Method and device for continuously preparing high-purity monochloropropanone by using micro-flow field reactor
By leveraging the enhanced mixing and mass and heat transfer characteristics of the microfluidic reactor, the problem of separating monochloroacetone from chlorine after contact in traditional processes has been solved, enabling continuous preparation and efficient production of high-purity monochloroacetone with a purity of over 98%. The reaction time has been significantly shortened, meeting the requirements of green chemistry.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- LANZHOU XINLONGTAI BIOTECHNOLOGY CO LTD
- Filing Date
- 2026-06-16
- Publication Date
- 2026-07-24
AI Technical Summary
In traditional batch reactor processes, the mixture formed after monochloroacetone comes into contact with chlorine is difficult to separate, especially since 1,1-dichloroacetone and monochloroacetone have similar boiling points, making separation difficult and resulting in low product purity.
A microfluidic reactor was used for continuous preparation. The process involved acetone vaporization, wet chlorine preparation, continuous chlorination reaction, product separation and recovery. The enhanced mixing and efficient mass and heat transfer characteristics within the microfluidic reactor were utilized to control reaction conditions and reduce the generation of byproducts.
The continuous preparation of high-purity monochloroacetone has been achieved, with a product purity of over 98%. The reaction time has been shortened to less than 60 seconds, reducing the risk of accidents, lowering energy consumption, and meeting the requirements of green chemical industry.
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Figure CN122444582A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of organic compound synthesis technology, and in particular to a method and apparatus for the continuous preparation of high-purity monochloroacetone using a microfluidic reactor. Background Technology
[0002] Monochloroacetone is an important organic synthesis intermediate used in dyes, pesticides, pharmaceuticals, fragrances, antioxidants, photosensitive resins, and coupling agents. It has wide applications in chemical, pharmaceutical, and pesticide synthesis. In the pharmaceutical industry, it is mainly used in the production of antibiotics and analgesics. Especially after the quinolone antibiotic ofloxacin was launched in Japan, its unique pharmacological effects led to its widespread adoption in over 80 countries and regions. With the increasing market for ofloxacin, the demand for monochloroacetone, a key raw material in its production, is also rising. In dye synthesis, monochloroacetone is used to synthesize disperse dyes such as 54# Yellow and 64# Yellow. These dyes have advantages such as good dispersion and high color fastness, and are widely used in dyeing acetate and polyester fibers. In addition, monochloroacetone is used to produce insecticides such as pymetrozine. In the fine chemical industry, it is used to manufacture antioxidants and enzyme activators. In the photosensitive industry, it is used to manufacture vinyl-type photosensitive resins and color film coupling agents, making it a versatile fine chemical raw material and intermediate.
[0003] The production process of the novel quinolone antibacterial drug ofloxacin requires a high content of monochloroacetone. The traditional batch process, which involves the reaction of chlorine and acetone, is simple and uses readily available raw materials. However, because all six hydrogen atoms in the acetone molecule are highly reactive, the monochloroacetone produced by the initial reaction of chlorine and acetone will continue to react upon contact with chlorine, resulting in a mixture of monochloro, dichloro, polychlorinated, and isopropylidene acetone compounds. Separating this mixture is difficult, especially 1,1-dichloroacetone, whose boiling point differs from that of monochloroacetone by only 0.3°C, making separation extremely challenging. Summary of the Invention
[0004] Based on the technical problems existing in the background art, the present invention proposes a method and apparatus for continuous preparation of high-purity monochloroacetone using a microfluidic reactor.
[0005] This invention proposes a method for the continuous preparation of high-purity monochloroacetone using a microfluidic reactor, comprising the following steps: Step 1, Acetone vaporization and feeding: Liquid acetone is pumped to the vaporization pipeline at a constant rate by a metering pump and vaporized into acetone gas at 65-90°C; the acetone gas is metered by a gas mass flow meter and then enters the microflow field reactor through the preheating pipeline at a constant flow rate. Step 2, Preparation and Feeding of Wet Chlorine: After the chlorine is reduced in pressure by a pressure reducing valve and buffered by a buffer tank, the flow rate is accurately measured by a gas mass flow meter and mixed online with water according to a preset ratio to form wet chlorine; the water is pumped into the mixing point at a constant flow rate by a plunger pump. Step 3, continuous chlorination reaction: The acetone gas and the wet chlorine gas are continuously introduced into the microflow field reactor at a preset flow ratio. At a reaction temperature of 60-90°C, they are intensified to mix and react through the multi-segment series spiral plate mixing internal components in the reactor. The reaction residence time is 1-60s. The reacted material enters the cooling heat exchanger and is cooled to 5-15°C. Step 4, Product Separation and Recovery: The cooled gas-liquid mixture enters the gas-liquid separator. The gas phase component is introduced into the tail gas cooler for further cooling, and the condensed acetone is recovered. The non-condensable gas is passed into the absorption tank and absorbed by water or a sodium hydroxide aqueous solution with a mass concentration of 5% to 30%. The liquid phase component is sent to the distillation column for separation. The unreacted acetone collected from the top of the column is recovered and reused in the vaporization process of Step 1. High-purity monochloroacetone product is collected from the bottom of the column or from the side stream.
[0006] Preferably, in step 1, the temperature of the vaporization pipe is preferably 80°C; the feed flow rate of liquid acetone is 0.3L / h-3L / h, corresponding to a vaporized acetone gas flow rate of 91.3L / h-913L / h.
[0007] Preferably, in step 2, the feed rate of the water is 0.1 mL / min to 0.5 mL / min.
[0008] Preferably, in step 3, the feed flow rate of chlorine gas is 30L / h-180L / h; the flow ratio of acetone gas to wet chlorine gas entering the microflow reactor is 1:1-10:1.
[0009] Preferably, the flow ratio of acetone gas to wet chlorine gas is 4:1-5:1.
[0010] Preferably, in step 3, the microfluidic reactor is a tubular structure with an inner diameter of 10mm-50mm, a reaction section length of 400mm-1200mm, and a cooling heat exchanger length of 400mm-1200mm.
[0011] Preferably, in step 3, each mixing unit of the multi-segment series spiral plate-shaped mixing internal component has an elongated hole on its spiral plate body; The ratio of the pitch of the spiral unit to the inner diameter of the reactor is 2.5:1, the ratio of the length of the elongated hole to the inner diameter of the reactor is 4:5, the ratio of the width of the elongated hole to the inner diameter of the reactor is 1:6, and the ratio of the spacing between two adjacent rows of elongated holes to the width of the elongated hole is 1:2.
[0012] Preferably, the materials of the tube body and mixing internal components of the microfluidic reactor include, but are not limited to, titanium alloys, Hastelloy, tantalum alloys, zirconium alloys, and silicon carbide.
[0013] A device for the continuous preparation of high-purity monochloroacetone using a microflow field reactor includes an acetone feeding unit, a chlorine feeding unit, a water feeding unit, a microflow field reactor, a cooling heat exchanger, a gas-liquid separation unit, a tail gas absorption unit, and a distillation separation unit connected in sequence. The acetone feeding unit includes an acetone raw material tank, a metering pump, an acetone vaporizer, and a first gas mass flow meter connected in sequence by pipelines. The chlorine feeding unit includes a chlorine cylinder, a pressure reducing valve, a buffer tank, and a second gas mass flow meter connected in sequence via pipelines. The water feed unit is a plunger pump, and the outlet of the plunger pump is connected to the pipeline between the second gas mass flow meter and the microflow field reactor. The microflow field reactor is a tubular reactor with multiple sections of series-connected spiral plate-shaped mixing internal components, and is equipped with a heat exchange jacket system for controlling the reaction temperature. The cooling heat exchanger is a tubular heat exchanger connected to the outlet of the microflow field reactor, and uses cold brine as the cooling medium. The gas-liquid separation unit is a gas-liquid separation tank, whose inlet is connected to the outlet of a cooling heat exchanger, the liquid phase outlet is connected to a distillation separation unit, and the gas phase outlet is connected to a tail gas absorption unit. The exhaust gas absorption unit includes an exhaust gas cooler and an absorption tank connected in sequence along the gas phase flow direction.
[0014] Preferably, the multi-segment series spiral plate-shaped hybrid internal component is made of stainless steel, titanium alloy, Hastelloy, nickel, zirconium, or tantalum.
[0015] The present invention proposes a method and apparatus for the continuous preparation of high-purity monochloroacetone using a microfluidic reactor, which has the following beneficial effects: Utilizing the unique "plug flow" characteristics and millisecond-level mixing capability within the microfluidic reactor, combined with an atmosphere of high acetone excess, further contact between the product monochloroacetone and chlorine is suppressed to the greatest extent, thereby reducing the generation of byproducts such as 1,1-dichloroacetone, 1,3-dichloroacetone, and isopropylideneacetone from the source; the primary selectivity of the crude product is consistently above 96.0%, and after a single conventional distillation, the product purity can reach above 98%, successfully solving the problem in traditional processes where the product and byproducts have similar boiling points and are difficult to separate.
[0016] Through the extremely large specific surface area and reinforced hybrid internal components within the microchannels, the mass and heat transfer efficiency is increased by orders of magnitude, overcoming the limitation of slow mass transfer in gas-gas reactions; the chlorination reaction time is drastically reduced from more than ten hours in traditional batch reactors to less than 60 seconds, achieving continuous and highly efficient industrial production.
[0017] The reactor has an extremely low liquid holdup, minimizing the risk of accidents even in extreme cases of runaway reaction. Reaction heat is rapidly removed through the microchannel walls and highly thermally conductive materials, completely eliminating localized hot spots. Precise control of gas flow ensures the stability and accuracy of the reaction process, resulting in a high degree of automation throughout.
[0018] Excess unreacted acetone is recovered and reused directly, resulting in low material loss. The hydrogen chloride tail gas generated during the reaction is absorbed and converted into hydrochloric acid as a byproduct, reducing the emission of waste gas, wastewater, and solid waste. The device has a compact structure, small footprint, and low energy consumption, which aligns with the development direction of green chemistry. According to experimental data, the chlorine conversion rate can reach over 99%, the entire reaction system maintains a slightly positive pressure (pressure drop in the tube side is less than 0.1 MPa), and there is no significant decrease in reaction selectivity or pressure rise after more than 10 hours of continuous operation, avoiding microchannel blockage and demonstrating excellent stability for industrial applications. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the overall structure of a method and apparatus for the continuous preparation of high-purity monochloroacetone using a microfluidic reactor, as proposed in this invention. Figure 2 This is a gas chromatography (GC) spectrum of the product in Example 1 of the method and apparatus for continuous preparation of high-purity monochloroacetone using a microfluidic reactor proposed in this invention. Figure 3 This is a gas chromatogram (GC) of the product in Example 2 of the method and apparatus for continuous preparation of high-purity monochloroacetone using a microfluidic reactor proposed in this invention. Figure 4 This is a gas chromatogram (GC) of the product in Example 3 of the method and apparatus for continuous preparation of high-purity monochloroacetone using a microfluidic reactor proposed in this invention. Figure 5 This is a schematic diagram of the internal mixing components of the microflow field reactor in the method and apparatus for continuous preparation of high-purity monochloroacetone proposed in this invention.
[0020] In the diagram: 1. Acetone raw material tank; 2. Chlorine gas cylinder; 3. Pressure reducing valve; 4. Acetone vaporizer; 5. Microflow reactor. Detailed Implementation
[0021] Reference Figures 1-5 This invention proposes a method for the continuous preparation of high-purity monochloroacetone using a microfluidic reactor, comprising the following steps: Step 1, Acetone vaporization and feeding: Liquid acetone is pumped to the vaporization pipeline at a constant rate by a metering pump and vaporized into acetone gas at 65-90°C; the acetone gas is metered by a gas mass flow meter and enters the microflow field reactor 5 through the preheating pipeline at a constant flow rate. Step 2, Preparation and Feeding of Wet Chlorine: After the chlorine is reduced in pressure by pressure reducing valve 3 and buffered by buffer tank, the flow rate is accurately measured by gas mass flow meter and mixed online with water according to a preset ratio to form wet chlorine; the water is pumped into the mixing point at a constant flow rate by plunger pump. Step 3, continuous chlorination reaction: The acetone gas and the wet chlorine gas are continuously introduced into the microflow field reactor 5 at a preset flow ratio. At a reaction temperature of 60-90°C, they are intensified to mix and react through the multi-segment series spiral plate mixing internal components in the reactor. The reaction residence time is 1-60s. The reacted material enters the cooling heat exchanger and is cooled to 5-15°C. Step 4, Product Separation and Recovery: The cooled gas-liquid mixture enters a gas-liquid separator. The gas phase mainly consists of hydrogen chloride and a small amount of acetone vapor, which is introduced into a tail gas cooler for further cooling. The condensed acetone is recovered. The non-condensable gas is passed into an absorption tank and absorbed by water or a sodium hydroxide aqueous solution with a mass concentration of 5% to 30%. The liquid phase mainly consists of a mixture containing acetone and monochloroacetone, which is sent to a distillation column for separation. Unreacted acetone is collected from the top of the column and recycled to the vaporization process in Step 1. High-purity monochloroacetone product is collected from the bottom of the column or from the side stream.
[0022] The microfluidic reactor 5 is an apparatus for the continuous preparation of high-purity monochloroacetone, and its connection relationship is as follows: The acetone raw material tank 1 is connected to the metering pump through a pipeline. The outlet of the metering pump is connected to the acetone vaporizer 4. The outlet gas pipeline of the acetone vaporizer 4 is connected to the preheating section. A first gas mass flow meter is installed after the preheating section. The outlet of the first gas mass flow meter is connected to the gas inlet of the microflow field reactor 5.
[0023] Chlorine cylinder 2 is connected to pressure reducing valve 3. The outlet of pressure reducing valve 3 is connected to the inlet of buffer tank. The outlet of buffer tank is connected to second gas mass flow meter through pipeline. A T-connector is installed on the pipeline between the outlet of second gas mass flow meter and the inlet of microflow reactor 5. The other port of the T-connector is connected to the outlet of plunger pump. The inlet of plunger pump is connected to deionized water storage tank.
[0024] Microflow field reactor 5 is an internally equipped with such Figure 5 The tubular reactor shown is a multi-segment series spiral plate-shaped mixing internal component. The reactor is surrounded by a jacket through which heat exchange medium can be introduced. The material outlet of the microflow field reactor is connected in sequence to a cooling heat exchanger and a gas-liquid separator.
[0025] The liquid phase outlet of the gas-liquid separator is connected to the distillation column via a pipeline. The gas phase outlet of the gas-liquid separator is connected to the hot flow inlet of the tail gas cooler. The condensate outlet of the tail gas cooler flows back to the gas-liquid separator, and its non-condensable gas outlet is connected to an absorption tank containing water or sodium hydroxide aqueous solution.
[0026] Example 1 Reference Figure 1 and Figure 2 High-purity monochloroacetone can be continuously prepared using the above-mentioned apparatus.
[0027] The temperature of acetone vaporizer 4 is controlled at 65℃. Liquid acetone is pumped into acetone vaporizer 4 at a flow rate of 3L / h using a metering pump, resulting in acetone gas (vaporization rate of approximately 913L / h). After preheating, this gas is introduced into microfluidic reactor 5 at a constant flow rate of 300L / h. Simultaneously, a plunger pump is turned on to inject deionized water into the chlorine pipeline at a flow rate of 0.2mL / min. Chlorine cylinder 2 is turned on, and chlorine gas is introduced at a flow rate of 60L / h, controlled by a pressure reducer, buffer, and mass flow meter. After water is mixed to form wet chlorine gas, it enters the microflow reactor 5. At this time, the molar ratio of acetone to chlorine gas is about 5.0:1.0. The temperature of the reactor jacket is controlled to stabilize the reaction temperature at 65℃. The back pressure valve is adjusted to maintain a slight positive pressure in the system (gauge pressure <0.1MPa). The material stays in the reactor for about 20 seconds. After the reaction effluent is cooled by a cooling heat exchanger at 5℃, it enters the gas-liquid separator. The gas phase is removed for tail gas absorption, and the liquid phase is collected for gas chromatography analysis.
[0028] Result: As Figure 2 As shown in the spectrum, the peak with a retention time of 3.6 min represents the acetone feedstock, and the peak with a retention time of 5.6 min represents the product monochloroacetone. The feedstock conversion rate is 18.5%, and the monochloroacetone selectivity is 96.64%.
[0029] Example 2 Reference Figure 1 and Figure 3 The difference from Example 1 is that: The temperature of acetone vaporizer 4 is controlled at 75℃, the liquid acetone feed rate corresponds to a gas flow rate of 120L / h, the chlorine feed rate is 30L / h (the acetone gas flow rate after vaporization is 120L / h; the chlorine feed flow rate is 30L / h), the aqueous phase feed rate is 0.1mL / min, and the molar ratio of acetone to chlorine is approximately 4.0:1.0. The reaction temperature is controlled at 75℃, the material residence time is 60s, and the cooling heat exchanger temperature is 5℃.
[0030] Result: As Figure 3 As shown, the raw material conversion rate was 23.19%, and the selectivity for monochloroacetone was 96.81%.
[0031] Example 3 Reference Figure 1 and Figure 4 The difference from Example 1 is that: The temperature of acetone vaporizer 4 is controlled at 80℃, the liquid acetone feed rate corresponds to a gas flow rate of 240L / h, the chlorine feed rate is 30L / h, the aqueous phase feed rate is 0.5mL / min, and the molar ratio of acetone to chlorine is approximately 8.0:1.0. The reaction temperature is controlled at 80℃, the material residence time is 25s, and the cooling heat exchanger temperature is 15℃.
[0032] Result: As Figure 4 As shown, the raw material conversion rate was 16.85%, and the selectivity for monochloroacetone was 96.68%.
[0033] As can be seen from the above three examples, although the conversion rate of raw materials varies due to differences in feed ratio, temperature and residence time, the method of the present invention can maintain the reaction selectivity of monochloroacetone at above 96.6% throughout the entire wide process window, which fully demonstrates the high robustness and reliability of the method of the present invention. Subsequent separation and purification of the crude products obtained in Examples 1-3 using conventional distillation equipment can stably obtain monochloroacetone products with a purity of over 98%.
[0034] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A method for the continuous preparation of high-purity monochloroacetone using a microfluidic reactor, characterized in that, Includes the following steps: Step 1, Acetone vaporization and feeding: Liquid acetone is pumped to the vaporization pipeline at a constant rate by a metering pump and vaporized into acetone gas at 65-90°C; the acetone gas is metered by a gas mass flow meter and then enters the microflow field reactor through the preheating pipeline at a constant flow rate. Step 2, Preparation and Feeding of Wet Chlorine: After the chlorine is reduced in pressure by a pressure reducing valve and buffered by a buffer tank, the flow rate is accurately measured by a gas mass flow meter and mixed online with water according to a preset ratio to form wet chlorine; the water is pumped into the mixing point at a constant flow rate by a plunger pump. Step 3, continuous chlorination reaction: The acetone gas and the wet chlorine gas are continuously introduced into the microflow field reactor at a preset flow ratio. At a reaction temperature of 60-90°C, they are intensified to mix and react through the multi-segment series spiral plate mixing internal components in the reactor. The reaction residence time is 1-60s. The reacted material enters the cooling heat exchanger and is cooled to 5-15°C. Step 4, Product Separation and Recovery: The cooled gas-liquid mixture enters the gas-liquid separator. The gas phase component is introduced into the tail gas cooler for further cooling, and the condensed acetone is recovered. The non-condensable gas is passed into the absorption tank and absorbed by water or a sodium hydroxide aqueous solution with a mass concentration of 5% to 30%. The liquid phase component is sent to the distillation column for separation. The unreacted acetone collected from the top of the column is recovered and reused in the vaporization process of Step 1. High-purity monochloroacetone product is collected from the bottom of the column or from the side stream.
2. The method for continuous preparation of high-purity monochloroacetone using a microfluidic reactor according to claim 1, characterized in that, In step 1, the temperature of the vaporization pipeline is preferably 80°C; the feed flow rate of liquid acetone is 0.3L / h-3L / h, corresponding to a vaporized acetone gas flow rate of 91.3L / h-913L / h.
3. The method for continuous preparation of high-purity monochloroacetone using a microfluidic reactor according to claim 1, characterized in that, In step 2, the water feed rate is 0.1 mL / min to 0.5 mL / min.
4. The method for continuous preparation of high-purity monochloroacetone using a microfluidic reactor according to claim 1, characterized in that, In step 3, the feed flow rate of chlorine gas is 30L / h-180L / h; the flow ratio of acetone gas to wet chlorine gas entering the microflow reactor is 1:1-10:
1.
5. The method for continuous preparation of high-purity monochloroacetone using a microfluidic reactor according to claim 1, characterized in that, The preferred flow ratio of acetone gas to wet chlorine gas is 4:1 to 5:
1.
6. The method for continuous preparation of high-purity monochloroacetone using a microfluidic reactor according to claim 1, characterized in that, In step 3, the microfluidic reactor is a tubular structure with an inner diameter of 10mm-50mm, a reaction section length of 400mm-1200mm, and a cooling heat exchanger length of 400mm-1200mm.
7. The method for continuous preparation of high-purity monochloroacetone using a microfluidic reactor according to claim 1, characterized in that, In step 3, each mixing unit of the multi-segment series spiral plate-shaped mixing internal component has an elongated hole on its spiral plate body; The ratio of the pitch of the spiral unit to the inner diameter of the reactor is 2.5:1, the ratio of the length of the elongated hole to the inner diameter of the reactor is 4:5, the ratio of the width of the elongated hole to the inner diameter of the reactor is 1:6, and the ratio of the spacing between two adjacent rows of elongated holes to the width of the elongated hole is 1:
2.
8. The method for continuous preparation of high-purity monochloroacetone using a microfluidic reactor according to claim 1, characterized in that, The materials used for the tube body and mixing internal components of the microfluidic reactor include, but are not limited to, titanium alloys, Hastelloy alloys, tantalum alloys, zirconium alloys, and silicon carbide.
9. An apparatus for the continuous preparation of high-purity monochloroacetone using a microfluidic reactor, for implementing the method for the continuous preparation of high-purity monochloroacetone using a microfluidic reactor as described in any one of claims 1-8, characterized in that, It includes an acetone feed unit, a chlorine feed unit, a water feed unit, a microflow reactor, a cooling heat exchanger, a gas-liquid separation unit, a tail gas absorption unit, and a distillation separation unit connected in sequence. The acetone feeding unit includes an acetone raw material tank, a metering pump, an acetone vaporizer, and a first gas mass flow meter connected in sequence by pipelines. The chlorine feeding unit includes a chlorine cylinder, a pressure reducing valve, a buffer tank, and a second gas mass flow meter connected in sequence via pipelines. The water feed unit is a plunger pump, and the outlet of the plunger pump is connected to the pipeline between the second gas mass flow meter and the microflow field reactor. The microflow field reactor is a tubular reactor with multiple sections of series-connected spiral plate-shaped mixing internal components, and is equipped with a heat exchange jacket system for controlling the reaction temperature. The cooling heat exchanger is a tubular heat exchanger connected to the outlet of the microflow field reactor, and uses cold brine as the cooling medium. The gas-liquid separation unit is a gas-liquid separation tank, whose inlet is connected to the outlet of a cooling heat exchanger, the liquid phase outlet is connected to a distillation separation unit, and the gas phase outlet is connected to a tail gas absorption unit. The exhaust gas absorption unit includes an exhaust gas cooler and an absorption tank connected in sequence along the gas phase flow direction.
10. The apparatus for continuous preparation of high-purity monochloroacetone using a microfluidic reactor according to claim 9, characterized in that, The multi-segment series-connected spiral plate-shaped hybrid internal components are made of stainless steel, titanium alloy, Hastelloy, nickel, zirconium, or tantalum.