JP2002320841A - Method for controlling gas liquid catalytic reaction and gas generating reaction using solid catalyst by gradient magnetic field - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controlling method for by which the gas-liquid catalytic reaction using a solid catalyst and the gas generating reaction from a liquid by using a solid catalyst can be controlled by a simple method without depending on the individual reaction conditions and the control can be efficiently performed. SOLUTION: In the gas-liquid catalytic reaction using a solid catalyst and in the gas generating reaction from a liquid, a gradient magnetic field is generated near the interface of the solid catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for controlling a gas-liquid contact reaction using a solid catalyst and a method for controlling a gas generation reaction using a solid catalyst.

[0002]

2. Description of the Related Art A chemical reaction in a mixed phase of a liquid phase and a gas phase using a solid catalyst has been widely used in the past, and in order to efficiently produce a target substance, a reaction temperature, a reaction pressure, a reaction time, a reaction time, A method of controlling a chemical reaction by selecting a reaction condition such as a concentration or an appropriate catalyst has been used.
However, such a control method has a drawback in that individual reaction conditions must be selected each time.

[0003] In a reaction in which a liquid reacts at a catalyst interface to generate a gas, the removal of bubbles from the catalyst surface may be a rate-determining process of the reaction, and a chemical reaction is used particularly in a space environment where buoyancy does not exist. In such a case, air bubbles that remain attached to the catalyst interface are a major obstacle to the continuation of the reaction.

[0004]

An object of the present invention is to control a gas-liquid contact reaction utilizing a solid catalyst and a gas generation reaction from a liquid utilizing a solid catalyst in a simple manner without being restricted to individual reaction conditions. It is an object of the present invention to provide a control method which can be controlled and can perform the control efficiently.

[0005]

Means for Solving the Problems The present inventor studied the control of a chemical reaction using a solid catalyst in a mixed phase of a liquid phase and a gaseous phase. It has been found that the chemical reaction of can be controlled efficiently. The present invention has been made based on this finding.

That is, according to the present invention, first, in a gas-liquid contact reaction utilizing a solid catalyst, a gradient magnetic field characterized by generating a gradient magnetic field near the interface of the solid catalyst is provided. A method for controlling a gas-liquid contact reaction that is utilized is provided. Secondly, in a gas generation reaction from a liquid using a solid catalyst, a method for controlling a gas generation reaction using a gradient magnetic field is characterized in that a gradient magnetic field is generated near an interface of the solid catalyst. Provided. Third, in the first or second invention, a magnetic force is applied to the bubble by using the gradient magnetic field by a difference in volume susceptibility between the liquid and the gas in the bubble to move the bubble in a predetermined direction. And controlling the reaction at the solid catalyst interface. Fourthly, in the third invention, there is provided a reaction control method, wherein the gradient magnetic field generating means is a permanent magnet or an electromagnet. Fifth, in the third invention, there is provided a method for controlling a reaction, wherein the gradient magnetic field generating means arranges a paramagnetic substance such as iron or stainless steel in a magnetic field generated by an electromagnet or a permanent magnet. .

Generally, a magnetic force is generated under a gradient magnetic field in which the magnetic field intensity changes according to the position coordinates. The magnetic force (F) acting on a substance per unit volume is represented by the following equation (1): volume susceptibility (χ), magnetic field strength (H), magnetic field gradient (dH / d)
X) (Chemical Encyclopedia, Volume 4, p. 167, Kyoritsu Shuppan (Showa 44)). F = χH (dH / dX) (1) (where F is the magnetic force per unit volume, χ is the volume susceptibility, H is the magnetic field strength, and dH / dX is the magnetic field gradient.)

According to the study of the present inventors, in a gravitational field, buoyancy caused by a difference in density between gas and liquid acts on bubbles.
As shown in Table 1 below, liquid and gas (bubbles) have different volume susceptibilities. Therefore, in a gas-liquid mixed system, when a gradient magnetic field is applied, magnetic buoyancy is generated. It has been found that the movement and control of bubbles is possible.

[0009]

[Table 1]

As shown in Table 1, most liquids such as water and organic solvents are diamagnetic, have a negative volume susceptibility, and a repulsive force acts on the magnet. Since the volume susceptibility is the product of the density and the mass susceptibility (magnetic susceptibility per unit mass), the volume susceptibility of a gas is smaller than that of a liquid. Exceptionally, oxygen gas involved in oxidation and combustion is paramagnetic, has a positive volume susceptibility (+ 1.5 × 10 −7 emu), and has a property of being attracted to magnets.

FIG. 1 is an explanatory diagram schematically showing the behavior of bubbles when a liquid and bubbles coexist in a gradient magnetic field. FIG. 1 (a) shows bubbles in a liquid phase, 1 shows bubbles, 2 shows a liquid, and FIG. 1 (b) shows the magnetic field strength H and the position X.
6 is a graph showing the relationship of. The X-axis direction and the position of the graph in FIG. 1B correspond to the horizontal direction and the position in FIG. 1A, and the gradient magnetic field in which the magnetic field intensity decreases as X increases is applied. Show. The magnetic buoyancy acting on the bubble in such a gradient magnetic field is expressed by the following equation. F = (χG-χL) H (dH / dX) (2) (where, χG and χL represent the volume susceptibilities of liquid and gas, respectively)

If the liquid is diamagnetic, such as water or an organic solvent, the bubbles move in the direction of increasing magnetic field strength (indicated by arrow 3) due to magnetic buoyancy. At this time, the moving direction of the bubble does not depend on the type of gas such as oxygen gas, air, and nitrogen gas. Since the absolute value of the volume susceptibility ΔL is much larger than ΔG, Equation (2) is approximated as follows, and the buoyancy is almost represented by the force acting on the liquid. F ≒ -χLH (dH / dX) (3)

[0013] It should be noted that the patent No. 26 has been proposed by the present inventors.
Although No. 15431 covers all the bubble transport using a magnetic field, it does not mention the application to the control of a chemical reaction using a solid catalyst in a mixed phase of a liquid phase and a gas phase. In the actual chemical industry, various chemical reactions for synthesizing various compounds in a mixed phase of a liquid phase and a gas phase using a solid catalyst are known.

The present inventor has studied the control of a chemical reaction using a solid catalyst in a mixed phase of a liquid phase and a gaseous phase. As a result, when the bubbles are transported by magnetic buoyancy, the above-mentioned chemical reaction can be efficiently performed. I found that I could control it. The present invention has been made based on this finding.

One reaction that is the subject of the present invention is a gas-liquid contact reaction using a solid catalyst, and any reaction that involves the transport of air bubbles through a solid catalyst in a liquid phase. Included.

Examples of such reactions include, for example, 1,
The first step of the production process for finally obtaining 1,4-butanediol from 3-butadiene through a three-step reaction can be mentioned. In the acetoxylation step, 1,3-butadiene, acetic acid, and air are subjected to a gas-liquid-solid contact reaction using a Pd-Te catalyst as a fixed bed to obtain 1,4-diacetoxybutene-2. The reaction is carried out at 70 ° C. under mild conditions of about 7 MPa. In addition, there is a production process in which methyl methacrylate is finally obtained from isobutylene or t-butyl alcohol through a two-step reaction. In the second step of the reaction, methanol and air are added to methacrolein (α, β-unsaturated aldehyde) obtained in the previous step using a multi-component catalyst to form a three-phase gas-liquid-solid-catalyst. The reaction is carried out in a fluidized bed to oxidize and esterify to obtain methyl methacrylate. The reaction is performed under mild conditions of about 50 ° C to 100 ° C. In addition, in the oxygen oxidation step in the synthesis step, air or oxygen is injected into the liquid together with treatment such as aeration to increase the dissolved oxygen concentration in the target liquid, and gas-liquid is mixed on the catalyst surface. The present invention also covers a reaction that repeats a state in which bubbles are attached and then washed away because they come into contact with each other.

In any of the above organic synthesis cases, the contact reaction between oxygen gas and the liquid, which is the reactant, and the gas-liquid-solid phase of the catalyst is carried out, but the supply rate of oxygen to the catalyst surface is low. It is rate-limiting. In other words, how to supply oxygen to the surface of the catalyst is a point for promptly performing the reaction. As described above, in the present invention, such a gas-liquid contact reaction system has a gradient. Since the magnetic field is applied, the oxygen gas bubbles move quickly onto the solid catalyst, so that the supply rate of oxygen to the catalyst surface is significantly improved, and the reaction efficiency can be increased.

Another reaction which is an object of the present invention is one in which a liquid reacts at a solid catalyst interface to produce a gas (bubble). In this gas generation reaction, the removal of bubbles from the surface of the solid catalyst is a rate-determining process of the reaction, and particularly when using the reaction in a space environment where buoyancy does not exist, bubbles attached to the catalyst interface are significant It is an obstacle. In such a case, by applying a gradient magnetic field such that the magnetic field strength decreases as the distance from the catalyst interface decreases, bubbles are effectively removed by magnetic buoyancy, and the gas generation reaction is significantly enhanced. Specific examples of such a reaction include a reaction such as decomposition of a hydrogen peroxide solution using a platinum catalyst.

In the present invention, the material of the solid catalyst is not particularly limited, and generally any catalyst material can be used. In the present invention, various catalysts are treated as a solid catalyst immobilized on a support. Regarding the material of the support, any material that is usually used for immobilization may be neutral, acidic, or basic.

As the means for generating the gradient magnetic field in the present invention, various means and materials, that is, electromagnets, superconducting magnets, permanent magnets, and magnetic materials can be used. The magnetic material and the permanent magnet that can be used in the present invention are not limited to these as long as they are materials based on the above concept. Ferrite, alnico-based materials, rare-earth cobalt-based materials, neodymium-based materials, and the like can be used. The permanent magnet is desirably subjected to various anticorrosion treatments such as plating and painting, and in that case, a material having high magnetic permeability is suitable.

When a permanent magnet is used, a relatively low temperature is desirable because the magnetic field of the permanent magnet is easily lost at a high temperature.
Needless to say, the stronger the generated magnetic force, the better. Needless to say, various magnet materials described below are used in a magnetized state. When using in a heated system, it is necessary to select a magnet material with high heat resistance in consideration of the Curie temperature according to the magnet material and the thermal demagnetization and demagnetization phenomena derived from the temperature coefficient of the residual magnetic flux density. There is.

To give an example, the maximum value of ferrite is about
It can be used up to about 250 ° C, up to about 450 ° C for alnico, up to about 350 ° C for samarium-cobalt, and up to about 150 ° C for neodymium. Needless to say, it is preferable that the strength of the spontaneous magnetic field after magnetization is higher.

[0023]

Next, the present invention will be described in detail with reference to examples. Embodiment 1 The present invention will be described according to one embodiment shown in the drawings. FIG. 2 is an explanatory view of air bubble transport to the solid catalyst interface according to the present invention. Bubbles 1 of the reactant are present in the organic liquid 2 which is the reactant. The carrier 5 on which the solid catalyst 4 is fixed is a permanent magnet 6
Exists in contact with. FIG. 2B is a graph showing the relationship between the magnetic field strength H and the position X. The X-axis direction and the position are shown in FIG.
In the horizontal direction and its position. In such a case, a steep gradient magnetic field is generated near the catalyst.
Moves toward the magnet (the catalyst interface above it) as indicated by the arrow 3 and contacts the solid catalyst interface, and the reaction proceeds. In this case, the larger the product of the magnetic field strength and the gradient,
The force of the magnetic field acting according to the formula (2) or (3) also increases, and the effect of promoting the reaction also increases. Although depending on the shape and type of the permanent magnet, in the case of a neodymium-based magnet, the product of the magnetic field strength and the gradient H (dH / d) is near the interface.
X) is about 30 kilogauss / cm ² and the magnetic force acting on the bubbles is about 19 dynes / cm ^{3 in} ethanol.

Embodiment 2 In the present invention, when a solid catalyst is provided on a permanent magnet, a plurality of permanent magnets can be used. In this case, in order to prevent the permanent magnets from being attracted to each other, it is desirable to fix the composite body 7 of the carrier 5 and the permanent magnet 6 to which the catalyst 4 is fixed in the liquid by using the support material 8 as shown in FIG. . These catalyst-magnet composites can be collected and filled into a reactor, or can be used after being molded into a honeycomb shape having a large number of parallel through holes when the flow rate of the reaction fluid is high.
It is desirable to optimize the porosity in consideration of the pressure loss depending on the viscosity and reactivity of the fluid to be passed, and to make full use of the fluid.

In each case, the permanent magnet 6 is dispersed, mixed, formed into a paint, coated, impregnated, spread, and unmagnetized.
Processing steps such as molding, hardening, and firing are performed, and a magnetizing process is performed after the molding is completed. This is to prevent magnetic particles from aggregating due to magnetic force during the processing step. In addition, these catalytic magnet composites improved to form a gradient magnetic field on the surface of the catalyst according to the present invention can be used in any of ordinary batch type and flow type reactors, and can be used in a fixed bed type. A fluidized bed type can also be applied.

Embodiment 3 In the present invention, a steep gradient magnetic field can be generated in the vicinity of a solid catalyst even when a permanent magnet is not directly inserted into a reacting liquid. As shown in FIG. 4, a catalyst 4 or a carrier 6 to which the catalyst 4 is fixed is placed on a net 9 made of a paramagnetic substance such as stainless steel. When the electromagnet 10 is used as a magnetic field generator, the reaction vessel 11 is installed in the gap, and a magnetic field is applied to the gas-liquid mixed phase.
A steep gradient magnetic field is locally generated near the catalyst interface on the net 9, and bubbles in the reaction liquid are easily attracted to the catalyst interface. The principle of local high gradient magnetic field generation is the same as high magnetic gradient separation (physical science dictionary, 5th edition,
p.571, Iwanami Shoten (1998)).

The paramagnetic substance on which the catalyst is provided may be in the form of a wire, a plate, or the like, in addition to a net. The reaction vessel is made of a non-magnetic substance.
What is necessary is just to select suitably.

Embodiment 4 In a space such as a space shuttle, there is no buoyancy.
Therefore, it is generally difficult to utilize a reaction involving bubbles. one
As an example, alumina pellets 12 carrying a platinum catalyst
(0.5% Pt alumina pellets, N.K.
8% hydrogen peroxide solution 13 decomposition reaction (2H_Two
O_Two→ 2H_TwoO + O_Two). Underground weightless in Hokkaido
The experiment was performed at the force experiment center. Here it falls freely
10 seconds in a zero gravity environment in a capsule. FIG.
As shown in (a), generation of oxygen gas bubbles on the catalyst surface
Birth was observed, but generation of bubbles stopped in a zero gravity environment
did. FIG. 6 (a) shows the vertical movement speed of the air bubbles from the catalyst surface.
It is a distribution along the horizontal position coordinate X 0.3 cm above. gravity
A solid line is shown below, and a broken line is shown under zero gravity. Become weightless
Reaction stops and no bubbles are generated. Next, in FIG.
As shown, place a U-shaped permanent magnet 14 on the outside of the container.
The gradient where the magnetic field strength increases as the distance from the catalyst increases.
Magnetic field (the product of magnetic field strength and gradient H (dH / dX) is up to about 6
0 kilogauss / cm ²), The oxygen gas bubble is the force of the magnetic field
At the catalyst interface. In this case, no weight
Under force, bubbles are generated and the reaction continues as in the gravity field.
Was confirmed. In FIG. 6B, under gravity (solid line),
The distribution of the bubble moving speed under zero gravity (broken line) is shown.

[0029]

According to the method of the present invention, a gradient magnetic field is generated in the vicinity of the catalyst to utilize the force of the magnetic field acting on the bubbles generated due to the difference in volume susceptibility between the liquid and the gas. It is possible to control a chemical reaction involving a gas-liquid utilizing a solid catalyst, regardless of reaction conditions. Especially in the process where the transport of bubbles becomes the rate limiting,
The contribution of the present invention is high. Further, since the method of the present invention has a configuration in which a gradient magnetic field is applied from the vicinity or the back side of the solid catalyst, there is an advantage that the method and the mechanism conventionally used can be applied without major changes. Further, the method of the present invention can be affected by the type of catalyst, and the type of material such as substrates, products, and by-products, as long as the overall reaction temperature is not higher than the allowable temperature limit of the permanent magnet used. And has the effect of being applicable to any reaction.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of bubble transport in a liquid using a magnetic field, wherein (a) shows bubble transport in a liquid phase;
(B) is a graph schematically showing the relationship between the position coordinates X and the magnetic field strength H.

FIG. 2 is an explanatory view of one embodiment of the present invention, in which (a) schematically shows a positional relationship among a catalyst, a carrier, and a permanent magnet;
FIG. 4B shows the behavior of bubbles near the catalyst, and FIG. 5B is a graph schematically showing the relationship between the position coordinates X and the magnetic field strength H. FIG.

FIG. 3 is an explanatory diagram of another embodiment of the present invention, and is a diagram schematically illustrating a positional relationship between a plurality of composites of a support material on which a catalyst is fixed and a permanent magnet.

FIG. 4 is an explanatory view showing still another embodiment of the present invention, in which a permanent magnet is not immersed in a directly reacting liquid,
It is a figure which shows the apparatus which generates a steep gradient magnetic field near a solid catalyst.

FIG. 5 is an explanatory view of an embodiment of the present invention, in which (a) shows a layout of an experimental apparatus for a decomposition reaction of a hydrogen peroxide solution using alumina pellets supporting a platinum catalyst,
(B) is a schematic diagram of an experimental apparatus in which a U-shaped permanent magnet is used to generate a gradient magnetic field in a reaction vessel and continue the reaction in a microgravity environment.

FIG. 6 is an explanatory view of an embodiment of the present invention. FIG. 6 (a) is 0.3c from the top of the catalyst pellet when no magnet is installed.
m under the gravity of the bubble transport velocity at the position above m (solid line),
It shows the position distribution under microgravity (broken line),
(B) shows an experimental result when a magnet is installed.

[Explanation of symbols]

 1. Bubble 2. Liquid 3. Bubble moving direction 4. Solid catalyst 5. Catalyst carrier 6. Permanent magnet 7. Catalyst magnet composite 8. Supporting material 9. Paramagnetic substance Net made of 10 Electromagnets 11 Reactor vessel 12 Alumina pellets carrying Pt catalyst 13 Hydrogen peroxide water 14 U-shaped permanent magnets

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C07C 67/055 C07C 67/055 67/08 67/08 67/39 67/39 69/16 69/16 69/54 69 / 54 Z

Claims (6)

[Claims] 1. A method for controlling a gas-liquid contact reaction using a gradient magnetic field, wherein a gradient magnetic field is generated near an interface of the solid catalyst in the gas-liquid contact reaction using a solid catalyst. 2. A method for controlling a gas generation reaction using a gradient magnetic field, wherein a gradient magnetic field is generated near an interface of the solid catalyst in a gas generation reaction from a liquid using a solid catalyst. . 3. A magnetic force is applied to the bubbles by using the gradient magnetic field according to the difference in volume susceptibility between the liquid and the gas in the bubbles, and the bubbles are moved in a predetermined direction to cause a reaction at the solid catalyst interface. 3. The method according to claim 1, wherein the reaction is controlled. 4. The method according to claim 3, wherein the gradient magnetic field generating means is a permanent magnet or an electromagnet. 5. The method according to claim 3, wherein the gradient magnetic field generating means arranges a paramagnetic substance in a magnetic field generated by an electromagnet or a permanent magnet. 6. The method according to claim 3, wherein the paramagnetic substance is iron or stainless steel.