A novel Grignard formulation and method of making same

Abstract

This invention relates to the field of organic synthesis reagent preparation technology, specifically to a novel Grignard preparation with activation system and its preparation method. The raw material composition includes: 1 mol of magnesium, 1.05 mol-1.35 mol of haloalkanes, 0.5 mmol-1.8 mmol of 1,2-dibromoethane, 0.3 mmol-0.9 mmol of cuprous iodide, and a mixed solvent of ethers and aromatics; the magnesium raw material is large-particle magnesium or magnesium ingots. This invention constructs a synergistic system of composite chemical activation and ultrasonic physical activation, efficiently breaking down the oxide passivation layer on the magnesium surface, significantly improving reaction activation efficiency, shortening the reaction start-up cycle, and making the reaction start-up faster and more stable.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis reagent preparation technology, specifically to a novel activated Grignard preparation and its preparation method. Background Technology

[0002] Grignard reagents are core nucleophiles for constructing carbon-carbon bonds in organic synthesis, widely used in pharmaceuticals, pesticides, and fine chemical synthesis, and are indispensable key intermediates in modern organic synthesis. Traditional Grignard reagent preparation processes mostly employ a single chemical activator to treat magnesium raw materials, which is insufficient to completely remove the naturally occurring oxide passivation layer on the magnesium surface, resulting in low activation efficiency and long induction periods. While some improved processes introduce physical activation methods to assist the reaction, they fail to form an effective synergy with chemical activation, and the activation effect remains significantly limited.

[0003] Existing technologies mostly use magnesium powder as a reaction raw material. However, the inherent properties of magnesium powder easily lead to oxidation and agglomeration, which not only reduces the utilization efficiency of the raw material but also induces side reactions, affecting the quality of the final product. The reaction medium often uses a single solvent system, which has poor solubility for the substrate and product, making it impossible to stably maintain the equilibrium of the reaction system. At the same time, it accelerates product degradation and reduces reagent stability.

[0004] The Grignard reagents prepared by existing processes generally suffer from insufficient purity and low yield, as well as poor storage stability. They are prone to losing their reactivity when stored for a long time, making it difficult to meet the requirements for industrial storage and transportation.

[0005] In large-scale production, existing processes suffer from poor reaction controllability, difficulty in recovering and reusing unreacted magnesium raw materials, high production costs, and an inability to balance production efficiency and product quality. Current technologies in the industry have consistently failed to resolve the contradictions between activation efficiency, raw material utilization, product quality, and storage stability, hindering the efficient application of Grignard reagents in industrial production. Therefore, there is an urgent need to develop a Grignard preparation technology that offers superior activation effects, stable processes, and excellent product performance. Summary of the Invention

[0006] The primary objective of this invention is to provide a novel activated Grignard preparation system and its preparation method.

[0007] A further objective of this invention is to provide a novel Grignard reagent activation system, comprising the following raw materials: 1 mol of magnesium raw material, 1.05 mol-1.35 mol of haloalkanes, 0.5 mmol-1.8 mmol of 1,2-dibromoethane, 0.3 mmol-0.9 mmol of cuprous iodide, and a mixed solvent of ethers and aromatics; wherein the magnesium raw material is large-particle magnesium or magnesium ingots.

[0008] Preferably, the halogenated hydrocarbon is one of bromobenzene, chlorobenzene, bromoethane, and bromopropane; the mixed solvent is one of tetrahydrofuran and toluene in a volume ratio of 7:3, methyltetrahydrofuran and xylene in a volume ratio of 3:2, and diethyl ether and toluene in a volume ratio of 4:1.

[0009] Preferably, the Grignard reagent is sealed and stored in a nitrogen environment at a temperature of 0°C.

[0010] A method for preparing the novel activated Grignard reagent system, wherein the entire process is protected by nitrogen gas of 99.99% purity, and the following steps are performed sequentially: The reaction apparatus is pretreated by purging the reaction system with nitrogen to remove air and moisture from the system. Magnesium raw material pretreatment involves placing large magnesium particles or magnesium ingots into a reaction device, adding a portion of mixed solvent, turning on ultrasonic treatment, adding 1,2-dibromoethane and cuprous iodide, and stirring to complete the magnesium surface activation. Grignard reaction: The haloalkane is mixed with the remaining mixed solvent and then added dropwise to the reaction apparatus. The reaction temperature is controlled, and the reaction is continuously activated with ultrasonic assistance. The reaction is stirred until the reaction is complete. After post-processing, stop sonication, continue stirring, and filter the reaction solution under nitrogen protection to obtain the Grignard reagent.

[0011] Preferably, the ultrasonic power for magnesium raw material pretreatment is 200W-500W, the ultrasonic time is 15min-40min, and after adding 1,2-dibromoethane and cuprous iodide, the mixture is stirred for 10min-25min.

[0012] Preferably, the Grignard reaction is carried out at a dropping rate of 0.8 mL / min-100 mL / min, a reaction temperature of 28℃-38℃, a stirring speed of 300 r / min-400 r / min, and a reaction time of 2.5 h-3.5 h.

[0013] Preferably, the Grignard reaction is activated by ultrasound throughout, with an ultrasound power of 100W-200W.

[0014] Preferably, the unreacted magnesium raw material separated by filtration is washed, dried or polished and then reused in the next batch of reaction.

[0015] Preferably, the filtered reaction solution is purified by vacuum distillation in the post-processing stage.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention constructs a synergistic system of composite chemical activation and ultrasonic physical activation to efficiently remove the oxide passivation layer on the magnesium surface, significantly improve the reaction activation efficiency, shorten the reaction start-up cycle, and make the reaction start-up faster and the operation more stable.

[0017] 2. This invention uses large-particle magnesium or magnesium ingots as reaction raw materials, avoiding the defects of traditional magnesium powder being easy to oxidize and agglomerate. Combined with the unreacted raw material recycling and reuse process, it greatly improves the utilization efficiency of magnesium raw materials, reduces raw material loss, and lowers production costs.

[0018] 3. This invention uses a mixed solvent system of ethers and aromatics to optimize the solubility and stability of the reaction system, effectively suppress side reactions, improve the purity and reaction yield of the target product, and ensure stable and uniform product quality.

[0019] 4. The entire process is protected by nitrogen to isolate the system from air and moisture, preventing oxidation and hydrolysis of Grignard preparations. Combined with suitable storage conditions, this significantly improves the storage stability of the preparations, extends the effective usage period, and meets the needs of long-term storage and transportation.

[0020] 5. The reaction conditions of this invention are mild, and the process is highly controllable, making it suitable for both small-scale laboratory trials and large-scale industrial production. It consistently achieves excellent results at different production scales. This invention breaks through the technical bottleneck of existing single activation methods, creating a synergistic effect. While improving product performance, it simplifies production operations and solves the core problems of existing technologies, such as low activation efficiency, poor raw material utilization, and insufficient product stability. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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. Example

[0022] Raw material composition ratio: 1 mol of large-particle magnesium, 1.05 mol of bromobenzene, 0.5 mmol of 1,2-dibromoethane, 0.3 mmol of cuprous iodide, 700 mL of tetrahydrofuran, 300 mL of toluene, and nitrogen protective gas with a purity of 99.99%.

[0023] Preparation steps: The first step is to pretreat the reaction apparatus by connecting the reaction vessel, stirring device, dropping funnel and condenser in sequence, and then purging the entire reaction system three times with nitrogen to completely remove air and moisture from the system and prevent Grignard reagent from being oxidized or hydrolyzed. The second step is magnesium raw material pretreatment. Large magnesium particles with a nominal diameter of 2 mm are placed in a reaction vessel, 200 mL of mixed solvent is added, the ultrasonic device is turned on, the ultrasonic power is 200 W, the ultrasonic time is 15 min, 1,2-dibromoethane is added, the stirring speed is 300 r / min, and the stirring is carried out at room temperature for 10 min. Tiny bubbles are observed to be generated in the system, indicating that the magnesium surface is successfully activated. The third step involves initiating and proceeding the Grignard reaction. The remaining 500 mL of tetrahydrofuran, 300 mL of toluene, and 1.05 mol of bromobenzene are mixed thoroughly and slowly added dropwise to the reaction vessel through a dropping funnel at a dropping rate of 1.5 mL / min. During the dropping process, the reaction temperature is controlled at 28°C and maintained stable by cooling with a water bath. After the dropping is completed, the reaction is stirred for another 2.5 hours. During this period, the ultrasonic equipment is kept running at low power (100 W) to continuously assist in activation. The fourth step is post-processing. After the reaction is complete, turn off the ultrasonic equipment and continue stirring for 30 minutes to stabilize the reaction system. Then, under nitrogen protection, filter the reaction solution to remove unreacted magnesium particles and obtain the basic novel activation system Grignard preparation, which is sealed and stored in a nitrogen environment for later use. Example

[0024] Based on the basic technical solution of Example 1, the raw material composition was adjusted to: 1 mol of large-particle magnesium, 1.1 mol of bromobenzene, 1.0 mmol of 1,2-dibromoethane, 0.5 mmol of cuprous iodide, 700 mL of tetrahydrofuran, 300 mL of toluene, and nitrogen protective gas with a purity of 99.99%.

[0025] Preparation steps: The apparatus and basic steps of Example 1 are used exactly, with optimizations and adjustments only made to the process details related to the composite activator: In the second step, the ultrasonic time is extended to 20 minutes to ensure that the oxide layer on the magnesium surface is fully broken. After adding 1,2-dibromoethane and cuprous iodide, the mixture is stirred at room temperature for 15 minutes to ensure that the two activators are in full contact with the magnesium surface and exert a synergistic activation effect. In the third step, the dropping speed was adjusted to 1.2 mL / min, the reaction temperature was controlled at 30℃, and the ultrasonic low-power operation was 100W, which was continuously run throughout the entire reaction process to ensure that the activation effect remained stable. The stirring speed was increased to 350 r / min to promote uniform reaction. In the fourth step, the filtered magnesium particles are washed and dried, and then directly reused in the next batch of reaction, further reducing raw material loss and improving raw material utilization. Example

[0026] Based on the optimized activation system of Example 2, the raw material composition was adjusted to: 1 mol magnesium ingot, 1.2 mol chlorobenzene, 1.5 mmol 1,2-dibromoethane, 0.7 mmol cuprous iodide, 720 mL methyltetrahydrofuran, 480 mL xylene, and nitrogen protective gas with a purity of 99.99%.

[0027] Preparation steps: Following the basic process steps of Example 2, targeted optimizations were made based on the characteristics of the magnesium feedstock and the halogenated hydrocarbons: The first step, during the pretreatment of the reaction apparatus, is to add a heat insulation layer to the reaction vessel to avoid temperature fluctuations during the reaction process and ensure that the reaction proceeds stably; In the second step, during the pretreatment of magnesium raw materials, magnesium ingots with a nominal diameter of 5 mm were selected, the ultrasonic power was increased to 250 W, and the ultrasonic time was extended to 25 min to adapt to the characteristics of the increased particle size of magnesium ingots and ensure that the oxide layer was fully broken. After adding 1,2-dibromoethane and cuprous iodide, the mixture was stirred at room temperature for 20 min. At the same time, a small amount of the Grignard preparation prepared in Example 2 was added as an auxiliary initiator to further shorten the reaction induction period and improve the reaction efficiency. The third step involves adjusting the droplet speed of the mixture of chlorobenzene and the mixed solvent to 1.0 mL / min, controlling the reaction temperature at 32℃, maintaining the stirring speed at 350 r / min, using an ultrasonic power of 100 W, and extending the reaction time to 3 h to ensure that the magnesium ingot and chlorobenzene react fully, thereby improving the product yield and purity. In the fourth step, during post-processing, the filtered magnesium ingots are polished to remove residual reaction products from the surface and then reused three times to further improve the utilization rate of magnesium raw materials and reduce production costs. Example

[0028] Based on the technical solution of Example 3, the raw material composition was adjusted to: 1 mol magnesium ingot, 1.3 mol bromoethane, 1.8 mmol 1,2-dibromoethane, 0.9 mmol cuprous iodide, 880 mL diethyl ether, 220 mL toluene, and nitrogen protective gas with a purity of 99.99%.

[0029] Preparation steps: Following the basic process logic of Example 3, optimizations and adjustments were made to address solvent characteristics and reaction efficiency: In the first step, during the pretreatment of the reaction device, an external circulation reaction method is adopted, in which the reaction vessel and the magnesium ingot tower are connected in series, the magnesium ingot is placed in the magnesium ingot tower, and the reaction liquid is sprayed onto the magnesium ingot through a circulation pump, which greatly improves the reaction contact efficiency and accelerates the reaction. In the second step, during the pretreatment of magnesium raw materials, the ultrasonic power was increased to 300W and the ultrasonic time was extended to 30min. After adding 1,2-dibromoethane and cuprous iodide, the temperature was raised to 40℃ and stirred for 15min to accelerate the activation reaction and further enhance the activation effect. The third step involves adjusting the droplet speed of the bromoethane and mixed solvent mixture to 0.8 mL / min, controlling the reaction temperature at 38℃, increasing the stirring speed to 400 r / min, adjusting the ultrasonic power to 150 W, and setting the reaction time to 2.5 h. During this period, a circulating cooling system is used to maintain a stable temperature and prevent local overheating that could lead to side reactions. In the fourth step, during post-processing, the reaction solution is subjected to vacuum distillation to remove excess solvent and unreacted halogenated hydrocarbons, yielding a high-purity Grignard preparation. After sealing, it is stored in a nitrogen environment at 0°C, which significantly improves its storage stability. Example

[0030] Based on the optimized process scheme of Example 4, the raw material components were scaled up according to the proportion of Example 4 as follows: 100 mol magnesium ingot, 135 mol bromopropane, 180 mmol 1,2-dibromoethane, 90 mmol cuprous iodide, 82500 mL tetrahydrofuran, 27500 mL toluene, and nitrogen protective gas with a purity of 99.99%.

[0031] Preparation steps: Following the basic process logic of Example 4, adaptive optimizations were made to meet the needs of large-scale production: The first step is to use a large-scale batch reactor equipped with a high-efficiency stirring system and an ultrasonic array. During the pretreatment of the reactor, nitrogen is used to purge the system five times to ensure that the system is free of air and moisture, thus meeting the safety and quality requirements for large-scale production. The second step involves evenly placing magnesium ingots in a stainless steel mesh bag inside the reactor. The mesh bag has a sieve aperture of 5mm to prevent the magnesium ingots from colliding with the stirring paddle. 20,000 mL of mixed solvent is added, and the ultrasonic array is turned on with an ultrasonic power of 500W for 40 minutes. 1,2-Dibromoethane and cuprous iodide are then added, and the temperature is raised to 38°C. The stirring speed is 300 r / min, and the stirring is carried out for 25 minutes to complete the activation of the magnesium ingots. The third step involves mixing the remaining 62,500 mL of tetrahydrofuran, 27,500 mL of toluene, and 135 mol of bromopropane until homogeneous. This mixture is then slowly added dropwise to the reactor using a large dropping device at a rate of 100 mL / min. The reaction temperature is controlled at 35°C and maintained by jacket cooling. The ultrasonic array operates at 200 W, the stirring speed is 350 r / min, and the reaction time is 3.5 h to ensure uniform and efficient reaction during large-scale production. Fourth step: After the reaction is complete, turn off the ultrasonic equipment and continue stirring for 1 hour to stabilize the reaction system. Remove unreacted magnesium ingots through a filtration device, and purify the reaction solution by vacuum distillation to obtain a new type of activated Grignard preparation for large-scale production. Store in sealed containers under nitrogen protection.

[0032] Comparative Example 1: Raw material composition: 1 mol of large-particle magnesium, 1.05 mol of bromobenzene, 0.8 mmol of 1,2-dibromoethane, 1000 mL of tetrahydrofuran, and nitrogen protective gas with a purity of 99.99%.

[0033] Preparation steps: The ultrasonic activation step was omitted, and only 1,2-dibromoethane was added for chemical activation. The remaining steps were the same as in Example 1, resulting in a Grignard formulation with a single chemical activator, as per existing technology. This comparative example corresponds to the most commonly used single activator preparation scheme in the prior art. It does not employ the composite activation system of this invention, nor does it involve physical activation assistance, and is a typical representative of existing technologies.

[0034] Comparative Example 2: Raw material composition: 1 mol of large-particle magnesium, 1.05 mol of bromobenzene, 700 mL of tetrahydrofuran, 300 mL of toluene, and nitrogen protective gas with a purity of 99.99%. Preparation steps: No chemical activator was added; only the ultrasonic equipment was turned on, and the ultrasonic parameters were the same as in Example 1. The remaining steps were the same as in Example 1, resulting in a prior art single-physical-activated Grignard preparation. This comparative example corresponds to an improved scheme of single physical activation in the prior art, without using the composite chemical activator of this invention.

[0035] Comparative Example 3: Raw material composition: 1 mol magnesium powder (100 mesh particle size), 1.05 mol bromobenzene, 0.5 mmol 1,2-dibromoethane, 0.3 mmol cuprous iodide, 700 mL tetrahydrofuran, 300 mL toluene, and nitrogen protective gas with a purity of 99.99%. Preparation steps: Same as in Example 1, except that the magnesium raw material was replaced with magnesium powder commonly used in the prior art, and the large-particle magnesium or magnesium ingots of this invention were not used.

[0036] Comparative Example 4: Raw material composition: 1 mol of large-particle magnesium, 1.05 mol of bromobenzene, 0.5 mmol of 1,2-dibromoethane, 0.3 mmol of iodine, 700 mL of tetrahydrofuran, 300 mL of toluene, and nitrogen protective gas with a purity of 99.99%. Preparation steps: 1,2-dibromoethane and iodine were simply mixed as an activator without ultrasonic-assisted activation. The remaining steps were the same as in Example 1, yielding a Grignard preparation with a simple mixture of activators, as described in the prior art. This comparative example corresponds to an improved scheme in the prior art that simply superimposes different activators, and does not form the synergistic activation system of this invention.

[0037] Comparative Example 5: Raw material composition: 1 mol of large-particle magnesium, 1.05 mol of bromobenzene, 0.5 mmol of 1,2-dibromoethane, 0.3 mmol of cuprous iodide, 1000 mL of toluene, and nitrogen protective gas with a purity of 99.99%. Preparation steps: Same as in Example 1, except that the mixed solvent was replaced with a commonly used single aromatic solvent in the prior art, and the mixed solvent system of this invention was not used.

[0038] Comparative Example 6: Raw material composition: 1 mol magnesium powder (100 mesh particle size), 1.05 mol bromobenzene, 0.5 mmol 1,2-dibromoethane, 0.3 mmol iodine, 1000 mL tetrahydrofuran, nitrogen protective gas purity 99.99%. Preparation steps: 1,2-dibromoethane and iodine were simply mixed as an activator. An ultrasonic device was turned on, and the ultrasonic parameters were the same as in Example 1. The remaining steps were the same as in Example 1, yielding the existing technology composite improved Grignard formulation. This comparative example corresponds to a simple combination of various improvement methods in the prior art, representing the highest level of improvement in the prior art.

[0039] Performance testing and results analysis: Test method: Reaction induction period: The time from the addition of the activator until the reaction system shows obvious reaction, i.e., bubble generation and temperature rise, accurate to 0.1 min; Magnesium utilization rate: The ratio of the mass of magnesium consumed in the reaction to the initial mass of magnesium is calculated by weighing the magnesium raw materials before and after the reaction, accurate to 0.1%. Product purity: The purity of the target product in the Grignard preparation was determined by gas chromatography. The chromatographic conditions were as follows: HP-5 capillary column, column temperature 80℃ for 2 min, increased to 200℃ at 10℃ / min and held for 5 min; flame ionization detector; nitrogen as carrier gas; flow rate 1 mL / min; accuracy to 0.1%. Reaction yield: The reaction yield is calculated based on the amount of haloalkanes used and the actual yield of the target product, accurate to 0.1%. Storage stability: The Grignard formulation was sealed and stored in a nitrogen atmosphere for 30 days at room temperature (25°C) and 90 days at low temperature (0°C). The purity and reactivity of the product were determined after different storage times. Reactivity was determined by performing an addition reaction with benzaldehyde, and the addition reaction yield was measured. Based on the initial product purity and reactivity, the purity retention rate and activity retention rate were calculated to an accuracy of 0.1%.

[0040] The test results are shown in Table 1 below: Table 1: Test sample reaction induction period min Magnesium utilization rate % Product purity % Reaction yield % Purity retention rate (%) at room temperature for 30 days Activity retention rate at low temperature for 90 days (%) Example 1 8.2 92.3 98.5 91.8 97.2 96.5 Example 2 6.5 94.7 99.1 94.2 97.8 97.3 Example 3 7.1 93.5 98.8 92.5 97.5 96.8 Example 4 5.8 95.2 99.3 95.1 98.1 97.6 Example 5 6.2 94.9 99.0 94.7 97.9 97.4 Comparative Example 1 18.7 81.5 95.3 82.3 92.1 90.8 Comparative Example 2 22.3 78.9 94.7 79.5 91.5 89.6 Comparative Example 3 10.5 85.7 97.2 86.9 94.3 93.2 Comparative Example 4 15.2 84.3 95.7 83.8 92.7 91.5 Comparative Example 5 15.8 83.2 95.8 84.1 93.5 92.4 Comparative Example 6 13.6 86.2 96.1 87.5 93.8 92.8 Test Result Analysis: (1) In terms of reaction induction period, the reaction induction period of the embodiments of the present invention is controlled between 5.8 min and 8.2 min. Among them, the shortest in Example 4 is only 5.8 min, while the reaction induction period of each comparative example is more than 10.5 min, and the longest in Comparative Example 2 is 22.3 min. This shows that the composite chemical activator and ultrasonic physical activation synergistic system constructed by the present invention can quickly break the oxide passivation layer on the magnesium surface, significantly shorten the reaction induction period, solve the core problem of low activation efficiency in the prior art, and this effect can be stably achieved through the parameters and steps disclosed in this specification.

[0041] (2) Regarding magnesium utilization, the magnesium utilization rates of the embodiments of the present invention are all above 92.3%, with Example 4 reaching a maximum of 95.2%, while the magnesium utilization rates of the comparative examples are all below 86.2%, with Comparative Example 2 being the lowest at only 78.9%, showing a significant difference. This result proves that the present invention uses large-particle magnesium or magnesium ingots as raw materials, effectively solving the defect of easy oxidation of traditional magnesium powder, improving the utilization rate of raw materials, and the magnesium raw material recycling scheme is simple and feasible, which can effectively reduce production costs. The relevant process details are clearly recorded in the embodiments, and those skilled in the art can implement them smoothly.

[0042] (3) Product purity and reaction yield are the core indicators for evaluating the quality of Grignard preparations. The product purity of the embodiments of the present invention is above 98.5%, with Example 4 reaching a maximum of 99.3%, and the reaction yield is above 91.8%, with Example 4 reaching a maximum of 95.1%. In contrast, the product purity of the comparative examples is below 96.1%, and the reaction yield is below 87.5%, with Comparative Example 2 having a reaction yield of only 79.5%. This indicates that the synergistic activation system of the present invention can not only accelerate the reaction but also effectively inhibit the occurrence of side reactions such as coupling, thereby improving product purity and reaction yield. Furthermore, the clearly defined control range of process parameters in each embodiment can ensure that high-quality Grignard preparations can be obtained under different conditions. The disclosed content is sufficient and reproducible.

[0043] (4) Regarding storage stability, the Grignard preparations prepared in the embodiments of the present invention maintained a purity retention rate of over 97.2% after 30 days of storage at room temperature (25°C) and an activity retention rate of over 96.5% after 90 days of storage at low temperature (0°C). The two indicators in Example 4 reached 98.1% and 97.6%, respectively. In contrast, the purity retention rates of the comparative examples were all below 94.3% after 30 days at room temperature and below 93.2% after 90 days at low temperature. The activity retention rate of Comparative Example 2 at low temperature was only 89.6%. This indicates that the optimized mixed solvent system and process conditions of the present invention significantly improve the storage stability of Grignard preparations, solving the problem of short shelf life and inability to be stored for long periods in the prior art. The relevant storage conditions and detection methods are clearly disclosed, ensuring that those skilled in the art can accurately verify them.

[0044] (5) By comparing the examples, it can be seen that the composite activator ratio, magnesium raw material specifications, halogenated hydrocarbon types, solvent ratio and reaction conditions are gradually optimized from Example 1 to Example 5. The performance indicators show a steady upward trend, proving that the technical optimization logic of the present invention is reasonable and the adjustment of each parameter has a clear technical purpose and effect.

[0045] (6) The comparison with the comparative examples further highlights the inventive advantages of the present invention. Comparative Examples 1 and 2 used single chemical activation and single physical activation, respectively, and their performance was far lower than that of the embodiments of the present invention, proving that the synergistic activation system of the present invention is not a simple improvement of the single activation method of the prior art, but produces unexpected technical effects; Comparative Example 3 used traditional magnesium powder, and the magnesium utilization rate and various performances were lower than those of the present invention, proving the rationality and superiority of the present invention in selecting large-particle magnesium or magnesium ingots; Comparative Example 4 used a simple mixture of different activators, which did not form a synergistic effect and had poor performance, proving that the ratio of the composite chemical activator of the present invention is inventive; Comparative Example 5 used a single solvent, and the reaction efficiency and stability were insufficient, proving the progressiveness of the mixed solvent system of the present invention; Comparative Example 6 integrated multiple improvement methods of the prior art, which is the highest level of the prior art, and its performance is still significantly lower than that of the embodiments of the present invention, proving that the technical solution of the present invention is not a simple superposition of the prior art, but has outstanding substantive features and significant progress.

[0046] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A novel activating system Grignard reagent, characterized in that, The raw material composition includes: 1 mol of magnesium raw material, 1.05 mol-1.35 mol of haloalkanes, 0.5 mmol-1.8 mmol of 1,2-dibromoethane, 0.3 mmol-0.9 mmol of cuprous iodide, and a mixed solvent of ethers and aromatics; the magnesium raw material is large-particle magnesium or magnesium ingots.

2. The Grignard reagent according to claim 1, wherein The halogenated hydrocarbon is one of bromobenzene, chlorobenzene, bromoethane, and bromopropane; the mixed solvent is one of tetrahydrofuran and toluene in a volume ratio of 7:3, methyltetrahydrofuran and xylene in a volume ratio of 3:2, and diethyl ether and toluene in a volume ratio of 4:

1.

3. The Grignard reagent of claim 1, wherein The Grignard reagent is sealed and stored in a nitrogen atmosphere at a temperature of 0°C.

4. A process for the preparation of the novel activated system Grignard reagent according to claim 1, characterized in that, The entire process is protected by 99.99% pure nitrogen gas, and the following steps are performed sequentially: The reaction apparatus is pretreated by purging the reaction system with nitrogen to remove air and moisture from the system. Magnesium raw material pretreatment involves placing large magnesium particles or magnesium ingots into a reaction device, adding a portion of mixed solvent, turning on ultrasonic treatment, adding 1,2-dibromoethane and cuprous iodide, and stirring to complete the magnesium surface activation. Grignard reaction: The haloalkane is mixed with the remaining mixed solvent and then added dropwise to the reaction apparatus. The reaction temperature is controlled, and the reaction is continuously activated with ultrasonic assistance. The reaction is stirred until the reaction is complete. After post-processing, stop sonication, continue stirring, and filter the reaction solution under nitrogen protection to obtain the Grignard reagent.

5. The preparation method according to claim 4, characterized in that, The ultrasonic power for magnesium raw material pretreatment is 200W-500W, the ultrasonic time is 15min-40min, and 1,2-dibromoethane and cuprous iodide are added and stirred for 10min-25min.

6. The preparation method according to claim 4, characterized in that, The Grignard reaction was carried out at a dropping rate of 0.8 mL / min-100 mL / min, a reaction temperature of 28℃-38℃, a stirring speed of 300 r / min-400 r / min, and a reaction time of 2.5 h-3.5 h.

7. The preparation method according to claim 4, characterized in that, The Grignard reaction was activated with ultrasound throughout, with an ultrasound power of 100W-200W.

8. The preparation method according to claim 4, characterized in that, The unreacted magnesium raw material separated by filtration is washed, dried or polished and then reused in the next batch of reaction.

9. The preparation method according to claim 4, characterized in that, In the post-processing stage, the filtered reaction solution is purified by vacuum distillation.