary pipeline reactor connected with the micro-reactor and a stirred tank reactor; the discharge port of the microreactor is communicated with the feed port of the primary pipeline reactor, and the overflow port of the stirred tank reactor is communicated with the material collecting device.

4. The micro-reaction device for preparing 2-nitro-4-methylsulfonyltoluene according to claim 1, wherein: the microdispersion-type reactor includes a dispersion medium film, a dispersed phase passage, a continuous phase passage, a reaction liquid passage, and a mixing passage.

5. The micro-reaction device for preparing 2-nitro-4-methylsulfonyltoluene according to claim 1, wherein: the micro-dispersed microreactor comprises a heat exchange module or maintains the reaction temperature through external heat exchange.

6. The micro-reaction device for preparing 2-nitro-4-methylsulfonyltoluene according to claim 1, wherein: the micro-dispersion medium film is a microporous film, a micro-sieve pore or a micro-narrow slit film, wherein the pore diameter of the microporous film, the pore diameter of the micro-sieve pore and the characteristic dimension of the micro-narrow slit film are in micron order.

7. The micro-reaction device for preparing 2-nitro-4-methylsulfonyltoluene according to claim 1, wherein: the mixed reactor comprises a dispersed phase passage, a continuous phase passage, a reaction liquid passage and a mixed passage, wherein the dispersed phase passage is connected with the dispersed phase inlet and used for conveying a dispersed phase, the continuous phase passage is connected with the continuous phase inlet and used for conveying a continuous phase, the mixed passage is used for communicating the dispersed phase passage, the continuous phase passage and the reaction liquid passage together and is used for mixing the dispersed phase and the continuous phase and conveying a mixed reaction liquid to the reaction liquid passage, and the reaction liquid passage is used for conveying the mixed reaction liquid to the first-stage pipeline reactor.

8. A method for preparing 2-nitro-4-methylsulfonyltoluene, which is characterized by using the micro-reaction device according to any one of claims 1 to 7, the method comprising:

(1) mixing and dissolving p-methylsulfonyl toluene and concentrated sulfuric acid to obtain a raw material solution;

(2) respectively pumping the raw material liquid and the concentrated nitric acid to a continuous phase and dispersed phase feed inlet of the microreactor through an advection pump, and mixing and reacting in the microreactor to obtain a reaction liquid;

(3) after the reaction liquid is completely reacted in the pipeline reactor or the stirred tank reactor, the reaction liquid enters the material collecting device for storage.

9. The method for producing 2-nitro-4-methylsulfonyltoluene according to claim 8, wherein: the mass fraction of the nitric acid is 65-98%; the mass fraction of the sulfuric acid is 97-99%.

10. The method for producing 2-nitro-4-methylsulfonyltoluene according to claim 9, wherein: the feeding molar ratio of the p-methylsulfonyl toluene to the concentrated nitric acid to the concentrated sulfuric acid is 1: 1-2: 2 to 10.

Technical Field

The invention belongs to the technical field of synthesis of 2-nitro-4-methylsulfonyl toluene, and relates to a micro-reaction device and a method for preparing 2-nitro-4-methylsulfonyl toluene.

Background

The 2-nitro-4-methylsulfonyltoluene is an important intermediate for preparing herbicide mesotrione, is also an important raw material for synthesizing a chemical intermediate 2-nitro-4-methylsulfonylbenzoic acid, is also used as an intermediate of medicines and dyes, is an important chemical raw material, and has huge market demand.

The 2-nitro-4-methylsulfonyl toluene is synthesized by nitrating 4-methylsulfonyl toluene with mixed acid of nitric acid and concentrated sulfuric acid. The reaction heat of mixed acid nitration is very large, and the reaction heat of adding a nitro group on a benzene ring is about 150KJ/mol, so the reaction process belongs to the production process of dangerous chemicals. At present, the preparation of 2-nitro-4-methylsulfonyl toluene at home and abroad is mostly carried out by adopting an intermittent production mode, namely, p-methylsulfonyl toluene and concentrated sulfuric acid are added into a stirring kettle, the reaction temperature is controlled, nitric acid is slowly dripped under the condition of continuous stirring, and after the dripping of the nitric acid is finished, the temperature is kept until the reaction is finished; the preparation method has simple process, but has the following problems: (1) the dripping speed is strictly controlled by adding the nitric acid in a dripping mode, the dripping time is long, and the production efficiency is low; (2) the stirring kettle has poor mass transfer and heat transfer effects, and is easy to cause uneven mixing of materials, local overheating and side reaction; (3) the process is easy to lose control, and has great potential safety hazard.

The Chinese patent application No. 201911201477.5 and No. CN 110845373A disclose a method for continuously preparing 2-nitro-4-methylsulfonyl toluene, and the method realizes continuous industrial production of 2-nitro-4-methylsulfonyl toluene by serially connecting n-stage nitration retention kettles, has the advantages of accurately controlling the charging ratio, the reaction time and the like, but production equipment mainly comprises a stirring kettle, and the multistage stirring kettles are serially connected, so that the occupied area is large.

The patent CN110759837A published in 2020 introduces a new method for continuously producing 2-nitro-4-methylsulfonyl toluene, and the method replaces the traditional stirred tank reactor with a microchannel reactor, thereby realizing the accurate control of conditions such as temperature, material proportion, retention time and the like, reducing the liquid holdup of the reactor and improving the safety of the process; but the size of the channel of the microchannel reactor is in micron order, when the total flow rate of the materials is 20ml/min, the pressure of the system is close to 2mpa, in order to ensure that the pressure drop generated by mixing the two materials cannot exceed the pressure range endured by the feed pump and the microchannel reactor, the total flow rate of the materials needs to be controlled in a lower range, and the single channel throughput is smaller.

Disclosure of Invention

The invention aims to provide micro-reaction equipment for preparing 2-nitro-4-methylsulfonyl toluene, which comprises a feeding device, a micro-reaction device and a material collecting device, wherein the feeding device is communicated with the micro-reaction device; the micro-reaction device comprises a micro-reactor, the micro-reactor is a micro-dispersion reactor and comprises a dispersed phase inlet, a continuous phase inlet, a dispersed phase passage, a dispersed medium film, a continuous phase passage, a mixing passage and a reaction liquid passage, concentrated nitric acid is pumped to the dispersed phase inlet, a raw material liquid obtained by mixing methyl sulfone-based toluene and concentrated sulfuric acid is pumped to the continuous phase inlet, the concentrated nitric acid is dispersed into micro droplets through the dispersed phase passage and the dispersed medium film and enters the mixing passage, the raw material liquid enters the mixing passage through the continuous phase passage and is fully mixed with the concentrated nitric acid in the mixing passage, and nitration reaction is completed in the micro-reaction device to generate a reaction product.

In some embodiments, the microreactor apparatus further comprises a first-stage channel reactor connected to the microreactor, and a multi-stage channel reactor; the discharge port of the microreactor is communicated with the feed port of the first-stage pipeline reactor, and the discharge port of the multi-stage pipeline reactor is communicated with the material collecting device.

In some embodiments, the microreactor apparatus further comprises a primary channel reactor connected to the microreactor, and a stirred-tank reactor; the discharge port of the microreactor is communicated with the feed port of the primary pipeline reactor, and the overflow port of the stirred tank reactor is communicated with the material collecting device.

In some embodiments, the microdispersion reactor comprises a dispersion medium film, a dispersed phase passage, a continuous phase passage, a reaction liquid passage, and a mixing passage.

In some embodiments, the microdispersion-type microreactor comprises a heat exchange module, or maintains reaction temperature through external heat exchange.

In some embodiments, the microdispersion media membrane is a microporous membrane, a micromesh membrane, or a micromesh membrane, wherein the pore size of the microporous membrane, the pore size of the micromesh membrane, and the characteristic dimension of the micromesh membrane are all on the order of microns.

In some embodiments, the dispersed phase passage is connected with the dispersed phase inlet for conveying a dispersed phase, the continuous phase passage is connected with the continuous phase inlet for conveying a continuous phase, the mixing passage is used for communicating the dispersed phase passage, the continuous phase passage and the reaction liquid passage together for mixing the dispersed phase and the continuous phase and conveying the mixed reaction liquid to the reaction liquid passage, and the reaction liquid passage is used for conveying the mixed reaction liquid to the first-stage pipeline reactor.

In some embodiments, there may be one or more mixing internals in the channel reactor after the microreactor, including but not limited to sudden enlargement means, sudden reduction means, heart-shaped mixing means, umbrella-shaped mixing means. The mixing member functions to enhance mixing of the reaction liquid in the pipe reactor. On the other hand, the addition of mixing elements will increase the resistance to flow, and the number of mixing elements is not preferably too large in view of the throughput and flow pressure of the system. Preferably, the following components are: each meter of pipeline reactor contains 0-10 mixing members; more preferably: there are 1-5 mixing elements per meter of pipe reactor. For an integrated channel tube reactor, it is preferred to: including but not limited to members that are machined to a sudden expansion or contraction, heart-shaped members, umbrella-shaped members, etc. For a separate tubular reactor, preferably: including but not limited to needle valves or needle valve-like members, static mixers.

In some embodiments, one or more stages of tubular reactors or tubular reactor-stirred tank reactors are employed after the microreactor, allowing for multi-stage temperature control and further reducing the overall time of the reaction process. The low-temperature control is adopted in the stages of the micro-reactor and the first-stage pipeline reactor to quickly finish most of reactions, and the low-temperature control effectively removes huge reaction heat generated instantly by the nitration reaction; intermediate temperature control is adopted in the stage of a two-stage tubular reactor or a stirring reactor, and the intermediate temperature control can improve the reaction rate of the rest small part of raw materials. And (3) controlling the reaction temperature of the microreactor and the first-stage pipeline reactor: preferably, the following components are: at 0-30 deg.C, more preferably 0-20 deg.C; a two-stage tubular reactor or stirred reactor stage, the reaction temperature preferably being: 20-70 deg.C, more preferably 30-65 deg.C.

The application also provides a method for preparing 2-nitro-4-methylsulfonyltoluene, which is characterized by adopting the micro-reaction equipment in any one of the schemes for preparation, and the method comprises the following steps:

(1) mixing and dissolving p-methylsulfonyl toluene and concentrated sulfuric acid to obtain a raw material solution;

(2) respectively pumping the raw material liquid and the concentrated nitric acid to a continuous phase and dispersed phase feed inlet of the microreactor through an advection pump, and mixing and reacting in the microreactor to obtain a reaction liquid;

(3) after the reaction liquid completely reacts in the pipeline reactor or the stirred tank reactor, the reaction liquid enters a material collecting device for storage;

in some embodiments, the mass fraction of nitric acid is 65 to 98%; the mass fraction of the sulfuric acid is 97-99%.

In some embodiments, the feeding molar ratio of the p-methylsulfonyltoluene to the concentrated nitric acid and the concentrated sulfuric acid is 1: 1-2: 2 to 10.

Compared with the prior art, the micro-reaction equipment and the method for preparing the 2-nitro-4-methylsulfonyl toluene have the following advantages that:

firstly, a traditional stirred tank reactor is replaced by a microreactor, the liquid holdup of the reactor is small, and the material retention time is short; the heat exchange performance in the microreactor is far higher than that of a stirred tank reaction kettle, most nitration reactions of materials are rapidly completed in the microreactor, reaction heat is rapidly removed out of the system, efficient reactions are realized, the reaction time is greatly shortened, and the process safety is improved; secondly, the dispersed phase nitric acid is dispersed into micro-droplets through the microreactor and is mixed with the continuous phase for reaction, so that the mass transfer surface area is increased, the mass transfer efficiency is improved, the reaction can be carried out under the condition of not being controlled by mass transfer, the utilization rate of the nitric acid is improved, and the acid dosage and the production cost are reduced; thirdly, the method for producing the 2-nitro-4-methylsulfonyl toluene can realize the accurate control of the material proportion, the retention time and the reaction temperature, reduce the byproducts and improve the product quality; compared with a microchannel reactor, the micro-dispersion type microreactor adopted by the method has the advantages of smaller material flow resistance, low system operation pressure, large single-channel handling capacity, more benefit for amplification to industrial production and low equipment cost.

Drawings

FIG. 1 is a schematic diagram of an apparatus for preparing 2-nitro-4-methylsulfonyltoluene according to the present application.

FIG. 2 is a schematic diagram of another apparatus for preparing 2-nitro-4-methylsulfonyltoluene according to the present application.

FIG. 3 is a schematic representation of a microreactor of the present application, wherein 3A is a cross-sectional view and 3B is a top view of a channel member.

FIG. 4 is a schematic diagram of the internals of a tubular reactor, wherein 4A is an internal diameter transition element; 4B is a heart-shaped member.

Wherein: 1. the device comprises a feeding device, 2, a micro-reaction device, 3, a material collecting device, 4, a first advection pump, 5, a second advection pump, 6, a micro-reactor, 7, a first-stage pipeline reactor, 8, a second-stage pipeline reactor, 9, a material collecting tank, 10, a heat exchange coil, 11, a raw material tank, 12, a nitric acid storage tank, 13, a stirring kettle reaction, 14, a mixing internal component 14, a first section of 14a, a second section of 14b, a small-diameter part of 14c, 14d, a middle cavity, 14e, an arc baffle, a first component of 61, 62, a second component, 63, a channel component, a dispersed phase channel, b, a continuous phase channel, c, a reaction liquid channel, d, a mixing channel, e and a micro-dispersed medium film.

Detailed Description

In order that those skilled in the art will better understand the present invention, the following detailed description of the invention is provided in conjunction with the accompanying drawings and its implementation method.

The invention discloses a micro-reaction device for preparing 2-nitro-4-methylsulfonyl toluene, which comprises a feeding device 1, a micro-reaction device 2 and a material collecting device 3, wherein the feeding device 1 is communicated with the micro-reaction device 2, and the micro-reaction device 2 is communicated with the material collecting device 3.

The micro-reaction device 2 comprises a micro-reactor 6, the micro-reactor comprises a dispersed phase inlet and a continuous phase inlet, concentrated nitric acid is pumped to the dispersed phase inlet, the methyl sulfone toluene and concentrated sulfuric acid are mixed to obtain a raw material liquid, the raw material liquid is pumped to the continuous phase inlet, the concentrated nitric acid and the raw material liquid are fully mixed in the micro-reactor 6, and nitration reaction is completed in the micro-reaction device 2 to generate a reaction product.

In some embodiments, the feed device includes a feedstock tank 11 for formulating a feedstock liquid, a nitric acid storage tank 12 for storing nitric acid, a first advection pump 4 for delivering concentrated nitric acid and a second advection pump 5 for delivering a feedstock liquid.

In some embodiments, the microreactor means 2 further comprises a primary pipeline reactor 7, a secondary pipeline reactor 8 or a stirred tank reactor 13. One or more stages (for example, two or more stages) of tubular reactors 7 and 8 or tubular reactor 7-stirred tank reactor 13 are adopted after the microreactor 6, so that the temperature control of multiple stages can be realized, and the total time of the reaction process is further reduced.

In some embodiments, low temperature control is employed at the microreactor 6 and first-stage channel reactor 7 stages. Thus, most of the reaction can be rapidly completed, and the huge reaction heat generated instantaneously by the nitration reaction is effectively removed through low-temperature control; in some embodiments, medium temperature control is employed in the two-stage tubular reactor 8 or stirred reactor 13 stage, which can increase the reaction rate of the remaining small portion of the feedstock. Preferably, the microreactor 6 and the primary channel reactor 7 are in the stage, and the reaction temperature is controlled to be 0-30 ℃, more preferably 0-20 ℃; in the stage of the two-stage tubular reactor 8 or the stirred reactor 13, the reaction temperature is controlled at 20 to 70 ℃ and more preferably 30 to 65 ℃.

In some embodiments, as shown in fig. 1, the micro-reaction device comprises a micro-reactor 6, a primary channel reactor 7 and a secondary channel reactor 8, wherein the discharge port of the micro-reactor 6 is communicated with the feed port of the primary channel reactor 7, and the discharge port of the secondary channel reactor 8 is communicated with the material collecting device 3, and the material residence time is short by adopting the operation mode of the scheme.

In some embodiments, as shown in fig. 2, the micro-reaction device includes a micro-reactor 6, a first-stage pipeline reactor 7 and a stirred tank reactor 13, the discharge port of the micro-reactor 6 is communicated with the feed port of the first-stage pipeline reactor 7, the discharge port of the first-stage pipeline reactor 7 is communicated with the feed port of the stirred tank reactor 13, the material flows out of the stirred tank reactor 13 in an overflow mode, and the overflow port is communicated with the material collecting device 3.

The first and second advection pumps 4, 5 respectively pump the concentrated nitric acid and the raw material liquid to the dispersed phase inlet and the continuous phase inlet of the micro-reactor 6, fully mix in the micro-reactor 6, and complete the nitration reaction in the micro-reactor 6 and the two-stage channel reactors 7,8 or the stirred tank reactor 13 to generate the reaction product.

In some embodiments, as shown in FIG. 3, the microreactor 6 is a microdispersion-type microreactor comprising a microdispersion medium membrane e, and also comprising a dispersed phase passage a, a continuous phase passage b, a reaction liquid passage c and a mixing passage d.

In some embodiments, the microdispersion media film e includes, and is not limited to, microporous films, micromesh, microflute films, and the like; wherein the aperture of the microporous membrane, the aperture of the micro-sieve pore and the characteristic dimension of the micro-slit membrane are all in micron order. The micro-dispersion medium film e is preferably a flat narrow slit film with the width of 0.1-0.8 mm; preferably the microporous membrane has a pore size of 1 to 100 microns, preferably the microsieve pore size is 50 to 600 microns. The concentrated nitric acid passes through the micro-dispersion medium film e by taking pressure difference as a driving force, and the micro-dispersion phase is micronized to form micro-droplets.

In some embodiments, the dispersed phase passage a is connected with the dispersed phase inlet for conveying a dispersed phase, the continuous phase passage b is connected with the continuous phase inlet for conveying a continuous phase, the mixing passage d communicates the dispersed phase passage a, the continuous phase passage b and the reaction liquid passage c together for mixing the dispersed phase with the continuous phase and conveying the mixed reaction liquid to the reaction liquid passage c, and the reaction liquid passage c is used for conveying the mixed reaction liquid to the primary pipeline reactor 7. The characteristic dimension of each channel is millimeter level, and compared with the micron-level channel of the micro-channel reactor, the material flow resistance of the mixing channel is obviously reduced, and the single-channel processing capacity is greatly improved.

In some embodiments, the width and height of the mixing channel d are 1-2mm, respectively. Preferably, the inner diameter of the primary pipe reactor 7 is 1-2mm, so that heat generated by the reaction can be rapidly transferred out, and the reaction stability can be maintained.

In some embodiments, the microdispersion-type microreactor 6 may itself comprise a heat exchange module, and the reaction temperature may also be maintained by external heat exchange, such as water bath heat exchange, preferably the microreactor itself comprises a heat exchange module.

In some embodiments, the microreactor 6 comprises a first member 61, a second member 62 and a channel member 63, wherein the dispersed phase inlet and the dispersed phase passage a are provided on the first member 61, and the continuous phase inlet and the continuous phase passage b and the reaction liquid passage c are provided on the second member. The mixing passage d is provided on the channel member 63, wherein the first member 61, the microdispersion medium film e, the channel member 63 and the second member 62 are stacked from top to bottom.

In some embodiments, the secondary pipeline reactor 8 has an internal diameter 2 to 4 times, e.g., 2 to 8mm, that of the primary pipeline reactor, which allows for extended residence time of the materials while maintaining the reaction temperature to ensure completion of the reaction.

In some embodiments, one or more mixed internals 14 are also present within the primary and secondary pipe reactors 7,8, the mixed internals 14 including, but not limited to, an abrupt internal diameter transition (sudden expansion means, sudden reduction means), heart-shaped mixing means, umbrella-shaped mixing means, combinations thereof or the like. The mixing member functions to make a sudden change in the diameter of the passage to improve the mixing of the reaction liquid in the pipe reactor. The addition of mixing elements will increase the resistance to flow, considering the throughput of the system and the flow pressure, and therefore the number of mixing elements should not be too large. According to experiments, the comprehensive effect is optimal when 1-10 mixing members are contained in each meter of pipeline reactor; more preferably: there are 1-5 mixing elements per meter of pipe reactor. For an integrated channel tube reactor, it is preferred to: including but not limited to members that are machined to a sudden expansion or contraction, heart-shaped members, umbrella-shaped members, etc. For a separate tubular reactor, preferably: including but not limited to needle valves or needle valve-like members, static mixers, and the like.

Referring to fig. 4, which shows two examples of the inner diameter transition member according to the present application, fig. 4A is an inner diameter transition member 14, specifically, an inner diameter suddenly-reduced member, specifically, including a first section 14A, a second section 14b, and a small diameter portion 14c connected between the two ends, where the first section 14A and the second section 14b are of a common inner diameter, and the small diameter portion 14c is in a right-angle transition with the first section 14A and the second section 14 b. The diameter of the reduced diameter portion 14c is 1/3-2/3 of the inner diameter of the first section 14 a.

Fig. 4B shows a heart-shaped mixing member comprising a first section 14a, a second section 14B and an intermediate chamber portion 14d between the first section 14a and the second section 14B, the intermediate chamber portion 14d being heart-shaped, an arcuate baffle 14e being disposed within the intermediate chamber portion 14d, the arcuate baffle 14e having a concave portion facing the first section 14 a.

In some embodiments, the stirred tank reactor 13 is provided with a heat exchange module, the material stays in the stirred tank reactor for 5-10min, sufficient reaction time is provided, the reaction temperature is reduced, decomposition of nitric acid due to overhigh temperature is avoided, the acid consumption is reduced, and the energy consumption is reduced.

The invention also provides a synthesis method of the 2-nitro-4-methylsulfonyl toluene, which is completed by adopting the equipment in the scheme, and the method comprises the following steps:

(1) the molar ratio of p-methylsulfonyltoluene to concentrated sulfuric acid is 1: 2-10 are mixed and dissolved to prepare raw material liquid.

(2) The advection pump 5 is used for conveying the raw material liquid to a continuous phase inlet of the microreactor 6, the dispersed phase concentrated nitric acid is conveyed to a dispersed phase inlet of the microreactor 6 by the advection pump 4, and is dispersed into micro droplets by a micro-dispersion medium film of the microreactor 6, and then the micro droplets are mixed with the raw material liquid and react.

(3) The reaction liquid completely reacts through a primary pipeline reactor 7, a secondary pipeline reactor 8 or a stirred tank reactor 13, then enters a material collecting tank 9, and is subjected to post-treatment to obtain the product 2-nitro-4-methylsulfonyl toluene.

Wherein the mass fraction of the nitric acid is 65-98%; the mass fraction of the sulfuric acid is 97-99%.

Wherein the feeding molar ratio of the p-methylsulfonyltoluene to the concentrated nitric acid to the concentrated sulfuric acid is 1: 1-2: 2 to 10.

Wherein, the reaction temperature of each stage is regulated and controlled by adopting a water bath mode, and the reaction temperature of the microreactor and the first-stage pipeline reactor is 0-30 ℃, preferably 20-25 ℃; the reaction temperature of the secondary pipeline reactor is 20-70 ℃, preferably 55-65 ℃; the reaction temperature of the stirred tank reactor is 15 to 60 ℃ and preferably 20 to 40 ℃.

Wherein the operating pressure of the system is preferably 0.1-2.0 Mpa; more preferably 0.1-0.5 mpa.

The present invention is described in further detail below with reference to examples, which should be construed as merely illustrative and not a limitation of the scope of the present invention. Furthermore, it should be understood that various changes or modifications of the present invention and further generalization thereof to other similar nitration reaction processes may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents also fall within the scope of the claims appended hereto.

Example 1

Adding p-methylsulfonyl toluene and concentrated sulfuric acid into a raw material tank, fully stirring to dissolve and uniformly mix the p-methylsulfonyl toluene, starting a temperature-controlled water bath, controlling the reaction temperature of a micro-reactor and a primary pipeline reactor to be 20 ℃, controlling the reaction temperature of a secondary pipeline reactor to be 50 ℃, starting a constant-flow pump after the temperature is stable, and controlling the feeding molar ratio of the p-methylsulfonyl toluene to the concentrated nitric acid to the concentrated sulfuric acid to be 1: 1.1: and 5, wherein the mass fraction of concentrated sulfuric acid is 98%, the mass fraction of nitric acid is 65%, the total feeding flow rate is 150ml/min, a micro-reactor dispersion medium is a 1-micron micro-filtration membrane, the system pressure in the reaction process is 0.5mpa, water is added into reaction liquid after the reaction is finished to precipitate solids, and the 2-nitro-4-methylsulfonyl toluene is obtained after suction filtration, washing and drying, and the purity of the product is 99.53% through liquid chromatography detection. Compared with the CN110759837A patent, the single-channel feeding total flow rate is 23ml/min, the system pressure is 1.9mpa, the single-channel treatment capacity of the embodiment is larger, about 7 times of that, and the operation pressure is smaller.

Example 2

Adding p-methylsulfonyl toluene and concentrated sulfuric acid into a raw material tank, fully stirring to dissolve and uniformly mix the p-methylsulfonyl toluene, starting a temperature-controlled water bath, controlling the reaction temperature of a micro-reactor and a primary pipeline reactor to be 30 ℃, controlling the reaction temperature of a secondary pipeline reactor to be 50 ℃, starting a constant-flow pump after the temperature is stable, and controlling the feeding molar ratio of the p-methylsulfonyl toluene to the concentrated nitric acid to the concentrated sulfuric acid to be 1: 1.1: and 5, wherein the mass fraction of concentrated sulfuric acid is 98%, the mass fraction of nitric acid is 70%, the total feeding flow rate is 120ml/min, a micro-reactor dispersion medium is a 1-micron micro-filtration membrane, the system pressure in the reaction process is 0.2mpa, water is added into reaction liquid after the reaction is finished to precipitate solids, and the 2-nitro-4-methylsulfonyl toluene is obtained after suction filtration, washing and drying, and the purity of the product is 99.17% through liquid chromatography detection.

Example 3

Adding p-methylsulfonyl toluene and concentrated sulfuric acid into a raw material tank, fully stirring to dissolve and uniformly mix the p-methylsulfonyl toluene, starting a temperature-controlled water bath, controlling the reaction temperature of a micro-reactor and a primary pipeline reactor to be 20 ℃, controlling the reaction temperature of a secondary pipeline reactor to be 70 ℃, starting a constant-flow pump after the temperature is stable, and controlling the feeding molar ratio of the p-methylsulfonyl toluene to the concentrated nitric acid to the concentrated sulfuric acid to be 1: 1.1: and 5, wherein the mass fraction of concentrated sulfuric acid is 98%, the mass fraction of nitric acid is 70%, the total feeding flow rate is 120ml/min, a micro-reactor dispersion medium is a 1-micron micro-filtration membrane, the system pressure in the reaction process is 0.1mpa, water is added into reaction liquid after the reaction is finished to precipitate solids, and the 2-nitro-4-methylsulfonyl toluene is obtained after suction filtration, washing and drying, and the purity of the product is 99.56% through liquid chromatography detection.

Example 4

Adding p-methylsulfonyl toluene and concentrated sulfuric acid into a raw material tank, fully stirring to dissolve and uniformly mix the p-methylsulfonyl toluene, starting a temperature-controlled water bath, controlling the reaction temperature of a micro-reactor and a primary pipeline reactor to be 20 ℃, controlling the reaction temperature of a secondary pipeline reactor to be 70 ℃, starting a constant-flow pump after the temperature is stable, and controlling the feeding molar ratio of the p-methylsulfonyl toluene to the concentrated nitric acid to the concentrated sulfuric acid to be 1: 1.05: and 5, wherein the mass fraction of concentrated sulfuric acid is 98%, the mass fraction of nitric acid is 65%, the total feeding flow rate is 150ml/min, a micro-reactor dispersion medium is a 1-micron micro-filtration membrane, the system pressure in the reaction process is 0.4mpa, water is added into reaction liquid after the reaction is finished to precipitate solids, and the 2-nitro-4-methylsulfonyl toluene is obtained after suction filtration, washing and drying, and the purity of the product is 99.38% through liquid chromatography detection.

Example 5

Adding p-methylsulfonyl toluene and concentrated sulfuric acid into a raw material tank, fully stirring to dissolve and uniformly mix the p-methylsulfonyl toluene, starting a temperature-controlled water bath, controlling the reaction temperature of a micro-reactor and a primary pipeline reactor to be 25 ℃, controlling the reaction temperature of a secondary pipeline reactor to be 65 ℃, starting a constant-flow pump after the temperature is stable, and controlling the feeding molar ratio of the p-methylsulfonyl toluene to the concentrated nitric acid to the concentrated sulfuric acid to be 1: 1.05: 5, wherein the mass fraction of the concentrated sulfuric acid is 97%, the mass fraction of the nitric acid is 65%, the total feeding flow rate is 150ml/min, the microreactor dispersion medium is a narrow slit membrane with the thickness of 0.3mm, the system pressure in the reaction process is 0.5mpa, water is added into reaction liquid after the reaction is finished to precipitate solid, the 2-nitro-4-methylsulfonyl toluene is obtained after suction filtration, washing and drying, and the purity of the product is 99.38% through liquid chromatography detection.

Example 6

Adding p-methylsulfonyl toluene and concentrated sulfuric acid into a raw material tank, fully stirring to dissolve and uniformly mix the p-methylsulfonyl toluene, starting a temperature-controlled water bath, controlling the reaction temperature of a micro-reactor and a primary pipeline reactor to be 25 ℃, controlling the reaction temperature of a secondary pipeline reactor to be 65 ℃, starting a constant-flow pump after the temperature is stable, and controlling the feeding molar ratio of the p-methylsulfonyl toluene to the concentrated nitric acid to the concentrated sulfuric acid to be 1: 1.05: 3, wherein the mass fraction of the concentrated sulfuric acid is 98%, the mass fraction of the nitric acid is 95%, the total feeding flow rate is 80ml/min, the microreactor dispersion medium is a narrow slit membrane with the thickness of 0.3mm, the system pressure in the reaction process is 0.2mpa, water is added into reaction liquid after the reaction is finished to precipitate solid, the 2-nitro-4-methylsulfonyl toluene is obtained after suction filtration, washing and drying, and the purity of the product is 99.55% through liquid chromatography detection.

Example 7

Adding p-methylsulfonyl toluene and concentrated sulfuric acid into a raw material tank, fully stirring to dissolve and uniformly mix the p-methylsulfonyl toluene, starting a temperature-controlled water bath, controlling the reaction temperature of a micro-reactor and a first-stage pipeline reactor to be 25 ℃, controlling the reaction temperature of a stirring kettle reactor to be 20 ℃, starting a constant-flow pump after the temperature is stable, and controlling the feeding molar ratio of the p-methylsulfonyl toluene to the concentrated nitric acid to be 1: 1.05: and 5, wherein the mass fraction of concentrated sulfuric acid is 98%, the mass fraction of nitric acid is 95%, the total feeding flow rate is 100ml/min, a microreactor dispersion medium is a narrow slit membrane with the thickness of 0.3mm, the system pressure in the reaction process is 0.2mpa, water is added into reaction liquid after the reaction is finished to separate out a solid, the 2-nitro-4-methylsulfonyl toluene is obtained after suction filtration, washing and drying, and the purity of the product is 99.44% through liquid chromatography detection.

Example 8

Adding p-methylsulfonyl toluene and concentrated sulfuric acid into a raw material tank, fully stirring to dissolve and uniformly mix the p-methylsulfonyl toluene, starting a temperature-controlled water bath, controlling the reaction temperature of a micro-reactor and a first-stage pipeline reactor to be 25 ℃, controlling the reaction temperature of a stirring kettle reactor to be 25 ℃, starting a constant-flow pump after the temperature is stable, and controlling the feeding molar ratio of the p-methylsulfonyl toluene to the concentrated nitric acid to be 1: 1.05: 3, wherein the mass fraction of the concentrated sulfuric acid is 98%, the mass fraction of the nitric acid is 65%, the total feeding flow rate is 120ml/min, a microreactor dispersion medium is a narrow slit membrane with the thickness of 0.3mm, the system pressure in the reaction process is 0.2mpa, water is added into reaction liquid after the reaction is finished to precipitate a solid, the 2-nitro-4-methylsulfonyl toluene is obtained after suction filtration, washing and drying, and the purity of the product is 99.34% through liquid chromatography detection.

Compared with the prior (such as CN110759837A) microchannel reactor, the method has the advantages of large processing capacity, low operation pressure and easy industrial scale-up. And in terms of material ratio, the patent adopts the following steps of 1: 1.5: 5 in the scheme of the application, the ratio of 1: 1-2: 2-10, especially in the scheme of each embodiment, the ratio is 1: 1.05-1.1: 3-5, the dosage of the nitric acid is reduced, and the dosage is consistent with the dosage of equipment production adopted in the applicant experiment.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

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