CN115594563A - Method for preparing o-chlorotrifluoromethane by micro-reaction continuous photocatalysis of o-chlorotoluene - Google Patents
Method for preparing o-chlorotrifluoromethane by micro-reaction continuous photocatalysis of o-chlorotoluene Download PDFInfo
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Abstract
The application provides a method for preparing o-chlorotrifluoromethane by micro-reaction continuous photocatalysis of o-chlorotoluene, which belongs to the technical field of chemical industry and comprises the following steps: providing a micro reactor, wherein the micro reactor comprises a mixing cavity and at least 3 reaction cavities, and ultraviolet lamps are arranged outside the reaction cavities; (1) Conveying the preheated o-chlorotoluene to the mixing cavity, and introducing chlorine into the mixing cavity to obtain a reaction solution; (2) And the reaction liquid sequentially flows through the reaction cavity, continuous photocatalytic reaction is carried out under the ultraviolet lamp, and the o-chlorotrifluoromethylene is obtained after post-treatment. The method uses a micro-reaction method to continuously carry out photocatalysis on the o-chlorotoluene to prepare the o-chlorotrifluoromethane, controls the micro amount of reactants to carry out the photocatalysis reaction at high flux, and can solve the problems of low conversion rate and low product purity caused by speed reduction in the later reaction period compared with the traditional batch kettle production process.
Description
Technical Field
The invention belongs to the technical field of chemical industry, and particularly relates to a method for preparing o-chlorotrifluorotoluene by micro-reaction continuous photocatalysis of o-chlorotoluene.
Background
The o-chlorotrifluoromethylene is mainly used for organic synthesis in industry, is an intermediate of clotrimazole and o-chlorobenzoic acid, and adopts a batch kettle production process for industrially preparing the o-chlorotrifluoromethylene. The batch still production process is characterized in that reaction raw materials are added into a reaction still and then react under proper conditions, on one hand, batch still equipment is not closed, so that the defects of serious pollution and high danger coefficient exist, on the other hand, the batch still production process is adopted, all reactants are added into the reaction still for reaction at one time, the catalytic preparation reaction efficiency is low, heat is violently released in the photocatalytic reaction process, and the reactants and products are concentrated in the reaction still, so that the temperature is not easy to control, and the purity and the yield of final products are low.
Disclosure of Invention
In order to solve the above problems, the present application aims to provide a method for preparing o-chlorotrifluoromethylene by micro-reaction continuous photocatalysis of o-chlorotoluene, which can improve the conversion rate and the product purity of the photocatalytic reaction.
In order to realize the purpose, the following technical scheme is especially provided, and the method for preparing the o-chlorotrifluorotoluene by the micro-reaction continuous photocatalysis of the o-chlorotrifluorotoluene comprises the following steps:
providing a microreactor, wherein the microreactor comprises a mixing cavity and at least 3 reaction cavities, and ultraviolet lamps are arranged outside the reaction cavities; (1) Conveying the preheated o-chlorotoluene to the mixing cavity, and introducing chlorine into the mixing cavity to obtain a reaction solution; (2) And the reaction liquid sequentially flows through the reaction cavity, continuous photocatalytic reaction is carried out under the ultraviolet lamp, and the o-chlorotrifluoromethylene is obtained after post-treatment.
The application provides a method for preparing o-chlorotrifluoromethane by continuous photocatalysis o-chlorotoluene, the reaction stage is in complete closed state, o-chlorotoluene and chlorine realize high-efficient the mixing in the microreactor, and the reaction volume is few, and reactant dwell time is short, and reactant and result can not pile up in the microreactor for a long time, can avoid taking place the problem that reaction rate descends in the reaction later stage, effectively improve the reaction conversion rate, and production process safety is pollution-free, the operation is automatic, reaction rate is fast, the product content is high.
Optionally, the temperature of the reaction chambers is 90-140 ℃, the temperature difference between the reaction chambers is not greater than 3 ℃, and by accurately controlling the temperature, side reactions can be effectively avoided, impurities generated by the reaction are reduced, and the purity of the product is improved.
Optionally, the reaction chamber outside sets up the heat exchange layer, heat exchange medium in the heat exchange layer is oil, adopts oil as heat exchange medium to set up it in the reaction chamber outside as the heat exchange layer, can the heat conduction efficiency high, and it is accurate to control the temperature, can effectively guarantee among the micro-reaction that the temperature difference between the reaction chamber can not be too big, and stable continuous reaction temperature is favorable to going on of micro-reaction more, improves the conversion rate of reaction and the purity of product, avoids leading to the emergence of secondary reaction because of the difference in temperature is too big.
Optionally, the molar ratio of the chlorine gas to the o-chlorotoluene is 3.1-4.2. By controlling the molar ratio of the chlorine to the o-chlorobenzoyl, the chlorine dosage is slightly excessive, the forward progress of the reaction can be effectively promoted, the cost increase caused by excessive chlorine introduction can be avoided, and if the chlorine content is too high, the conversion of the o-chlorobenzoyl to the o-chlorobenzoyl rate can be promoted, so that the content of the acyl chloride impurities is increased.
Optionally, the wavelength of the ultraviolet lamp is 360-370nm, the power of the ultraviolet lamp is 15-80 w, in the method provided by the application, the ultraviolet lamp with low power is used for catalysis, if the power is too low, the catalysis effect is not good, if the power is too high, carbonization occurs in the reaction process due to too high energy of the ultraviolet lamp, the conversion rate of the product is affected, and the content of impurities is increased.
Optionally, the power of the ultraviolet lamp outside the reaction chamber is increased along with the flowing direction of the reaction liquid, and since the reaction mixture reacts in the microreactor along with the flowing direction, the reactant proportion is smaller and smaller along the flowing direction, and the product is higher and higher, by setting the power of the ultraviolet lamp outside the reaction chamber to be increased along with the flowing direction of the reaction liquid, the reaction can be further promoted to proceed towards the direction of generating the product, and the conversion rate of the reaction is improved.
Optionally, the number of the reaction chambers is 6, the reaction chambers are respectively a first reaction chamber, a second reaction chamber, a third reaction chamber, a fourth reaction chamber, a fifth reaction chamber and a sixth reaction chamber, and the reaction liquid sequentially flows through the first reaction chamber, the second reaction chamber, the third reaction chamber, the fourth reaction chamber, the fifth reaction chamber and the sixth reaction chamber to perform continuous photocatalytic reaction; the power of ultraviolet lamps of the first reaction cavity, the second reaction cavity and the third reaction cavity is 15 to 50w, the power of ultraviolet lamps of the fourth reaction cavity is 55 to 60w, the power of ultraviolet lamps of the fifth reaction cavity is 65 to 70w, and the power of ultraviolet lamps of the sixth reaction cavity is 75 to 80w.
Optionally, the total residence time of the reaction liquid in the reaction chamber is 80-150 s, the total residence time of the reaction liquid in the reaction chamber is very short compared with the conventional reaction mode, a trace amount of reactants can efficiently proceed towards the direction of generating a reaction product in a short reaction residence time, and the reaction liquid flows through the microreactor in a flowing manner, so that the reaction can be performed at a high flux although the amount of the reactant is trace. If the reaction residence time is too short, the reaction is insufficient, the yield of the product of the catalytic reaction is low, if the reaction residence time is too long, the reaction efficiency is greatly influenced, and the total residence time of the reaction liquid in the reaction cavity is selected, so that the reaction can be fully carried out, and the higher production efficiency can be ensured.
Optionally, the mixing chamber and the reaction chamber are internally provided with heart-shaped micro-reaction channels, the o-chlorotoluene and the chlorine gas are mixed in the heart-shaped micro-reaction channels to obtain the reaction liquid, the reaction liquid flows in the heart-shaped micro-reaction channels in the reaction chamber and is subjected to photocatalytic reaction, the reaction channels are arranged as the heart-shaped reaction channels which are connected in series, the contact area between the reaction liquid and the reaction channels can be effectively increased, the wide and narrow staggered shapes in the heart-shaped reaction channels can promote the reaction liquid to collide in the flowing process, the flowability is higher, and the high-efficiency reaction is promoted.
Optionally, at least 40 heart-shaped micro-cavities are included in the heart-shaped micro-reaction channel in each reaction cavity, a reaction liquid baffle is arranged in each heart-shaped micro-cavity, the reaction liquid baffle is located on the wide side of each heart-shaped micro-cavity, the reaction liquid flows in from the wide side of each heart-shaped micro-cavity, is uniformly mixed by the reaction liquid baffles, flows out from the narrow side of each heart-shaped micro-cavity and flows into the wide side of the next heart-shaped micro-cavity, the collision mixing effect of the reaction liquid in the reaction channel can be further improved by arranging the reaction liquid baffles, the reaction liquid contacts with the wall of the reaction cavity after collision, flows to the wide side of each heart-shaped micro-cavity, and finally flows out of the heart-shaped micro-cavity and enters the next heart-shaped micro-cavity, so that the retention time of the reaction liquid in the reaction cavity can be prolonged, the reaction efficiency can be improved, the reaction liquid can be fully attached to the wall of the reaction cavity, the ultraviolet light catalysis effect is improved, and the reaction conversion rate is improved.
Optionally, the microreactor further comprises a preheating chamber, in the step (1), after the o-chlorotoluene is preheated by the preheating chamber, the o-chlorotoluene is mixed with chlorine in the mixing chamber, the temperature of the preheating chamber is 90-140 ℃, the o-chlorotoluene is preheated by the preheating step, the preheated o-chlorotoluene has higher fluidity and higher energy, so that thermal motion is more active, sufficient mixing with chlorine can be promoted, the reaction efficiency of the reaction liquid entering the reaction chamber after preheating can be improved, and the reaction conversion rate is prevented from being influenced by the slow reaction rate in the initial reaction stage due to the slow temperature rise of the o-chlorotoluene in the early reaction stage.
Optionally, in the step (1), the chlorine gas is dried by calcium chloride and enters the mixing cavity, and the drying agent is an anhydrous calcium chloride drying agent.
Optionally, the microreactor further comprises a cooling chamber, the reaction liquid after the photocatalytic reaction in step (2) enters the cooling chamber from the reaction chamber, the reaction liquid can continue to react in the cooling chamber to generate a small amount of reactants, and the post-treatment operation is performed after the reaction liquid is cooled.
Optionally, the post-treatment operation in step (2) comprises nitrogen purging, alkali liquor absorption and rectification of the reaction liquid.
Optionally, the mass concentration of the alkali liquor is 10% -30%, and the alkali liquor is a sodium hydroxide solution.
Optionally, the purity of the prepared o-chlorotrifluoroethylene is 97.5 to 99.5 percent, and the conversion rate is not lower than 98 percent.
The beneficial effects of this application include several aspects at least:
1. the continuous photocatalysis o-chlorotoluene using the micro-reaction device is used for preparing o-chlorotrifluoromethane, and a method using a traditional batch kettle reaction is replaced, on one hand, because reaction intermediates and final products in the photo-chlorination reaction process are easy to react with water to generate impurities, the reaction stage of the scheme is in a completely closed state and isolates air, thereby reducing the contact with water in the air and reducing the generation of the impurities, on the other hand, reactants are subjected to chlorination reaction under the catalysis of ultraviolet light in a high-efficiency and trace manner, the generation of benzene ring chlorination byproducts can be reduced, the utilization efficiency of side chain dichlorides is improved, thereby reducing the surplus of the dichlorides and improving the conversion rate of the reaction, and in addition, the safe, environment-friendly and pollution-free low-power ultraviolet light is used as a catalyst, so that the production process is safer and pollution-free.
2. Because there is the problem that reaction rate descends in the later stage of photocatalytic reaction, this application scheme is through setting up the microreaction passageway for the reaction thing is trace and the high efficiency carries out photocatalytic reaction in the microreactor, can improve the reaction rate of photocatalytic reaction in the later stage, thereby can effectively improve the conversion of reaction.
3. The utilization ratio of chlorine atom is not high in the reaction of conventional cauldron formula, leads to needing to consume a large amount of chlorine, causes manufacturing cost's promotion, and this application scheme is through using little reaction unit to further optimize the proportion of adjacent chlorine toluene and chlorine, thereby effectively reduce the waste of chlorine, improve the utilization ratio of chlorine atom.
4. By controlling the power of the ultraviolet lamps outside the reaction cavity, the power of the ultraviolet lamps outside the reaction cavity is increased along with the flowing direction of the reaction liquid, particularly the power of the ultraviolet lamps outside a plurality of reaction cavities before the reaction liquid flows out in the microreactor is improved in a targeted manner, so that the reaction rate in the later stage of the reaction can be further improved, and the conversion rate of the product is improved.
Drawings
FIG. 1 is a schematic view of a reaction apparatus used in an example of the present application;
FIG. 2 is a schematic view showing the structure of a heart-shaped micro-reaction channel of a micro-reaction device used in an example of the present application.
The labels and names in the figure correspond to the following: 1-preheating cavity, 2-mixing cavity, 3-first reaction cavity, 4-second reaction cavity, 5-third reaction cavity, 6-fourth reaction cavity, 7-fifth reaction cavity, 8-sixth reaction cavity, 9-cooling cavity, 10-microreactor, 11-chlorine storage tank, 12-calcium chloride desiccant, 13-flowmeter, 14-advection pump, 15-aftertreatment device, 16-temperature control system, 17-heart-shaped micro-reaction channel, 18-reaction liquid baffle, 19-heart-shaped microcavity wide side and 20-heart-shaped microcavity narrow side.
Detailed Description
To further illustrate the technical means and effects of the present invention, the present invention is further described with reference to the following examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention.
The examples do not show the specific techniques or conditions, according to the technical or conditions described in the literature in the field, or according to the product specifications. The reagents or apparatus used are conventional products commercially available from normal sources, not indicated by the manufacturer.
Example 1
As shown in figure 1, in the method for preparing o-chlorotrifluoromethylene by continuous photocatalysis, the used micro-reaction equipment comprises: the method comprises the following steps that (1) a microreactor 10 is arranged, wherein one end of a preheating cavity 1 of the microreactor 10 is provided with an adjacent chlorotoluene inlet, a mixing cavity 2 of the microreactor 10 is provided with an adjacent chlorotoluene inlet and a chlorine inlet and is communicated with a first reaction cavity 3, a second reaction cavity 4, a third reaction cavity 5, a fourth reaction cavity 6, a fifth reaction cavity 7, a sixth reaction cavity 8 and a cooling cavity 9, the cooling cavity 9 is communicated with a post-processing device 15, and reaction liquid is processed by the post-processing device 15 to obtain an adjacent chlorotrifluoromethane product; the chlorine inlet is communicated with a chlorine storage tank 11, the chlorine storage tank 11 sequentially passes through a calcium chloride drying agent 12 and a flowmeter 13 and then is introduced into the chlorine inlet to enter the mixing chamber 2, the adjacent chlorotoluene inlet is communicated with a advection pump 14, the adjacent chlorotoluene enters the preheating chamber 1 to be preheated through the advection pump 14, and the preheated adjacent chlorotoluene enters the mixing chamber 2 through the adjacent chlorotoluene inlet; the outer sides of a preheating cavity 1, a mixing cavity 2, a first reaction cavity 3 to a sixth reaction cavity 8 and a cooling cavity 9 in the microreactor 10 are provided with heat exchange layers, high-efficiency heat exchange oil is filled in the heat exchange layers to serve as a heat conducting medium, the temperatures of the preheating cavity 1, the mixing cavity 2, the first reaction cavity 3 to the sixth reaction cavity 8 in the microreactor 10 can be controlled through a temperature control system 16, and ultraviolet lamps are arranged outside the first reaction cavity 3 to the sixth reaction cavity 8.
As shown in fig. 2, the heart-shaped micro-reaction channel 17 is formed by connecting heart-shaped micro-cavities in series, the heart-shaped micro-cavities further comprise reaction liquid baffles 18, the reaction liquid baffles are positioned on the wide sides 19 of the heart-shaped micro-cavities, the reaction liquid flows in from the wide sides 19 of the heart-shaped micro-cavities in the flowing direction, is uniformly mixed by the reaction liquid baffles 18, flows out from the narrow sides 20 of the heart-shaped micro-cavities and flows into the wide sides 19 of the next heart-shaped micro-cavities.
Example 2
The embodiment designs a method for preparing o-chlorotrifluoromethane by micro-reaction continuous photocatalysis of o-chlorotoluene, which comprises the following steps:
providing a microreactor, wherein the microreactor comprises a preheating cavity, a mixing cavity and 6 reaction cavities, the reaction cavities are respectively a first reaction cavity, a second reaction cavity, a third reaction cavity, a fourth reaction cavity, a fifth reaction cavity and a sixth reaction cavity, and ultraviolet lamps are arranged outside the first reaction cavity to the sixth reaction cavity;
(1) Preheating o-chlorotoluene at 90-140 ℃ by using a preheating cavity, conveying the preheated o-chlorotoluene to a mixing cavity, and introducing the chlorine gas after water removal into the mixing cavity to obtain a reaction solution, wherein the molar ratio of the chlorine gas to the o-chlorotoluene is 3.1-4.2;
(2) The reaction liquid flows through the first to sixth reaction cavities in sequence, continuous photocatalytic reaction is carried out under an ultraviolet lamp, and after post-treatment, the trichlorotoluene ortho-chloride is obtained, wherein the wavelength of the ultraviolet lamp is 360-370nm, the power is 15-80 w, the total residence time of the reaction liquid in the reaction cavities is 80-150 s, and as the reaction cavities are connected in series and comprise small sections of channels, the total residence time of the reaction liquid in the reaction cavities accurately comprises the total residence time of the reaction liquid in the reaction cavities and the passing time of the reaction liquid in small sections of pipelines connected between the reaction cavities.
The preparation method comprises the following steps of preparing the o-chlorotrifluoromethane 1# -3# and the comparative o-chlorotrifluoromethane D1# -D3#, wherein the specific differences are as follows:
1# o-chlorotrifluoromethylene
(1) Enabling ortho-chlorotoluene to enter a preheating cavity in the microreactor through a constant-flow pump, and preheating to 110 ℃;
(2) According to the reaction molar ratio of chlorine to o-chlorotoluene of 3.6, setting the flow rates of the o-chlorotoluene and the chlorine plunger pump to be 42ml/min and 24.7L/min respectively, and continuously conveying the flows to the microreactor respectively;
(3) Chlorine and preheated o-chlorotoluene enter a mixing cavity to be mixed;
(4) The reaction liquid sequentially passes through the first reaction cavity to the sixth reaction cavity, and is subjected to photocatalytic reaction under the catalysis of ultraviolet light of 365nm and 50w, the temperature of the reaction cavity is controlled to be 110 ℃, and the total retention time of the reaction liquid in the reaction cavity is 105s.
(5) And cooling the reaction liquid flow through a cooling cavity, then feeding the reaction liquid flow into a post-treatment device, sequentially carrying out nitrogen purging and alkali liquor absorption tail gas treatment, wherein the used alkali liquor is a sodium hydroxide solution, the mass concentration is 20%, and finally rectifying to obtain the product of the o-chlorotrifluoromethylene No. 1.
O-chlorotrifluoromethylene 2#
(1) Enabling ortho-chlorotoluene to enter a preheating cavity in the microreactor through a constant-flow pump and preheating to 90 ℃;
(2) According to the reaction molar ratio of chlorine to o-chlorotoluene of 3.1, setting the flow rates of the o-chlorotoluene and the chlorine plunger pump to be 53.6ml/min and 36.6L/min respectively, and continuously conveying the flows to the microreactor respectively;
(3) Chlorine and preheated o-chlorotoluene enter a mixing cavity to be mixed;
(4) The reaction liquid sequentially passes through the first reaction cavity to the sixth reaction cavity, photocatalytic reaction is carried out under the catalysis of ultraviolet light of 360nm and 15w, the temperature of the reaction cavities is controlled to be 90 ℃, and the total retention time of the reaction liquid in the reaction cavities is 80s.
(5) And cooling the reaction liquid flow through a cooling cavity, then feeding the reaction liquid flow into a post-treatment device, sequentially carrying out nitrogen purging and alkali liquor absorption tail gas treatment, wherein the used alkali liquor is a sodium hydroxide solution, the mass concentration is 20%, and finally rectifying to obtain the product of the o-chlorotrifluoromethylene No. 2.
O-chlorotrifluoromethylene 3#
(1) Enabling ortho-chlorotoluene to enter a preheating cavity in the microreactor through a constant-current pump and preheating to 140 ℃;
(2) According to the reaction molar ratio of chlorine to o-chlorotoluene of 4.2, setting the flow rates of the o-chlorotoluene and the chlorine plunger pump to be 24.5ml/min and 12.35L/min respectively, and continuously conveying the flows to the microreactor respectively;
(3) Chlorine and preheated o-chlorotoluene enter a mixing chamber to be mixed;
(4) The reaction liquid sequentially passes through the first reaction cavity to the sixth reaction cavity, and is subjected to photocatalytic reaction under the catalysis of ultraviolet light of 370nm and 80w, the temperature of the reaction cavity is controlled to be 140 ℃, and the total retention time of the reaction liquid in the reaction cavity is 150s.
(5) And cooling the reaction liquid flow through a cooling cavity, then feeding the reaction liquid flow into a post-treatment device, sequentially carrying out nitrogen purging and alkali liquor absorption tail gas treatment, wherein the used alkali liquor is a sodium hydroxide solution, the mass concentration is 20%, and finally rectifying to obtain the product of the o-chlorotrifluoromethylene No. 3.
Comparison of o-chlorotrifluoromethylene D1#
And (3) compared with the o-chlorotrifluoromethane No. 1, enabling the reaction liquid to only flow through one reaction cavity, controlling the flow of the o-chlorotrifluoromethane and the chlorine plunger pump to keep the total residence time of the reaction liquid in the reaction cavity to be 105s, and finally obtaining a product, namely, the o-chlorotrifluoromethane D1 No. by controlling the flow of the o-chlorotrifluoromethane and the chlorine plunger pump, wherein other steps and conditions are the same as those in the example 1.
Comparison of o-chlorotrifluoromethylene D2#
Compared with the o-chlorotrifluoromethane No. 1, the o-chlorotrifluoromethane directly enters the mixing cavity through the advection pump to be mixed with chlorine, does not enter the preheating cavity to be preheated, and other steps and conditions are the same as those in the embodiment 1, and finally the product, namely the comparative o-chlorotrifluoromethane D2# is obtained.
Comparison of o-chlorotrifluoromethylene D3#
Compared with the o-chlorotrifluoromethane No. 1, the o-chlorotrifluoromethane enters the preheating cavity through the advection pump to be preheated, then directly enters the reaction cavity to carry out photocatalytic reaction without being mixed with chlorine gas through the mixing cavity, other steps and conditions are the same as those in the embodiment 1, and finally the product, namely the o-chlorotrifluoromethane D3 is obtained.
Example 3
This example relates to the preparation of o-chlorotrifluoromethylene # 4-11, the preparation process and conditions are shown in table 1, and the other conditions are the same as those of the o-chlorotrifluoromethylene # 1 in example 2.
Example 4
The embodiment relates to preparation of o-chlorotrifluoromethylene 12#, and the power of an ultraviolet lamp in a reaction cavity arranged in the preparation process is increased along with the flowing direction of reaction liquid, and the preparation method specifically comprises the following steps: the power of the ultraviolet lamps of the first reaction cavity, the second reaction cavity and the third reaction cavity is 50w, the power of the ultraviolet lamps of the fourth reaction cavity is 55w, the power of the ultraviolet lamps of the fifth reaction cavity is 65w, the power of the ultraviolet lamps of the sixth reaction cavity is 75w, and other conditions are the same as the preparation conditions of the o-chlorotrifluoromethylene 1# in the embodiment 2.
Experimental example 1
The o-chlorotrifluoromethane conversion rate, the content of acyl chloride impurities, the content of other impurities and the product purity of the o-chlorotrifluoromethane 1# -12 # prepared in the examples 2-4 and the comparative o-chlorotrifluoromethane D1# -D3# were detected and calculated, and the results are shown in the following table 2.
As can be seen from the data in table 2, from nos. 1#, 4#, and 5#, the too low ratio of chlorine to o-chlorotoluene results in incomplete reaction of o-chlorotoluene, resulting in too much residual o-chlorotoluene and very low conversion rate of reactants, while the too high ratio of chlorine to o-chlorotoluene of example No. 5# does not improve the conversion rate of o-chlorotrifluoroethylene compared to example 1# and also results in increased content of acid chloride impurities due to promotion of conversion of o-chlorotrifluoroethylene to o-chlorobenzoyl, but the too high ratio of chlorine to o-chlorotoluene of example 5# results in a more complete reaction of o-chlorotrifluoroethylene compared to example 4# in which the ratio of chlorine to o-chlorotoluene is too low, and thus the conversion rate of o-chlorotrifluoroethylene is higher; it is known from # 1, # 6 and # 7 that when the temperature is too low, the conversion rate of the reaction is low, and when the temperature is too high, the conversion rate of the reaction is high, but when the temperature is too high, the impurity content is also increased correspondingly, because the carbonization of the reactant is caused by the too high temperature. It can be known from # 1, # 8 and # 9 that the residence time is too short, the reaction of the reactant is insufficient, the conversion rate of the reaction is low, and the residence time is long, although the reaction of the reactant is more thorough, the reaction conversion rate is also high, but because the photocatalytic reaction in the application is a micro reaction every time, the reaction time is too long, the flux can be greatly reduced, and the production efficiency can be greatly influenced. It is known from # 1, # 10 and # 11 that the power of the ultraviolet lamp is too low, the photocatalysis effect is poor, the reaction conversion rate is too low, while the power of the ultraviolet lamp is too high, although the reaction conversion rate is improved, the power of the ultraviolet lamp is too high, the energy is too strong, reactants are carbonized, the impurity content is increased, and the reaction conversion rate is reduced.
Those not described in detail in this specification are within the skill of the art. The above description is only an example of the present application and is not intended to limit the present application. Various modifications and changes may occur to those skilled in the art to which the present application pertains. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.
Claims (10)
1. A method for preparing o-chlorotrifluoromethane by micro-reaction continuous photocatalysis of o-chlorotoluene is characterized in that,
providing a micro reactor, wherein the micro reactor comprises a mixing cavity and at least 3 reaction cavities, and ultraviolet lamps are arranged outside the reaction cavities;
the method specifically comprises the following steps:
(1) Conveying the preheated o-chlorotoluene to the mixing cavity, and introducing chlorine into the mixing cavity to obtain a reaction solution;
(2) And the reaction liquid sequentially flows through the reaction cavity, continuous photocatalytic reaction is carried out under the ultraviolet lamp, and the o-chlorotrifluoromethylene is obtained after post-treatment.
2. The method of claim 1, wherein the temperature of the reaction chambers is 90-140 ℃ and the temperature difference between the reaction chambers is no greater than 3 ℃.
3. The method of claim 1, wherein the molar ratio of chlorine to o-chlorotoluene is 3.1 to 4.2.
4. The method according to claim 1, wherein the ultraviolet lamp has a wavelength of 360 to 370nm and a power of 15 to 80w.
5. The method of claim 4, wherein the number of the reaction chambers is at least 6, and the power of the ultraviolet lamps outside the reaction chambers increases along the flowing direction of the reaction liquid.
6. The method according to claim 5, wherein the number of the reaction chambers is 6, and the reaction chambers are respectively a first reaction chamber, a second reaction chamber, a third reaction chamber, a fourth reaction chamber, a fifth reaction chamber and a sixth reaction chamber, and the reaction solution flows through the first reaction chamber, the second reaction chamber, the third reaction chamber, the fourth reaction chamber, the fifth reaction chamber and the sixth reaction chamber in sequence to perform continuous photocatalytic reaction;
the power of ultraviolet lamps of the first reaction cavity, the second reaction cavity and the third reaction cavity is 15 to 50w, the power of ultraviolet lamps of the fourth reaction cavity is 55 to 60w, the power of ultraviolet lamps of the fifth reaction cavity is 65 to 70w, and the power of ultraviolet lamps of the sixth reaction cavity is 75 to 80w.
7. The method of claim 1, wherein the total residence time of the reaction solution in the reaction chamber is 80 to 150 seconds.
8. The method of claim 1, wherein the microreactor further comprises a preheating chamber, and the o-chlorotoluene is preheated in the preheating chamber and mixed with chlorine gas in the mixing chamber after being preheated in the preheating chamber in the step (1), and the temperature of the preheating chamber is 90-140 ℃.
9. The method as claimed in claim 1, wherein heart-shaped micro reaction channels are arranged in the mixing chamber and the reaction chamber, the o-chlorotoluene and the chlorine gas are mixed in the heart-shaped micro reaction channels to obtain the reaction liquid, and the reaction liquid flows in the heart-shaped micro reaction channels in the reaction chamber and is subjected to photocatalytic reaction.
10. The method as claimed in claim 9, wherein the heart-shaped micro-reaction channel comprises at least two heart-shaped micro-cavities, reaction liquid baffles are arranged in the heart-shaped micro-cavities, the reaction liquid baffles are positioned on the wide sides of the heart-shaped micro-cavities, the flow direction of the reaction liquid is from the wide sides of the heart-shaped micro-cavities to the narrow sides of the heart-shaped micro-cavities after being uniformly mixed by the reaction liquid baffles, and then flows into the wide sides of the next heart-shaped micro-cavities.
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| CN202211612829.8A CN115594563A (en) | 2022-12-15 | 2022-12-15 | Method for preparing o-chlorotrifluoromethane by micro-reaction continuous photocatalysis of o-chlorotoluene |
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| CN110818558A (en) * | 2019-12-17 | 2020-02-21 | 山东民基化工有限公司 | Method and device for continuously preparing chloro pivaloyl chloride by using micro-channel |
| CN112237892A (en) * | 2020-10-16 | 2021-01-19 | 中国恩菲工程技术有限公司 | Novel filler microchannel reaction device |
| WO2022091014A1 (en) * | 2020-10-30 | 2022-05-05 | Hikal Limited | Industrial method of producing benzisothiazolinone |
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| CN110818558A (en) * | 2019-12-17 | 2020-02-21 | 山东民基化工有限公司 | Method and device for continuously preparing chloro pivaloyl chloride by using micro-channel |
| CN112237892A (en) * | 2020-10-16 | 2021-01-19 | 中国恩菲工程技术有限公司 | Novel filler microchannel reaction device |
| WO2022091014A1 (en) * | 2020-10-30 | 2022-05-05 | Hikal Limited | Industrial method of producing benzisothiazolinone |
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| 刘诗飞等: "邻氯甲苯光氯化合成邻氯苯甲酸", 《精细石油化工》 * |
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