A reaction device for preparing a benzyl nicotinic acid salt and a preparation process thereof

Abstract

The present application relates to the technical fields of chemical synthesis, in particular to a kind of benzyl nicotinic acid salt preparation reaction equipment and its preparation process.Wherein, a kind of benzyl nicotinic acid salt preparation reaction equipment, comprising: heat preservation shell, inside having installation space;Mixing cavity, setting in the top of installation space, inside is equipped with top and is equipped with feed pipe, bottom is equipped with discharge port;Mixed reaction module, including feed cavity, mixed reaction tube and discharge cavity;Mixed reaction tube includes detection unit, mixing unit and verification unit;Collection cavity, setting below mixed reaction tube, for collection and transport mixed liquid that mixed reaction tube comes, pass through delivery line and mixing cavity and / or feed cavity communication;Two-way stirring mechanism, setting in mixing cavity and collection cavity inside.The present application can effectively inhibit side reaction without using catalyst, reduce the generation of byproduct, effectively improve the ability of walking and deep plating, with good industrial value.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis technology, and in particular to a reaction apparatus and preparation process for the preparation of benzylnicotinic acid humate salt. Background Technology

[0002] Benzylpyridinium 3-carboxylate (BPC), as a core brightener in cyanide-free zinc plating processes, has become a key material driving technological upgrades in the industry due to its superior brightening and leveling properties. It can precisely control the deposition behavior of metal ions during electroplating, significantly improve the leveling of the coating, and achieve a mirror-like gloss, effectively enhancing the appearance quality and corrosion resistance of products.

[0003] Currently, BPC is mainly prepared through the chemical reaction of nicotinic acid with benzyl chloride and sodium hydroxide. The main synthetic reaction is: C6H5NO2 + C7H7Cl + NaOH → C 13 H 11 NO2 + +NaCl + H₂O, the specific equation is as follows: Figure 1 As shown.

[0004] Several side reactions occur alongside the main reaction. The primary side reaction occurs at lower pH levels, where benzyl chloride hydrolyzes to produce benzyl alcohol: C7H7Cl + H2O → C7H7OH + HCl. The specific equation is as follows: Figure 2 As shown; or at high temperature, benzyl alcohol undergoes dehydration coupling to generate dibenzyl ether: 2C7H7OH→C6H5CH2-O-C6H5CH2+H2O, the specific equation is as follows. Figure 3 As shown. At higher pH levels, benzyl chloride readily undergoes hydrolysis to produce benzyl alcohol: C6H5CH2Cl + NaOH → C6H5CH2OH + NaCl, or undergoes an elimination reaction to produce styrene: C6H5CH2Cl + 2NaOH → C6H5=CH2 + NaCl + H2O.

[0005] To suppress side reactions and improve product purity, the market currently mainly uses a mixture of K2CO3 or Na2CO3 and quaternary ammonium salts as composite catalysts, and introduces buffers to shorten the overall reaction time and increase purity.

[0006] However, the catalyst components introduced into the reaction system, such as quaternary ammonium salts, may react with metal ions (such as Zn) in the electroplating solution. 2+The formation of complexes alters the deposition behavior, leading to uneven metal deposition rates and potentially resulting in uneven coating thickness or localized "burning." It also affects the coating crystallization process, potentially causing coarse crystals or a loose coating. Furthermore, besides affecting the coating appearance, the introduction of catalysts can contaminate the plating solution during continuous use, impacting its long-term stability and increasing the difficulty of process control and wastewater treatment. Additionally, quaternary ammonium salts may decompose in strong alkalis, generating colored polymers or oxidation products, causing the solution to darken.

[0007] As mentioned above, the conventional synthesis of benzyl nicotinic acid humate involves a composite catalyst and buffer. However, this approach results in catalyst residue in the obtained benzyl nicotinic acid humate, which affects the coating effect during the zinc plating process. Without a catalyst, existing reaction equipment provides relatively crude control over the reaction process, failing to precisely control the pH and temperature in different regions. It can only add a conditioning solution dropwise through the feed structure and then disperse the conditioning solution in the mixture using a stirring device. As the main reaction proceeds, numerous side reactions occur, leading to excessive byproducts and ultimately affecting the product yield.

[0008] Furthermore, at high temperatures, benzyl nicotinic acid salt not only undergoes a side reaction of benzyl alcohol dehydration coupling to form dibenzyl ether, but also a reaction involving the elimination of benzyl chloride to form styrene. When the system temperature is above 90 °C and alkaline conditions are present, benzyl chloride readily forms benzyl alcohol, with the hydrolysis rate increasing 5-8 times for every 10 °C increase in temperature; and at temperatures above 100 °C, a significant elimination reaction to form styrene occurs, with trace amounts also forming above 80 °C. If insufficient stirring is performed during the dropwise addition of benzyl chloride or in the initial stage of the reaction, it can lead to excessively high local concentrations of benzyl chloride, resulting in localized violent reactions and a rapid rise in local temperature. Traditional reaction equipment relies solely on a single stirring device to mix the materials during feeding and reaction. However, stirring can cause laminar flow of the materials under centrifugal force, or create dead zones in the peripheral areas, leading to uneven material distribution or failure to disperse accumulated heat, ultimately resulting in the failure of reaction condition control.

[0009] Therefore, there is an urgent need to develop a reaction device that can produce high-purity benzyl nicotinic acid salts without introducing a catalyst by precisely controlling parameters such as the temperature and pH of the reaction solution during the reaction process, while enabling large-scale continuous production. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide a reaction apparatus for the preparation of benzyl nicotinic acid humate salt, thereby solving the problem that the existing benzyl nicotinic acid humate salt preparation process requires the introduction of a composite catalyst, which affects the coating during subsequent use.

[0011] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a reaction apparatus for preparing benzyl nicotinic acid humate salt, comprising:

[0012] Insulated housing with internal installation space;

[0013] The mixing chamber is located at the top of the installation space, and has a feed pipe at the top and a discharge port at the bottom.

[0014] The mixing reaction module includes a feed chamber, mixing reaction tubes, and a discharge chamber. Multiple mixing reaction tubes are arranged in a ring below the feed chamber. The feed chamber is connected to the discharge port via a connecting pipe. The feed chamber has a distribution port corresponding to each mixing reaction tube. The mixed liquid in the feed chamber flows through the mixing reaction tubes and enters the discharge chamber, which is connected to the feed chamber via a conveying pipe. The mixing reaction tube includes at least one detection unit, a mixing unit, and a verification unit. The detection unit detects the pH value of the solution entering the mixing unit. The side wall of the mixing unit has an adjustment pipe connected to an adjustment liquid conveying pipe, which delivers adjustment liquid to the mixing reaction tube according to the signal from the detection unit. The verification unit is located below the mixing unit and is used to detect changes in the transmittance of the liquid flowing through the verification unit.

[0015] A collecting chamber, located below the mixing reaction tube, is used to collect and transport the mixed liquid from the mixing reaction tube, and is connected to the mixing chamber and / or the feeding chamber through a conveying pipeline;

[0016] A two-way stirring mechanism is installed inside the mixing chamber and the collecting chamber to fully stir the liquids in the mixing chamber and the collecting chamber.

[0017] In one embodiment, the detection unit is disposed on top of the mixing unit, and a pH meter and a temperature sensor are embedded in the side wall of the detection unit.

[0018] In one embodiment, the detection unit, the mixing unit, and the verification unit are fitted with segmented heat exchange rings, which adjust the heat exchange temperature according to the signals from the detection unit and / or the verification unit.

[0019] In one embodiment, the verification unit includes a cylindrical body, a fixed sleeve, a transparent window, a laser, and a receiver. The side wall of the cylindrical body has a pair of fitting grooves, and the transparent window is disposed in the fitting grooves. The fixed sleeve is fitted onto the cylindrical body, and the fixed sleeve has two illumination holes, which extend from the fixed sleeve to the corresponding transparent window. The laser and the receiver are respectively disposed in the illumination holes.

[0020] In one embodiment, the diameter of the mixing unit is first reduced and then increased to form a Venturi structure, and the regulating pipe is connected to the part of the mixing unit with the smallest diameter.

[0021] In one embodiment, the outer walls of the mixing chamber and the collecting chamber are provided with heat exchange ring pipes.

[0022] In one embodiment, a circulation pump and a delivery pump are provided on the delivery pipeline. The circulation pump circulates the mixture in the mixing reaction module, and the delivery pump pumps the mixture in the collection chamber to the mixing chamber or the feeding chamber.

[0023] In one embodiment, the bidirectional stirring mechanism includes a drive motor, a gear frame, a drive bevel gear, a first bevel gear and a second bevel gear, a hollow rotating shaft and a driven shaft. The drive bevel gear, the first bevel gear and the second bevel gear are mounted on the gear frame. The drive bevel gear is connected to the output end of the drive motor. The first bevel gear and the second bevel gear mesh with the drive bevel gear and are respectively mounted on the upper and lower sides of the drive bevel gear. The hollow rotating shaft is connected to the second bevel gear. The driven shaft is connected to the first bevel gear and passes through the axis of the hollow rotating shaft and extends downward. The drive motor causes the hollow rotating shaft and the driven shaft to rotate in opposite directions. Both the hollow rotating shaft and the driven shaft are provided with stirring paddles at their ends.

[0024] A process for preparing benzylnicotinic acid humate salt, using the reaction equipment for preparing benzylnicotinic acid humate salt as described above, includes the following steps:

[0025] In the reaction apparatus for preparing benzyl nicotinic acid monoxide, sodium hydroxide solution is added to dissolve nicotinic acid in sodium hydroxide solution. Then, benzyl chloride is added dropwise at 70℃~75℃ with thorough stirring during the dropwise addition process. Then, the first stage, the second stage and the third stage of reaction are carried out in sequence to obtain benzyl nicotinic acid monoxide.

[0026] The first stage reaction was carried out at pH 6.5–6.8 for 35–50 min; the second stage reaction was carried out at pH 6.8 at a uniformly increased pH of 7.3 for 45–60 min; and the third stage reaction was carried out at pH 7.4 ± 0.1 for 25–35 min. The reaction temperature for the first stage was 70℃–75℃, and the reaction temperature for the second and third stages was 75℃–80℃.

[0027] In one embodiment, the molar ratio of nicotinic acid, sodium hydroxide and benzyl chloride is 1.01-1.05:1.01-1.05:1.

[0028] In one embodiment, the concentration of the sodium hydroxide solution is 5% to 40% by mass fraction, and the concentration of the sodium hydroxide solution used in the pH adjustment process is 5% to 15%. Preferably, the concentration of the sodium hydroxide solution is 22%.

[0029] In one embodiment, the ratio of the sodium hydroxide solution addition rate in the first stage to the sodium hydroxide solution addition rate in the second stage is 2 to 3:1.

[0030] In one embodiment, the first stage, the second stage, and the third stage are respectively cyclical within the mixing reaction module, and the cycle from the mixing reaction module to the collection cavity and then back to the mixing cavity occurs when different reaction stages alternate.

[0031] The beneficial effects of this invention are as follows:

[0032] 1. The reaction equipment for preparing benzyl nicotinic acid monoxide provided by the present invention forms a reaction chamber that integrates, disperses, and reassembles through a mixing chamber, a mixing reaction module, and a collecting chamber. While enabling mass production, it allows for precise control of the reaction at different stages within the mixing reaction module, significantly improving reaction efficiency and shortening reaction time. At the same time, it can suppress the occurrence of side reactions, resulting in a low content of byproducts in the obtained benzyl nicotinic acid monoxide, effectively improving its penetration depth in galvanizing applications, and has good industrial application value.

[0033] 2. This invention employs a mixing chamber combined with a bidirectional stirring mechanism. This allows for timely dispersion of the feed material upon addition, and the bidirectional stirring mechanism creates turbulence within the mixing chamber, ensuring a uniform overall component distribution in the resulting mixture and preventing localized excessive concentrations. Furthermore, the mixing reaction module of this invention disperses the mixture into multiple mixing reaction tubes via the feed chamber, which then flows into a collecting chamber. This allows the mixture to circulate within the mixing reaction module, preventing localized heat buildup and effectively suppressing side reactions.

[0034] 3. The preparation process provided by this invention has strict pH control requirements for the first, second, and third stages of the benzyl nicotinic acid humate reaction. Traditional reaction equipment typically relies on the feed pipe to regulate the overall pH value when adding the adjusting solution. This overall adjustment process is lagging and cannot obtain actual feedback, thus traditional reaction equipment cannot meet the pH control requirements of this invention. However, this invention, by setting a detection unit in the mixing reaction tube, detects the pH value of the mixture in different sections of the mixing reaction tube, thereby transmitting the signal to the adjusting solution delivery pipe in real time. The adjusting solution delivery pipe then delivers the adjusting solution into the reaction tube according to the actual pH of the mixture, ensuring that the pH of the mixture meets the requirements and guaranteeing the accuracy of parameter adjustment.

[0035] 4. The overall appearance of benzylnicotinic acid humeral salt varies from pale yellow to dark brown depending on its concentration and the content of byproducts. During the reaction, if excessive byproducts are generated due to local temperature or pH fluctuations, dark brown or blackish-brown substances will appear in the final product, seriously affecting product quality. This invention disperses the reaction solution using a mixing reaction module and detects and adjusts the pH value during the reaction process using a detection unit. While this can suppress side reactions, benzylnicotinic acid humeral salt has numerous side reactions, and the overall process is affected by multiple factors such as stirring, temperature, and pH. Furthermore, the degree of influence of different factors varies at different stages of the reaction. The detection unit only reflects one aspect of the reaction environment; operators still cannot directly obtain the actual effect of pH or dispersion adjustments, and cannot effectively monitor the overall reaction process. Relying on the quality of the final product to compare reaction conditions is not only costly in the initial stages and prone to causing waste, but also makes it difficult for operators to identify the source of problems due to control deviations and other factors. Therefore, this invention employs a verification unit to irradiate the reaction solution with light. When dark brown or blackish-brown substances disperse and flow through the verification unit, they absorb a significant amount of light emitted by the laser compared to a normal mixture, resulting in a substantial decrease in the light intensity received by the receiver. The intensity changes detected by the verification unit can display the formation of byproducts during the reaction process in real time, directly indicating whether byproducts are formed. The effect of parameter adjustments can be directly verified during the reaction, providing operators with real-time feedback and enabling effective control of the reaction environment.

[0036] In specific control, when the verification unit detects a significant drop in light intensity, the corresponding mixing reaction tube can automatically lower the corresponding reaction temperature or pH value according to the settings, thereby suppressing side reactions. If the verification unit continues to malfunction or multiple mixing reaction tubes malfunction, the delivery path of the reaction liquid can be adjusted through the delivery pipeline, causing the reaction liquid to flow into the collecting chamber for re-stirring before being input into the mixing reaction module. An alarm signal will be sent to the operator, indicating that the overall process is abnormal and prompting manual intervention. This allows the equipment to automatically maintain dynamic balance in the reaction process and promptly alert manual intervention in the event of significant abnormalities. This not only allows for timely adjustment of the reaction process but also alerts manual intervention in the event of significant abnormalities, thereby ensuring the quality of the final product.

[0037] 5. The reaction equipment for preparing benzyl nicotinic acid hum salt provided by the present invention can combine data from the detection unit and the verification unit in real time to control the reaction parameters in a timely manner and provide intuitive feedback on the adjustment effect, making the overall reaction process more controllable. Thus, it can accurately suppress the generation of by-products without introducing a catalyst, and effectively improve the reaction yield and purity of benzyl nicotinic acid hum salt.

[0038] 6. The preparation process of benzyl nicotinic acid humate provided by this invention precisely controls the pH and temperature of the three stages using reaction equipment for benzyl nicotinic acid humate preparation. The reaction process is adjusted in real time according to actual conditions, and timely feedback is obtained for further adjustments to ensure the normal progress of the main reaction. Therefore, without the use of a catalyst, side reactions can be effectively suppressed and the formation of byproducts reduced, demonstrating significant industrial value.

[0039] Other features and beneficial effects of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects of the invention and other beneficial effects may be realized and obtained by means of the structures and / or components pointed out in the description and claims. Attached Figure Description

[0040] Figure 1 The main reaction equation for the synthesis of benzylnicotinic acid humate salt;

[0041] Figure 2 The equation for the hydrolysis of benzyl chloride to produce benzyl alcohol;

[0042] Figure 3 The equation for the dehydration coupling of benzyl alcohol to dibenzyl ether;

[0043] Figure 4 This is a perspective view of an embodiment of the present invention;

[0044] Figure 5 for Figure 4 Top view;

[0045] Figure 6 for Figure 5 Cross-sectional view at point AA;

[0046] Figure 7 for Figure 6 A magnified view of a section at point B in the middle;

[0047] Figure 8 for Figure 4 Exploded view;

[0048] Figure 9 This is an exploded view of a unit group of mixing reaction tubes in one embodiment of the present invention;

[0049] Figure 10 This is a cross-sectional view of a unit group of mixing reaction tubes in one embodiment of the present invention;

[0050] Figure 11 This is a cross-sectional view of a unit group of mixing reaction tubes in another embodiment of the present invention;

[0051] Figure 12 The images show a comparison of the physical objects of Embodiment 1 of the present invention with Comparative Examples 1 and 2.

[0052] Label Explanation:

[0053] 1. Insulated shell; 2. Mixing chamber; 21. Feed pipe; 22. Discharge port; 3. Mixing reaction module; 31. Feed chamber; 311. Connecting pipe; 312. Distribution port; 32. Mixing reaction tube; 321. Detection unit; 3211. pH meter; 3212. Temperature sensor; 322. Mixing unit; 323. Verification unit; 3231. Cylinder; 3232. Fixing sleeve; 3233. Transparent window; 3234. Laser 3235, Receiver; 324, Heat exchanger ring; 33, Discharge chamber; 34, Regulating pipeline; 35, Regulating liquid conveying pipe; 4, Collecting chamber; 5, Conveying pipeline; 51, Circulating pump; 52, Conveying pump; 6, Bidirectional stirring mechanism; 61, Drive motor; 62, Gear frame; 63, Drive bevel gear; 64, First bevel gear; 65, Second bevel gear; 66, Hollow rotating shaft; 67, Driven shaft; 68, Stirring paddle; 7, Heat exchanger ring. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. The technical features designed in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] In the description of this invention, it should be noted that all terms used in this invention (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains, and should not be construed as limiting the invention; it should be further understood that the terms used in this invention should be understood to have the same meaning as those in the context of this specification and in the relevant field, and should not be understood in an idealized or overly formal sense, except as expressly defined in this invention.

[0056] like Figures 4-11 As shown, a reaction apparatus for preparing benzylnicotinic acid humate salt includes:

[0057] Insulated housing 1, with internal installation space;

[0058] The mixing chamber 2 is located at the top of the installation space, and has a feed pipe 21 at the top and a discharge port 22 at the bottom.

[0059] The mixing reaction module 3 includes a feeding chamber 31, mixing reaction tubes 32, and a discharging chamber 33. Multiple mixing reaction tubes 32 are arranged in a ring shape and positioned below the feeding chamber 31. The feeding chamber 31 is connected to the discharging port 22 via a connecting pipe 311. The feeding chamber 31 has a distribution port 312 corresponding to the mixing reaction tubes 32. The mixed liquid in the feeding chamber 31 flows through the mixing reaction tubes 32 and enters the discharging chamber 33. The discharging chamber 33 is connected to the feeding chamber 31 via a conveying pipe 5. The mixing reaction tubes 32 include... At least one set of detection unit 321, mixing unit 322 and verification unit 323. Detection unit 321 is used to detect the pH value of the solution entering mixing unit 322. The side wall of mixing unit 322 is provided with regulating pipe 34, which is connected to regulating liquid delivery pipe 35. Regulating liquid delivery pipe 35 delivers regulating liquid to mixing reaction pipe 32 according to the signal sent by detection unit 321. Verification unit 323 is located below mixing unit 322 and is used to detect the change in transmittance of liquid flowing through verification unit 323.

[0060] The collecting chamber 4 is located below the mixing reaction tube 32 and is used to collect and transport the mixed liquid transported from the mixing reaction tube 32. It is connected to the mixing chamber 2 and the feeding chamber 31 separately through the conveying pipeline 5; or the collecting chamber 4 is connected to the mixing chamber 2 and the feeding chamber 31 simultaneously through the conveying pipeline 5.

[0061] A bidirectional stirring mechanism 6 is installed inside the mixing chamber 2 and the collecting chamber 4 to fully stir the liquids in the mixing chamber 2 and the collecting chamber 4.

[0062] Specifically, in the mixing reaction tube 32, a detection unit 321, a mixing unit 322, and a verification unit 323 are connected in sequence to form a unit group.

[0063] Specifically, the conditioning solution is a 15% sodium hydroxide solution.

[0064] Specifically, the collecting chamber 4 outputs the mixture to the outside through the delivery pipeline 5.

[0065] Preferably, each mixing reaction tube 32 consists of at least three sets of detection units 321, mixing units 322, and verification units 323. This arrangement ensures that the mixture has sufficient detection, adjustment, and reaction time when passing through the mixing reaction tube 32 once. Those skilled in the art can adjust the length of the mixing reaction tube 32, the number of sets in each unit, and the number of mixing reaction tubes 32 according to production volume, without making specific limitations.

[0066] Preferably, the dispensing port 312 is equipped with a solenoid valve. In actual operation, the operator can control the mixture to enter a specific mixing reaction tube 32 or shield a specific mixing reaction tube 32 through the solenoid valve on the dispensing port 312, thereby improving the overall adjustability.

[0067] Specifically, a solenoid valve is installed on the regulating pipeline 34. The solenoid valve can adjust its opening degree according to the signal transmitted from the detection unit 321, thereby controlling the amount of regulating liquid added and ensuring the accuracy of pH value control.

[0068] Specifically, the actual transmittance range can be adjusted by those skilled in the art based on the concentration of the target product, and is not specifically limited.

[0069] Preferably, the middle part of the discharge cavity 33 is positioned to avoid the bidirectional stirring mechanism 6 of the collection cavity 4, thus saving installation space.

[0070] In this embodiment, the detection unit 321 is disposed on the top of the mixing unit 322, and the side wall of the detection unit 321 is embedded with a pH meter 3211 and a temperature sensor 3212.

[0071] Preferably, to ensure detection accuracy and prevent detection failure due to malfunctions of the pH meter 3211 and temperature sensor 3212, each detection unit 321 is equipped with two pH meters 3211 and two temperature sensors 3212. This arrangement allows the pH meters 3211 and temperature sensors 3212 in each detection unit 321 to compare with each other, improving detection accuracy. Furthermore, the solenoid valve on the regulating liquid delivery pipe 35 can be adjusted based on the average values ​​of the pH meters 3211 and temperature sensors 3212, thereby ensuring the accuracy of the adjustment.

[0072] As a crucial parameter in the synthesis of benzyl nicotinic acid humate, the reaction temperature is precisely controlled. In this embodiment, the detection unit 321, mixing unit 322, and verification unit 323 are fitted with segmented heat exchange rings 324. The heat exchange rings 324 at different positions adjust the heat exchange temperature according to the signals from the detection unit 321 or verification unit 323, or the entire device adjusts the heat exchange temperature after judging the signals from the detection unit 321 and verification unit 323.

[0073] Specifically, a semiconductor cooling chip is provided inside the heat exchange ring 324. When the semiconductor cooling chip receives a signal from the detection unit 321 or the verification unit 323 that the temperature is too high or that a large number of side reactions are occurring, it cools down to ensure that the temperature of the reaction liquid does not exceed the limit value.

[0074] Preferably, the temperature of the heat exchange ring 324 corresponding to the detection unit 321 is adjusted according to the temperature of the mixed liquid measured by the detection unit 321. The initial temperature of the heat exchange ring 324 on the verification unit 323 and the mixing unit 322 is the same as that of the heat exchange ring 324 corresponding to the detection unit 321. When the verification unit 323 detects that the transmittance fluctuates beyond the range, the temperature of the heat exchange ring 324 on the current and next verification units 323 and the mixing unit 322 is reduced or cooled until the transmittance returns to the normal range.

[0075] In this embodiment, the verification unit 323 includes a cylindrical body 3231, a fixing sleeve 3232, a transparent window 3233, a laser 3234, and a receiver 3235. A pair of fitting grooves are formed on the side wall of the cylindrical body 3231, and the transparent window 3233 is disposed within the fitting grooves. The fixing sleeve 3232 is fitted onto the cylindrical body 3231, and two illumination holes are formed on the fixing sleeve 3232, extending from the fixing sleeve 3232 to the corresponding transparent window 3233. The laser 3234 and receiver 3235 are respectively disposed within the illumination holes. Specifically, the fixing sleeve 3232 has a clearance groove corresponding to the transparent window 3233, allowing the transparent window 3233 to be partially embedded in the fixing sleeve 3232, so that the laser 3234 and receiver 3235 abut against the transparent window 3233, ensuring that the relative positions of the laser 3234 and receiver 3235 remain unchanged.

[0076] Preferably, the inner diameter of the verification unit 323 gradually increases from the connection point with other units to the transparent window 3233, and the ratio of the maximum inner diameter of the verification unit 323 to the maximum inner diameter of the mixing unit 322 is 1.2 to 3:1. That is, the internal cavity structure of the verification unit 323 has an overall structure that first expands and then shrinks. This arrangement can slow down the mixing liquid entering the verification unit 323 from the mixing unit 322, and at the same time allow any air bubbles that may exist in the mixing liquid to fully break, effectively avoiding interference from air bubbles in the transmittance detection.

[0077] Preferably, the laser wavelength emitted by laser 3234 is 400–700 nm. More preferably, the laser wavelength emitted by laser 3234 is 400–450 nm or 500–700 nm. Preferably, laser 3234 emits lasers of different wavelengths simultaneously, and by simultaneously detecting the intensity attenuation of multiple lasers, the situation of by-product testing can be accurately reflected.

[0078] To ensure that the regulating liquid is fully mixed with the mixed liquid in the pipeline after addition, in this embodiment, the diameter of the mixing unit 322 first decreases and then increases to form a Venturi structure. The regulating pipeline 34 is connected to the point where the diameter of the mixing unit 322 is at its minimum. That is, the mixing unit 322 adopts a Venturi structure, and the diameter of the mixing unit 322 first decreases and then increases. When the mixed liquid flows through the mixing unit 322, the regulating liquid enters the mixing unit 322 through the throat of the Venturi structure. The high-speed flow of the mixed liquid impacts the regulating liquid, allowing the regulating liquid to be fully mixed with the mixed liquid.

[0079] To ensure the temperature throughout the reaction process and prevent excessive local heating of the mixture in direct contact with the heat exchange tubes, in this embodiment, heat exchange ring tubes 7 are provided on the outer walls of the mixing chamber 2 and the collecting chamber 4. These outer heat exchange ring tubes 7 conduct heat to the liquid within the mixing chamber 2 and the collecting chamber 4, ensuring the reaction temperature while suppressing side reactions. Simultaneously, the heat exchange ring tubes 7, in conjunction with the heat exchange ring sleeve 324 of the mixing reaction module 3, enable the entire device to have segmented temperature control capabilities, enhancing its adjustability. Specifically, the temperature of the heat exchange medium within the heat exchange ring tubes 7 is slightly lower than the initial set temperature to prevent a drastic temperature rise when reactants are added, which could lead to temperatures exceeding the set range. Furthermore, the heat exchange ring tubes 7 are equipped with backup heat exchange tubes that can be connected to different heat exchange media. When the temperature becomes too high and cooling is required, the backup heat exchange tubes can be activated to cool the reaction liquid promptly, thereby ensuring effective control.

[0080] In this embodiment, the conveying pipeline 5 is equipped with a circulation pump 51 and a delivery pump 52. The circulation pump 51 circulates the mixture within the mixing reaction module 3, while the delivery pump 52 pumps the mixture from the collecting chamber 4 to the mixing chamber 2 or the feeding chamber 31. This configuration allows the equipment to have both small-scale circulation within the reaction stage and large-scale circulation across stages. Alternatively, it can be configured to allow the mixture from the mixing reaction module 3 to be thoroughly stirred in the collecting chamber 4 before continuing its reaction in the mixing reaction module 3, thus improving the equipment's adjustability. Specifically, the conveying pipeline 5 is equipped with solenoid valves, allowing technicians to control the path of the mixture by switching the solenoid valves at different positions.

[0081] Preferably, a control valve is provided between the mixing reaction tube 32 and the discharge chamber 33. The control valve allows the operator to control whether different mixing reaction tubes 32 are connected to the discharge chamber 33. When the verification unit 323 detects a large number of by-products in a single mixing reaction tube 32, the valves of other mixing reaction tubes 32 can be closed while adjusting the reaction parameters. The by-products are discharged separately and the reaction cycle continues, so as to avoid the generated by-products affecting the judgment of the verification unit 323 in the cycle.

[0082] Preferably, it also includes a control module, which is electrically connected to the solenoid valve in the mixing reaction module 3, the bidirectional stirring mechanism 6, and the delivery pipeline 5 or the regulating pipeline 34, so that the operator can obtain real-time data feedback and adjust the reaction process.

[0083] In this embodiment, the bidirectional stirring mechanism 6 includes a drive motor 61, a gear frame 62, a drive bevel gear 63, a first bevel gear 64 and a second bevel gear 65, a hollow rotating shaft 66, and a driven shaft 67. The drive bevel gear 63, the first bevel gear 64, and the second bevel gear 65 are mounted on the gear frame 62. The drive bevel gear 63 is connected to the output end of the drive motor 61. The first bevel gear 64 and the second bevel gear 65 mesh with the drive bevel gear 63 and are respectively mounted on the upper and lower sides of the drive bevel gear 63. The hollow rotating shaft 66 is connected to the second bevel gear 65. The driven shaft 67 is connected to the first bevel gear 64 and passes through the axis of the hollow rotating shaft 66 and extends downward. The drive motor 61 causes the hollow rotating shaft 66 and the driven shaft 67 to rotate in opposite directions. The ends of both the hollow rotating shaft 66 and the driven shaft 67 are provided with stirring paddles 68.

[0084] In this embodiment, the mixing chamber 2 and the collecting chamber 4 adopt a structure with a cylindrical upper part and a conical lower part. The bidirectional stirring mechanism 6 includes two stirring paddles 68 of the drive motor 61, which stir in the cylindrical region and the conical region respectively. The diameter of the stirring paddle 68 in the cylindrical region is larger than that in the conical region.

[0085] The following examples are based on the reaction equipment for preparing benzyl nicotinic acid hum salt provided by the present invention. During the preparation, the first stage, the second stage and the third stage are respectively circulated in the mixing reaction module 3. When different reaction stages alternate, the cycle is performed from the mixing reaction module 3 to the collection chamber 4 and then to the mixing chamber 2.

[0086] Example 1

[0087] Add 366.6 g of sodium hydroxide solution (22% by mass) to the reaction equipment for preparing benzyl nicotinic acid humate, dissolve 250 g of nicotinic acid in the sodium hydroxide solution, and then add 250 g of benzyl chloride dropwise at 70 °C with thorough stirring during the dropwise addition process. Then carry out the first, second and third stage reactions in sequence to obtain benzyl nicotinic acid humate.

[0088] The first stage reaction was carried out at 70℃ and pH 6.5–6.8 for 40 min; the second stage reaction was carried out at 75℃ and pH 6.8 was uniformly increased to 7.2 for 50 min; the third stage reaction was carried out at 78±0.5℃ and pH 7.4±0.1 for 30 min. The pH was adjusted using 15% NaOH solution.

[0089] Upon completion of the reaction, benzylnicotinic acid humate is obtained, which is a pale yellow liquid with a product content of 48.4% (HPLC).

[0090] Example 2

[0091] 732.0 g of sodium hydroxide solution (22% by mass) was added to the reaction apparatus for the preparation of benzyl nicotinic acid humate. 500 g of nicotinic acid was dissolved in the sodium hydroxide solution. Then, 500 g of benzyl chloride was added dropwise at 70 °C with thorough stirring during the dropwise addition. The first, second and third stages of the reaction were carried out in sequence to obtain benzyl nicotinic acid humate.

[0092] The first stage reaction was carried out at 70℃ and pH 6.5–6.8 for 40 min; the second stage reaction was carried out at 75℃ and pH 6.8 was uniformly increased to 7.2 for 50 min; the third stage reaction was carried out at 78±0.5℃ and pH 7.4±0.1 for 30 min. The pH was adjusted using 15% NaOH solution.

[0093] Upon completion of the reaction, benzylnicotinic acid humate is obtained, which is a pale yellow liquid with a product content of 48.3% (HPLC).

[0094] Example 3

[0095] Add 3657.1g of sodium hydroxide solution (22% by mass) to the reaction equipment for preparing benzyl nicotinic acid humate, dissolve 2500g of nicotinic acid in the sodium hydroxide solution, and then add 2500g of benzyl chloride dropwise at 70℃ with thorough stirring during the dropwise addition process. Then carry out the first, second and third stage reactions in sequence to obtain benzyl nicotinic acid humate.

[0096] The first stage reaction was carried out at 70℃ and pH 6.5–6.8 for 40 min; the second stage reaction was carried out at 75℃ and pH 6.8 was uniformly increased to 7.3 for 50 min; the third stage reaction was carried out at 78±0.5℃ and pH 7.4±0.1 for 30 min. The pH was adjusted using 15% NaOH solution.

[0097] Upon completion of the reaction, benzylnicotinic acid humate is obtained, which is a light yellow liquid with a product content of 48.5% (HPLC).

[0098] Comparative Example 1

[0099] 366.6 g of sodium hydroxide solution (22% by mass) was added to the reaction apparatus for the preparation of benzyl nicotinic acid monoxide. 250 g of nicotinic acid was dissolved in the sodium hydroxide solution. Then, 250 g of benzyl chloride was added dropwise at 70 °C with thorough stirring during the dropwise addition. The reaction was carried out at 75 °C and pH 7.4 ± 0.1 for 2 h.

[0100] Upon completion of the reaction, benzylnicotinic acid humate is obtained, which is a light brown liquid with a product content of 40.2% (HPLC).

[0101] Comparative Example 2

[0102] Add 366.6 g of sodium hydroxide solution (22% by mass) to a conventional reactor, dissolve 250 g of nicotinic acid in the sodium hydroxide solution, adjust the pH to 7.4, and then add 250 g of benzyl chloride dropwise at 75 °C with thorough stirring during the dropwise addition. Then react at 75 °C for 2 h.

[0103] Upon completion of the reaction, benzylnicotinic acid humate is obtained, which is a dark brown liquid with a product content of 38.4% (HPLC).

[0104] Comparison charts of actual products from Example 1, Comparative Example 1, and Comparative Example 2 are shown below. Figure 12 As shown, Figure 12 From left to right, the final products of Example 1, Comparative Example 1, and Comparative Example 2 are shown in Table 1. A 500ml Hull bath experiment and a deep plating capability experiment were conducted on Example 1 and Comparative Example 2, and the specific results are shown in Table 1.

[0105] Table 1 Experimental data and results

[0106]

[0107] It should be noted that the specific parameters or some commonly used reagents in the above embodiments are specific or preferred embodiments under the concept of the present invention, and not limitations thereof; those skilled in the art can make adaptive adjustments within the concept and protection scope of the present invention.

[0108] In addition, unless otherwise specified, the raw materials used may be commercially available products in the field, or prepared by conventional methods in the field.

[0109] Furthermore, those skilled in the art should understand that although many problems exist in the prior art, each embodiment or technical solution of the present invention can be improved in only one or a few aspects, without necessarily solving all the technical problems listed in the prior art or background art simultaneously. Those skilled in the art should understand that any content not mentioned in a claim should not be construed as a limitation on that claim.

[0110] Although terms such as thermal insulation shell and hybrid cavity are frequently used in this document, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of the invention; interpreting them as any kind of additional limitation would contradict the spirit of the invention. Terms such as "first," "second," etc. (if present) in the description and claims of the embodiments of the invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A reaction apparatus for preparing benzylnicotinic acid humate, characterized in that, include: Insulated shell (1), with internal installation space; A mixing chamber (2) is located at the top of the installation space, and has a feed pipe (21) at the top and a discharge port (22) at the bottom. The mixing reaction module (3) includes a feeding chamber (31), a mixing reaction tube (32), and a discharging chamber (33). Multiple mixing reaction tubes (32) are arranged in a ring shape and positioned below the feeding chamber (31). The feeding chamber (31) is connected to the discharging port (22) via a connecting pipe (311). The feeding chamber (31) has a distribution port (312) corresponding to the mixing reaction tube (32). The mixed liquid in the feeding chamber (31) flows through the mixing reaction tube (32) and enters the discharging chamber (33). The discharging chamber (33) is connected to the feeding chamber (31) via a conveying pipe (5). The mixing reaction tube... (32) Includes at least one detection unit (321), a mixing unit (322), and a verification unit (323). The detection unit (321) is used to detect the pH value of the solution entering the mixing unit (322). The side wall of the mixing unit (322) is provided with an adjustment pipe (34). The adjustment pipe (34) is connected to an adjustment liquid delivery pipe (35). The adjustment liquid delivery pipe (35) delivers adjustment liquid to the mixing reaction tube (32) according to the signal sent by the detection unit (321). The verification unit (323) is located below the mixing unit (322) and is used to detect the change in transmittance of the liquid flowing through the verification unit (323). A collecting chamber (4) is located below the mixing reaction tube (32) and is used to collect and transport the mixed liquid transported by the mixing reaction tube (32). It is connected to the mixing chamber (2) and / or the feeding chamber (31) through the conveying pipeline (5). A bidirectional stirring mechanism (6) is disposed inside the mixing chamber (2) and the collecting chamber (4) for fully stirring the liquid in the mixing chamber (2) and the collecting chamber (4); The detection unit (321) is located on the top of the mixing unit (322), and a pH meter (3211) and a temperature sensor (3212) are embedded in the side wall of the detection unit (321). The detection unit (321), mixing unit (322) and verification unit (323) are fitted with segmented heat exchange rings (324), and the heat exchange rings (324) adjust the heat exchange temperature according to the signals of the detection unit (321) and / or the verification unit (323).

2. The reaction apparatus for preparing benzylnicotinic acid humate according to claim 1, characterized in that: The verification unit (323) includes a cylindrical body (3231), a fixing sleeve (3232), a transparent window (3233), a laser (3234), and a receiver (3235). The side wall of the cylindrical body (3231) is provided with a pair of fitting grooves, and the transparent window (3233) is disposed in the fitting grooves. The fixing sleeve (3232) is fitted on the cylindrical body (3231), and the fixing sleeve (3232) is provided with two illumination holes. The illumination holes extend from the fixing sleeve (3232) to the corresponding transparent window (3233), and the laser (3234) and the receiver (3235) are respectively disposed in the illumination holes.

3. The reaction apparatus for preparing benzylnicotinic acid humate according to claim 1, characterized in that: The diameter of the mixing unit (322) first decreases and then increases to form a Venturi structure, and the regulating pipe (34) is connected to the smallest diameter part of the mixing unit (322).

4. The reaction apparatus for preparing benzylnicotinic acid humate salt according to claim 1, characterized in that: The outer walls of the mixing chamber (2) and the collecting chamber (4) are provided with heat exchange ring pipes (7).

5. The reaction apparatus for preparing benzylnicotinic acid humate according to claim 1, characterized in that: The conveying pipeline (5) is equipped with a circulation pump (51) and a delivery pump (52). The circulation pump (51) circulates the mixture in the mixing reaction module (3), and the delivery pump (52) pumps the mixture in the collecting cavity (4) to the mixing cavity (2) or the feeding cavity (31).

6. The reaction apparatus for preparing benzylnicotinic acid humate according to claim 1, characterized in that: The bidirectional stirring mechanism (6) includes a drive motor (61), a gear carrier (62), a drive bevel gear (63), a first bevel gear (64) and a second bevel gear (65), a hollow rotating shaft (66), and a driven shaft (67). The drive bevel gear (63), the first bevel gear (64), and the second bevel gear (65) are mounted on the gear carrier (62). The drive bevel gear (63) is connected to the output end of the drive motor (61), and the first bevel gear (64) and the second bevel gear (65) are connected to the driven shaft (67). The drive bevel gear (63) meshes and is respectively disposed on the upper and lower sides of the drive bevel gear (63). The hollow rotating shaft (66) is connected to the second bevel gear (65). The driven shaft (67) is connected to the first bevel gear (64) and passes through the axis of the hollow rotating shaft (66) and extends downward. The drive motor (61) causes the hollow rotating shaft (66) and the driven shaft (67) to rotate in opposite directions. The ends of the hollow rotating shaft (66) and the driven shaft (67) are provided with stirring paddles (68).

7. A process for preparing benzylnicotinic acid monoxide, comprising using the reaction equipment for preparing benzylnicotinic acid monoxide as described in any one of claims 1 to 6, characterized in that, The preparation steps are as follows: Sodium hydroxide solution is added to the reaction equipment for preparing benzyl nicotinic acid humate salt to dissolve nicotinic acid in the sodium hydroxide solution. Then, benzyl chloride is added dropwise at 70℃~75℃ with thorough stirring during the dropwise addition process. Then, the first stage, the second stage and the third stage of the reaction are carried out in sequence to obtain benzyl nicotinic acid humate salt. The first stage is carried out at a pH of 6.5–6.8 for 35–50 min; the second stage is carried out at a pH of 7.2–7.3 with the pH being increased uniformly from 6.8 to 7.2–7.3 for 45–60 min; and the third stage is carried out at a pH of 7.4 ± 0.1 for 25–35 min. The reaction temperature of the first stage is 70℃–75℃, and the reaction temperature of the second and third stages is 75℃–80℃.

8. The preparation process of benzyl nicotinic acid humate according to claim 7, characterized in that: The molar ratio of nicotinic acid, sodium hydroxide and benzyl chloride is 1.01-1.05:1.01-1.05:1.

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