CN110961041B - Continuous flow catalytic reactor, assembly method and application thereof - Google Patents

Abstract

The present invention discloses a continuous flow catalytic reactor, an assembly method and application thereof. The continuous flow catalytic reactor comprises a reaction vessel, a filler encapsulated in the reaction vessel and a charged catalytic component, wherein the catalytic component is fixed on the filler under the action of a direct current electric field. The continuous flow catalytic reactor can be applied to continuous flow reactions such as monosaccharide epimerization reaction. The continuous flow catalytic reactor of the present invention has the advantages of simple structure, unattended operation, safe and convenient operation, etc., and in the process of being applied to the continuous flow reaction, since the catalytic component is fixed by the direct current electric field, it will not flow out with the product, thus saving the catalyst separation step and improving the utilization efficiency of the catalyst.

Description

Continuous flow catalytic reactor, assembly method and application thereof

Technical Field

The present invention particularly relates to a continuous flow catalytic reactor, an assembly method and an application thereof, for example, an application in monosaccharide epimerization reaction.

Background technique

Traditional kettle liquid phase reaction solves the problem of large-scale demand for chemical products, but it also has many shortcomings that are difficult to overcome, such as potential safety hazards, environmental pollution, huge energy consumption, unstable product quality, large floor space and difficulty in process scale-up (Progress in Chemistry, 2016, 28(6):829-838). Continuous flow reaction solves these problems with its unique mixing mode, efficient mass transfer and heat transfer, and low solvent demand. "Continuous flow chemistry" or "flow chemistry" refers to the technology of transporting materials by pumps and conducting chemical reactions in a continuous flow mode. In the past 20 years, continuous flow reaction technology has become increasingly popular in academia and industry. Its advantages are mainly reflected in: (1) small reactor size, rapid mass and heat transfer, and easy process intensification; (2) precise parameter control and good reaction selectivity, especially suitable for inhibiting cascade side reactions; (3) small amount of online material, inherent flame retardant properties of micro-channels, small structure enhancement device explosion-proof performance, and safe operation; (4) continuous operation and high time and space efficiency; (5) easy to achieve automated control, enhance operational safety, and save labor resources (Chinese Journal of Pharmaceutical Industry, 2017, 48(4): 469-482).

Most liquid-phase continuous flow reactions are catalytic reactions. Generally, the catalyst is premixed with the raw material and then introduced into the reactor for reaction. If the catalyst is fixed in the reactor, the catalyst separation step can be saved, the loss of the catalyst can be reduced, its utilization efficiency can be improved, and its service life can be extended. Common catalyst fixation methods are physical adsorption and chemical bonding. CN101033192A discloses a continuous flow reaction method for producing mononitrobenzene by nitration of benzene with nitric acid, in which metal oxides are loaded onto MFI topological structure molecular sieves and pseudo-boehmite by impregnation, and then pressed into a fixed bed catalyst; Biggelaar et al. fixed ω-aminotransferase on 3-aminopropyltriethoxysilane-modified porous silica by covalent bonds for continuous flow reaction of enantioselective amino transfer (Catalysts, 2017, 7(54): 1-13); et al. used ionic bonds to fix molybdate ions on anion exchange resin for the diastereoisomerization reaction of glucose to mannose (Applied Catalysis A, 2008, 334(1–2): 112-118). However, the catalytic active components have limited binding force with the carrier and are easily dissolved into the liquid medium in the continuous flow reaction, resulting in loss of activity and limited catalyst life.

Summary of the invention

The main purpose of the present invention is to provide a continuous flow catalytic reactor, an assembly method and application thereof, so as to overcome the deficiencies in the prior art.

In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

An embodiment of the present invention provides a continuous flow catalytic reactor, comprising a reaction container and a filler encapsulated in the reaction container; characterized in that: the continuous flow catalytic reactor also includes a charged catalytic component, and the catalytic component is fixed on the filler under the action of a DC electric field.

The embodiment of the present invention further provides an assembly method of the continuous flow catalytic reactor, comprising:

The filler is loaded into the reaction container, and the liquid inlet and the liquid outlet of the reaction container are blocked with fiber plugging materials, wherein the fiber plugging materials allow the liquid to pass through but block the filler;

The liquid inlet and the liquid outlet of the reaction container are electrically connected to the positive electrode or the negative electrode of the DC power supply, and the negative electrode or the positive electrode of the DC power supply is connected to the middle part of the filler;

A solution containing charged catalytic components is introduced into the reaction container from the liquid flow inlet and then discharged from the liquid flow outlet, so that the catalytic components are fixed on the filler.

The embodiment of the present invention also provides the use of a continuous flow catalytic reactor in the epimerization reaction of monosaccharides.

The embodiment of the present invention also provides a monosaccharide epimerization reaction method, comprising:

Providing the continuous flow catalytic reactor;

electrically connecting the continuous flow catalytic reactor to a DC power source to form the DC electric field; and

The reaction container is heated to a target temperature, and a monosaccharide solution is introduced from a liquid inlet of the reaction container, and then a solution containing a target product is collected from a liquid outlet of the reaction container.

Compared with the prior art, the continuous flow catalytic reactor of the present invention uses a direct current electric field to fix the charged catalytic component on the filler to form a fixed bed catalyst. The reaction solution is input at the target temperature, and the reaction occurs under the action of the catalytic component, thereby continuously obtaining the target product. In this process, since the catalytic component is fixed by the direct current electric field and will not flow out with the product, the catalyst separation step is saved and the utilization efficiency of the catalyst is improved. Using this reactor, molybdenum oxide quantum dots or molybdate ions can be used as catalytic components to achieve continuous reactions of monosaccharide epimerization. In addition, the external direct current electric field may promote certain chemical reactions that are sensitive to electric fields.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a continuous flow catalytic reactor in Example 1 of the present invention.

Detailed ways

In view of the deficiencies in the prior art, the inventor of this case, after long-term research and practice, was able to propose the technical solution of the present invention, which will be explained in more detail below.

A continuous flow catalytic reactor provided in an embodiment of the present invention comprises a reaction container, a filler encapsulated in the reaction container, and a charged catalytic component, wherein the catalytic component is fixed on the filler under the action of a direct current electric field.

In some embodiments, the reaction vessel is a tubular structure.

In some embodiments, the reaction container is made of glass, but may also be made of other materials, such as ceramic, organic materials, and the like.

In some embodiments, the filler includes any one of activated carbon and ion exchange resin or a combination of both, but is not limited thereto.

In some embodiments, the catalytic component includes quantum dots, such as molybdenum oxide quantum dots.

In some embodiments, the catalytic component includes molybdate ions and iron hydroxide colloidal particles, but is not limited thereto.

In some embodiments, the reaction container has an inner diameter of 1.5 to 2 cm, a length of 50 to 80 cm, and a volume of 100-200 ml.

In some embodiments, the particle size of the filler is 10-50 mesh, and the mass-to-volume ratio of the total mass of the filler to the volume of the reaction container is 50-120 g:100-200 ml.

In some embodiments, the voltage of the DC power source used to form the DC electric field is 5 to 50 volts.

An embodiment of the present invention further provides an assembly method of any of the above-mentioned continuous flow catalytic reactors, comprising:

The filler is loaded into the reaction container, and the liquid inlet and the liquid outlet of the reaction container are blocked with fiber plugging materials, wherein the fiber plugging materials allow the liquid to pass through but block the filler;

The liquid inlet and the liquid outlet of the reaction container are electrically connected to the positive electrode or the negative electrode of the DC power supply, and the negative electrode or the positive electrode of the DC power supply is connected to the middle part of the filler;

A solution containing charged catalytic components is introduced into the reaction container from the liquid flow inlet and then discharged from the liquid flow outlet, so that the catalytic components are fixed on the filler.

In some embodiments, the fiber sealant includes glass wool or quartz wool, but is not limited thereto.

In some more specific embodiments, the filler can be loaded into the reaction tube, and the two ends are sealed with glass wool or quartz wool. The middle part of the filler is short-circuited with the positive or negative electrode of the DC power supply, and the glass wool or quartz wool at both ends are short-circuited with the opposite electrodes. After power is turned on, a certain volume of aqueous solution containing the catalytic components is pumped into one end of the reaction tube and pumped out from the other end.

In some embodiments, the voltage of the DC power supply is 5 to 50 volts.

In some embodiments, the solution comprising charged catalytic components is a quantum dot solution.

In some embodiments, the concentration of the quantum dot solution is 0.5 to 1 g/L, and the flow rate is 0.2 to 1 ml/min.

In some embodiments, the solution comprising a charged catalytic component is a solution containing iron hydroxide colloidal particles or molybdate ions.

The embodiments of the present invention also provide the use of any of the above-mentioned continuous flow catalytic reactors in the epimerization reaction of monosaccharides.

The embodiment of the present invention also provides a monosaccharide epimerization reaction method, which comprises:

Providing any one of the aforementioned continuous flow catalytic reactors;

electrically connecting the continuous flow catalytic reactor to a DC power source to form the DC electric field; and

The reaction container is heated to a target temperature, and a monosaccharide solution is introduced from a liquid inlet of the reaction container, and then a solution containing a target product is collected from a liquid outlet of the reaction container.

In some embodiments, the target temperature is 60-120°C.

In some embodiments, the voltage of the DC power supply is 5 to 50 volts.

In some embodiments, the monosaccharide solution comprises any one or more combinations of glucose, mannose, arabinose, ribose, xylose, and lyxose, but is not limited thereto.

In some embodiments, the concentration of the monosaccharide solution is 1-10 wt %.

In some embodiments, the flow rate of the monosaccharide solution is 0.1 to 2 ml/min.

In the continuous flow catalytic reactor provided by the present invention, a direct current electric field is used to fix the charged catalytic components on the filler to form a fixed bed catalyst, thereby effectively suppressing the loss of the charged catalytic components in the continuous flow reaction.

The continuous flow catalytic reactor of the present invention has the advantages of simple structure, unattended operation, safe and convenient operation, etc. A variety of continuous flow reactions can be carried out by using the continuous flow catalytic reactor of the present invention. For example, a continuous reaction of monosaccharide diastereomerization can be realized by using molybdenum oxide quantum dots or molybdate ions as catalytic components. During the continuous flow reaction, the reaction solution is pumped in at the target temperature to react with the catalytic component, thereby continuously obtaining the target product. Among them, since the catalytic component is fixed by the direct current field and will not flow out with the product, the catalyst separation step is saved and the utilization efficiency of the catalyst is improved.

The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other.

Embodiment 1: The structure of a continuous flow catalytic reactor of this embodiment is shown in FIG1 . Among them, the reaction tube 1 is W-shaped, made of glass, with an inner diameter of 1.8 cm, a length of 70 cm, and a volume of 178 ml. The reaction tube 1 is filled with coconut shell activated carbon filler 2, with a particle size of 12 to 30 meshes and a mass of 80 g, and the two ends of the filler are respectively encapsulated with quartz wool 3 and 4; openings 7 and 8 are respectively opened near the liquid inlet 5 and the liquid outlet 6, and the graphite electrodes 11 and 12 are sealed and fixed with silicone plugs 9 and 10; the two electrodes penetrate into the reaction tube 1 and short-circuit with the quartz wool 3 and 4, and short-circuit with the negative electrode of the DC power supply 13; an opening 14 is opened in the middle of the reaction tube, and a graphite electrode 16 is sealed and fixed with a silicone plug 15, and the electrode penetrates into the reaction tube 1 and short-circuit with the filler 2, and short-circuit with the positive electrode of the DC power supply 13.

200 ml of molybdenum oxide quantum dot solution with a concentration of 0.8 g/L was prepared. The DC power supply 13 was turned on, the voltage was maintained at 24 volts, the solution was pumped into the reaction tube 1 from the liquid inlet at a flow rate of 0.5 ml/min, flowed through the filler 2, and pumped out from the liquid outlet 6. The quantum dots were electrically adsorbed on the filler 2, and a continuous flow catalytic reactor was obtained after all the solution flowed out.

Example 2: The reaction tube 1 described in Example 1 is filled with a chloride ion exchange resin filler 2 with a particle size of 20 to 50 meshes and a mass of 100 grams. Both ends of the filler are respectively encapsulated with glass wool 3 and 4, and the connection method with the DC power supply is the same as in Example 1.

Prepare 400 ml of molybdic acid solution with a concentration of 0.2 g/L. Turn on the DC power supply 13, keep the voltage at 10 volts, pump the solution into the reaction tube 1 from the liquid inlet at a flow rate of 2 ml/min, flow through the filler 2, and pump out from the liquid outlet 6. The molybdate ions are electrically adsorbed on the filler 2, and a continuous flow catalytic reactor is obtained.

Example 3: The reaction tube 1 described in Example 1 is filled with coconut shell activated carbon filler 2, with a particle size of 12-30 mesh and a mass of 80 grams. The two ends of the filler are respectively encapsulated with glass wool 3 and 4. The connection direction of the positive and negative poles of the DC power supply is opposite to that of Example 1. The glass wool 3 and 4 at the two ends of the filler are short-circuited with the positive pole of the power supply 13, and the middle part is short-circuited with the negative pole of the power supply 14.

Prepare 100 ml of ferric hydroxide sol with a concentration of 2 g/L. Turn on the DC power supply 13, keep the voltage at 50 volts, pump the sol into the reaction tube 1 from the liquid inlet at a flow rate of 0.2 ml/min, flow through the filler 2, and pump out from the liquid outlet 6. The ferric hydroxide colloidal particles are electrically adsorbed on the filler 2 to obtain a continuous flow catalytic reactor.

Example 4: The reactor of Example 1 was heated by water bathing, the reaction tube 1 was immersed in a water bath, the liquid inlet 5 and the liquid outlet 6 were kept above the water surface, heated to 80°C, the DC power supply 13 was turned on, and the voltage was maintained at 24V; a glucose solution was pumped into the liquid inlet 5, the mass concentration of the glucose solution was 3%, and the flow rate was 0.3 ml/min; the solution containing the target product mannose was collected from the liquid outlet 6. The reaction was continued for 7 days, and the yield of mannose was maintained at about 23%.

Example 5: The reactor of Example 1 was heated by oil bath, the reaction tube 1 was immersed in the oil bath, the liquid inlet 5 and the liquid outlet 6 were kept above the oil surface, heated to 90°C, the DC power supply 13 was turned on, and the voltage was maintained at 24V; mannose solution was pumped into the liquid inlet 5, the mass concentration of the mannose solution was 1%, and the flow rate was 0.1 ml/min; the solution containing the target product glucose was collected from the liquid outlet 6. The reaction was continued for 7 days, and the yield of glucose was maintained at about 60%.

Example 6: The reactor of Example 2 was heated by oil bath, the reaction tube 1 was immersed in the oil bath, the liquid inlet 5 and the liquid outlet 6 were kept above the oil surface, heated to 100°C, the DC power supply 13 was turned on, and the voltage was maintained at 40V; the arabinose solution was pumped into the liquid inlet 5, the mass concentration of the arabinose solution was 5%, and the flow rate was 1 ml/min; the solution containing the target product ribose was collected from the liquid outlet 6. The reaction was continued for 3 days, and the yield of ribose was maintained at about 35%.

Example 7: The reactor of Example 2 was heated by oil bath, the reaction tube 1 was immersed in the oil bath, the liquid inlet 5 and the liquid outlet 6 were kept above the water surface, heated to 100°C, the DC power supply 13 was turned on, and the voltage was maintained at 40V; ribose solution was pumped into the liquid inlet 5, the mass concentration of the ribose solution was 5%, and the flow rate was 1 ml/min; the solution containing the target product arabinose was collected from the liquid outlet 6. The reaction was continued for 3 days, and the yield of arabinose was maintained at about 62%.

Example 8: The reactor of Example 1 was heated by oil bath, the reaction tube 1 was immersed in the oil bath, the liquid inlet 5 and the liquid outlet 6 were kept above the oil surface, heated to 110°C, the DC power supply 13 was turned on, and the voltage was maintained at 10V; a xylose solution was pumped into the liquid inlet 5, the mass concentration of the xylose solution was 10%, and the flow rate was 2 ml/min; the solution containing the target product lyxose was collected from the liquid outlet 6. The reaction was continued for 3 days, and the yield of lyxose was maintained at about 30%.

Example 9: The reactor of Example 1 was heated by oil bath, the reaction tube 1 was immersed in the oil bath, the liquid inlet 5 and the liquid outlet 6 were kept above the oil surface, heated to 120°C, the DC power supply 13 was turned on, and the voltage was maintained at 10V; a lyxose solution was pumped in from the liquid inlet 5, the mass concentration of the lyxose solution was 10%, and the flow rate was 2 ml/min; the solution containing the target product xylose was collected from the liquid outlet 6. The reaction was continued for 3 days, and the yield of xylose was maintained at about 52%.

Comparative Example 1: 250 g of sodium molybdate was dissolved in water and the volume was adjusted to 500 ml. 303 g of chloride ion exchange resin was added. The mixture was stirred at room temperature for 16 hours. 5 drops of 33% hydrogen peroxide solution were added. The solid was washed and filtered for 5 times with water. After drying, 1 mol/L hydrochloric acid was added to adjust the pH to 3.5. The wet catalyst was filtered to obtain a wet catalyst. The wet catalyst was placed in a 25 ml glass tube with an electric heater and a thermocouple, and was encapsulated with glass wool at the molten glass to obtain a continuous flow reactor. A glucose solution (mass concentration 50%, 1 mol/L hydrochloric acid to adjust the pH to 3.5) was pumped into the reactor at 90°C at a flow rate of 50 ml/h for a continuous flow reaction of epimerization. The initial yield of mannose was about 22%. Due to the loss of molybdenum, the yield dropped to 3% after 3 days of reaction. (Reference: Applied Catalysis A, 2008, 334 (1–2): 112-118).

Comparative Example 2: 44.14 g of molybdic acid was dissolved in water at 70°C, the volume was adjusted to 500 ml, 50 g of chloride ion exchange resin was added, stirred at 40°C for 24 hours, 1 mol/L hydrochloric acid was added dropwise to adjust the pH to 3.5, and then the filtered solid was washed with water 5 times to obtain a wet catalyst. The wet catalyst was loaded into a 25 ml glass tube with an electric heater and a thermocouple, and was encapsulated with glass wool at the molten glass to obtain a continuous flow reactor. A glucose solution (mass concentration 50%, 1 mol/L hydrochloric acid to adjust the pH to 3.5) was pumped into the reactor at 90°C at a flow rate of 50 ml/h for a continuous flow reaction of epimerization. The initial yield of mannose was about 27%, and due to the loss of molybdenum, the yield dropped to about 23% after 7 days of reaction. After 33 days of reaction, the yield dropped to about 12%, and about 1/3 of the molybdenum was lost (reference: Applied Catalysis A, 2008, 334 (1–2): 112-118).

In addition, the inventors of the present case also conducted experiments with other raw materials and conditions listed in this specification in accordance with the methods of Examples 1-9, and also successfully applied the continuous flow catalytic reactor of the present invention to continuous flow reactions.

The above examples are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims (16)

1. A method for assembling a continuous flow catalytic reactor, comprising: The filler is loaded into the reaction container, and the liquid inlet and the liquid outlet of the reaction container are blocked with fiber plugging materials, wherein the fiber plugging materials allow the liquid to pass through but block the filler; The liquid inlet and the liquid outlet of the reaction container are electrically connected to the positive electrode or the negative electrode of the DC power supply, and the negative electrode or the positive electrode of the DC power supply is connected to the middle part of the filler; A solution containing charged catalytic components is introduced into the reaction container from the liquid flow inlet and then discharged from the liquid flow outlet, so that the catalytic components are fixed on the filler under the action of the DC electric field to form a fixed bed catalyst; The filler is selected from any one or a combination of activated carbon and ion exchange resin, and the catalytic component includes molybdenum oxide quantum dots, molybdate ions or iron hydroxide colloidal particles. 2. The assembly method according to claim 1 is characterized in that the reaction container is a tubular structure. 3. The assembly method according to claim 2 is characterized in that the inner diameter of the reaction container is 1.5 to 2 cm, the length is 50 to 80 cm, and the volume is 100 to 200 ml. 4. The assembly method according to claim 1 is characterized in that the reaction container is made of glass. 5. The assembly method according to claim 1 is characterized in that the particle size of the filler is 10-50 mesh, and the mass-to-volume ratio of the total mass of the filler to the volume of the reaction container is 50-120 g:100-200 ml. 6. The assembly method according to claim 1, wherein the voltage of the DC power supply is 5 to 50 volts. 7. The assembly method according to claim 1, wherein the fiber sealant comprises glass wool or quartz wool. 8. The assembly method as described in claim 1 is characterized in that the solution containing the charged catalytic component is a quantum dot solution with a concentration of 0.5 to 1 g/L, and the flow rate of the quantum dot solution is 0.2 to 1 ml/min. 9. A continuous flow catalytic reactor, characterized in that it is assembled by the method according to any one of claims 1 to 8. 10. Use of the continuous flow catalytic reactor as claimed in claim 9 in monosaccharide epimerization reaction. 11. A monosaccharide epimerization reaction method, characterized by comprising: Providing a continuous flow catalytic reactor as claimed in claim 9; The continuous flow catalytic reactor is electrically connected to a DC power supply to form a DC electric field; The reaction container is heated to a target temperature, and a monosaccharide solution is introduced from a liquid inlet of the reaction container, and then a solution containing a target product is collected from a liquid outlet of the reaction container. 12. The monosaccharide epimerization reaction method according to claim 11, characterized in that the target temperature is 60-120°C. 13. The monosaccharide epimerization reaction method according to claim 11, characterized in that the voltage of the DC power supply is 5 to 50 volts. 14. The monosaccharide epimerization reaction method according to claim 11, characterized in that the monosaccharide solution comprises any one or more combinations of glucose, mannose, arabinose, ribose, xylose and lyxose. 15. The monosaccharide epimerization reaction method according to claim 11, characterized in that the concentration of the monosaccharide solution is 1-10 wt%. 16. The monosaccharide epimerization reaction method according to claim 11, characterized in that the flow rate of the monosaccharide solution is 0.1-2 ml/min.