JP2011156524A - Simple cooling microwave chemical reactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems that a conventional cooling microwave chemical reactor needs a cooling device providing a function for cooling and circulating a refrigerant, and requires a great deal of time for maintaining a cooling agent and the refrigerant, in which whole system is complicated and expensive, and also costly in running costs. <P>SOLUTION: The simple cooling microwave chemical reactor provides a method for discharging the refrigerant into the air as it is, by using, as the refrigerant, carbon dioxide or cooling air which are harmless to human body, and eliminating a cooling device for cooling and circulating the refrigerant. Hence, the system is simple; the handling is easy; so the cost becomes inexpensive and the running cost can be reduced. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a chemical reaction apparatus using microwaves.

  Conventionally, microwaves are mainly used in radar and microwave ovens. Among them, heating devices using microwaves have characteristics that differ from heating by heat conduction from the outside. In the case of heating, it is said that when microwave energy is applied, the electric dipoles of water molecules cause rotational movement and generate heat due to friction with surrounding water molecules. The heating method using microwaves is called internal heating compared to the heating method using heat conduction. The reaction rate is remarkably fast, the synthesis efficiency is high, there are few by-products, the reaction can be reduced or the catalyst is not used. It has been reported that synthesis reactions may occur that do not occur under certain conditions. A microwave chemical reaction apparatus applies this reaction promoting effect to a chemical reaction apparatus.

  In the microwave chemical reaction apparatus, in order to obtain the maximum effect of promoting the chemical synthesis reaction, the temperature of the reaction object is examined in advance so that the generation of unnecessary by-products generated during the reaction process is less. It is desirable to maintain the reactants at that temperature while irradiating. When the set temperature of the reactant during heating is sufficiently higher than room temperature, the reactant can be maintained at a constant temperature by adjusting the amount of microwave irradiation. Further, when it is desired to increase the amount of microwave irradiation or to heat the reaction product at a temperature lower than room temperature, a function for cooling the reaction product is required.

  There exist patent document 1 and patent document 2 as a microwave chemical reaction apparatus with this cooling function. As a structure for realizing the cooling function, a cooling part having a hollow structure is provided so as to surround the reaction vessel containing the reactant, and an inlet and an outlet for circulating the refrigerant are provided in the cooling part. As a cooling method, a method of cooling a reaction object via a reaction vessel by circulating a refrigerant cooled to a low temperature in the cooling unit is used. Further, cooling and circulation of the refrigerant are performed by a separate cooling device, and the cooling device includes a device for circulating and cooling the refrigerant in a liquid tank containing a low-temperature coolant and a device for circulating the refrigerant by a pump.

  As a conventional cooling type microwave chemical reaction apparatus, FIG. 1 is a block diagram of the cooling type microwave chemical reaction apparatus of Patent Document 1. In FIG. As shown in FIG. 1, the cooling-type microwave chemical reaction device of Patent Document 1 includes an applicator portion 84, a cooling device 94, and a fluorine-based resin tube 95 that connects them. The cooling device 94 includes a liquid tank 92 in which the refrigerant liquid is stored and a pump 93 for sending out the refrigerant liquid. The flow rate of the refrigerant liquid delivered from the pump 93 is automatically adjusted by controlling the solenoid valve 87 by the flow rate control box 89 that is linked to the measuring device 88. Note that the flow rate of the refrigerant liquid can be manually adjusted by the flow rate adjusting valve 86.

  The cooling unit 80 has a hollow structure, and is provided with a refrigerant liquid circulation unit 82 for circulating the refrigerant liquid. The cooling unit 80 is made of a microwave permeable glass material, and the refrigerant liquid uses a microwave permeable nonpolar oil liquid. A reaction object 85 is placed in the reaction vessel 81, and the temperature of the reaction object 85 is measured by an optical fiber thermometer 91 inserted in the reaction object and stored in the measuring device 88.

  The applicator section 84 is a chamber that reflects microwaves like a casing of a microwave oven, and exhibits a high heating effect by passing through a microwave-permeable reaction vessel 81. That is, the microwave irradiated from the outside of the applicator unit 84 is reflected in the applicator unit 84 and heats the reactant while passing through the reaction vessel 81 from the top, bottom, left and right.

  FIG. 2 is a partial schematic cross-sectional view of an instrument 10 for performing the microwave-assisted organic chemical synthesis of Patent Document 2 at a low temperature (meaning 25 ° C. or lower) as a conventional cooled microwave chemical reaction apparatus. The reaction vessel 20 is a test tubular device having a reaction vessel wall 21 made of a microwave permeable material and defines an internal reaction chamber 17 for microwave assisted reaction.

  The cooling jacket 22 is defined by a space in the cooling jacket wall 28 that is also formed of a microwave transparent material and generally surrounds the vessel wall 21. The cooling jacket 22 directly surrounds the reaction vessel 20 to cool the vessel 20 and vessel content 24 (ie, composition) while microwave energy 25 is applied to the content 24. The container 20 is cooled when the microwave transmission medium used as a fluid coolant is in the cooling jacket 22. In this way, the cooling jacket 22 surrounding the reaction vessel acts as a heat absorber for the reaction vessel 20 and its contents 24. In other words, the cooling jacket 22 serves to maintain a low temperature in the internal reaction chamber 17.

  The cooling jacket 22 includes a mechanism for supplying fluid coolant to the cooling jacket 22, shown as a supply tube 18 in physical communication with the cooling jacket 22 and the coolant reservoir 59. The supply pipe 18 supplies the cooling jacket 22 via the coolant inlet pipe 23. The coolant inlet tube 23 projects close to the bottom of the cooling jacket 22 so that the coolant is initially routed to the cooling jacket 22 and thus near the bottom of the reaction vessel 20. Thereby, the coolant is initially pumped to the desired location, i.e. near the contents 24 in the internal reaction chamber 17.

  The coolant flows into the cooling jacket 22 and occupies the space, and then exits the cooling jacket 22 via the discharge mechanism. The discharge mechanism includes a discharge pipe, indicated generally at 19. The discharge pipe 19 is in physical communication with the cooling jacket 22 and the coolant reservoir 59 via the coolant outlet pipe 27. The reservoir 59 is further in physical communication with the pump 61. The pump 61 circulates a fluid coolant around the reaction vessel 20 from the fluid coolant reservoir 59 via the cooling jacket 22. Other alternatives for encouraging fluid coolant flow include a volumetric transfer mechanism such as a gravity feed coolant reservoir (not shown) or a pump injector (not shown).

  The microwave transmission medium flows from the coolant reservoir 59 through the supply tube 18 and the coolant inlet tube 23 to the cooling jacket 22 surrounding the reaction vessel 20. Thereafter, the coolant exits the cooling jacket 22 through the coolant outlet tube 27 and the discharge tube 19.

W02005 / 113133 Cooling-type microwave chemical reactor / National Institute of Advanced Industrial Science and Technology, Shikoku Keiki Kogyo Publication 2006-75824 Methods and apparatus for low temperature microwave assisted organic chemical synthesis / CMEM Corporation

  In order to realize a cooling function, Patent Documents 1 and 2 of a conventional apparatus have, as main components, a cooling unit, a liquid tank, which surrounds a reaction vessel containing a reaction object and circulates a refrigerant in a hollow structure. And a cooling device having a function of cooling the refrigerant and a function of forcibly circulating the refrigerant by a pump. In particular, it is necessary to keep the temperature of the refrigerant low and enhance the cooling effect, so the liquid tank in which the coolant is stored, the pump that circulates the refrigerant, the pipe that circulates the refrigerant withstands low temperatures, and the pressure of the pump It is necessary to have a structure that can withstand. Further, since the coolant needs to be a cryogenic material, the running cost is also increased. In addition, for maintenance, the coolant and refrigerant in the liquid layer need to be constantly replenished (or replaced in some cases). For this reason, the conventional cooling-type microwave chemical reaction apparatus is complicated and requires a lot of maintenance, and maintenance costs for the coolant and the like are necessary, so that the entire apparatus is expensive.

  In order to solve the above-described problems, a simplified cooling type microwave chemical reaction device according to the present invention is provided as a refrigerant in a cooling unit having a hollow structure so as to surround a reaction vessel containing a reactant. A harmless gas was used, and the refrigerant was used as it was without being circulated and exhausted as it was after cooling the reactants. Low-temperature carbon dioxide gas (low-temperature carbon dioxide gas generated when liquefied carbon dioxide is released into the atmosphere) and low-temperature compressed air (low-temperature air generated from compressed air using a vortex tube) as refrigerants that meet the above conditions ). In addition, carbon dioxide used in the refrigerant, air (gas), and dry ice (solid) that is rarely generated when carbon dioxide is generated do not absorb microwaves and thus do not affect microwave heating. In addition, since there is no need to provide a cooling device for cooling and circulating the refrigerant, the cost is not required, and maintenance of the coolant is simplified by only replacing the liquefied carbon dioxide cylinder. Therefore, the components of the entire system are reduced, and a system that is easy to maintain and operate, inexpensive, and easy to handle can be realized. Furthermore, the cooling effect can be expected to be improved by devising the flow of the refrigerant.

The contents are shown below as an example for realizing the simplified cooling type microwave chemical reaction device of the present invention.
(1) A structure in which an antenna is provided in a cavity to irradiate an object to be reacted. At least, a gas is used as a refrigerant, and a simple structure including a microwave signal source, a cavity, a temperature sensor, a temperature control device, and a reaction vessel is used. The cavity of the mold-cooled microwave chemical reaction apparatus has a cavity cooling part surrounding the reaction vessel, and the cooling part is made of a microwave permeable material. In the present invention, the refrigerant is a low-temperature and high-pressure carbon dioxide gas generated when liquefied carbon dioxide gas is released into the atmosphere, and the refrigerant gas used for cooling is harmless to the human body. To do. In the cooling unit, a nozzle for injecting the refrigerant is provided as a method for effectively injecting the refrigerant to effectively lower the temperature of the reaction vessel (reactant). The direction is directed between the reaction vessel and the cooling pipe so that the injection speed of the refrigerant does not decrease, and the nozzle angle is such that the refrigerant passes through the entire surface of the reaction vessel as wide as possible and at the maximum speed. Set. The flow of the refrigerant in the cooling unit is shown in FIG. The refrigerant reaches the discharge port of the cooling unit while spirally winding around the space between the reaction vessel and the cooling unit pipe.
(2) When carbon dioxide gas is used as the refrigerant, the refrigerant temperature is extremely low (−70 ° C. or lower), and depending on the conditions, the cooling capacity may be excessively excessive with respect to the reactant in the reaction vessel. . In order to solve this problem, cooled air generated by a vortex tube can be used as a refrigerant that can be set to an appropriate temperature. The vortex tube has the function of separating into high and low temperature air by the vortex effect by compressed air. Since the temperature of the generated cooled air can be varied by adjusting the vortex tube (adjustment screw, etc.), it can be set to any temperature. Moreover, a compressor etc. are used for the compressed air input into a vortex tube. The cooling air used for cooling is discharged directly into the air.
(3) Any structure may be used in which the coolant is injected from the upper part of the cavity (the upper block of the cooling unit) or the lower part (the lower block of the cooling unit) through the nozzle.

The simplified cooling type microwave chemical reaction device of the present invention has the following features and effects.
・ Use refrigerant gas that is harmless to human body.
• The refrigerant gas does not absorb microwaves and does not affect microwave heating.
・ There is no need for refrigerant cooling and refrigerant circulation equipment, so there is no cost.
・ The direction and angle of the nozzle for injecting the refrigerant are set to the direction and angle with high cooling effect to increase the cooling efficiency.
・ Refrigerant is injected from the upper part of the cavity or the lower part of the cavity through the nozzle into the cooling part.
・ Refrigerant can be selected as carbon dioxide when high cooling effect is required, and cooling air when cooling effect is low.
・ The running cost of refrigerant gas is low.
・ The reaction object is heated from the antenna in the cavity.
For these reasons, the simplified cooling type microwave chemical reaction device of the present invention eliminates the circulation of the cooling device and the refrigerant by using the gas as a refrigerant, and therefore has the same function as the conventional one with a simpler system configuration. It can be realized, and both the initial cost and running cost can be reduced, and the system can be easily operated and maintained and has good cooling efficiency.

Configuration diagram of a cooling-type microwave chemical reaction device according to Example 1 of Patent Document 1 Partial schematic cross-sectional view of reaction vessel and reaction cavity of Patent Document 2 Partial schematic sectional drawing of the simple cooling type microwave chemical reaction apparatus which concerns on Example 1 of this invention FIG. 5 is a flow chart of refrigerant in the cooling unit according to the first and second embodiments of the present invention. Partial schematic sectional drawing of the example which provided the position of the nozzle which concerns on Example 1 and Example 2 of this invention in the cooling unit lower block (a temperature sensor is abbreviate | omitted) Partial schematic sectional drawing of the simple cooling type microwave chemical reaction apparatus which concerns on Example 2 of this invention Temperature characteristics when only cooling is applied according to Example 1 of the present invention Temperature characteristics of water according to Example 1 of the present invention when the temperature is set to 20 ° C. Temperature characteristics when the alcohol according to Example 1 of the present invention is set to 0 ° C. and 10 ° C. The figure which changed the angle of the nozzle of the cooling unit which concerns on Example 1 and Example 2 of this invention, and compared the cooling effect.

  FIG. 3 is a configuration diagram of the simplified cooling type microwave chemical reaction device according to the first embodiment of the present invention. This is an example in which liquefied carbon dioxide gas is used as a coolant. The microwave chemical reaction apparatus includes a cavity 101 made of a material that reflects microwaves, a liquefied carbon dioxide gas cylinder (vessel with a siphon tube) 113, an electromagnetic valve 114 that controls the flow rate, and a thermometer 112 that measures the temperature of the reactant 104. In addition, a temperature control device 115 that controls opening and closing of the electromagnetic valve 114, and other components, which are not shown in this figure, include a microwave signal source. The reaction object is heated by transmitting the microwave input from the microwave signal source from the antenna 121 in the cavity 101 through the cooling pipe 108 and the reaction vessel 103 made of a microwave transmissive material. By irradiating the object 104.

  On the other hand, the reaction object is cooled by a liquefied carbon dioxide cylinder (container with siphon tube) 113 containing a coolant through a solenoid valve 114 that adjusts the flow rate of the liquefied carbon dioxide gas through a nozzle 110 of the cooling unit upper block 106. More liquid is injected into the cooling section. When injected, the liquefied carbon dioxide vaporizes from the liquid and expands into a cryogenic carbon dioxide gas of 5 to 6 atmospheres. By applying this gas to the reaction vessel 103, heat from the reactant 104 is absorbed, and as a result, the reactant 104 is cooled. Since the carbon dioxide gas of the refrigerant is injected at a high pressure from the nozzle 110 between the reaction vessel 103 and the cooling unit pipe 108 at an optimum angle, the refrigerant is separated from the reaction vessel 103 and the cooling unit as shown in FIG. Since the gap between the pipes 108 is swirled and flows at high speed over the entire outer surface of the reaction vessel 103, it is effectively cooled, and then flows out from the exhaust port 109. In order to keep the cooling temperature of the reactant 104 constant, the electromagnetic valve 114 is opened and closed to control the flow rate of carbon dioxide. The nozzle angle varies depending on the size of the cooling part (mainly the height and the inner diameter). However, when the cooling part has a height of about 50 mm and an inner diameter of about 22 mm, as shown in FIG. Good cooling efficiency was obtained when the angle was from 45 ° to 45 °.

  In order to eliminate unevenness of the temperature in the reaction vessel, although not shown, a stirrer may be provided below the cavity and a stirring bar may be inserted into the reaction vessel to stir the reaction object.

  In FIG. 3, the nozzle 110 is provided on the cooling unit upper block side. However, as shown in FIG. 5, the nozzle 110 may be provided on the cooling unit lower block side and exhausted to the cooling unit upper block side.

  In FIG. 3, the thermometer 112 measures the temperature of the reaction object 104 by the temperature sensor 111 inserted into the reaction object, and sends the measured value to the temperature control device 115. The temperature controller 115 stores the measured temperature, microwave heating (controls the microwave output from a microwave signal source (not shown)) and the above-described cooling so that the set temperature of the reactant is reached. Either one of (control of the refrigerant flow rate by the electromagnetic valve 114) is set to a constant amount, the other is controlled, or both heating and cooling are simultaneously controlled.

  Note that the present invention is not limited to the configuration shown in the above embodiment. For example, microwaves can be replaced with high frequencies. Moreover, although the use was demonstrated as a chemical reaction, if it is an apparatus which heats and cools, it can apply other than a chemical reaction.

  The graph of FIG. 7 shows the characteristics of comparing the time when the water 12 cc is heated to 80 ° C., then the heating is stopped, and the opening / closing time of the solenoid valve 114 is changed only by cooling to lower the temperature to 20 ° C. It can be seen that the ratio of the opening / closing time of the electromagnetic valve 114 and the temperature drop time have a correlation, and cooling control is possible by the opening / closing time of the electromagnetic valve 114.

  The graph of FIG. 8 shows the temperature when the cooling by carbon dioxide gas is controlled while heating by setting the microwave output to be constant at 20, 30 and 40 W with the water temperature set to 20 ° C. when the room temperature is 25 to 27 ° C. Control characteristics are shown. In either case, the temperature could be controlled within ± 1 ° C after reaching the set temperature.

  The graph of FIG. 9 shows the temperature control characteristic when cooling with carbon dioxide gas is controlled while heating the microwave output at a constant 15 W with the alcohol 12 cc set at the set temperature 0 ° C. and 10 ° C. at room temperature 27-28 ° C. When set to 10 ° C, the temperature can be controlled within ± 1 ° C with respect to the set temperature, and when set to 0 ° C, it can be controlled within + 1 / -2 ° C with respect to the set temperature.

  FIG. 6 is a configuration diagram of a simplified cooling type microwave chemical reaction device according to the second embodiment. This is an example using a vortex tube that can generate air cooled from compressed air as a refrigerant. The microwave chemical reaction apparatus includes a cavity 101 made of a material that reflects microwaves, a compressor-116 that generates compressed air, a pressure control valve or electromagnetic valve 119 that controls the flow rate of the compressed air, and air cooled from the compressed air. A vortex tube 118 for generating a temperature, a thermometer 112 for measuring the temperature of the reactant 104, a temperature control device 115 for controlling a pressure control valve or a solenoid valve 119, and the like, although not shown in this figure, a microwave signal Consists of sources. Regarding the heating of the reaction object, the microwave from the antenna 121 in the cavity 101 is transmitted through the cooling pipe 108 and the reaction vessel 103 made of a microwave permeable material as in the first embodiment of the present invention. By irradiating the reaction object 104.

  Regarding the cooling of the reactant 104, the compressed air generated by the compressor 116 is controlled by the pressure control valve or solenoid valve 119, and then the pressure or flow rate is controlled and then sent to the vortex tube 118, where high-pressure cooled air is generated. The The cooled air is injected into the cooling unit of the cooling unit upper block 106 through the nozzle 117 and applied to the reaction vessel 103 to absorb heat from the reaction product. To be cooled. Since the cooling air of the refrigerant is injected at a high pressure from the nozzle 117 between the reaction vessel 103 and the cooling pipe 108 at an optimum angle, the refrigerant is shown in FIG. 4 as in the first embodiment of the present invention. As described above, the reaction vessel 103 can be effectively cooled by flowing in a gap between the reaction vessel 103 and the cooling unit pipe 108 in a spiral manner.

  In addition, in order to eliminate the uneven temperature in the reaction vessel, a stirrer may be provided under the cavity, and a stirring bar may be inserted into the reaction vessel to stir the reaction object.

  In FIG. 6, the nozzle 117 is provided on the cooling unit upper block 106 side, but a nozzle may be provided on the cooling unit lower block 107 side and exhausted on the cooling unit upper block 106 side as in the first embodiment of the present invention.

  The thermometer 112 measures the temperature of the reaction object 104 by the temperature sensor 111 inserted into the reaction object, and sends the measured value to the temperature controller 115. The temperature controller 115 memorizes the measured temperature and keeps either heating (microwave output control) or cooling (pressure control valve or solenoid valve control) constant so that the set temperature of the reactant is reached. The other is controlled or both are controlled.

  Note that the present invention is not limited to the configuration shown in the above embodiment. For example, microwaves can be replaced with high frequencies. Also, the present invention can be applied to other than chemical reaction apparatus.

  The present invention uses gas as a refrigerant in a reaction apparatus using microwave heating, and enables cooling that is inexpensive and easy to handle, and is a simple type that can perform one or both of heating and cooling of an object to be reacted. This is a cooling type microwave chemical reaction device, and can be applied to a simple experimental device such as a chemical reaction or biotechnology or a small-scale system.

DESCRIPTION OF SYMBOLS 101 Cavity 102 Microwave 103 Reaction container 104 Reactor 105 Cooling part internal space 106 Cooling part upper block 107 Cooling part lower block 108 Cooling part pipe 109 Exhaust port 110 Nozzle 111 Temperature sensor 112 Thermometer 113 Liquefied carbon dioxide cylinder (with siphon tube) container)
114 Solenoid valve 115 Temperature control device 116 Compressor 117 Nozzle 118 Vortex tube 119 Pressure control valve or solenoid valve 120 Flow of refrigerant 121 Antenna 15 Sensor 29 Upper part of cooling jacket 39 Cavity 50 Upper part of reaction vessel 54 Cooling jacket ground glass joint 55 Annular Cap 62 Reaction vessel ground glass joint The same number in the figure indicates the same or corresponding part.

Claims (6)

  At least a microwave chemical reaction device equipped with a microwave signal source, cavity, temperature sensor, temperature control device, and reaction vessel, with a cavity sandwiched between the reaction vessel and microwave permeable cooling pipe The cooled gas is injected as a refrigerant from a nozzle provided in one of the cavities into the cavity and is allowed to flow spirally to cool the reaction vessel and the reactant in the reaction vessel, and then an exhaust port provided in the other of the cavities. A simple cooling-type microwave chemical reactor characterized by being discharged into the air from   2. The simplified cooling type microwave chemical reaction apparatus according to claim 1, wherein the cooled gas is a low-temperature high-pressure carbon dioxide gas obtained by vaporizing the gas obtained from a liquefied carbon dioxide gas cylinder.   2. The simplified cooling type microwave chemical reaction device according to claim 1, wherein the cooled gas is low-temperature and high-pressure air generated from compressed air using a vortex tube.   The nozzle is equipped with a control valve, and the temperature of the reaction object in the reaction vessel is measured with a temperature sensor by irradiating a microwave of constant power, and at the control valve so as to reach the desired set temperature from the temperature controller. 2. The simplified cooling type microwave chemical reaction device according to claim 1, wherein the amount of refrigerant is controlled.   The temperature of the reaction object in the reaction vessel is measured with a temperature sensor while injecting a certain amount of refrigerant, and the output of the microwave signal source is controlled from the temperature control device so as to reach the desired set temperature. The simplified cooling type microwave chemical reaction device according to claim 1.   6. The simplified cooling micro of claim 1, wherein the set angle of the nozzle is an angle inclined from the reference to the inside of the cooling pipe by 30 to 45 degrees with respect to the hole surface of the cooling pipe. Wave chemical reactor.

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